EP0973475B1 - Curb-climbing power wheelchair - Google Patents
Curb-climbing power wheelchair Download PDFInfo
- Publication number
- EP0973475B1 EP0973475B1 EP98918220A EP98918220A EP0973475B1 EP 0973475 B1 EP0973475 B1 EP 0973475B1 EP 98918220 A EP98918220 A EP 98918220A EP 98918220 A EP98918220 A EP 98918220A EP 0973475 B1 EP0973475 B1 EP 0973475B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- frame
- seat
- wheelchair
- wheels
- wheel
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
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Classifications
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/04—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven
- A61G5/041—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs motor-driven having a specific drive-type
- A61G5/042—Front wheel drive
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/06—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs with obstacle mounting facilities, e.g. for climbing stairs, kerbs or steps
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/10—Parts, details or accessories
- A61G5/1089—Anti-tip devices
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G2203/00—General characteristics of devices
- A61G2203/10—General characteristics of devices characterised by specific control means, e.g. for adjustment or steering
- A61G2203/14—Joysticks
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G2203/00—General characteristics of devices
- A61G2203/70—General characteristics of devices with special adaptations, e.g. for safety or comfort
- A61G2203/72—General characteristics of devices with special adaptations, e.g. for safety or comfort for collision prevention
- A61G2203/723—Impact absorbing means, e.g. bumpers or airbags
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61G—TRANSPORT, PERSONAL CONVEYANCES, OR ACCOMMODATION SPECIALLY ADAPTED FOR PATIENTS OR DISABLED PERSONS; OPERATING TABLES OR CHAIRS; CHAIRS FOR DENTISTRY; FUNERAL DEVICES
- A61G5/00—Chairs or personal conveyances specially adapted for patients or disabled persons, e.g. wheelchairs
- A61G5/10—Parts, details or accessories
- A61G5/1056—Arrangements for adjusting the seat
- A61G5/1075—Arrangements for adjusting the seat tilting the whole seat backwards
Definitions
- This invention relates to wheelchairs, particularly to powered wheelchairs, for use by handicapped and disabled persons, which can climb curbs.
- Power wheelchairs known heretofore resemble conventional, manual wheelchairs; many such power wheelchairs have merely been conventional wheelchairs equipped with motors. Use of such power wheelchairs sometimes results in the user feeling a stigma in that unthoughtful persons may view the power wheelchair user in a quizzical or even offensive manner.
- Typical rear wheel drive power wheelchairs which are conventionally manual wheelchairs modified to be equipped with motors, have turning circles of about 1.83m (72 inches) in diameter; whereas typical front wheel drive power wheelchairs known heretofore for the most part have turning circles in the neighborhood of 1.32m (52 inches) in diameter. These turning circles are too big for the user of a conventional power wheelchair to reverse the wheelchair direction by turning the wheelchair around within corridors or hallways of conventional office buildings or most homes.
- Dual drive motor power wheelchairs are known; one is illustrated in United States patent 5,540,297. Other power wheelchairs are disclosed in United States patents 4,513,832; 4,538,857; 5,094,310; 5,145,020 and 5,366,037.
- Forward or front wheel drive power wheelchairs are sold by Permobile, Inc. in Woburn, Massachusetts and have the driving wheels at the extreme forward end of the vehicle chassis thereby requiring substantial space in order to turn the power wheelchair.
- This large chair turning circle results from the axis of rotation of the chair, when turning, being at the mid-point of the drive wheel axes, which is at the extreme forward end of the chair. Hence, the radius of the chair turning circle cannot be substantially less than length of the chair chassis.
- Wheelchairs having relatively large diameter forward wheels located under the central portion of the seat are known; one such wheelchair is disclosed in U.S. patent 4,538,857.
- WO 9615752A discloses a mid-wheel drive power wheelchair.
- a pair of drive wheels are mounted on one end of a chassis member, the other end of which is supported on a first ground-contact caster.
- a frame supporting a seat rests at one end on a second ground contact caster, and at the other end on an articulation supported by the chassis member. The articulation permits both the first and second casters to remain in contact with uneven ground.
- a spring between the frame and the chassis member may assist in maintaining contact.
- Curbs may be 0.15m to 0.20m (six to eight inches) or even higher. Curbs of this height present very substantial, often insurmountable obstacles for known power wheelchairs.
- This invention provides a power wheelchair comprising:
- Curb-climbing power wheelchair 10 includes a frame, best illustrated in Figure 7, which is designated generally 12 and a seat designated generally 14 supported by frame 12.
- Curb-climbing power wheelchair 10 further includes a pair of drive wheels, each of which has been designated generally 16, which are rotatably connected to frame 12 and are rotatable about transverse axes under a central portion of seat 14.
- An important aspect of the wheelchairs shown in the drawings is the selected geometry and configuration of the components of the curb-climbing power wheelchair.
- the inventors recognized in developing the configuration and geometry of the curb-climbing power wheelchair the importance of the sight and balance senses to human beings in connection with operation of power wheelchairs.
- the eyes provide vision; the otolith organs in the ears provide information regarding balance and changes in position.
- the otolith organs provide a point of reference for humans respecting movement. Humans find movements easier to perform and control where such movements are about axes which are aligned with the otolith organs.
- a curb-climbing power wheelchair having the axles of the drive wheels essentially vertically aligned with the wheelchair user's otolith organs makes the power wheelchair much, much easier for a wheelchair user to maneuver; this is especially the case for a disabled or handicapped wheelchair user.
- Ease of maneuverability is provided in the curb-climbing power wheelchair with a seat having a cushion supporting a wheelchair user's thighs and lower portions of the buttocks.
- the seat has a back for supporting the wheelchair user's back. With seat cushion and back portions, the wheelchair user is in a seated upright position when using the wheelchair.
- the wheelchair user's otolith organs are located above the drive wheels of the curb-climbing power wheelchair; the axis about which the drive wheels rotate is below the central portion of the wheelchair seat.
- This arrangement results in the drive wheel axis being at substantially a longitudinally common location with the otolith organs when the wheelchair user occupies the wheelchair seat and sits with the user's back against the seat back.
- custom seating may be provided thereby to locate the severely disabled or deformed person's otolith organs substantially at a longitudinally common location with the drive wheel axis when the severely disabled or deformed person cannot sit upright.
- drive wheels 16 of curb-climbing power wheelchair 10 are connected to frame 12 so that each drive wheel 16 rotates about a transverse axis 24 which is below a cushion portion 20 of the curb-climbing power wheelchair seat designated generally 14, and specifically below the portion of cushion 20 which supports the curb-climbing power wheelchair occupant's thighs.
- drive wheels 16 are rotatable about transverse axes which are preferably slightly forward of the longitudinal mid-point of the wheelchair seat 14 and specifically are rotatable about transverse axes which are preferably slightly forward of the longitudinal mid-point of seat cushion 20.
- Seat 14 is preferably mounted on frame 12 proximate the longitudinal mid-point of frame 12.
- Drive wheels 16 are connected to frame 12 and independently rotatable with respect thereto about a transverse axis 24 which is under a central portion of frame 12 adapted to support seat 14.
- Drive wheels 16, which are rotatably connected to frame 12, are rotatable about a transverse axis 24 which is preferably under a central portion of seat 14.
- the axis of drive wheels 16 is desirably between the mid-point of seat 12 and the seat forward extremity and is most preferably closer to the mid-point of seat 14 than to the longitudinal extremity thereof.
- Cushion portion 20 of seat 14, and especially the forward portion of cushion 20, is the portion of cushion 20 which supports a seat occupant's thighs.
- Frame 12 is illustrated isometrically in Figure 7 and has an upper rectangular frame portion designated generally 60 which includes left and right longitudinally extending tubular upper members 62 and forward and rear transversely extending tubular upper members 64. Members 62 and 64 are preferably welded together. As illustrated in Figure 7, frame 12 is preferably fabricated of hollow tubular rectangular cross-section steel members welded together.
- Frame 12 further includes a pair of forward vertically downwardly extending members 66 which are preferably welded to and extend downwardly from forward extremities of longitudinally extending tubular upper members 62, as illustrated in Figure 7.
- a transversely extending forward lower cross-member 68 is preferably welded to lower extremities of downwardly extending members 66 and extends therebetween.
- a rear vertically downwardly extending member 74 forming a portion of frame 12.
- a pan 70 for carrying electrochemical means, for powering the motors rotating drive wheels 16, in the form of one or more batteries 32, may be welded along its forward edge to forward transversely extending lower cross-member 68.
- a rear transversely extending lower cross-member 69 is welded to the lower extremity of rear vertically downwardly extending member 74.
- the rear edge of pan 70 may be welded to the forward facing surface of rear transversely extending lower cross-member 69, which is of length equal to the width of pan 70; rear transversely extending lower cross-member 69 is not as long in the transverse direction as transversely extending cross-members 64, 68.
- pan 70 may be removable from frame 12 and may merely rest at its forward and rearward edges on lower cross members 68, 69 respectively.
- Longitudinally extending tubular upper members 62 preferably have apertures 174 formed therein, preferably by drilling or stamping. Apertures 174 receive front and rear upwardly extending seat support members providing manual height and tilt adjustment of the curb-climbing power wheelchair seat without use of tools. Between apertures 174 in longitudinally extending tubular upper members 62 are apertures 176 for mounting a spring-strut portion of drive wheel suspension means of wheelchair 10.
- Frame 12 further includes upper and lower longitudinally extending central tubular members 178, 179 respectively.
- Upper member 178 is preferably welded to and extends rearwardly from the center of rear upper transversely extending tubular member 64.
- Lower longitudinally extending central tubular member 179 is preferably welded to, and extends rearwardly from, the center of the rearwardly facing surface of rear transversely extending cross-member 69, immediately below the point of welding connection between rear vertically downwardly extending member 74 and rear transversely extending lower cross-member 69.
- Frame 12 further includes a longitudinally extending forward tubular extension member 198 which is secured to transversely extending lower forward cross-member 68 preferably at the center thereof, and preferably by welding.
- An alternative method for attaching a footrest 172 to frame 12 is to mount the footrest to the upstanding footrest vertical guide 200 with mechanical means such as a nut and bolt.
- box-like frame 256 is first mounted on the upstanding footrest vertical guide 200 utilizing a nut and bolt.
- the footrest 172 is then bolted to box-like frame 256 for footrest 172. This allows footrest 172 to be adjustably mounted to upstanding footrest vertical guide 200 without welding the components together.
- Frame 12 may yet further include a forward upstanding extension member 200 secured by welding to the forward extremity of forward tubular extension member 198 and extending transversely upwardly therefrom, as illustrated in Figure 7.
- Frame 12 may yet further include a pair of eye portions designated generally 82 in Figure 7, which may consist of a pair of parallel plates 348 affixed to rearwardly facing surfaces of respective vertically downwardly extending forward members 66.
- the plates 348 constituting eye portions 82 include apertures 84 formed therein where apertures 84 are aligned in respective ones of plates forming eye portion 82 so that each pair of plates may receive shafts for suspension of drive wheels and associated motors and forward anti-tip wheels from eye portions 82, as described below.
- Eye portions 82, specifically the parallel plate portions thereof, are preferably formed from single pieces of metal by bending the pieces of metal into a U-shaped bracket where the upstanding portions of the "U" define the longitudinally extending rearwardly facing plates 348 of eye portion 82. Such one piece, U-shaped bracket construction of eye portion 82 is visible in Figure 4.
- Frame 12 may yet further include a pair of forwardly extending pedestals 202 secured to forwardly facing surfaces of forward vertically downwardly extending members 66, preferably by welding. Pedestals 202 may be secured at positions on members 66 somewhat below the upper extremities thereof, as illustrated in Figure 7. Forwardly extending pedestals 202 provide points of attachment for spring-strut combinations 44 which may be provided to moderate arcuate movement of anti-tip wheels 42, and the drive motors which are associated therewith, and, preferably fixedly connected thereto, relative to frame 12. The spring-strut combinations 44 and anti-tip wheels 42 are not illustrated in Figure 7.
- the preferred construction according to the invention is illustrated in Figures 28 through to 36.
- An alternative construction embodying the invention is illustrated in Figure 27.
- the spring strut combinations 44 shown in Figures 2 to 6 and 9 to 12 do not embody the present invention, but are useful for understanding the invention.
- Pan 70 is preferably welded to a forward portion of rear vertically downwardly extending member 74 as well as to a rear portion of transversely extending lower tubular cross-member 68.
- the preferably welded, box-like construction of frame 12 illustrated in Figure 7 provides a rigid, high strength frame for curb-climbing power wheelchair 10.
- drive wheels 16 are preferably oriented and positioned respecting frame 12 so that the axis of rotation 24 of drive wheels 16 is between the longitudinal mid-point 26 and forward extremity 28 of seat 14. Most desirably the axis of rotation 24 of drive wheels 16 is closer to the mid-point 26 of seat 14 than to the forward longitudinal extremity 28 of seat 14.
- Seat 14 preferably includes a cushion portion 20 and a back portion 22.
- the longitudinal mid-point of seat 14, specifically the longitudinal mid-point of seat cushion 20, is identified as 26.
- the forward longitudinal extremity of seat 14 is identified as 28 while the rear longitudinal extremity of seat 14, and specifically seat cushion 20, is identified as 30.
- the axis of rotation of drive wheel 16 is identified as 24.
- the longitudinal mid-point 26 of seat 14, specifically of cushion 20 of seat 14 is indicated by both a lead line from an indicator numeral and by a dotted vertical line.
- the longitudinal location of the axes of rotation of drive wheels 16 is indicated by dotted vertical line 27 in Figure 2.
- Curb-climbing power wheelchair 10 further includes at least one battery, which has been designated generally 32, and is carried by frame 12 (specifically by pan 70). As illustrated in Figure 4, curb-climbing power wheelchair 10 further includes motors 76 powered by one or more batteries 32 for driving drive wheels 16; each drive wheel 16 preferably has a drive motor 76 associated therewith. Drive motors 76 are reversible and drive an associated drive wheel independently. As a result, power wheelchair 10 can be made to pivot or turn, thus able to effectively spin about a vertical axis, by motors 76 rotating drive wheels 16 in opposite directions.
- curb-climbing power wheelchair 10 further includes a pair of idler wheels 18 which are the rear ground engaging wheels of curb-climbing power wheelchair 10; drive wheels 16 are the forward ground engaging wheels of curb-climbing power wheelchair 10.
- the curb-climbing power wheelchair 10 of the invention is a front wheel drive curb-climbing power wheelchair.
- rear ground engaging wheels 18 are caster-type idler wheels, which are pivotally mounted for rotation about vertical axes.
- the curb-climbing power wheelchair 10 has the drive wheels 16 positioned towards the longitudinal center 27 of the curb-climbing power wheelchair ( Figure 2). This configuration concentrates, and effectively maximizes, weight on drive wheels 16.
- Yet another benefit of the geometry of the power wheelchair is an extremely tight turning radius, resulting from the available independent rotation of the drive wheels, in opposite directions. This allows the user of the curb-climbing power wheelchair to gain access to, and to turn around in, confined areas such as those encountered in hallways, bathrooms, small kitchens and office areas.
- the curb-climbing power wheelchair has an extremely small footprint. Placement of the drive wheels near the center of the curb-climbing power wheelchair results in the curb-climbing power wheelchair having a turning radius of only about 0.49m (19.5 inches) in the preferred embodiment.
- idler wheels 18 located at the rear of curb-climbing power wheelchair 10 are mounted to frame 12 and are pivotable about vertical axes identified 36 in Figure 2.
- Idler wheels 18 are not powered and are desirably caster-type wheels.
- Idler wheels 18 are preferably connected to frame 12 behind drive wheels 16 and, preferably, behind seat 14.
- rear idler wheels 18 are connected to a transverse beam 38 via U-shaped spindles 142 having conventional bearing assemblies 144. With this arrangement, U-shaped spindles 142, and hence rear idler wheels 18, are pivotable about vertical axes 36, shown in Figure 2, upon wheelchair 10 turning and/or one of rear idler wheels 18 encountering an obstacle such as illustrated in Figure 3.
- Rear idler wheels 18 are rotatably mounted within U-shaped spindles 142 for rotation within the spindles about horizontal axes 50 as illustrated in Figure 4.
- transverse beam 38 is pivotally connected to frame 12, specifically to the upper portion of outboard vertically extending tubular rear frame member 180.
- the point of pivotal connection of transverse beam 38 to vertically extending outboard rear frame member 180 is designated 204.
- Pivotal connection of beam 38 to frame member 180 at 204 is preferably effectuated using a conventional bearing with a pin journaled in the bearing.
- member 180 preferably extends upwardly from a lower longitudinally extending frame rear extension member 179, which in turn extends rearwardly from a rear transversely extending lower cross-member 69.
- Pivotally mounting transverse beam 38 to vertically extending rear frame member 180 provides a smoother ride in the event wheelchair 10 encounters a bump.
- beam 38 rotates about pivotal connection 204 as indicated by double ended arrows G in Figure 3.
- Vertical displacement of right hand idler wheel 18 is depicted by double ended arrow H in Figure 3; this displacement results from idler wheel 18 encountering the obstacle.
- curb-climbing power wheelchair 10 further includes means for releasably supporting seat 14 on frame 12 where frame 12 includes upstanding extension portions for supporting seat 14. These upstanding portions are designated generally 46 in Figure 5 and include rear upstanding seat support members designated 98 and forward upstanding seat support members 96, which are shown in Figures 2, 3 and 5.
- Rear seat support members 98 extend upwardly, preferably vertically, from frame 12 and are transversely spaced one from another.
- forward seat support members 96 extend upwardly, preferably vertically, from frame 12 and are transversely spaced one from another.
- Rear seat support members 98 preferably include slots, which are preferably horizontally disposed and preferably face forward seat support members 96. These slots are visible in Figures 5, 6, 13, 14, 15 and 16 but have not been numbered, to enhance drawing clarity.
- forward seat support members 96 preferably include hooking members 100 (Figure 18) which are preferably pivotally mounted in U-shaped frame portions 150 (Figure 17) of forward seat support members 96. Hooking members 100 are mounted on shafts 104 to be movable by rotation respecting frame portion 150 of forward seat support member 96 as illustrated generally in Figure 19, where arrow A denotes rotational movement of hooking member 100.
- a hooking member 100 is shown in phantom lines having rotated in the direction of arrow A from its normal operational position illustrated in solid lines.
- hooking members 100 can rotate rearwardly, as indicated by arrow A in Figure 19, to an orientation such that mouth portions of the hooking members preferably move at least to a horizontal orientation so that seat 14 may be removed from seat support members 46, specifically from forward upstanding seat support members 96.
- upstanding seat support portions 46 specifically forward and rear upstanding seat support members 96, 98, are movable upwardly respecting the remainder of frame 12 and specifically respecting longitudinally extending tubular members 62 to which respective forward and rear upstanding seat support members 96, 98 are connected.
- Forward and rear seat support members 96, 98 are vertically adjustably positionable independently of one another, with respect to longitudinally extending tubular upper member 62, thereby permitting adjustment of height and/or tilt of seat 14 with respect to frame 12, and specifically cushion portion 20 of seat 14.
- Upstanding seat support members 96, 98 have shaft portions 154 which are preferably cylindrical so as to preferably slidably reside in the apertures 174 in the upper and lower portions of tubular members 62.
- shaft portions 154 are preferably cylindrical so as to preferably slidably reside in the apertures 174 in the upper and lower portions of tubular members 62.
- a plurality of horizontal semi-circular bottomed grooves 156 are formed in each shaft 154; grooves 156 are vertically spaced from one another and aligned at a common position on the periphery of shaft 154, as illustrated in Figure 19.
- Pins 158 are sized to fit in a selected one of horizontal semi-circular bottomed grooves 156 formed in shaft portion 154, as illustrated generally in Figures 20 and 21.
- One pin 158 is provided for each of upstanding seat support members 96, 98 to retain the same in place respecting an associated tubular member 62.
- the associated pin 158 is removed. This is normally accomplished by manually pulling on a pull ring 160, which is preferably attached to pin 158 by residence in an unnumbered aperture at one end of pin 158, as indicated generally by double ended arrow B in Figure 21.
- a pull ring 160 which is preferably attached to pin 158 by residence in an unnumbered aperture at one end of pin 158, as indicated generally by double ended arrow B in Figure 21.
- pin 158 is replaced. This is done by pushing pin 158 through the aligned apertures in the parallel side walls of tubular member 62, into position in the desired semi-circular bottomed groove 156 in shaft portion 154 of the associated forward or rear seat support member 96, 98, as depicted by double ended arrow B in Figure 21. This secures seat support member 96 or 98 in position. Seat support member 96 or 98 is precluded from moving vertically, being held in place respecting vertical movement by pin 158 residing within a groove 156 formed in shaft portion 154 of an associated seat support member 96 or 98.
- FIGS 20 and 21 depict interaction of a forward upstanding seat support member 96 and pin 158 to effectuate vertical adjustment of upstanding seat support member 96; the same structure is provided for rear seat support members 98.
- front and rear seat support members 96, 98 may be positioned vertically respecting frame 12 independently one of another. This permits cushion portion 20 of seat 14 to be affixed to frame 12 in a level position, accomplished by seat support members 96, 98 being at a common height respecting longitudinally extending tubular upper member 62 in which forward and rear seat support members 96, 98 reside.
- Cushion 20 may be tilted back; this is accomplished by having upstanding forward seat support members 96 positioned higher respecting associated longitudinally extending tubular upper member 62 than rear upstanding seat support members 98.
- cushion 20 may be positioned tilted forward by having rear upstanding seat support members 98 positioned higher respecting associated longitudinally extending tubular upper member 62 of frame 12 than forward upstanding seat support members 96.
- seat 14 is preferably mounted on and may be considered to include a subframe designated generally 108 which provides a part of means for connecting seat 14, specifically cushion 20 of seat 14, to frame 12 of curb-climbing power wheelchair 10 so that seat 14 is releasably supported above frame 12 and may be removed from frame 12 by hand, without use of tools.
- Subframe 108 preferably includes a pair of circular cross-section longitudinally extending tubular members designated 110 affixed to the bottom of cushion 20 of seat 14. Longitudinally extending tubular members 110 are visible in Figures 2, 3, 5, 6, 8 and 13 through 18 and are shown partially broken in Figures 22 and 23. As shown in Figure 3, subframe 108 further preferably includes a pair of transverse tubular members 111, longitudinally separated from one another, extending between and secured to inwardly facing surfaces of longitudinally extending members 110.
- Seat 14 specifically cushion portion 20 of seat 14, is secured to subframe 108 via screws passing through tubular members 111 and into the bottom of cushion portion 20 of seat 14.
- Tubular members 111 are preferably separated from the lower, downwardly facing surface of cushion 20 of seat 14 by thermoplastic washers which are illustrated in Figure 3. Neither the screws which pass through the thermoplastic washers to secure tubular members 111 to the bottom of cushion portion 20 of seat 14 nor the thermoplastic washers themselves have been numbered in Figure 3 to aid drawing clarity.
- Pushbutton 114 has a portion 162 which extends longitudinally forwardly out of tubular member 110 and a longitudinally forwardly facing end surface 166 for receiving axial manually generated force to move pushbutton 114.
- Pushbutton 114 is preferably of unitary construction.
- the section view illustrated in Figure 23 is a vertical section respecting Figure 22; for this reason pushbutton 114 in Figure 23 appears to be a two part member.
- pushbutton 114 is preferably a single, unitary member having an opening therein, appearing as an open space 168 in Figure 23, which registers with slot 210 illustrated in Figure 22.
- a roll pin 164 preferably extends through the walls of tubular member 110 for limiting axial travel of pushbutton 114.
- Spring 112 is maintained in compression between roll pin 164, which extends through the wall of tubular member 110 and remains stationary respecting pushbutton 114, and an unnumbered internal shoulder portion of pushbutton 114 against which spring 112 abuts at its right hand extremity viewed in Figure 23.
- pushbutton 114 When pushbutton 114 has traveled the full permissible length of its longitudinal travel within tubular member 110, to the left in Figure 23, and a shoulder portion 119 of pushbutton 114 contacts roll pin 164, pushbutton 114 pushes hooking member 100 sufficiently that hooking member 100 rotates into a position at which the mouth indicated by arrow J in Figure 19 is slightly open upwardly, as illustrated by the phantom line depiction of hooking member 100 in Figure 19, and rod 206 is no longer constrained by hooking member 100. This permits the user to lift seat 14 vertically upwardly thereby removing seat 14 from forward seat support member 96 without the use of tools.
- Springs 112 are under compression. When manual force is applied to exterior button portion 166 in the axial direction indicated generally by double ended arrow M in Figures 22 and 23, pushbutton 114 moves to the left in Figures 22 and 23, against the resilient force continuously applied to pushbutton 114 by spring 112.
- Transverse rod 206 is fixedly retained within an arcuate cut-out 208 formed in the bottom of longitudinally extending tubular member 110 as illustrated in Figure 23. Rod 206 is preferably secured to tubular member 110 by welding.
- Pushbutton 114 can traverse substantially the longitudinal length of slot 210 under the influence of axial force manually applied to exterior surface 162 against bias applied by spring 112.
- Axial force denotes force such as can be applied in a single direction by pushing with the palm of the hand.
- seat 14 may be removed from frame 12 and reengaged with frame 12 solely by application of such axial force such as may be applied using the palm of the hand.
- Use of the thumb is not required. This is extremely helpful for elderly, infirm, disabled and handicapped persons such as those who through the effects of arthritis or other diseases, or from injury or accident, have lost use of, or strength in, the thumb and/or other fingers.
- the required axial force may be applied in a single direction just by pushing with the palm.
- Axially extending tubular members 110 further include rear transverse rods 212, illustrated in Figure 16, which are resident within rear arcuate cut-outs similar to forward arcuate cut-outs 208 illustrated in Figure 23, but which have not been numbered in the drawings.
- Rear transverse rods 212 are preferably secured to longitudinally extending tubular members 110 by welding, similar to forward transverse rods 206.
- Rear seat support members 98 are similar to forward seat support members 96 in that rear seat support members 98 also include an upwardly facing U-shaped frame portion similar to that of U-shaped frame portion 150 of forward seat support members 96 ( Figure 19).
- the U-shaped frame portion of a rear seat support member 98 is illustrated in elevation in Figures 13 through 16.
- Rear seat support members 98 include a pair of spaced-apart vertically upstanding walls, one of which is visible in the view presented by Figures 13 through 16 and is designated 214 in the drawings.
- Walls 214 are separated transversely sufficiently to receive longitudinally extending tubular member 110 therebetween as generally illustrated in Figures 13 through 16.
- Walls 214 each preferably have parallel, transversely aligned forwardly opening longitudinally elongated slots 210 formed therein as shown in Figure 16.
- the slots 210 in walls 214 of rear seat support members 98 receive rear transverse rods 212 which are affixed to lower portions of longitudinally extending tubular members 110 closer to the rear terminus thereof than to the forward terminus, as illustrated in Figure 16.
- rear transverse rods 212 may be easily slid into the slots in walls 214 of rear seat support members 98.
- Rear transverse rods 212 are similar to forward transverse rods 206.
- rear seat support members 98 include shafts 154 which, as described above, are preferably cylindrical in configuration, to preferably slidably reside in holes in the upper and lower portions of tubular members 62.
- Rear seat support members 98 are retained in position respecting tubular members 62 using pins 158 received in a selected one of semi-circular bottomed grooves 156 formed in shaft portions 154, as discussed above and as shown in the drawings ( Figures 20, 21) respecting the forward seat support members 96.
- semi-circular bottomed grooves 156 formed in shaft 154 of rear seat support member 98 are formed facing the rear of the curb-climbing power wheelchair; this provides assurance that the curb-climbing power wheelchair in general and the seat mounting system in particular is properly assembled. If rear seat support member 98 is inserted into longitudinally extending tubular frame member 62 backwards, with slot 210 facing towards the rear, rear seat support member 98 cannot be secured in place because pin 158 will not be able to engage a semi-circular bottomed groove 156 but rather will interfere with a solid portion of shaft 154 of rear seat support member 98, as is apparent from Figure 16.
- Seat support members 96, 98 are preferably plastic composite materials, most preferably glass filled nylon. These materials are stronger in compression than in tension. Positioning forward and rear seat support members 96, 98 in the manner illustrated, with the grooves of the respective forward and rear seat support members facing oppositely, takes advantage of the higher compression strength characteristic of the glass filled nylon, providing maximum strength regions in the respective seat support members resisting stresses received when wheelchair 10 is rapidly decelerated or accelerated,
- an individual lifts seat 12 first to position circular cross-sectioned longitudinally extending tubular members 110 of subframe 108 between the upstanding walls of rear seat support member 98 and then to position rear transverse rods 212 in a position within forwardly opening longitudinally elongated slots 210 as indicated generally by arrow N in Figure 16.
- rear transverse rods 212 engage slots 210, rearward force is applied to seat 14, specifically to cushion 20, to slide rear transverse rods into flush engagement with the closed bottoms of horizontal slots 210 formed in walls 214 of rear seat support members 98.
- seat 14 may be pivoted downwardly about an axis defined by rear transverse rods 212 in the direction indicated by arrow P in Figure 14.
- forward transverse rods 206 reside on horizontal shoulder surfaces 218, abutting forward facing shoulder surfaces 220, illustrated in Figure 21, of forward seat support member 96 and forward transverse rod 206 has cleared tip 152 of hooking member 100, bias applied to hooking member 100 by spring 102 causes hooking member 100 to rotate clockwise in Figures 13 through 21 with open slot J closing over forward transverse rod 206.
- Forward rod 206 is then constrained against forward movement by hooking member 100 and against rearward movement by forwardly facing vertical shoulder surfaces 220.
- rear transverse rod 212 is constrained against rearward movement by the closed bottom of horizontal slot 210 in rear seat support member 98. As a result, seat 14 is securely retained in position, connected by vertical seat support members 96, 98 to frame 12.
- seat 14 may be moved upwardly in a pivotal fashion about a pivot defined by rear transverse rods 212, with seat 14 moving in a direction opposite that indicated by arrow P in Figure 14.
- seat 14 may be moved horizontally, to the right viewing Figure 14, thereby disengaging rear transverse rods 212 from the horizontal forwardly facing open slots formed in walls 214 of rear seat support members 98 and completely disengaging seat 14 from frame 12.
- curb-climbing power wheelchair 10 preferably includes two motors for driving respective drive wheels 16. These motors are designated generally 76 and are each resident within a preferably rigid housing (not shown) which houses, in addition to a motor 76, a transmission 78 for transferring driving rotation from an output shaft of motor 76 to an associated drive wheel 16.
- the drive wheel/motor transmission combination housing defines a portion of a suspension member designated generally 310 which connects with frame 12 at a pivot connection denoted 318 in Figures 28 through 36.
- each drive wheel 16 is free to move respecting frame 12 upon encountering an obstacle without the remaining drive wheel 16 moving respecting frame 12. There is no common axle for the two drive wheels 16.
- Each drive wheel/motor/transmission combination suspension member 310 is independently suspended respecting frame 12.
- Frame 12 includes eye portions 82 which are fixedly connected, preferably by welding, to forward vertical members 66 of frame 12 as illustrated in Figures 7 and 28 through 36. Eye portions 82 have apertures 84 formed therein. As illustrated in Figures 7 and 28 through 36, eye portions 82 preferably include two parallel, transversely spaced-apart rearwardly facing longitudinally elongated plates 348 having apertures 84 which are transversely aligned therein. Eye portions 82 are preferably generally of U-shape configuration with plates 348 visible in Figures 7 and 36 forming the legs of the U and the base of the U being welded to the rearwardly facing surface of an upstanding frame member 66.
- transmission 78 is preferably a right angle worm drive serving to change the axis about which driving rotation is provided by motor 76.
- motor 76 is preferably positioned so that the motor output shaft extends generally longitudinally.
- Associated transmission 78 through the right angle worm drive provides driving rotation output via an axle, which is not numbered in the drawings but is journaled in housing 80, drivingly connected to a drive wheel 16.
- a shift lever 79 extending out of transmission 78 may be manually rotated to disengage transmission 78 thereby providing free wheel operation of an associated drive wheel 16.
- shift levers 79 protrude through apertures in body 34, permitting facile switchover from driven to freewheeling operation of an associated drive wheel 16 by the wheelchair operator merely manually turning the associated shift lever 79.
- Motor 76 and transmission 78 are preferably rigidly connected together and are preferably maintained within a rigid preferably one-piece motor/transmission housing 80.
- the cover 81 of motor transmission housing 80 is preferably glass filled nylon, which is extremely strong and provides extremely quite operation.
- Housing 80 includes an ear portion 86 extending forwardly therefrom as illustrated in Figures 28 through 36.
- Ear portions 86 preferably include apertures 88 sized and positioned to be congruent with apertures 84 illustrated in Figure 7, so that apertures 84, 88 may be aligned.
- a pivot pin 90 illustrated in Figure 36, fits within aligned apertures 84, 88 and permits rotation of housing 80, and hence motor 76 and transmission 78 housed therewithin, relative to frame 14 responsively to acceleration or deceleration of associated drive wheel 16.
- shaft-spring combination 95 is preferably pivotally affixed to a web 170 which is preferably formed integrally as a part of the glass filled nylon cover 81 of motor/transmission housing 80.
- webs 170 are provided as a part of glass filled nylon cover 81 of housing 80, which webs 170 are longitudinally commonly positioned and transversely aligned such that only a single web 170 is visible in Figures 28 through 35; the second, remaining web is immediately behind the visible web 170, is transversely spaced therefrom and is a part of the same cover 81 of motor/transmission housing 80.
- pivotal connection of shaft 92 to web 170 is provided by means of a transversely extending shaft, not numbered but illustrated in Figures 28 through 35, which extends between web 170 and the web which is hidden from view, and is pivotally mounted in both of these webs for freely rotatable motion respecting each of these webs.
- Shaft 92 is preferably secured to a member which fits rotatably on the unnumbered transverse shaft extending between web 170 and the unnumbered web hidden from view.
- Shaft 92 extends preferably upwardly from connection with web 170 through an aperture formed in upper longitudinally extending member 62 of frame 14.
- a coil spring 94 is wrapped around shaft 92 and at one end preferably abuts web 170.
- the lower end of spring 94 may be fixedly connected to shaft 92 or to a sleeve fitted about the unnumbered shaft which extends transversely between web 170 and the web which is hidden from view in Figures 28 through 35.
- Spring 94 at its upper end fits into a spring pivot member 380, illustrated in Figures 38 through 42, which is rotatably retained within longitudinally extending member 62 by a pair of shoulder bolts 382, illustrated in Figure 42.
- housing 80 pivots in a clockwise direction about pin 90.
- This upward pivotal movement of housing 80 compresses spring 94 as web 170 moves upwardly thereby reducing distance from web 170 to the lower surface of longitudinally extending member 62.
- Spring 94 being compressed, exerts downward force on web 170 and hence on housing 80. This force urges housing 80 to rotate counter-clockwise about pivot pin 90 as drive wheel 16 passes over the obstacle and moves downwardly.
- the drive wheel motor/transmission combination suspension member 310 attempts to rotate about pivot pin 90 in a counter-clockwise direction in reaction to acceleration of the drive wheel.
- the counter-clockwise rotation lifts anti-tip wheels 42 further off the ground.
- Shaft 92 is preferably slidably retained within spring pivot member 380 in longitudinally extending tubular member 62. Sliding passage of shaft 92 through spring pivot member 380 connected to longitudinal tubular member 62 permits shaft 92 to rise in response to an associated drive wheel encountering an obstacle such as illustrated in Figure: 29 or to effectively rise as the motor/transmission combination suspension member 310 rotates clockwise about pivot point 318 in reaction to deceleration of an associated drive wheel 16.
- a clearance aperture cut in the upper wall of longitudinally extending member 62, immediately above shaft 92, permits upward movement of shaft 92 without shaft 92 interfering with frame 12 or with longitudinally extending member 62.
- curb-climbing power wheelchair 10 further preferably includes a body 34 which not only provides a decorative, aesthetically pleasing appearance for curb-climbing power wheelchair 10 but also protects the wheelchair user from batteries 32 and from the electrical connections between batteries 32 and motor 76.
- Body 34 further provides protection for batteries 32 and, to some extent motors 76 and transmissions 78 within housings 80, from liquids.
- Body 34 preferably includes a central generally planar portion 172 which, when body 34 is in place on frame 12, overlies batteries 32 as illustrated in Figures 5 and 6 and, to a lesser extent, in Figure 1.
- body 34 preferably further includes fender portions 126 which preferably substantially wrap around upper semi-circular portions of respective drive wheels 16.
- Fenders 126 preferably extend outwardly preferably over at least major portions of the width of associated drive wheels 16, to fit closely about the drive wheel portions which are enveloped by respective fenders 126.
- Body 34 may further include a rearwardly facing openable bonnet portion (not shown). There may be further provided as a portion of body 34 a planar portion extending downwardly from the openable bonnet for preferably at least substantially concealing the rear suspension of wheelchair 10, especially transverse beam 38 from which rear idler wheels 18 are suspended.
- body 34 preferably further has rear corner portions 132 which are preferably rounded and also extend over the suspension gear for rear idler wheels 18, specifically transverse beam 38 and U-shaped spindles 142.
- Rounded rear corners 132 and fender portions 126 preferably transition to central planar portion 172 via at least partially concave transition portions 134 which have apertures for passage therethrough of upstanding front and rear seat support members 96, 98 and additional apertures for passage therethrough of shift levers 79 (not shown).
- body 34 preferably yet further includes, and has formed therein, a pair of forwardly facing integral bumper members 138 lying over and protecting forward suspension members such as spindle flanges 320 which form a part of pivotally connected suspension member 310 which is illustrated in Figures 28 through 37 but is not present in the version of the power wheelchair illustrated in Figure 1, where a wishbone is used to suspend the forward anti-tip wheel.
- Forwardly facing integral bumper members 138 serve to protect suspension parts such as spindle flange 320 and associated spring-strut combinations, which resist and cushion arcuate upward movement of forward anti-tip wheels 42 in spindle flanges 320 relative to frame 12 as suspension member 310 pivotally rotates about pivot connection 318. This is as illustrated in Figures 28 through 35 where the suspension and the spring-strut structure is shown.
- the forwardly facing integral bumper members 138 lie over and protect the spring-strut-beam combinations designated generally 44 which govern arcuate movement of forward anti-tip wheels 42 relative to frame 12.
- Body 34 preferably further includes a planar portion extending between forward bumper members 138 where such planar portion is designated 136 and provides a kick panel for the power wheelchair occupant.
- the kick panel is designated 136 and is illustrated in Figure 1.
- Body 34 preferably rests directly on frame 12.
- Body 34 is preferably a single molded piece of high impact plastic and is exceedingly light. Body 34 may be manually directly lifted off of frame 12 once seat 14 has been removed, without use of tools. Because body 34 fits closely about frame 12 and is effectively contoured to the shape of frame 12 and the associated members by which the rear idler wheels 18, the forward anti-tip wheels 42 and the other structure are connected directly or indirectly to frame 12, body 34 need not be fixed to frame 12.
- the power wheelchair 10 operates well with body 34 resting on but not secured to frame 12.
- Body 34 may be retained in place on frame 12 by mating pads of respective hook and eye material (not shown), such as that sold under the trademark Velcro, affixed to upwardly facing surfaces of longitudinally extending tubular member 62, preferably at the forward extremities thereof. Corresponding mating pieces of Velcro are affixed to the undersurface of body 34 at planar portions thereof which rest directly on the forward extremities of longitudinally extending tubular members 62. Use of the hook and eye material attachments minimizes any rattles which might otherwise occur as body 34 moves slightly relatively to frame 12 during operation of power wheelchair 10.
- hook and eye material such as that sold under the trademark Velcro
- Figure 8 illustrates structure providing means for adjustably transversely separatingly positioning arms of seat 14 where the arms are designated generally 182 with the left (looking forward) arm designated 182L and the right (looking forward) arm designated 182R.
- the structure facilitating adjustable transverse separation and positioning of arms 182L, 182R includes an arm support base 184 which is preferably a hollow rectangular cross-section tubular member. Arm support base 184 is connected to seat 14, specifically to cushion portion 20 thereof, indirectly.
- Arm support base 184 directly connects to rearwardly facing portions of L-shaped brackets 222, the lateral portion of one of which is visible in Figures 13 through 16 and is partially visible in Figure 8.
- the portion of L-shaped bracket 222 which faces rearwardly and is preferably in facing contact with a rearwardly facing surface of cushion portion 20 of seat 14, is not visible in Figure 8; it is hidden behind the hollow rectangular cross-section tubular member defining arm support base 184.
- Lateral portions of L-shaped brackets 222 are connected to laterally facing, flange surfaces of cushion support brackets 224 which are secured to cushion portion 20 of seat 14 and are illustrated in Figures 13 through 16.
- Preferably L-shaped brackets 222 are secured to laterally facing flange surfaces of cushion support brackets 224 via a pair of Phillips head screws as illustrated in Figures 13 through 16 but not numbered to aid clarity of the drawings.
- Cushion support brackets 224 preferably include upstanding flange portions, which run along the longitudinally extending side of seat cushion 20, and bottom portions which run longitudinally along the bottom of seat cushion 20. Cushion support brackets 224 are preferably secured to cushion portion 20 of seat 14 via screw-type fasteners driven into the bottom of seat cushion portion 20 through apertures in bottom longitudinally extending portions of cushion support brackets 224.
- a seat back support bracket 226 illustrated in Figure 8 and Figures 13 through 16 is of generally L-shaped transverse cross-section and includes a rearwardly facing flange portion and a side facing flange portion.
- the rearwardly facing flange portion has apertures for screw-type fasteners to pass therethrough and into the rearwardly facing surface of seat back 22, to secure seat back 22 to the associated seat back support bracket 226.
- Seat back support brackets 226 are preferably connected to seat cushion support brackets 224 via a single pivot rivet connection at each side of seat cushion 20 and
- seat back 22 the single pivot rivet connection is partially visible in Figures 13 through 16.
- the single pivot rivet connection is partially hidden by a portion of the arm support structure, specifically a vertically extending arm support member 190 in Figures 13 through 16.
- the single rivet connection between seat back support brackets 226 and seat cushion support brackets 224 facilitates folding or pivoting movement of seat back 22 towards seat cushion 20 about the points of single pivot rivet connection between cushion support brackets 224 and seat back support brackets 226.
- Arm support extensions are designated generally 186 in Figure 8 and include horizontal supports 188 and vertically extending supports 190.
- Arm cushions 192 are pivotally connected, as indicated by 252 in Figures 24 and 25, to vertical supports 190 for arcuate motion of arm cushions 192 with respect thereto.
- Arm support base 184 includes a pair of tapped holes, not illustrated in Figure 8, which receive complementary threaded shafts (not shown) fixed to hand knobs 194, illustrated in Figure 8.
- Knobs 194 are rotated by application of manual force thereto. Once the knobs are turned to a position at which threaded shafts associated therewith only lightly contact or are removed from contact with horizontal arm support portions 188, these horizontal arm support portions may be moved by hand, to adjust transverse separation of arm cushions 192 and hence the effective width of seat 14, all without use of tools.
- Forward anti-tip wheels 42 do not normally contact the ground or other reasonably smooth surface on which curb-climbing power wheelchair 10 operates. Anti-tip wheels 42 are maintained above the ground and provide protection against tipping in the event of forward pitching of wheelchair 10 due to encounter with an obstacle, traverse of a significant downgrade, and the like.
- the off-the-ground, anti-tip positioning of wheels 42 is illustrated in Figures 1, 2, 5, 6, 9 through 11 and 27 through 29.
- a suspension member is designated generally 310 and shown schematically.
- Suspension member 310 has a central portion 314 and a spindle flange 320 which defines the forward portion of suspension member 310, as illustrated in Figures 28 through 36.
- Suspension member 310 is connected to frame 12 at pivotal connection 318 via pin 90 passing through aperture 84 of frame eye 82.
- Each suspension member 310 is located on either side of the power wheelchair 10.
- Each suspension member 310 houses a motor 76, which is one of the pair of motors, with one motor 76 driving each drive wheel 16.
- Suspension member 310 additionally houses transmission means 78 for transmitting torque from the associated motor 76 to an axle of the associated drive wheel 16.
- the associated drive wheel is journaled in suitable bearings within the front of motor/transmission housing 80 which forms the central portion of suspension member 310.
- the axis of rotation of the drive wheel 16 is indicated as 24 in Figure 28.
- Spindle flange 320 of suspension member 310 has a box-like configuration with forwardly extending sides of the box being designated 328, 330 in Figure 36.
- Box side 330 is the outboard side of spindle flange 320; as a result of the illustrated geometry of spindle flange 320 and suspension member 310, the associated anti-tip wheel 42 is essentially longitudinally aligned with the associated drive wheel 16 (not shown). This provides enhanced wheelchair stability and also permits a wider footrest 172 ( Figure 1).
- a shaft 234 (Figure 28).
- a spring support base 354 Mounted on each shaft 234 is a spring support base 354, not visible in Figures 28 through 35 but shown schematically in Figure 38.
- This spring pivot 380 resides within an aperture formed in a horizontally extending planar portion of a forwardly extending pedestal 202 visible in Figures 28 through 35.
- Pedestal 202 extends forwardly from frame member 66.
- a coil spring 236 is positioned about shaft 238 between spring support base 354 and spring pivot 380, as illustrated in Figures 28 through 36, and as best shown in Figure 38.
- Spindle flange 320 further includes a forwardly facing anti-tip arm designated generally 331 in Figures 28 through 36 on which a forward anti-tip wheel 42 is rotatably mounted.
- Spindle flange 320 forms the forward portion of suspension member 310 and is secured about motor/transmission housing 80 by a suitable clamp designated generally 338 in Figures 36 and 37.
- Clamp 338 may be of the type conventionally used to secure mufflers or tailpipes in automobiles and consists of a base plate 340, visible in Figures 36 and 37, a hoop member 342 and nuts or other means for retaining hoop member 342 to base plate 340.
- One such nut is illustrated as 344 in Figure 37 engaging a threaded extremity of hoop member 342.
- the pivotal connection 318 of the suspension member 310 which is defined by motor/transmission housing 80 and spindle-flange 320, with frame 12, is illustrated in Figures 28 through 37.
- the forward portion of motor/transmission housing 80 which may be considered the central portion 314 of suspension member 310, has a narrowed shoulder 346 to fit between two rearwardly extending transversely spaced apart plates designated 348 defining frame eye portion 82 ( Figure 36).
- Shoulder portion 346 is equipped with suitable bearings; corresponding bores or apertures are formed in plates 348 of eye portion 82 and in outboard 334 and inboard 332 extensions of box sides 328, 330 of spindle flange 320.
- a suitable pin 90 or nut and bolt combination passes through the aligned apertures in these elements, as illustrated schematically by pivot connection 318 in Figure 36.
- spindle flange 320 having forward anti-tip wheel 42 mounted thereon is fixedly connected to motor/transmission housing 80 by clamp 338, and specifically by hoop portion 342 wrapping tightly thereabout, spindle flange 320 and motor/transmission housing 80 move unitarily about pivotal connection 318 responsively to acceleration and deceleration of drive wheel 16, whether due to torque applied by motor 76 or due to wheel 16 encountering an obstacle.
- forward vertically downwardly extending member 66 has been depicted in section, as has eye portion 82, to aid the clarity of the drawing.
- the forward portion of motor/transmission housing 80 has not been shaded, to aid the clarity of the drawing.
- Pivotal mounting of suspension member 310 to frame 12 via pivotal connection 318 at frame eye 82 facilitates operation of the power wheelchair and particularly facilitates climbing high curbs and descending therefrom.
- reaction of suspension member 310 to such acceleration causes suspension member 310 to tend to rotate about pivot connection 318 in a direction opposite that of rotation of the drive wheels 16.
- acceleration of drive wheel 16 by the drive motor causes drive wheel 16 to rotate clockwise, driving the power wheelchair to the right in Figure 28.
- This acceleration of drive wheel 16 causes suspension member 310 to tend to rotate counterclockwise about pivot connection 318, lifting forward anti-tip wheel 42.
- This rotation of suspension member 310 and consequent lifting of anti-tip wheel 42 facilitates the climbing of obstacles of a height which would otherwise not be surmountable by power wheelchair 10.
- Springs 94 and 236 are respectively compressed upon clockwise and counterclockwise rotation of suspension member 310 in the orientation illustrated in Figure 28.
- spring 236 urges suspension member 310 to rotate in the clockwise direction illustrated in Figure 28 thereby urging anti-tip wheel 42 downwardly in order to contact the ground or other running surface along which power wheelchair 10 is moving. This tendency towards clockwise movement or rotation of suspension member 310 is resisted by compression of spring 94.
- the spring constant of spring 236 is preferably about 1965kg/m (110 lb/inch), while the spring constant of spring 94 is preferably about 5144kg/m (288 lb/inch). When power wheelchair 10 is at rest, springs 94 and 236 are not compressed and not extended.
- power wheelchair 10 may yet further preferably include a generally triangularly-shaped skid 350 mounted on the bottom and at the rear of frame 12.
- Skid 350 is most preferably mounted on the bottom of and at the rear of horizontal rear extension member 148 which is shown in Figure 4.
- Skid 350 is preferably nylon or another preferably polymeric material having good lubricity characteristics.
- skid 350 may be equipped with a skid wheel 352 ( Figure 2) which is preferably mounted on a transverse axle for rotation in a direction generally parallel with drive wheels 16 and is oriented so that the lower extremity surface of skid wheel 352 is essentially at the same position off the ground as the rear, lower extremity of skid 350, as depicted schematically in Figure 2.
- Skid 350 and optional skid wheel 352 serve to facilitate the ascension of power wheelchair 10 over steep curbs of a height such as illustrated in Figures 32 and 33.
- Skid 350 and optional skid wheel 352 prevent this and provide for sliding, non-damaging contact between the high curb and the rear portion of the power wheelchair 10, until such time as rear idler wheel 18 can traverse up the curb thereby preventing hang-up of the rear castors.
- a principal advantage of the power wheelchair is provided by the spring-loaded anti-tip forward wheels 42 located in front of each drive wheel 16.
- Spring-loading of wheels 42 allows power wheelchair 10 to be driven over obstacles and over inclined transitions without fear of drive wheel 16 lifting, thereby breaking traction and causing stoppage of forward motion of wheelchair 10.
- High maneuverability of the power wheelchair is achieved by locating drive wheels 16 close to the longitudinal center of the power wheelchair.
- longitudinal distance between the center of aperture 84 in eye 82 and the drive axle for the associated drive wheel, where the drive axle emerges from suspension member 310 to drive associated drive wheel 16 is preferably in the neighborhood of from 0.07m (2.75 inches) to 0.08m (3 inches), measured longitudinally.
- Longitudinal distance between pivotal connection 318 and shaft 234 defining the point of application of downward bias of spring 236 to suspension member 310 is preferably about 0.14m (5.63 inches).
- This pivotal connection of suspension member 310 to frame 12 via eye 82 provides the active independent suspension system for the combination of suspension member 310, anti-tip wheel 42 and associated drive wheel 16.
- distance between the point of attachment of shaft 92 with suspension member 310 and drive wheel axis of rotation 24 is substantially less than distance between the point of attachment of shaft 234 to spindle portion 320 and pivotal connection 318 of suspension member 310 with frame eye 82.
- spring 236 urges suspension member 310 to rotate in a clockwise direction (as viewed in Figure 35), causing anti-tip wheel 42 to drop towards the lower surface, minimizing forward tip of the power wheelchair when descending curbs.
- anti-tip idler wheels 42 are connected directly to frame 12 via U-shaped spindles 228; one leg (of the U-shape) of one of spindles 228 is shown in side view in Figure 27.
- the U-shape of spindles 228 is readily apparent from Figure 4.
- U-shaped spindles 228 are preferably fabricated by welding rectangular cross-section tubular stock between two parallel plates with the tubular stock forming the base of the U.
- Spindles 228 are pivotally connected directly to downwardly extending members 66 of frame 12, preferably using screw-bolt assemblies.
- the side plate portions of spindles 228 fit pivotally on either side about the lower portions of respective downwardly extending vertical tubular members 66, which are illustrated in Figure 7.
- Nut and bolt pivotal connections of U-shaped spindles 228 to vertically downwardly extending members 66 are depicted schematically by indicator numeral 230 in Figure 27.
- anti-tip wheels 42 move arcuately, together with U-shaped spindle 228, as they pivot about pivotal connection 230 relative to frame 12.
- upward movement of spindle 228 causes distance between shaft 234 and pedestal 202 to decrease, thereby compressing spring 236, as illustrated in Figure 27.
- spring pivot 380 has a head portion 388 and a tapered sleeve portion 390 that are rigidly connected.
- upstanding shaft 238, spring 236, and spring pivot 380 are held together by shoulder bolts 382 which pass through apertures 384 in the relevant frame member and threaded apertures 386 in the head of spring pivot 380. Shoulder bolts 382 allow the spring 236 and upstanding shaft 238 to pivot on the shoulder bolts 382 of the spring pivot 380 when the spring 236 is compressed.
- spring pivot 380 allows upstanding shaft 238 and spring 236 to pivot on shoulder bolts 382 as spring 236 is compressed when anti-tip wheels 42 of the power wheelchair contact an obstacle on the ground.
- Compression of spring 236 provides a cushioning effect when anti-tip wheels 42 contact an obstacle or contact the ground due to forward pitching of curb-climbing power wheelchair 10.
- the suspension of anti-tip wheels 42 provided by spindle 228, connects anti-tip idler wheels 42 to frame 16 for arcuate upward motion relative to frame 12 upon forward tipping of power wheelchair 10 or contact of anti-tip wheels 42 with an above-grade obstacle, as illustrated in Figure 33.
- a nut 240 mounted on a threaded portion of the shaft extending above pedestal 202 permits selectable compression of spring 236 thereby providing adjustment of the spring force applied to anti-tip wheels 42 to resist arcuate upward movement thereof upon forward tipping of power wheelchair 10 or upon wheels 42 encountering an obstacle. Rotation of nut 240 also adjusts the distance at which wheels 42 are from the ground.
- longitudinal distance between pivot 90 defined by the position of aperture 88 in ear 86 of housing 80 and the drive axle (not shown) for the associated drive wheel 16, where the axle emerges from housing 80 to drive associated drive wheel 16, is preferably in the neighborhood of from 0.07m (2.75 inches) to 0.08m (3 inches), measured longitudinally.
- This pivotal connection of the drive motor/transmission housing 80 to frame 12 via pivotal connection 90 of ear portion 86 with eye portion 82 provides active independent suspension for the combination of motor 76 and transmission 78 in housing 80, and associated drive wheel 16.
- a pivoting beam 270 is pivotally connected to forward vertically extending member 66 of frame 12 via a pivotal connection denoted 276 in Figure 27.
- a vertical link 268 is pivotally connected thereto at a pivot connection denoted 278.
- the lower end of vertical link 268 is pivotally connected to spindle 238 via a pivotal connection which has not been numbered in Figure 27.
- an intermediate link 274 is pivotally connected thereto via a connection denoted 280 in Figure 27.
- pivotal connection 282 effectuating connection of intermediate link 274 and motor link 272, which is preferably fixedly connected to housing 80 of motor 76 and transmission 78.
- the linkage consisting of pivoting beam 270, vertical link 268 and intermediate line 274 transfer motion between the rear end of motor/transmission housing 80 remote from pivot point 90 and forward anti-tip wheels 42, thereby accomplishing indirectly the same action/reaction of these components to drive wheel acceleration/deceleration as accomplished by the direct connection structure illustrated in Figures 28 through 37.
- Each arm generally denoted 182, includes an arm cushion portion 192 which is preferably upholstered to provide cushioning for the arm of the user of power wheelchair 10.
- Arm cushion portion 192 is mounted on a longitudinally elongated support web 244.
- Arm cushion portion 192 and longitudinally elongated support web 244 together constitute arm 182 of curb-climbing power wheelchair 10.
- Support web 244 has a horizontally oriented central portion 246, on which arm cushion portion 242 is supported, and two vertically extending webs (unlabeled), which are visible in Figure 8.
- Webs 246 may be of different size and shape with one of webs 246 supporting joystick controller 196 and electronics associated therewith and the remaining web 246 being of more tapered, somewhat truncated shape.
- Web 246 supporting joystick 196 and the associated electronics is denoted 246J in the drawings ( Figure 24).
- mounting block 248, Affixed to the lower longitudinal extremity, preferably by welding, of a vertical support portion 190 of arm support extension 186 ( Figure 8) is a mounting block 248, as illustrated in Figures 24 and 25.
- Mounting block 248 preferably has a tapped hole (not shown) therein. Residing within the tapped hole is a bolt 250 threadedly engaging the tapped hole. Bolt 250 can be advanced into or withdrawn from the tapped hole in mounting block 248 to vary length of bolt 250 protruding from mounting block 248.
- Arm 192 connects to vertical support portion 190 via a pivotal connection provided by a rivet indicated as 252 in Figures 24 and 25.
- vertical webs 246, 246J of longitudinally elongated support web 244 are spaced apart to receive the extremity of arm vertical support portion 190 therebetween.
- Mounting block 248 is preferably of the same width, measured transversely to the plane of the paper, as the interior of vertical arm support portion 190; mounting block 248 and bolt 250 fit easily slidably between webs 246, 246J of arm 182.
- Footrest 172 (Figure 1) is adjustable to accommodate users of the curb-climbing power wheelchair of various heights. Additionally, the angle of footrest 172 is adjustable to provide maximum foot comfort for the user of the power wheelchair.
- Footrest 172 is mounted for adjustable vertical movement along upstanding extension member 200 illustrated in Figure 7.
- Member 200 preferably has vertically elongated slots formed in its forwardly and rearwardly facing surfaces; only the slot in the forward facing surface of member 200 is visible in Figure 7.
- a knob and threaded shaft combination 253 Mounted in the opening at the top of upstanding extension member 200 is a knob and threaded shaft combination 253.
- the knob which is designated 254 and is at the extreme upper portion of the attached threaded shaft is visible in Figures 1 and 2.
- the threaded shaft portion (not shown) preferably runs down the length of the interior of upstanding extension member 200.
- the knob/threaded shaft combination 253 is retained in place by a square bushing which preferably fits flushly within the upper opening of upstanding extension member 200, which opening is visible in Figure 7. The bushing is not shown in the drawings.
- Footrest 172 is connected to upstanding extension member 200 by an open, box-like frame 256 shown in Figure 7.
- Frame 256 fits slidably about upstanding extension member 200, in essentially complemental-facing contact with the four exterior surfaces of upstanding extension member 200.
- a transversely extending pivot pin 257 visible in Figure 1, provides pivotal connection between footrest 172 and open box-like frame 256, permitting footrest 172 to tilt upwardly by pivotal motion about the pivot pin respecting open box-like frame 256 and upstanding extension member 200.
- a nut (not shown), preferably a ball nut, threadedly engages the threaded shaft portion of the knob/threaded shaft combination 253 and is resident within vertically upstanding extension member 200.
- a pair of threaded shafts extend through apertures in the forwardly and rearwardly facing walls of open box-like frame 256 and through the vertically elongated slots in the forward and rearwardly facing surfaces of vertically upstanding member 200 and engage the nut within upstanding member 200. This pair of threaded shafts restrain the nut from rotating with the threaded shaft of the knob/shaft combination 253 upon rotation of the knob 254.
- knob 254 produces corresponding rotation of the attached threaded shaft (not shown) since the knob 254 and threaded shaft are fixedly connected. Since the interior nut threadedly engages the threaded shaft, if the nut were not restrained against rotation, the nut would rotate with the shaft. However the threaded shafts restrain the interior nut against rotation and hence cause the interior nut to rise or fall according to the direction of rotation of the shaft and knob 254. This rise and fall of the interior nut carries the associated threaded shafts and hence open box-like frame 256 and footrest 172 therewith, as the knob 254 is rotated clockwise or counter-clockwise. Hence, vertical position of footrest 172 can be adjusted along the length of the vertically elongated slots present in vertically upstanding member 200 by manually turning knob 254; no tools are required for adjusting vertical position of footrest 172.
- Angular orientation of footrest 172 relative to vertically upstanding member 200 may also be adjusted.
- Footrest 172 includes an upstanding lip, visible in Figure 1 and designated generally 264.
- a correspondingly threaded shaft (not shown) is provided for complemental threaded engagement with the tapped aperture 265 in lip 264.
- the threaded shaft which has a knob attached thereto designated generally 266, abuttingly contacts the forward facing portion of a plate-like downward extension portion of open box-like frame 256. This forwardly facing downward plate-like extension covers the vertically elongated slot in the forwardly facing surface of vertically extending member 200 and provides a place for abutment of the threaded shaft.
- cushion portion 20 of seat 14 is about 0.43m (17 inches) wide.
- Back portion 22 of seat 14 is preferably about 0.41m (16 inches) high in the seat style illustrated in Figures 2 through 6. In the style illustrated in Figure 1, back portion 22 of seat 14 is about 0.46m (18 inches) high.
- the longitudinal length of cushion portion 20 of seat 14 is preferably between 0.41m (16 inches) and 0.46m (18 inches), most preferably 0.41m (16 inches).
- seat height adjustment means provided by forward and rear upstanding seat support members 96, 98 permits adjustment of the height of seat 14 from about 0.42m (16.5 inches) to about 0.47m (18.5 inches), measured from the bottom of seat 14 to the surface on which power wheelchair 10 rests.
- Drive wheels 16 are preferably 0.36m (14 inches) or 0.41m (16 inches) diameter drive wheels.
- Rear idler wheels 18 are preferably 0.20m (8 inches) or 0.25m (10 inches) in diameter.
- Forward anti-tip wheels 42 are preferably 0.15m (six inches) or 0.20m (8 inches) in diameter.
- Power wheelchair 10 preferably has an overall length of 1.00m (39.5 inches) and a width of 0.65m (24.4 inches). This results in the vehicle having a turning radius of 0.49m (19.5 inches), permitting power wheelchair 10 to be used easily in indoor environments, that have not been modified to accommodate handicapped personnel and conventional wheelchairs.
- Suitable joystick controllers are available from Penny & Giles in Cristchurch, England, and are programmable and adjustable to provide variable sensitivity for the user.
- a power wheel chair with body 34 in place on frame 12 has a center of gravity, when empty, about 0.05m (1.9 inches) above the axis of rotation 24 ( Figure 2) of drive wheels 16. Further, the center of gravity of the wheelchair 10 when empty is about 0.08m (3.1 inches) behind the axis of rotation 24 of drive wheels 16.
- the center of gravity of wheelchair 10 is about 15.2% of the longitudinal distance between the axis 24 of drive wheels 16 and rear idler wheels 18.
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- Road Paving Structures (AREA)
- Compounds Of Unknown Constitution (AREA)
- Automatic Cycles, And Cycles In General (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
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Abstract
Description
- This invention relates to wheelchairs, particularly to powered wheelchairs, for use by handicapped and disabled persons, which can climb curbs.
- As used herein, the term "conventional wheelchair", including plurals and variants thereof, denotes manually powered wheelchair apparati of the type generally disclosed in United States patent 3,953,054.
- As used herein, the terms "conventional power wheelchair", "known power wheelchair" and "rear wheel drive power wheelchair", including plurals and variants thereof, denote powered wheelchair apparati of the type generally disclosed in United States patent 4,387,325.
- Power wheelchairs are known and have been the subject of increasing development efforts to provide handicapped and disabled persons with independent mobility to assist them in leading more normal lives.
- Power wheelchairs known heretofore resemble conventional, manual wheelchairs; many such power wheelchairs have merely been conventional wheelchairs equipped with motors. Use of such power wheelchairs sometimes results in the user feeling a stigma in that unthoughtful persons may view the power wheelchair user in a quizzical or even offensive manner.
- Known power wheelchairs tend to be large and not particularly manoeuvrable. These power wheelchairs present difficulties for the user in navigating within conventional dwellings which have not been modified to accommodate such conventional power wheelchairs.
- Typical rear wheel drive power wheelchairs, which are conventionally manual wheelchairs modified to be equipped with motors, have turning circles of about 1.83m (72 inches) in diameter; whereas typical front wheel drive power wheelchairs known heretofore for the most part have turning circles in the neighborhood of 1.32m (52 inches) in diameter. These turning circles are too big for the user of a conventional power wheelchair to reverse the wheelchair direction by turning the wheelchair around within corridors or hallways of conventional office buildings or most homes.
- Dual drive motor power wheelchairs are known; one is illustrated in United States patent 5,540,297. Other power wheelchairs are disclosed in United States patents 4,513,832; 4,538,857; 5,094,310; 5,145,020 and 5,366,037.
- Forward or front wheel drive power wheelchairs are sold by Permobile, Inc. in Woburn, Massachusetts and have the driving wheels at the extreme forward end of the vehicle chassis thereby requiring substantial space in order to turn the power wheelchair. This large chair turning circle results from the axis of rotation of the chair, when turning, being at the mid-point of the drive wheel axes, which is at the extreme forward end of the chair. Hence, the radius of the chair turning circle cannot be substantially less than length of the chair chassis.
- A forward wheel drive power wheelchair of the type sold by Permobile, Inc., with the drive wheels at the extreme forward end of the wheelchair chassis, is disclosed in a brochure entitled "Permobile Power Chair Empowering the Human Spirit" available from that company.
- Wheelchairs having relatively large diameter forward wheels located under the central portion of the seat are known; one such wheelchair is disclosed in U.S. patent 4,538,857.
- WO 9615752A, on which the preamble of
claim 1 is based, discloses a mid-wheel drive power wheelchair. A pair of drive wheels are mounted on one end of a chassis member, the other end of which is supported on a first ground-contact caster. A frame supporting a seat rests at one end on a second ground contact caster, and at the other end on an articulation supported by the chassis member. The articulation permits both the first and second casters to remain in contact with uneven ground. A spring between the frame and the chassis member may assist in maintaining contact. - Known power and manual wheelchairs have significant difficulty in climbing curbs. Curbs may be 0.15m to 0.20m (six to eight inches) or even higher. Curbs of this height present very substantial, often insurmountable obstacles for known power wheelchairs.
- This invention provides a power wheelchair comprising:
- a. a frame;
- b. a pair of drive wheels connected to said frame and rotatable about transverse axes below a portion of a seat supporting, in use, an occupant's thighs;
- c. motors for driving respective drive wheels, respective motor/drive wheel combinations being pivotally connected to said frame;
- d. at least one ground engaging idler wheel connected to said frame and located rearward of said drive wheels; and
- e. at least one anti tip wheel forward of said drive wheels, connected to one of said motor/drive wheel combinations for pivotal movement therewith relative to said frame responsively to changes in drive wheel velocity, characterised in that
- f. the at least one anti tip wheel is positioned above ground.
-
- Preferred features of the invention are set out in
claims 2 to 9. - The embodiments of Figures 2 to 6 and 9 to 12 do not form part of the invention but are useful for understanding the invention.
- Figure 1 is a perspective view looking at the right front of a power wheelchair manifesting aspects of the invention.
- Figure 2 is a side view of a power wheelchair with the decorative body removed.
- Figure 3 is a rear view of the power wheelchair illustrated in Figure 2, with the decorative body similarly removed.
- Figure 4 is a top view of the power wheelchair illustrated in Figures 2 and 3, with the power wheelchair seat and decorative body removed.
- Figure 5 is an exploded side view of the power wheelchair illustrated in Figures 2 through 4 taken in the same direction as Figure 2, illustrating the manner in which the power wheelchair batteries, decorative body and seat are assembled with the power wheelchair frame and running gear.
- Figure 6 is a partially exploded side view of the power wheelchair illustrated in Figures 2 through 5 taken looking in the same direction as Figure 5, with the batteries and wheelchair body in position and supported by the wheelchair frame and with the wheelchair seat illustratively removed from the frame and above the frame/body assembly.
- Figure 7 is an isometric view of a frame for a power wheelchair.
- Figure 8 is a view of a wheelchair seat back looking in the same direction as Figure 3, illustrating wheelchair seat arm width adjustment.
- Figure 9 is a partially broken side view taken at arrows 21-21 in Figure 4, illustrating one form of power wheelchair independent drive wheel suspension.
- Figure 10 is a partially broken side view of power wheelchair drive wheel suspension illustrated in Figure 9, illustrating operation of the drive wheel independent suspension upon the drive wheel encountering an obstacle.
- Figure 11 is identical to Figure 9 and is presented for purposes of ready reference when considering Figure 12.
- Figure 12 is a partially broken side view of the drive wheel independent suspension apparatus shown in Figures 9 through 11, illustrating aspects of operation of this suspension apparatus in conjunction with independent anti-tip wheel suspension apparatus upon descending down a step to a lower level.
- Figure 13 is a broken side view of a seat and an upper portion of a frame for a power wheelchair as illustrated in Figures 2 through 6, including means operable responsively to manually generated force for releasably connecting the seat to the frame, illustrating certain aspects of the invention.
- Figure 14 is a broken side view of a seat and an upper portion of a frame for a power wheelchair, as illustrated in Figure 13, showing the seat support structure partially engaged with the frame.
- Figure 15 is a broken side view of a seat and an upper portion of a frame similar to Figures 13 and 14, showing the wheelchair seat mounted on the frame in a position tilted back relative to the position illustrated in Figure 13.
- Figure 16 is a broken side view of a seat and an upper portion of a frame, similar to Figures 13 through 15, depicting the operation of means for releasably connecting the seat to the frame.
- Figure 17 is a side view taken at the position of circle 29 in Figure 13 illustrating a latch portion of the means for releasably connecting the seat to the frame.
- Figure 18 is a side view taken at the same position as Figure 17 illustrating the seat subframe ready to engage a latch portion of the means for releasably connecting the seat to the frame.
- Figure 19 is a side view of the latch illustrated in Figures 17 and 18, depicting movement of latch parts.
- Figure 20 is a view of the portion of a frame and a latch illustrated in Figures 17 and 18, taken at the same position, illustrating vertical adjustment of a seat support member.
- Figure 21 is a front elevation of the structure illustrated in Figure 20 taken at arrows 33-33 in Figure 20.
- Figure 22 is a partially broken view looking upwardly of a portion of the seat subframe taken at arrows 34-34 in Figure 18.
- Figure 23 is a partially broken side sectional view of the structure illustrated in Figure 22.
- Figure 24 is a side view of an arm of a wheelchair seat as illustrated generally in Figures 13 through 16, showing the manner in which the arm may be swung upwardly.
- Figure 25 is an enlarged view of structure illustrated in circle 37 in Figure 24.
- Figure 26 is an enlarged view of structure illustrated in Figure 8 taken at the position indicated by the circle marked Fig. 26 in Figure 8.
- Figure 27 is a broken schematic side view of an alternate embodiment of suspension apparatus for the power wheelchair drive wheels and forward anti-tip wheels which is to be considered to be taken at arrows 21-21 in Figure 4 for reference with the drive wheel shown in phantom similarly to Figure 9, illustrating certain aspects of the invention.
- Figure 28 is a broken schematic side view of a preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels which is to be considered to be taken at arrows 21-21 in Figure 4 for reference with the drive wheel shown in phantom similarly to Figure 9, illustrating certain aspects of the invention.
- Figure 29 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels similar to Figure 28 with the drive wheel illustrated traversing a small bump.
- Figure 30 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels illustrated in Figures 28 and 29, with a drive wheel further illustrated as being on a curb elevated respecting grade.
- Figure 31 is a view identical to Figure 28 and is presented for contrast with Figure 30.
- Figure 32 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels illustrated in Figures 28 through 31, with the forward anti-tip wheels shown encountering a vertical edge of a high curb.
- Figure 33 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels illustrated in Figures 28 through 32 with the forward anti-tip wheels shown on the top of the high curb illustrated in Figure 32.
- Figure 34 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels illustrated in Figures 28 through 33 with the drive wheels and the forward anti-tip wheels shown on a common downgrade.
- Figure 35 is a broken schematic side view of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels illustrated in Figures 28 through 34 showing the drive wheels descending from a curb with the forward anti-tip wheels contacting grade.
- Figure 36 is a partially sectioned broken plan view, taken along arrows 48-48 in Figure 28, of the preferred embodiment of suspension apparatus for the curb-climbing power wheelchair drive wheels and forward anti-tip wheels shown schematically in Figures 28 through 35 formed on the side of the power wheelchair.
- Figure 37 is a broken schematic side view of the suspension apparatus for the power wheelchair drive wheels and forward anti-tip wheels as illustrated in Figures 28 through 35, with the drive wheel illustrated in phantom, illustrating certain structural details.
- Figure 38 is an exploded isometric view of portions of the frame and suspension apparatus of the power wheelchair illustrated in Figures 28 through 37.
- Figure 39 is a top view of a spring pivot for securing cylindrical spring support bases and upstanding shafts.
- Figure 40 is a front view of the spring pivot shown in Figure 39.
- Figure 41 is a side view of the spring pivot shown in Figure 40.
- Figure 42 is a sectional side view of the spring pivot and shoulder bolts, in position within the pedestal, taken along line A-A m Figures 37 and 38, for securing cylindrical spring support bases and upstanding shafts.
-
- Referring to the drawings in general and to Figures 2 through 8 in particular, a curb-climbing power wheelchair is illustrated therein and is designated generally 10. Curb-climbing
power wheelchair 10 includes a frame, best illustrated in Figure 7, which is designated generally 12 and a seat designated generally 14 supported byframe 12. Curb-climbingpower wheelchair 10 further includes a pair of drive wheels, each of which has been designated generally 16, which are rotatably connected to frame 12 and are rotatable about transverse axes under a central portion ofseat 14. - An important aspect of the wheelchairs shown in the drawings is the selected geometry and configuration of the components of the curb-climbing power wheelchair. The inventors recognized in developing the configuration and geometry of the curb-climbing power wheelchair the importance of the sight and balance senses to human beings in connection with operation of power wheelchairs. The eyes provide vision; the otolith organs in the ears provide information regarding balance and changes in position.
- The otolith organs provide a point of reference for humans respecting movement. Humans find movements easier to perform and control where such movements are about axes which are aligned with the otolith organs.
- A curb-climbing power wheelchair having the axles of the drive wheels essentially vertically aligned with the wheelchair user's otolith organs makes the power wheelchair much, much easier for a wheelchair user to maneuver; this is especially the case for a disabled or handicapped wheelchair user. The less the horizontal separation of the center of rotation of the chair and the otolith organs in the ears, the easier it is for the user to maneuver and to control the power wheelchair.
- Ease of maneuverability is provided in the curb-climbing power wheelchair with a seat having a cushion supporting a wheelchair user's thighs and lower portions of the buttocks. The seat has a back for supporting the wheelchair user's back. With seat cushion and back portions, the wheelchair user is in a seated upright position when using the wheelchair.
- In this position the wheelchair user's otolith organs are located above the drive wheels of the curb-climbing power wheelchair; the axis about which the drive wheels rotate is below the central portion of the wheelchair seat. This arrangement results in the drive wheel axis being at substantially a longitudinally common location with the otolith organs when the wheelchair user occupies the wheelchair seat and sits with the user's back against the seat back. For severely handicapped or deformed persons, custom seating may be provided thereby to locate the severely disabled or deformed person's otolith organs substantially at a longitudinally common location with the drive wheel axis when the severely disabled or deformed person cannot sit upright.
- As is apparent from the drawings, drive
wheels 16 of curb-climbingpower wheelchair 10 are connected to frame 12 so that eachdrive wheel 16 rotates about atransverse axis 24 which is below acushion portion 20 of the curb-climbing power wheelchair seat designated generally 14, and specifically below the portion ofcushion 20 which supports the curb-climbing power wheelchair occupant's thighs. As is apparent from the drawings, drivewheels 16 are rotatable about transverse axes which are preferably slightly forward of the longitudinal mid-point of thewheelchair seat 14 and specifically are rotatable about transverse axes which are preferably slightly forward of the longitudinal mid-point ofseat cushion 20. -
Seat 14 is preferably mounted onframe 12 proximate the longitudinal mid-point offrame 12. Drivewheels 16 are connected to frame 12 and independently rotatable with respect thereto about atransverse axis 24 which is under a central portion offrame 12 adapted to supportseat 14. Drivewheels 16, which are rotatably connected to frame 12, are rotatable about atransverse axis 24 which is preferably under a central portion ofseat 14. The axis ofdrive wheels 16 is desirably between the mid-point ofseat 12 and the seat forward extremity and is most preferably closer to the mid-point ofseat 14 than to the longitudinal extremity thereof. -
Cushion portion 20 ofseat 14, and especially the forward portion ofcushion 20, is the portion ofcushion 20 which supports a seat occupant's thighs. -
Frame 12 is illustrated isometrically in Figure 7 and has an upper rectangular frame portion designated generally 60 which includes left and right longitudinally extending tubularupper members 62 and forward and rear transversely extending tubularupper members 64.Members frame 12 is preferably fabricated of hollow tubular rectangular cross-section steel members welded together. -
Frame 12 further includes a pair of forward vertically downwardly extendingmembers 66 which are preferably welded to and extend downwardly from forward extremities of longitudinally extending tubularupper members 62, as illustrated in Figure 7. A transversely extending forward lower cross-member 68 is preferably welded to lower extremities of downwardly extendingmembers 66 and extends therebetween. - Preferably welded to and extending vertically downwardly from the center of a rear transversely extending tubular
upper member 64 is a rear vertically downwardly extendingmember 74 forming a portion offrame 12. - A
pan 70 for carrying electrochemical means, for powering the motors rotatingdrive wheels 16, in the form of one ormore batteries 32, may be welded along its forward edge to forward transversely extendinglower cross-member 68. A rear transversely extendinglower cross-member 69 is welded to the lower extremity of rear vertically downwardly extendingmember 74. The rear edge ofpan 70 may be welded to the forward facing surface of rear transversely extendinglower cross-member 69, which is of length equal to the width ofpan 70; rear transversely extendinglower cross-member 69 is not as long in the transverse direction as transversely extendingcross-members frame 12 and may merely rest at its forward and rearward edges onlower cross members - Longitudinally extending tubular
upper members 62 preferably haveapertures 174 formed therein, preferably by drilling or stamping.Apertures 174 receive front and rear upwardly extending seat support members providing manual height and tilt adjustment of the curb-climbing power wheelchair seat without use of tools. Betweenapertures 174 in longitudinally extending tubularupper members 62 areapertures 176 for mounting a spring-strut portion of drive wheel suspension means ofwheelchair 10. -
Frame 12 further includes upper and lower longitudinally extending centraltubular members Upper member 178 is preferably welded to and extends rearwardly from the center of rear upper transversely extendingtubular member 64. Lower longitudinally extending centraltubular member 179 is preferably welded to, and extends rearwardly from, the center of the rearwardly facing surface of rear transversely extendingcross-member 69, immediately below the point of welding connection between rear vertically downwardly extendingmember 74 and rear transversely extendinglower cross-member 69. - Extending vertically between longitudinally extending central upper and lower
tubular members tubular member 180, which is preferably secured to the rear extremities of longitudinally extendingmembers -
Frame 12 further includes a longitudinally extending forwardtubular extension member 198 which is secured to transversely extending lowerforward cross-member 68 preferably at the center thereof, and preferably by welding. - An alternative method for attaching a
footrest 172 to frame 12 is to mount the footrest to the upstanding footrestvertical guide 200 with mechanical means such as a nut and bolt. In such case, box-like frame 256 is first mounted on the upstanding footrestvertical guide 200 utilizing a nut and bolt. Thefootrest 172 is then bolted to box-like frame 256 forfootrest 172. This allowsfootrest 172 to be adjustably mounted to upstanding footrestvertical guide 200 without welding the components together. -
Frame 12 may yet further include a forwardupstanding extension member 200 secured by welding to the forward extremity of forwardtubular extension member 198 and extending transversely upwardly therefrom, as illustrated in Figure 7. -
Frame 12 may yet further include a pair of eye portions designated generally 82 in Figure 7, which may consist of a pair ofparallel plates 348 affixed to rearwardly facing surfaces of respective vertically downwardly extending forwardmembers 66. Theplates 348 constitutingeye portions 82 includeapertures 84 formed therein whereapertures 84 are aligned in respective ones of plates formingeye portion 82 so that each pair of plates may receive shafts for suspension of drive wheels and associated motors and forward anti-tip wheels fromeye portions 82, as described below.Eye portions 82, specifically the parallel plate portions thereof, are preferably formed from single pieces of metal by bending the pieces of metal into a U-shaped bracket where the upstanding portions of the "U" define the longitudinally extending rearwardly facingplates 348 ofeye portion 82. Such one piece, U-shaped bracket construction ofeye portion 82 is visible in Figure 4. -
Frame 12 may yet further include a pair of forwardly extendingpedestals 202 secured to forwardly facing surfaces of forward vertically downwardly extendingmembers 66, preferably by welding.Pedestals 202 may be secured at positions onmembers 66 somewhat below the upper extremities thereof, as illustrated in Figure 7.Forwardly extending pedestals 202 provide points of attachment for spring-strut combinations 44 which may be provided to moderate arcuate movement ofanti-tip wheels 42, and the drive motors which are associated therewith, and, preferably fixedly connected thereto, relative to frame 12. The spring-strut combinations 44 andanti-tip wheels 42 are not illustrated in Figure 7. The preferred construction according to the invention is illustrated in Figures 28 through to 36. An alternative construction embodying the invention is illustrated in Figure 27. Thespring strut combinations 44 shown in Figures 2 to 6 and 9 to 12 do not embody the present invention, but are useful for understanding the invention. -
Pan 70 is preferably welded to a forward portion of rear vertically downwardly extendingmember 74 as well as to a rear portion of transversely extending lowertubular cross-member 68. The preferably welded, box-like construction offrame 12 illustrated in Figure 7 provides a rigid, high strength frame for curb-climbingpower wheelchair 10. - As illustrated in Figure 2, drive
wheels 16 are preferably oriented and positioned respectingframe 12 so that the axis ofrotation 24 ofdrive wheels 16 is between the longitudinal mid-point 26 andforward extremity 28 ofseat 14. Most desirably the axis ofrotation 24 ofdrive wheels 16 is closer to the mid-point 26 ofseat 14 than to the forwardlongitudinal extremity 28 ofseat 14. -
Seat 14 preferably includes acushion portion 20 and aback portion 22. In Figure 2 the longitudinal mid-point ofseat 14, specifically the longitudinal mid-point ofseat cushion 20, is identified as 26. The forward longitudinal extremity ofseat 14 is identified as 28 while the rear longitudinal extremity ofseat 14, and specifically seatcushion 20, is identified as 30. The axis of rotation ofdrive wheel 16 is identified as 24. In Figure 2, thelongitudinal mid-point 26 ofseat 14, specifically ofcushion 20 ofseat 14, is indicated by both a lead line from an indicator numeral and by a dotted vertical line. The longitudinal location of the axes of rotation ofdrive wheels 16 is indicated by dottedvertical line 27 in Figure 2. - Curb-climbing
power wheelchair 10 further includes at least one battery, which has been designated generally 32, and is carried by frame 12 (specifically by pan 70). As illustrated in Figure 4, curb-climbingpower wheelchair 10 further includesmotors 76 powered by one ormore batteries 32 for drivingdrive wheels 16; eachdrive wheel 16 preferably has adrive motor 76 associated therewith. Drivemotors 76 are reversible and drive an associated drive wheel independently. As a result,power wheelchair 10 can be made to pivot or turn, thus able to effectively spin about a vertical axis, bymotors 76rotating drive wheels 16 in opposite directions. - As illustrated in Figures 2 and 3, curb-climbing
power wheelchair 10 further includes a pair ofidler wheels 18 which are the rear ground engaging wheels of curb-climbingpower wheelchair 10; drivewheels 16 are the forward ground engaging wheels of curb-climbingpower wheelchair 10. Hence the curb-climbingpower wheelchair 10 of the invention is a front wheel drive curb-climbing power wheelchair. - In the preferred embodiment of the invention rear
ground engaging wheels 18 are caster-type idler wheels, which are pivotally mounted for rotation about vertical axes. - The curb-climbing
power wheelchair 10, as illustrated in the drawings, has thedrive wheels 16 positioned towards thelongitudinal center 27 of the curb-climbing power wheelchair (Figure 2). This configuration concentrates, and effectively maximizes, weight ondrive wheels 16. A curb-climbing power wheelchair so constructed in accordance with the drawings and having dimensions as set forth herein, when carrying a 160 pound passenger, results in about eighty-two percent (82%) of the total weight of the curb-climbing power wheelchair and passenger being carried bydrive wheels 16. - The configuration illustrated in the drawings, positioning a large amount of total chair and passenger weight over
drive wheels 16, provides several benefits. Primarily, overall traction is increased. With increased traction, better obstacle climbing ability results, increasing overall capability and usability of the curb-climbing power wheelchair. Additionally, with increased traction, deceleration is more positive and more predictable. This is an important safety factor in light of the fact that most, if not all, users of curb-climbing power wheelchairs manifesting the invention will be handicapped or disabled persons. - With increased traction also comes superior straight line stability. The mass centralization created by the battery placement and the user position in the curb-climbing power wheelchair contributes to straight line stability by reducing the "pendulum effect" present in many prior art power wheelchairs, where the user and battery weight are effectively removed from the pivot axis of the drive wheels.
- Increased traction results in extremely accurate response of the curb-climbing power wheelchair to inputs provided by the wheelchair user through a joystick control. This translates into more predictable and positive handling and a much easier learning curve for the curb-climbing power wheelchair user when the user is first becoming accustomed to the curb-climbing power wheelchair.
- Yet another benefit of the geometry of the power wheelchair is an extremely tight turning radius, resulting from the available independent rotation of the drive wheels, in opposite directions. This allows the user of the curb-climbing power wheelchair to gain access to, and to turn around in, confined areas such as those encountered in hallways, bathrooms, small kitchens and office areas.
- As illustrated in the drawings, the curb-climbing power wheelchair has an extremely small footprint. Placement of the drive wheels near the center of the curb-climbing power wheelchair results in the curb-climbing power wheelchair having a turning radius of only about 0.49m (19.5 inches) in the preferred embodiment.
- As illustrated in Figures 3 and 4,
idler wheels 18 located at the rear of curb-climbingpower wheelchair 10 are mounted to frame 12 and are pivotable about vertical axes identified 36 in Figure 2.Idler wheels 18 are not powered and are desirably caster-type wheels.Idler wheels 18 are preferably connected to frame 12 behinddrive wheels 16 and, preferably, behindseat 14. - As illustrated in Figure 3,
rear idler wheels 18 are connected to atransverse beam 38 viaU-shaped spindles 142 havingconventional bearing assemblies 144. With this arrangement,U-shaped spindles 142, and hence rearidler wheels 18, are pivotable aboutvertical axes 36, shown in Figure 2, uponwheelchair 10 turning and/or one of rearidler wheels 18 encountering an obstacle such as illustrated in Figure 3. - Rear
idler wheels 18 are rotatably mounted withinU-shaped spindles 142 for rotation within the spindles abouthorizontal axes 50 as illustrated in Figure 4. - As illustrated in Figure 3,
transverse beam 38 is pivotally connected to frame 12, specifically to the upper portion of outboard vertically extending tubularrear frame member 180. The point of pivotal connection oftransverse beam 38 to vertically extending outboardrear frame member 180 is designated 204. Pivotal connection ofbeam 38 to framemember 180 at 204 is preferably effectuated using a conventional bearing with a pin journaled in the bearing. As illustrated in Figure 7,member 180 preferably extends upwardly from a lower longitudinally extending framerear extension member 179, which in turn extends rearwardly from a rear transversely extendinglower cross-member 69. - Pivotally mounting
transverse beam 38 to vertically extendingrear frame member 180 provides a smoother ride in theevent wheelchair 10 encounters a bump. As illustrated in Figure 3, where the right hand one of rearidler wheels 18 has been depicted encountering an obstacle, as right handidler wheel 18 rides over the obstacle,beam 38 rotates aboutpivotal connection 204 as indicated by double ended arrows G in Figure 3. Vertical displacement of right handidler wheel 18 is depicted by double ended arrow H in Figure 3; this displacement results fromidler wheel 18 encountering the obstacle. - As illustrated in Figures 2, 3, 5, 6, 8 and 13 through 23, curb-climbing
power wheelchair 10 further includes means for releasably supportingseat 14 onframe 12 whereframe 12 includes upstanding extension portions for supportingseat 14. These upstanding portions are designated generally 46 in Figure 5 and include rear upstanding seat support members designated 98 and forward upstandingseat support members 96, which are shown in Figures 2, 3 and 5. - Rear
seat support members 98 extend upwardly, preferably vertically, fromframe 12 and are transversely spaced one from another. Similarly, forwardseat support members 96 extend upwardly, preferably vertically, fromframe 12 and are transversely spaced one from another. Rearseat support members 98 preferably include slots, which are preferably horizontally disposed and preferably face forwardseat support members 96. These slots are visible in Figures 5, 6, 13, 14, 15 and 16 but have not been numbered, to enhance drawing clarity. - As best illustrated in Figures 14, 16, 17, 18, 19, 20 and 21, forward
seat support members 96 preferably include hooking members 100 (Figure 18) which are preferably pivotally mounted in U-shaped frame portions 150 (Figure 17) of forwardseat support members 96. Hookingmembers 100 are mounted onshafts 104 to be movable by rotation respectingframe portion 150 of forwardseat support member 96 as illustrated generally in Figure 19, where arrow A denotes rotational movement of hookingmember 100. In Figure 19, a hookingmember 100 is shown in phantom lines having rotated in the direction of arrow A from its normal operational position illustrated in solid lines. - Thus, hooking
members 100 can rotate rearwardly, as indicated by arrow A in Figure 19, to an orientation such that mouth portions of the hooking members preferably move at least to a horizontal orientation so thatseat 14 may be removed fromseat support members 46, specifically from forward upstandingseat support members 96. -
Springs 102 aboutshafts 104bias hooking members 100 forwardly respecting Figure 19, in a direction opposite to that indicated by arrow A, to an orientation at which the mouth portion of a slot in hookingmember 100 faces below horizontal as illustrated in solid lines in Figure 19. The mouth portion of hookingmember 100 is designated by arrow J in Figure 19 and is defined by an opening between atip 152 of hookingmember 100 and a remainingsurface 218 of the slot formed in hookingmember 100. - As depicted schematically by double ended arrow L in Figure 20, upstanding
seat support portions 46, specifically forward and rear upstandingseat support members frame 12 and specifically respecting longitudinally extendingtubular members 62 to which respective forward and rear upstandingseat support members seat support members upper member 62, thereby permitting adjustment of height and/or tilt ofseat 14 with respect to frame 12, and specifically cushionportion 20 ofseat 14. - Height adjustment of forward and/or rear upstanding
seat support members seat support members apertures 174 formed intubular members 62 as depicted generally in Figures 20 and 21. Upstandingseat support members shaft portions 154 which are preferably cylindrical so as to preferably slidably reside in theapertures 174 in the upper and lower portions oftubular members 62. Preferably, a plurality of horizontal semi-circular bottomedgrooves 156 are formed in eachshaft 154;grooves 156 are vertically spaced from one another and aligned at a common position on the periphery ofshaft 154, as illustrated in Figure 19. - Side walls of
tubular members 62 are drilled to slidably receive pins 158.Pins 158 are sized to fit in a selected one of horizontal semi-circular bottomedgrooves 156 formed inshaft portion 154, as illustrated generally in Figures 20 and 21. Onepin 158 is provided for each of upstandingseat support members tubular member 62. - To adjust vertical position of one of
seat support members pin 158 is removed. This is normally accomplished by manually pulling on apull ring 160, which is preferably attached to pin 158 by residence in an unnumbered aperture at one end ofpin 158, as indicated generally by double ended arrow B in Figure 21. Oncepin 158 has been removed from a given horizontal semi-circular bottomedgroove 156 and is outsidetubular member 62, the associated forward or rearseat support member - When the
seat support member pin 158 through the aligned apertures in the parallel side walls oftubular member 62, into position in the desired semi-circular bottomedgroove 156 inshaft portion 154 of the associated forward or rearseat support member seat support member Seat support member pin 158 residing within agroove 156 formed inshaft portion 154 of an associatedseat support member - Figures 20 and 21 depict interaction of a forward upstanding
seat support member 96 andpin 158 to effectuate vertical adjustment of upstandingseat support member 96; the same structure is provided for rearseat support members 98. Hence, front and rearseat support members frame 12 independently one of another. This permitscushion portion 20 ofseat 14 to be affixed to frame 12 in a level position, accomplished byseat support members upper member 62 in which forward and rearseat support members -
Cushion 20 may be tilted back; this is accomplished by having upstanding forwardseat support members 96 positioned higher respecting associated longitudinally extending tubularupper member 62 than rear upstandingseat support members 98. - Further alternatively, cushion 20 may be positioned tilted forward by having rear upstanding
seat support members 98 positioned higher respecting associated longitudinally extending tubularupper member 62 offrame 12 than forward upstandingseat support members 96. - Since vertical position of upstanding
seat support members - As shown in Figure 16,
seat 14 is preferably mounted on and may be considered to include a subframe designated generally 108 which provides a part of means for connectingseat 14, specifically cushion 20 ofseat 14, to frame 12 of curb-climbingpower wheelchair 10 so thatseat 14 is releasably supported aboveframe 12 and may be removed fromframe 12 by hand, without use of tools. -
Subframe 108 preferably includes a pair of circular cross-section longitudinally extending tubular members designated 110 affixed to the bottom ofcushion 20 ofseat 14. Longitudinally extendingtubular members 110 are visible in Figures 2, 3, 5, 6, 8 and 13 through 18 and are shown partially broken in Figures 22 and 23. As shown in Figure 3,subframe 108 further preferably includes a pair of transversetubular members 111, longitudinally separated from one another, extending between and secured to inwardly facing surfaces of longitudinally extendingmembers 110. -
Seat 14, specifically cushionportion 20 ofseat 14, is secured tosubframe 108 via screws passing throughtubular members 111 and into the bottom ofcushion portion 20 ofseat 14.Tubular members 111 are preferably separated from the lower, downwardly facing surface ofcushion 20 ofseat 14 by thermoplastic washers which are illustrated in Figure 3. Neither the screws which pass through the thermoplastic washers to securetubular members 111 to the bottom ofcushion portion 20 ofseat 14 nor the thermoplastic washers themselves have been numbered in Figure 3 to aid drawing clarity. - Longitudinally extending
tubular members 110 preferablyhouse pushbuttons 114 havingcoil springs 112 therewithin at the forward portions thereof as illustrated in Figures 22 and 23.Pushbutton 114 has aportion 162 which extends longitudinally forwardly out oftubular member 110 and a longitudinally forwardly facingend surface 166 for receiving axial manually generated force to movepushbutton 114. -
Pushbutton 114 is preferably of unitary construction. The section view illustrated in Figure 23 is a vertical section respecting Figure 22; for thisreason pushbutton 114 in Figure 23 appears to be a two part member. In fact,pushbutton 114 is preferably a single, unitary member having an opening therein, appearing as anopen space 168 in Figure 23, which registers withslot 210 illustrated in Figure 22. - A
roll pin 164 preferably extends through the walls oftubular member 110 for limiting axial travel ofpushbutton 114. - The
open void 168 appearing inpushbutton 114 shown in Figure 23, registers withslot 210 intubular member 110 and houses spring 112.Spring 112 is maintained in compression betweenroll pin 164, which extends through the wall oftubular member 110 and remains stationary respectingpushbutton 114, and an unnumbered internal shoulder portion ofpushbutton 114 against which spring 112 abuts at its right hand extremity viewed in Figure 23. - With
spring 112 under compression, a user applying manually generated axially oriented force toexterior surface 166 urges pushbutton 114 to the left in Figures 22 and 23. The longitudinally extremeleft end 115 ofpushbutton 114, in Figure 23, at the end opposite fromsurface 166, passes over forwardtransverse rod 206, since there is a slight clearance provided by arelief 117 in the surface ofpushbutton 114 facingrod 206 androd 206 itself as illustrated in Figure 23.Relief 117 permits longitudinally extremeleft end surface 115 ofpushbutton 114 at the left extremity of travel ofpushbutton 114 to contact forward facingsurface 216 of hooking member 100 (Figure 19) thereby rotating hookingmember 100 in the direction indicated by arrow A in Figure 19, against the bias applied thereto byspring 102. - When
pushbutton 114 has traveled the full permissible length of its longitudinal travel withintubular member 110, to the left in Figure 23, and ashoulder portion 119 ofpushbutton 114 contacts rollpin 164,pushbutton 114pushes hooking member 100 sufficiently that hookingmember 100 rotates into a position at which the mouth indicated by arrow J in Figure 19 is slightly open upwardly, as illustrated by the phantom line depiction of hookingmember 100 in Figure 19, androd 206 is no longer constrained by hookingmember 100. This permits the user to liftseat 14 vertically upwardly thereby removingseat 14 from forwardseat support member 96 without the use of tools. -
Springs 112 are under compression. When manual force is applied toexterior button portion 166 in the axial direction indicated generally by double ended arrow M in Figures 22 and 23,pushbutton 114 moves to the left in Figures 22 and 23, against the resilient force continuously applied topushbutton 114 byspring 112. -
Transverse rod 206 is fixedly retained within an arcuate cut-out 208 formed in the bottom of longitudinally extendingtubular member 110 as illustrated in Figure 23.Rod 206 is preferably secured totubular member 110 by welding. - Longitudinally elongated
slot 210 in the bottom oftubular member 110, as illustrated in Figure 22, receives hookingmember 100, thus permitting mouth J of hookingmember 100 to rotate and close overrod 206 in response to the bias ofspring 112. -
Pushbutton 114 can traverse substantially the longitudinal length ofslot 210 under the influence of axial force manually applied toexterior surface 162 against bias applied byspring 112. - "Axial" force denotes force such as can be applied in a single direction by pushing with the palm of the hand. One of the major advantages of the curb-climbing power wheelchair is that
seat 14 may be removed fromframe 12 and reengaged withframe 12 solely by application of such axial force such as may be applied using the palm of the hand. Use of the thumb is not required. This is extremely helpful for elderly, infirm, disabled and handicapped persons such as those who through the effects of arthritis or other diseases, or from injury or accident, have lost use of, or strength in, the thumb and/or other fingers. The required axial force may be applied in a single direction just by pushing with the palm. - Axially extending
tubular members 110 further include reartransverse rods 212, illustrated in Figure 16, which are resident within rear arcuate cut-outs similar to forward arcuate cut-outs 208 illustrated in Figure 23, but which have not been numbered in the drawings. Reartransverse rods 212 are preferably secured to longitudinally extendingtubular members 110 by welding, similar to forwardtransverse rods 206. However, at the position on longitudinally extendingtubular members 110 at which reartransverse rods 212 are connected thereto, there is no slot analogous toaxial slot 210 illustrated in Figures 22 and 23, nor is there any spring or pushbutton structure analogous topushbutton 114,spring 112 andexterior surface 162 illustrated in Figures 22 and 23. - Rear
seat support members 98 are similar to forwardseat support members 96 in that rearseat support members 98 also include an upwardly facing U-shaped frame portion similar to that ofU-shaped frame portion 150 of forward seat support members 96 (Figure 19). The U-shaped frame portion of a rearseat support member 98 is illustrated in elevation in Figures 13 through 16. Rearseat support members 98 include a pair of spaced-apart vertically upstanding walls, one of which is visible in the view presented by Figures 13 through 16 and is designated 214 in the drawings. -
Walls 214 are separated transversely sufficiently to receive longitudinally extendingtubular member 110 therebetween as generally illustrated in Figures 13 through 16.Walls 214 each preferably have parallel, transversely aligned forwardly opening longitudinallyelongated slots 210 formed therein as shown in Figure 16. Theslots 210 inwalls 214 of rearseat support members 98 receive reartransverse rods 212 which are affixed to lower portions of longitudinally extendingtubular members 110 closer to the rear terminus thereof than to the forward terminus, as illustrated in Figure 16. Hence, reartransverse rods 212 may be easily slid into the slots inwalls 214 of rearseat support members 98. Reartransverse rods 212 are similar to forwardtransverse rods 206. - As shown in Figure 16, rear
seat support members 98 includeshafts 154 which, as described above, are preferably cylindrical in configuration, to preferably slidably reside in holes in the upper and lower portions oftubular members 62. Rearseat support members 98 are retained in position respectingtubular members 62 usingpins 158 received in a selected one of semi-circular bottomedgrooves 156 formed inshaft portions 154, as discussed above and as shown in the drawings (Figures 20, 21) respecting the forwardseat support members 96. - However, as illustrated in Figure 16, semi-circular bottomed
grooves 156 formed inshaft 154 of rearseat support member 98 are formed facing the rear of the curb-climbing power wheelchair; this provides assurance that the curb-climbing power wheelchair in general and the seat mounting system in particular is properly assembled. If rearseat support member 98 is inserted into longitudinally extendingtubular frame member 62 backwards, withslot 210 facing towards the rear, rearseat support member 98 cannot be secured in place becausepin 158 will not be able to engage a semi-circular bottomedgroove 156 but rather will interfere with a solid portion ofshaft 154 of rearseat support member 98, as is apparent from Figure 16. -
Seat support members seat support members wheelchair 10 is rapidly decelerated or accelerated, - To secure
seat 14 in position onframe 12, an individual liftsseat 12 first to position circular cross-sectioned longitudinally extendingtubular members 110 ofsubframe 108 between the upstanding walls of rearseat support member 98 and then to position reartransverse rods 212 in a position within forwardly opening longitudinallyelongated slots 210 as indicated generally by arrow N in Figure 16. By initially positioning circularly cross-sectioned longitudinally extendingtubular members 110 ofsubframe 108 between the respective walls of rearseat support members 98, this helps to align reartransverse rods 212 in a position to easily engage forwardly opening longitudinally elongatedaxial slots 210, all as indicated by arrow N in Figure 16. Once reartransverse rods 212 engageslots 210, rearward force is applied toseat 14, specifically to cushion 20, to slide rear transverse rods into flush engagement with the closed bottoms ofhorizontal slots 210 formed inwalls 214 of rearseat support members 98. - Once rear
transverse rods 212 are in this position withinslots 210,seat 14 may be pivoted downwardly about an axis defined by reartransverse rods 212 in the direction indicated by arrow P in Figure 14. - As
seat 14 pivots about reartransverse rod 212 and moves downwardly as indicated by arrow P in Figure 14, hookingmembers 100 are received withinslots 210 formed in the bottoms of longitudinally extendingtubular members 110. Upwardly extending walls 151, illustrated in Figure 21, ofU-shaped frame portion 150 of forwardseat support member 96 are, similar towalls 214 of rearseat support member 98, transversely spaced one from another sufficiently to receive longitudinally extendingtubular member 110 therebetween, as depicted in Figure 17. Receipt of longitudinally extendingtubular members 110 between upwardly extending walls 151 of the rear seat support members assists in alignment of the seat with the seat support members when the seat is being engaged with the seat support members, as described above. - As
seat 14 pivots downwardly about the axis defined by reartransverse rods 212,rods 206 encounter rounded, downwardly sloped upwardly and forwardly facingsurfaces 216 of hookingmembers 100.Surface 216 is so-designated and illustrated in Figures 19, 20 and 21. - As forward
transverse rod 206 bears downwardly onsurface 216, the rounded configuration ofrod 206 and the rounded downwardly sloping configuration ofsurface 216 resolves the force applied byrod 206 due to the weight ofseat 14 to produce a force vector on hookingmember 100 which tends to rotate hookingmember 100 in the direction illustrated by arrow A in Figure 19. - As hooking member rotates in the direction indicated by Arrow A in Figure 19,
tip 152 of hookingmember 100 rotates into the position illustrated in phantom lines in Figure 19 thereby opening the mouth indicated by arrow J in Figure 19. This permits forwardtransverse rod 206 to move downwardly to a position at which forwardtransverse rod 206 is supported by ahorizontal shoulder portion 218, illustrated in Figure 18, ofU-shaped frame 150 offorward seat member 96. This arcuate movement is indicated by arrow P in Figure 14.Horizontal shoulder surface 218 is illustrated and so-designated in Figures 18 and 19.Seat 14 in position, with forwardtransverse rods 206 resting on horizontal shoulder surfaces 218 and engaged with forwardseat support members 96, is illustrated in Figures 13 and 15. - Once forward
transverse rods 206 reside on horizontal shoulder surfaces 218, abutting forward facing shoulder surfaces 220, illustrated in Figure 21, of forwardseat support member 96 and forwardtransverse rod 206 has clearedtip 152 of hookingmember 100, bias applied to hookingmember 100 byspring 102causes hooking member 100 to rotate clockwise in Figures 13 through 21 with open slot J closing over forwardtransverse rod 206.Forward rod 206 is then constrained against forward movement by hookingmember 100 and against rearward movement by forwardly facing vertical shoulder surfaces 220. Additionally, reartransverse rod 212 is constrained against rearward movement by the closed bottom ofhorizontal slot 210 in rearseat support member 98. As a result,seat 14 is securely retained in position, connected by verticalseat support members - To remove
seat 14 fromwheelchair 10, the procedure is reversed. An individual begins by pushing exterior end surfaces 166 ofpushbuttons 114 to the left, along the direction indicated by double ended arrow M in Figures 22 and 23. This axially applied manual force movespushbuttons 114 to the left in Figures 22 and 23, against the restraining force constantly applied byspring 112. Aspushbuttons 114 move to the left, end surfaces 115 of pushbuttons 116 encounter rounded forwardly and downwardly slopingsurfaces 216 of hookingmembers 100. Continued application of manual force topushbutton surfaces 166 against bias ofspring 112 causes end surfaces 115 ofpushbuttons 114 to push againstsurfaces 216 of hookingmembers 100, causing hookingmembers 100 to rotate counter-clockwise as viewed in Figures 17 through 19, withtips 152 rotating upwardly and thereby causing the mouth indicated by arrow J to assume a position where it opens slightly upwardly, as illustrated in phantom lines in Figure 19. - At this position forward ends of longitudinally extendingly
tubular members 110 may be lifted since forwardtransverse rods 206 are no longer restrained against vertically upward movement by hookingmembers 100. Henceseat 14 may be moved upwardly in a pivotal fashion about a pivot defined by reartransverse rods 212, withseat 14 moving in a direction opposite that indicated by arrow P in Figure 14. Onceseat 14 has been rotated somewhat in a direction opposite to arrow P in Figure 14,seat 14 may be moved horizontally, to the right viewing Figure 14, thereby disengaging reartransverse rods 212 from the horizontal forwardly facing open slots formed inwalls 214 of rearseat support members 98 and completely disengagingseat 14 fromframe 12. - As illustrated in Figure 4, curb-climbing
power wheelchair 10 preferably includes two motors for drivingrespective drive wheels 16. These motors are designated generally 76 and are each resident within a preferably rigid housing (not shown) which houses, in addition to amotor 76, atransmission 78 for transferring driving rotation from an output shaft ofmotor 76 to an associateddrive wheel 16. - As illustrated in Figures 28 through 36 in the preferred embodiment, the drive wheel/motor transmission combination housing defines a portion of a suspension member designated generally 310 which connects with
frame 12 at a pivot connection denoted 318 in Figures 28 through 36. Hence, eachdrive wheel 16 is free to move respectingframe 12 upon encountering an obstacle without the remainingdrive wheel 16 moving respectingframe 12. There is no common axle for the twodrive wheels 16. - Each drive wheel/motor/transmission
combination suspension member 310 is independently suspended respectingframe 12.Frame 12 includeseye portions 82 which are fixedly connected, preferably by welding, to forwardvertical members 66 offrame 12 as illustrated in Figures 7 and 28 through 36.Eye portions 82 haveapertures 84 formed therein. As illustrated in Figures 7 and 28 through 36,eye portions 82 preferably include two parallel, transversely spaced-apart rearwardly facing longitudinallyelongated plates 348 havingapertures 84 which are transversely aligned therein.Eye portions 82 are preferably generally of U-shape configuration withplates 348 visible in Figures 7 and 36 forming the legs of the U and the base of the U being welded to the rearwardly facing surface of anupstanding frame member 66. - As shown in Figure 4,
transmission 78 is preferably a right angle worm drive serving to change the axis about which driving rotation is provided bymotor 76. Specifically,motor 76 is preferably positioned so that the motor output shaft extends generally longitudinally.Associated transmission 78 through the right angle worm drive provides driving rotation output via an axle, which is not numbered in the drawings but is journaled inhousing 80, drivingly connected to adrive wheel 16. - A
shift lever 79 extending out oftransmission 78 may be manually rotated to disengagetransmission 78 thereby providing free wheel operation of an associateddrive wheel 16. When body 34 (Figure 1) is in place onframe 12,shift levers 79 protrude through apertures inbody 34, permitting facile switchover from driven to freewheeling operation of an associateddrive wheel 16 by the wheelchair operator merely manually turning the associatedshift lever 79. -
Motor 76 andtransmission 78 are preferably rigidly connected together and are preferably maintained within a rigid preferably one-piece motor/transmission housing 80. Thecover 81 ofmotor transmission housing 80 is preferably glass filled nylon, which is extremely strong and provides extremely quite operation.Housing 80 includes anear portion 86 extending forwardly therefrom as illustrated in Figures 28 through 36. -
Ear portions 86 preferably include apertures 88 sized and positioned to be congruent withapertures 84 illustrated in Figure 7, so thatapertures 84, 88 may be aligned. Apivot pin 90, illustrated in Figure 36, fits within alignedapertures 84, 88 and permits rotation ofhousing 80, and hence motor 76 andtransmission 78 housed therewithin, relative to frame 14 responsively to acceleration or deceleration of associateddrive wheel 16. - Further preferably forming a part of the drive wheel independent suspension apparatus is a shaft-spring combination, which combination has been designated 95 in Figures 28 through 35.
Shaft 92 of shaft-spring combination 95 is preferably pivotally affixed to aweb 170 which is preferably formed integrally as a part of the glass fillednylon cover 81 of motor/transmission housing 80. Most preferably twoparallel webs 170 are provided as a part of glass fillednylon cover 81 ofhousing 80, whichwebs 170 are longitudinally commonly positioned and transversely aligned such that only asingle web 170 is visible in Figures 28 through 35; the second, remaining web is immediately behind thevisible web 170, is transversely spaced therefrom and is a part of thesame cover 81 of motor/transmission housing 80. - Further desirably, pivotal connection of
shaft 92 toweb 170 is provided by means of a transversely extending shaft, not numbered but illustrated in Figures 28 through 35, which extends betweenweb 170 and the web which is hidden from view, and is pivotally mounted in both of these webs for freely rotatable motion respecting each of these webs.Shaft 92 is preferably secured to a member which fits rotatably on the unnumbered transverse shaft extending betweenweb 170 and the unnumbered web hidden from view.Shaft 92 extends preferably upwardly from connection withweb 170 through an aperture formed in upperlongitudinally extending member 62 offrame 14. - A
coil spring 94 is wrapped aroundshaft 92 and at one end preferably abutsweb 170. Alternatively the lower end ofspring 94 may be fixedly connected toshaft 92 or to a sleeve fitted about the unnumbered shaft which extends transversely betweenweb 170 and the web which is hidden from view in Figures 28 through 35.Spring 94 at its upper end fits into aspring pivot member 380, illustrated in Figures 38 through 42, which is rotatably retained within longitudinally extendingmember 62 by a pair ofshoulder bolts 382, illustrated in Figure 42. - When a
drive wheel 16 encounters an obstacle as illustrated in Figure 29 and moves upwardly,housing 80 pivots in a clockwise direction aboutpin 90. This upward pivotal movement ofhousing 80compresses spring 94 asweb 170 moves upwardly thereby reducing distance fromweb 170 to the lower surface of longitudinally extendingmember 62.Spring 94, being compressed, exerts downward force onweb 170 and hence onhousing 80. This force urgeshousing 80 to rotate counter-clockwise aboutpivot pin 90 asdrive wheel 16 passes over the obstacle and moves downwardly. - When a
drive wheel 16 accelerates, the drive wheel motor/transmissioncombination suspension member 310 attempts to rotate aboutpivot pin 90 in a counter-clockwise direction in reaction to acceleration of the drive wheel. The counter-clockwise rotation liftsanti-tip wheels 42 further off the ground. -
Shaft 92 is preferably slidably retained withinspring pivot member 380 in longitudinally extendingtubular member 62. Sliding passage ofshaft 92 throughspring pivot member 380 connected to longitudinaltubular member 62permits shaft 92 to rise in response to an associated drive wheel encountering an obstacle such as illustrated in Figure: 29 or to effectively rise as the motor/transmissioncombination suspension member 310 rotates clockwise aboutpivot point 318 in reaction to deceleration of an associateddrive wheel 16. A clearance aperture cut in the upper wall of longitudinally extendingmember 62, immediately aboveshaft 92, permits upward movement ofshaft 92 withoutshaft 92 interfering withframe 12 or with longitudinally extendingmember 62. - As shown in Figure 1, curb-climbing
power wheelchair 10 further preferably includes abody 34 which not only provides a decorative, aesthetically pleasing appearance for curb-climbingpower wheelchair 10 but also protects the wheelchair user frombatteries 32 and from the electrical connections betweenbatteries 32 andmotor 76.Body 34 further provides protection forbatteries 32 and, to someextent motors 76 andtransmissions 78 withinhousings 80, from liquids. -
Body 34 preferably includes a central generallyplanar portion 172 which, whenbody 34 is in place onframe 12, overliesbatteries 32 as illustrated in Figures 5 and 6 and, to a lesser extent, in Figure 1. - As illustrated in Figures 1, 5 and 6,
body 34 preferably further includesfender portions 126 which preferably substantially wrap around upper semi-circular portions ofrespective drive wheels 16.Fenders 126 preferably extend outwardly preferably over at least major portions of the width of associateddrive wheels 16, to fit closely about the drive wheel portions which are enveloped byrespective fenders 126. -
Body 34 may further include a rearwardly facing openable bonnet portion (not shown). There may be further provided as a portion of body 34 a planar portion extending downwardly from the openable bonnet for preferably at least substantially concealing the rear suspension ofwheelchair 10, especiallytransverse beam 38 from whichrear idler wheels 18 are suspended. - As illustrated in Figures 1, 5 and 6
body 34 preferably further hasrear corner portions 132 which are preferably rounded and also extend over the suspension gear for rearidler wheels 18, specificallytransverse beam 38 andU-shaped spindles 142. Roundedrear corners 132 andfender portions 126 preferably transition to centralplanar portion 172 via at least partiallyconcave transition portions 134 which have apertures for passage therethrough of upstanding front and rearseat support members - As illustrated in Figure 1,
body 34 preferably yet further includes, and has formed therein, a pair of forwardly facingintegral bumper members 138 lying over and protecting forward suspension members such asspindle flanges 320 which form a part of pivotally connectedsuspension member 310 which is illustrated in Figures 28 through 37 but is not present in the version of the power wheelchair illustrated in Figure 1, where a wishbone is used to suspend the forward anti-tip wheel. Forwardly facingintegral bumper members 138 serve to protect suspension parts such asspindle flange 320 and associated spring-strut combinations, which resist and cushion arcuate upward movement of forwardanti-tip wheels 42 inspindle flanges 320 relative to frame 12 assuspension member 310 pivotally rotates aboutpivot connection 318. This is as illustrated in Figures 28 through 35 where the suspension and the spring-strut structure is shown. - When the alternate suspension structure illustrated in Figure 27 is used, the forwardly facing
integral bumper members 138 lie over and protect the spring-strut-beam combinations designated generally 44 which govern arcuate movement of forwardanti-tip wheels 42 relative to frame 12. -
Body 34 preferably further includes a planar portion extending betweenforward bumper members 138 where such planar portion is designated 136 and provides a kick panel for the power wheelchair occupant. The kick panel is designated 136 and is illustrated in Figure 1. -
Body 34 preferably rests directly onframe 12.Body 34 is preferably a single molded piece of high impact plastic and is exceedingly light.Body 34 may be manually directly lifted off offrame 12 onceseat 14 has been removed, without use of tools. Becausebody 34 fits closely aboutframe 12 and is effectively contoured to the shape offrame 12 and the associated members by which therear idler wheels 18, the forwardanti-tip wheels 42 and the other structure are connected directly or indirectly to frame 12,body 34 need not be fixed toframe 12. Thepower wheelchair 10 operates well withbody 34 resting on but not secured to frame 12. -
Body 34 may be retained in place onframe 12 by mating pads of respective hook and eye material (not shown), such as that sold under the trademark Velcro, affixed to upwardly facing surfaces of longitudinally extendingtubular member 62, preferably at the forward extremities thereof. Corresponding mating pieces of Velcro are affixed to the undersurface ofbody 34 at planar portions thereof which rest directly on the forward extremities of longitudinally extendingtubular members 62. Use of the hook and eye material attachments minimizes any rattles which might otherwise occur asbody 34 moves slightly relatively to frame 12 during operation ofpower wheelchair 10. - Figure 8 illustrates structure providing means for adjustably transversely separatingly positioning arms of
seat 14 where the arms are designated generally 182 with the left (looking forward) arm designated 182L and the right (looking forward) arm designated 182R. The structure facilitating adjustable transverse separation and positioning ofarms arm support base 184 which is preferably a hollow rectangular cross-section tubular member.Arm support base 184 is connected toseat 14, specifically to cushionportion 20 thereof, indirectly. -
Arm support base 184 directly connects to rearwardly facing portions of L-shapedbrackets 222, the lateral portion of one of which is visible in Figures 13 through 16 and is partially visible in Figure 8. The portion of L-shapedbracket 222, which faces rearwardly and is preferably in facing contact with a rearwardly facing surface ofcushion portion 20 ofseat 14, is not visible in Figure 8; it is hidden behind the hollow rectangular cross-section tubular member definingarm support base 184. Lateral portions of L-shapedbrackets 222 are connected to laterally facing, flange surfaces ofcushion support brackets 224 which are secured to cushionportion 20 ofseat 14 and are illustrated in Figures 13 through 16. Preferably L-shapedbrackets 222 are secured to laterally facing flange surfaces ofcushion support brackets 224 via a pair of Phillips head screws as illustrated in Figures 13 through 16 but not numbered to aid clarity of the drawings. -
Cushion support brackets 224 preferably include upstanding flange portions, which run along the longitudinally extending side ofseat cushion 20, and bottom portions which run longitudinally along the bottom ofseat cushion 20.Cushion support brackets 224 are preferably secured to cushionportion 20 ofseat 14 via screw-type fasteners driven into the bottom ofseat cushion portion 20 through apertures in bottom longitudinally extending portions ofcushion support brackets 224. - A seat back
support bracket 226 illustrated in Figure 8 and Figures 13 through 16 is of generally L-shaped transverse cross-section and includes a rearwardly facing flange portion and a side facing flange portion. The rearwardly facing flange portion has apertures for screw-type fasteners to pass therethrough and into the rearwardly facing surface of seat back 22, to secure seat back 22 to the associated seat backsupport bracket 226. - Seat back
support brackets 226 are preferably connected to seatcushion support brackets 224 via a single pivot rivet connection at each side ofseat cushion 20 and - seat back 22; the single pivot rivet connection is partially visible in Figures 13 through 16. The single pivot rivet connection is partially hidden by a portion of the arm support structure, specifically a vertically extending
arm support member 190 in Figures 13 through 16. The single rivet connection between seat backsupport brackets 226 and seatcushion support brackets 224 facilitates folding or pivoting movement of seat back 22 towardsseat cushion 20 about the points of single pivot rivet connection betweencushion support brackets 224 and seat backsupport brackets 226. - Arm support extensions are designated generally 186 in Figure 8 and include
horizontal supports 188 and vertically extending supports 190. Arm cushions 192 are pivotally connected, as indicated by 252 in Figures 24 and 25, tovertical supports 190 for arcuate motion ofarm cushions 192 with respect thereto. -
Arm support base 184 includes a pair of tapped holes, not illustrated in Figure 8, which receive complementary threaded shafts (not shown) fixed to handknobs 194, illustrated in Figure 8. The threaded shafts affixed toknobs 194, when advanced or retracted by rotation ofknobs 194, through complemental engagement of the threaded shafts with tapped holes inarm support base 184, move against or retract from contact with respective horizontalarm support portions 188 of arm support extensions designated generally 186, which are associated with left andright arms - Frictional contact between the threaded shafts fixed to
knobs 194 and respective horizontalarm support portions 188 fixesarm support extensions 186 in position when the threaded shafts are tightly turned thereagainst. Fixation ofarm support extensions 186 in position fixes the lateral position ofarms arm support portions 188 are laterally movable into and out ofarm support base 184,arms arm cushions 192 may be manually moved between the positions illustrated in solid lines in Figure 8 and the positions illustrated in dotted lines in Figure 8, thereby adjusting effective width ofseat 14 ofpower wheelchair 10. -
Knobs 194 are rotated by application of manual force thereto. Once the knobs are turned to a position at which threaded shafts associated therewith only lightly contact or are removed from contact with horizontalarm support portions 188, these horizontal arm support portions may be moved by hand, to adjust transverse separation of arm cushions 192 and hence the effective width ofseat 14, all without use of tools. - Forward
anti-tip wheels 42 do not normally contact the ground or other reasonably smooth surface on which curb-climbingpower wheelchair 10 operates.Anti-tip wheels 42 are maintained above the ground and provide protection against tipping in the event of forward pitching ofwheelchair 10 due to encounter with an obstacle, traverse of a significant downgrade, and the like. The off-the-ground, anti-tip positioning ofwheels 42 is illustrated in Figures 1, 2, 5, 6, 9 through 11 and 27 through 29. - In Figures 28 through 36, a suspension member is designated generally 310 and shown schematically. The portion of
housing 80 in which motor 76 resides, as shown in more detail in Figure 37, forms the rear ofsuspension member 310 viewing Figures 28 through 36.Suspension member 310 has acentral portion 314 and aspindle flange 320 which defines the forward portion ofsuspension member 310, as illustrated in Figures 28 through 36.Suspension member 310 is connected to frame 12 atpivotal connection 318 viapin 90 passing throughaperture 84 offrame eye 82. - One
suspension member 310 is located on either side of thepower wheelchair 10. Eachsuspension member 310 houses amotor 76, which is one of the pair of motors, with onemotor 76 driving eachdrive wheel 16.Suspension member 310 additionally houses transmission means 78 for transmitting torque from the associatedmotor 76 to an axle of the associateddrive wheel 16. The associated drive wheel is journaled in suitable bearings within the front of motor/transmission housing 80 which forms the central portion ofsuspension member 310. The axis of rotation of thedrive wheel 16 is indicated as 24 in Figure 28. -
Spindle flange 320 ofsuspension member 310 has a box-like configuration with forwardly extending sides of the box being designated 328, 330 in Figure 36.Box side 330 is the outboard side ofspindle flange 320; as a result of the illustrated geometry ofspindle flange 320 andsuspension member 310, the associatedanti-tip wheel 42 is essentially longitudinally aligned with the associated drive wheel 16 (not shown). This provides enhanced wheelchair stability and also permits a wider footrest 172 (Figure 1). - Extending between
box sides spindle flange 320 is a shaft 234 (Figure 28). Mounted on eachshaft 234 is aspring support base 354, not visible in Figures 28 through 35 but shown schematically in Figure 38. Secured to and extending upwardly fromspring support base 354 is anupstanding shaft 238, the upper extremity of which extends through and is slidably retained within aspring pivot 380 illustrated in Figures 38 through 42. Thisspring pivot 380 resides within an aperture formed in a horizontally extending planar portion of a forwardly extendingpedestal 202 visible in Figures 28 through 35.Pedestal 202 extends forwardly fromframe member 66. Acoil spring 236 is positioned aboutshaft 238 betweenspring support base 354 andspring pivot 380, as illustrated in Figures 28 through 36, and as best shown in Figure 38. -
Spindle flange 320 further includes a forwardly facing anti-tip arm designated generally 331 in Figures 28 through 36 on which aforward anti-tip wheel 42 is rotatably mounted. -
Spindle flange 320 forms the forward portion ofsuspension member 310 and is secured about motor/transmission housing 80 by a suitable clamp designated generally 338 in Figures 36 and 37.Clamp 338 may be of the type conventionally used to secure mufflers or tailpipes in automobiles and consists of abase plate 340, visible in Figures 36 and 37, ahoop member 342 and nuts or other means for retaininghoop member 342 tobase plate 340. One such nut is illustrated as 344 in Figure 37 engaging a threaded extremity ofhoop member 342. - The
pivotal connection 318 of thesuspension member 310, which is defined by motor/transmission housing 80 and spindle-flange 320, withframe 12, is illustrated in Figures 28 through 37. The forward portion of motor/transmission housing 80, which may be considered thecentral portion 314 ofsuspension member 310, has a narrowedshoulder 346 to fit between two rearwardly extending transversely spaced apart plates designated 348 defining frame eye portion 82 (Figure 36).Shoulder portion 346 is equipped with suitable bearings; corresponding bores or apertures are formed inplates 348 ofeye portion 82 and inoutboard 334 andinboard 332 extensions ofbox sides spindle flange 320. Asuitable pin 90 or nut and bolt combination passes through the aligned apertures in these elements, as illustrated schematically bypivot connection 318 in Figure 36. - Since
spindle flange 320 having forwardanti-tip wheel 42 mounted thereon is fixedly connected to motor/transmission housing 80 byclamp 338, and specifically byhoop portion 342 wrapping tightly thereabout,spindle flange 320 and motor/transmission housing 80 move unitarily aboutpivotal connection 318 responsively to acceleration and deceleration ofdrive wheel 16, whether due to torque applied bymotor 76 or due towheel 16 encountering an obstacle. - In Figure 36, forward vertically downwardly extending
member 66 has been depicted in section, as haseye portion 82, to aid the clarity of the drawing. The forward portion of motor/transmission housing 80 has not been shaded, to aid the clarity of the drawing. - Pivotal mounting of
suspension member 310 to frame 12 viapivotal connection 318 atframe eye 82 facilitates operation of the power wheelchair and particularly facilitates climbing high curbs and descending therefrom. When the power wheelchair accelerates, as torque generated by the drive motors is applied to the associated drive wheels, reaction ofsuspension member 310 to such acceleration causessuspension member 310 to tend to rotate aboutpivot connection 318 in a direction opposite that of rotation of thedrive wheels 16. For example, in considering Figure 28, acceleration ofdrive wheel 16 by the drive motor (not shown) causesdrive wheel 16 to rotate clockwise, driving the power wheelchair to the right in Figure 28. This acceleration ofdrive wheel 16causes suspension member 310 to tend to rotate counterclockwise aboutpivot connection 318, lifting forwardanti-tip wheel 42. This rotation ofsuspension member 310 and consequent lifting ofanti-tip wheel 42 facilitates the climbing of obstacles of a height which would otherwise not be surmountable bypower wheelchair 10. - When curb-climbing
power wheelchair 10 descends from a curb or other elevated area to a lower position, deceleration ofdrive wheel 16 results in the tendency ofsuspension member 310 to rotate in the opposite direction, namely clockwise, in drawing Figures 28 through 35. For example, considering Figure 30, aspower wheelchair 10 approaches adrop edge 322 of apath 324, the occupant ofpower wheelchair 10 reduces output torque of the drive motors (not shown) creating a load ondrive wheels 16 from the associated drive motors. This tends to decelerate the drive wheels respecting rotation in the direction indicated by arrow AA in Figure 30. This deceleration ofdrive wheels 16causes suspension member 310 to rotate aboutpivot point 84 in the direction of arrow AA in Figure 30, causinganti-tip wheel 42 to move downwardly in Figure 30. As a result,power wheelchair 10 desirably makes contact withlower path 326 prior to drivewheel 16 reachingedge 322 separating raisedpath 324 fromlower path 326. This permitspower wheelchair 10 to travel over dropoffs and curbs, such as represented byedge 322, of substantially greater height than otherwise possible. -
Springs suspension member 310 in the orientation illustrated in Figure 28. Hence, considering movement ofpower wheelchair 10 to be to the right in Figure 28, aspower wheelchair 10 goes down a slight grade (such as illustrated in Figure 29) or approaches a vertical dropoff (such as illustrated in Figure 30),spring 236urges suspension member 310 to rotate in the clockwise direction illustrated in Figure 28 thereby urginganti-tip wheel 42 downwardly in order to contact the ground or other running surface along whichpower wheelchair 10 is moving. This tendency towards clockwise movement or rotation ofsuspension member 310 is resisted by compression ofspring 94. The spring constant ofspring 236 is preferably about 1965kg/m (110 lb/inch), while the spring constant ofspring 94 is preferably about 5144kg/m (288 lb/inch). Whenpower wheelchair 10 is at rest, springs 94 and 236 are not compressed and not extended. - When
power wheelchair 10 approaches an obstacle of moderate height, such as a curb as illustrated generally in Figures 32 and 33, and whentip wheel 42 encounters the obstacle, this in combination with acceleration ofdrive wheel 16 tends to causesuspension member 310 to rotate in the counterclockwise direction as illustrated in Figures 32 and 33. This compressesspring 236, providing a cushioning effect. - As illustrated in Figures 2, 5 and 6,
power wheelchair 10 may yet further preferably include a generally triangularly-shapedskid 350 mounted on the bottom and at the rear offrame 12.Skid 350 is most preferably mounted on the bottom of and at the rear of horizontalrear extension member 148 which is shown in Figure 4.Skid 350 is preferably nylon or another preferably polymeric material having good lubricity characteristics. Optionally, skid 350 may be equipped with a skid wheel 352 (Figure 2) which is preferably mounted on a transverse axle for rotation in a direction generally parallel withdrive wheels 16 and is oriented so that the lower extremity surface ofskid wheel 352 is essentially at the same position off the ground as the rear, lower extremity ofskid 350, as depicted schematically in Figure 2. - Skid 350 and
optional skid wheel 352 serve to facilitate the ascension ofpower wheelchair 10 over steep curbs of a height such as illustrated in Figures 32 and 33. Whenpower wheelchair 10 ascends such a steep curb, after thedrive wheel 16 has traveled from the lower grade to the curb, and if the curb is of sufficient height, then the curb can contact the lower portion offrame 12, behinddrive wheel 16. Skid 350 andoptional skid wheel 352 prevent this and provide for sliding, non-damaging contact between the high curb and the rear portion of thepower wheelchair 10, until such time asrear idler wheel 18 can traverse up the curb thereby preventing hang-up of the rear castors. - A principal advantage of the power wheelchair is provided by the spring-loaded anti-tip forward
wheels 42 located in front of eachdrive wheel 16. Spring-loading ofwheels 42 allowspower wheelchair 10 to be driven over obstacles and over inclined transitions without fear ofdrive wheel 16 lifting, thereby breaking traction and causing stoppage of forward motion ofwheelchair 10. - When attempting to climb obstacles such as ramp transitions or small curbs, acceleration of
motor 76 transmitted to drivewheels 16 tends to cause the rear ofmotor 76 withinhousing 80 to drop; this creates an upward force onanti-tip wheels 42. This helpsanti-tip wheels 42 climb the obstacle encountered bywheelchair 10. Additionally, in situations involving ramp transition, and as the driving surface rises and contacts theanti-tip wheels 42 thereby applying upward force onwheels 42, downward force is created at the center portion ofsuspension member 310, forcing the tires of thedrive wheels 16 into the ground, thereby further increasing traction and the chances of the wheelchair overcoming the obstacle. - In a deceleration situation, such as when reducing speed going down a ramp, the opposite effect is used advantageously. As the rear of
suspension member 310 rises during deceleration, this exerts downward force onanti-tip wheels 42 which effectively increases the anti-tip force provided byspring 236. - High maneuverability of the power wheelchair is achieved by locating
drive wheels 16 close to the longitudinal center of the power wheelchair. - As shown, for example, in Figure 28, longitudinal distance between the center of
aperture 84 ineye 82 and the drive axle for the associated drive wheel, where the drive axle emerges fromsuspension member 310 to drive associateddrive wheel 16, is preferably in the neighborhood of from 0.07m (2.75 inches) to 0.08m (3 inches), measured longitudinally. - Longitudinal distance between
pivotal connection 318 andshaft 234 defining the point of application of downward bias ofspring 236 tosuspension member 310 is preferably about 0.14m (5.63 inches). This pivotal connection ofsuspension member 310 to frame 12 viaeye 82 provides the active independent suspension system for the combination ofsuspension member 310,anti-tip wheel 42 and associateddrive wheel 16. - In Figure 35, depicting a power wheelchair descending from a curb, at the position illustrated both
springs suspension member 310 thereby cushioning the power wheelchair just asdrive wheel 16 contacts the lower level.Spring 94 is compressed due to deceleration ofdrive wheel 16 and the resultant tendency ofsuspension member 310 to rotate clockwise, as in Figure 35;spring 236 is compressed as a result ofanti-tip wheel 42 contacting the lower level beforedrive wheel 16. - As shown in Figure 35, distance between the point of attachment of
shaft 92 withsuspension member 310 and drive wheel axis ofrotation 24 is substantially less than distance between the point of attachment ofshaft 234 tospindle portion 320 andpivotal connection 318 ofsuspension member 310 withframe eye 82. In situations such as depicted in Figure 35,spring 236urges suspension member 310 to rotate in a clockwise direction (as viewed in Figure 35), causinganti-tip wheel 42 to drop towards the lower surface, minimizing forward tip of the power wheelchair when descending curbs. - In the embodiment illustrated in Figure 27, anti-tip
idler wheels 42 are connected directly to frame 12 viaU-shaped spindles 228; one leg (of the U-shape) of one ofspindles 228 is shown in side view in Figure 27. The U-shape ofspindles 228 is readily apparent from Figure 4. -
U-shaped spindles 228 are preferably fabricated by welding rectangular cross-section tubular stock between two parallel plates with the tubular stock forming the base of theU. Spindles 228 are pivotally connected directly to downwardly extendingmembers 66 offrame 12, preferably using screw-bolt assemblies. The side plate portions ofspindles 228 fit pivotally on either side about the lower portions of respective downwardly extending verticaltubular members 66, which are illustrated in Figure 7. Nut and bolt pivotal connections ofU-shaped spindles 228 to vertically downwardly extendingmembers 66 are depicted schematically byindicator numeral 230 in Figure 27. - Extending upwardly between the legs of
U-shaped spindles 228 are shafts (not shown) about which springs 236 reside. These shafts are mounted on spring support bases 354, in the same manner as illustrated in Figure 38. The upper extremities of the shafts extend through and are slidably retained within spring pivots 380, in the same manner as illustrated in Figure 38, residing in horizontally extending planar portions of forwardly extendingpedestals 202, which are visible in Figure 7 as well as in Figure 27. - With this arrangement, upon an
anti-tip wheel 42 encountering an obstacle or uponwheelchair 10 pitching forwardly,anti-tip wheels 42 move arcuately, together withU-shaped spindle 228, as they pivot aboutpivotal connection 230 relative to frame 12. As the illustratedanti-tip wheel 42 andU-shaped spindle 228 pivot aboutconnection point 230, upward movement ofspindle 228 causes distance betweenshaft 234 andpedestal 202 to decrease, thereby compressingspring 236, as illustrated in Figure 27. - As shown in Figures 39 through 42,
spring pivot 380 has ahead portion 388 and atapered sleeve portion 390 that are rigidly connected. As shown in Figures 37 and 38, anupstanding shaft 238, which is secured to and extends from the cylindricalspring support base 354, fits inside tapered sleeve portion 390 (not shown in Figures 37 and 38) of thespring pivot 380. - As shown in Figure 42,
upstanding shaft 238,spring 236, andspring pivot 380 are held together byshoulder bolts 382 which pass throughapertures 384 in the relevant frame member and threadedapertures 386 in the head ofspring pivot 380.Shoulder bolts 382 allow thespring 236 andupstanding shaft 238 to pivot on theshoulder bolts 382 of thespring pivot 380 when thespring 236 is compressed. - In the embodiment illustrated in Figure 27, as the
anti-tip wheels 42 encounter an obstacle,spring 236 is compressed upward and the upstanding shaft 288 (not shown) pivots onspring pivot 380 mounted topedestal 202 offrame 12. Therefore,spring pivot 380 allowsupstanding shaft 238 andspring 236 to pivot onshoulder bolts 382 asspring 236 is compressed whenanti-tip wheels 42 of the power wheelchair contact an obstacle on the ground. - Compression of
spring 236 provides a cushioning effect whenanti-tip wheels 42 contact an obstacle or contact the ground due to forward pitching of curb-climbingpower wheelchair 10. The suspension ofanti-tip wheels 42 provided byspindle 228, connects anti-tipidler wheels 42 to frame 16 for arcuate upward motion relative to frame 12 upon forward tipping ofpower wheelchair 10 or contact ofanti-tip wheels 42 with an above-grade obstacle, as illustrated in Figure 33. - As shown in Figure 27, a
nut 240 mounted on a threaded portion of the shaft extending abovepedestal 202 permits selectable compression ofspring 236 thereby providing adjustment of the spring force applied toanti-tip wheels 42 to resist arcuate upward movement thereof upon forward tipping ofpower wheelchair 10 or uponwheels 42 encountering an obstacle. Rotation ofnut 240 also adjusts the distance at whichwheels 42 are from the ground. - In this embodiment illustrated in Figure 27, longitudinal distance between
pivot 90 defined by the position of aperture 88 inear 86 ofhousing 80 and the drive axle (not shown) for the associateddrive wheel 16, where the axle emerges fromhousing 80 to drive associateddrive wheel 16, is preferably in the neighborhood of from 0.07m (2.75 inches) to 0.08m (3 inches), measured longitudinally. This pivotal connection of the drive motor/transmission housing 80 to frame 12 viapivotal connection 90 ofear portion 86 witheye portion 82 provides active independent suspension for the combination ofmotor 76 andtransmission 78 inhousing 80, and associateddrive wheel 16. - Movement of
motor 76 and especially pivotal movement ofhousing 80 relative to frame 12 indirectly controls action ofanti-tip wheels 42 in the embodiment illustrated schematically in Figure 27. Apivoting beam 270 is pivotally connected to forward vertically extendingmember 66 offrame 12 via a pivotal connection denoted 276 in Figure 27. At a forward end of pivoting beam 270 avertical link 268 is pivotally connected thereto at a pivot connection denoted 278. The lower end ofvertical link 268 is pivotally connected to spindle 238 via a pivotal connection which has not been numbered in Figure 27. - At the opposite, rearward end of pivoting
beam 270, anintermediate link 274 is pivotally connected thereto via a connection denoted 280 in Figure 27. At the remaining end ofintermediate link 274 there ispivotal connection 282 effectuating connection ofintermediate link 274 andmotor link 272, which is preferably fixedly connected tohousing 80 ofmotor 76 andtransmission 78. The linkage consisting of pivotingbeam 270,vertical link 268 andintermediate line 274 transfer motion between the rear end of motor/transmission housing 80 remote frompivot point 90 and forwardanti-tip wheels 42, thereby accomplishing indirectly the same action/reaction of these components to drive wheel acceleration/deceleration as accomplished by the direct connection structure illustrated in Figures 28 through 37. - With tilt of
seat 14 being adjustable in a manner thatcushion portion 20 ofseat 14 may be level or positioned tilted forward or tilted back, it is desirable to provide adjustment forarm cushion portions 192 ofseat 14 so thatarm portions 192 may be adjustably positioned, desirably in a level orientation regardless of whethercushion portion 20 ofseat 14 is level, tilted forward or tilted back. Structure facilitating adjustment of the position ofarm portion 192 and permittingarm portion 192 always to be positioned in a level orientation is illustrated in Figure 24. - Each arm, generally denoted 182, includes an
arm cushion portion 192 which is preferably upholstered to provide cushioning for the arm of the user ofpower wheelchair 10.Arm cushion portion 192 is mounted on a longitudinallyelongated support web 244.Arm cushion portion 192 and longitudinally elongatedsupport web 244 together constitutearm 182 of curb-climbingpower wheelchair 10. -
Support web 244 has a horizontally orientedcentral portion 246, on which arm cushion portion 242 is supported, and two vertically extending webs (unlabeled), which are visible in Figure 8.Webs 246 may be of different size and shape with one ofwebs 246 supportingjoystick controller 196 and electronics associated therewith and the remainingweb 246 being of more tapered, somewhat truncated shape.Web 246 supportingjoystick 196 and the associated electronics is denoted 246J in the drawings (Figure 24). - Affixed to the lower longitudinal extremity, preferably by welding, of a
vertical support portion 190 of arm support extension 186 (Figure 8) is a mountingblock 248, as illustrated in Figures 24 and 25. Mountingblock 248 preferably has a tapped hole (not shown) therein. Residing within the tapped hole is abolt 250 threadedly engaging the tapped hole.Bolt 250 can be advanced into or withdrawn from the tapped hole in mountingblock 248 to vary length ofbolt 250 protruding from mountingblock 248. -
Arm 192 connects tovertical support portion 190 via a pivotal connection provided by a rivet indicated as 252 in Figures 24 and 25. - As shown in Figures 24 and 25,
vertical webs support web 244 are spaced apart to receive the extremity of armvertical support portion 190 therebetween. Mountingblock 248 is preferably of the same width, measured transversely to the plane of the paper, as the interior of verticalarm support portion 190; mountingblock 248 and bolt 250 fit easily slidably betweenwebs arm 182. - When
arm 182 is pivoted downwardly about the pivotal connection provided byrivet 252, in the direction indicated by the double ended arrow in Figure 24, the central portion of longitudinally elongatedsupport web 244 contacts the head ofbolt 250;support web 244 cannot move further arcuately downwardly as a result. Adjustment of the position ofbolt 250, by rotatingbolt 250 and advancingbolt 250 into or out of mountingblock 248, adjusts the angle at which arm 182 (and specifically the central portion of longitudinally elongated support web 244)contacts bolt 250. This facilitates the adjustment of the angular position ofarm 182 relative to the remainder ofseat 14 whenarm 182 is positioned at the limit of its arcuate downward travel. - Footrest 172 (Figure 1) is adjustable to accommodate users of the curb-climbing power wheelchair of various heights. Additionally, the angle of
footrest 172 is adjustable to provide maximum foot comfort for the user of the power wheelchair. -
Footrest 172 is mounted for adjustable vertical movement alongupstanding extension member 200 illustrated in Figure 7.Member 200 preferably has vertically elongated slots formed in its forwardly and rearwardly facing surfaces; only the slot in the forward facing surface ofmember 200 is visible in Figure 7. - Mounted in the opening at the top of
upstanding extension member 200 is a knob and threaded shaft combination 253. The knob, which is designated 254 and is at the extreme upper portion of the attached threaded shaft is visible in Figures 1 and 2. The threaded shaft portion (not shown) preferably runs down the length of the interior ofupstanding extension member 200. The knob/threaded shaft combination 253 is retained in place by a square bushing which preferably fits flushly within the upper opening ofupstanding extension member 200, which opening is visible in Figure 7. The bushing is not shown in the drawings. -
Footrest 172 is connected toupstanding extension member 200 by an open, box-like frame 256 shown in Figure 7.Frame 256 fits slidably aboutupstanding extension member 200, in essentially complemental-facing contact with the four exterior surfaces ofupstanding extension member 200. A transversely extending pivot pin 257, visible in Figure 1, provides pivotal connection betweenfootrest 172 and open box-like frame 256, permittingfootrest 172 to tilt upwardly by pivotal motion about the pivot pin respecting open box-like frame 256 andupstanding extension member 200. - A nut (not shown), preferably a ball nut, threadedly engages the threaded shaft portion of the knob/threaded shaft combination 253 and is resident within vertically
upstanding extension member 200. A pair of threaded shafts extend through apertures in the forwardly and rearwardly facing walls of open box-like frame 256 and through the vertically elongated slots in the forward and rearwardly facing surfaces of verticallyupstanding member 200 and engage the nut withinupstanding member 200. This pair of threaded shafts restrain the nut from rotating with the threaded shaft of the knob/shaft combination 253 upon rotation of theknob 254. - With this arrangement, rotation of
knob 254 produces corresponding rotation of the attached threaded shaft (not shown) since theknob 254 and threaded shaft are fixedly connected. Since the interior nut threadedly engages the threaded shaft, if the nut were not restrained against rotation, the nut would rotate with the shaft. However the threaded shafts restrain the interior nut against rotation and hence cause the interior nut to rise or fall according to the direction of rotation of the shaft andknob 254. This rise and fall of the interior nut carries the associated threaded shafts and hence open box-like frame 256 andfootrest 172 therewith, as theknob 254 is rotated clockwise or counter-clockwise. Hence, vertical position offootrest 172 can be adjusted along the length of the vertically elongated slots present in verticallyupstanding member 200 by manually turningknob 254; no tools are required for adjusting vertical position offootrest 172. - Angular orientation of
footrest 172 relative to verticallyupstanding member 200 may also be adjusted. -
Footrest 172 includes an upstanding lip, visible in Figure 1 and designated generally 264. An aperture 265 through the rear portion of lip 264, located at the transverse mid-point thereof, is tapped. A correspondingly threaded shaft (not shown) is provided for complemental threaded engagement with the tapped aperture 265 in lip 264. The threaded shaft, which has a knob attached thereto designated generally 266, abuttingly contacts the forward facing portion of a plate-like downward extension portion of open box-like frame 256. This forwardly facing downward plate-like extension covers the vertically elongated slot in the forwardly facing surface of vertically extendingmember 200 and provides a place for abutment of the threaded shaft. By rotating a hub (not shown) attached to the threaded shaft, thereby advancing or retracting the threaded shaft relative to lip 264, a greater or lesser portion of the shaft extends from the rear of lip 264 to contact the downward plate-like extension of the forwardly facing portion of open box-like frame 256. This provides adjustment of angular position offootrest 172. - Preferably,
cushion portion 20 ofseat 14 is about 0.43m (17 inches) wide.Back portion 22 ofseat 14 is preferably about 0.41m (16 inches) high in the seat style illustrated in Figures 2 through 6. In the style illustrated in Figure 1,back portion 22 ofseat 14 is about 0.46m (18 inches) high. - In the seat style illustrated in Figures 2 through 6, the longitudinal length of
cushion portion 20 ofseat 14 is preferably between 0.41m (16 inches) and 0.46m (18 inches), most preferably 0.41m (16 inches). - The use of seat height adjustment means provided by forward and rear upstanding
seat support members seat 14 from about 0.42m (16.5 inches) to about 0.47m (18.5 inches), measured from the bottom ofseat 14 to the surface on whichpower wheelchair 10 rests. - Drive
wheels 16 are preferably 0.36m (14 inches) or 0.41m (16 inches) diameter drive wheels. Rearidler wheels 18 are preferably 0.20m (8 inches) or 0.25m (10 inches) in diameter. Forwardanti-tip wheels 42, are preferably 0.15m (six inches) or 0.20m (8 inches) in diameter. -
Power wheelchair 10 preferably has an overall length of 1.00m (39.5 inches) and a width of 0.65m (24.4 inches). This results in the vehicle having a turning radius of 0.49m (19.5 inches), permittingpower wheelchair 10 to be used easily in indoor environments, that have not been modified to accommodate handicapped personnel and conventional wheelchairs. - Power wheelchair control is effectuated utilizing a joystick controller designated generally 196 in the drawings. Suitable joystick controllers are available from Penny & Giles in Cristchurch, England, and are programmable and adjustable to provide variable sensitivity for the user.
- The geometry provided by the arrangement of the
frame 12,seat 14,drive motors 76,drive wheels 16,idler wheels 18 andanti-tilt wheels 42 provides outstanding handling and control as a result of weight distribution of the power wheel chair being very low. - A power wheel chair with
body 34 in place onframe 12, has a center of gravity, when empty, about 0.05m (1.9 inches) above the axis of rotation 24 (Figure 2) ofdrive wheels 16. Further, the center of gravity of thewheelchair 10 when empty is about 0.08m (3.1 inches) behind the axis ofrotation 24 ofdrive wheels 16. - With the aforementioned dimensions, and when
wheelchair 10 is empty, the center of gravity ofwheelchair 10 is about 15.2% of the longitudinal distance between theaxis 24 ofdrive wheels 16 and rearidler wheels 18.
Claims (9)
- A power wheelchair comprising:a. a frame (12);b. a pair of drive wheels (16) connected to said frame and rotatable about transverse axes (24) below a portion of a seat (14) supporting, in use, an occupant's thighs;c. motors (76) for driving respective drive wheels (16), respective motor/drive wheel combinations being pivotally connected to said frame;d. at least one ground engaging idler wheel connected to said frame and located rearward of said drive wheels; ande. at least one anti tip wheel (42) forward of said drive wheels, connected to one of said motor/drive wheel combinations (16, 76) for pivotal movement therewith relative to said frame (12) responsively to changes in drive wheel velocity, characterised in thatf. the at least one anti tip wheel (42) is positioned above ground.
- The power wheelchair of claim 1, wherein the axes (24) of said drive wheels are between said motors (76) and the points (318) at which said motor/drive wheel combinations are pivotally connected to the frame, in the lengthwise direction of the vehicle.
- The power wheelchair of claim 1 or claim 2, wherein the weight of the frame (12) is transmitted to each drive wheel by the pivotal connection and a spring (94), and the axis of the drive wheel (24) is between the pivotal connection and the spring in the lengthwise direction of the vehicle.
- The power wheelchair of any preceding claim, wherein said connection between said anti-tip wheel (42) and said motor/drive wheel combination is rigid.
- The wheelchair of any one of claims 1 to 3, wherein said connection between said anti-tip wheel and said motor/drive wheel combination comprises a linkage.
- The wheelchair of any preceding claim, wherein said anti-tip wheel (42) is spring-loaded.
- The wheelchair of any preceding claim, wherein the seat (14) is removably mounted on said frame (12).
- The wheelchair of any preceding claim, comprising a pair of said anti-tip wheels (42), and wherein said connection between said anti-tip wheel and said motor/drive wheel combination comprises means for transmitting pivotal motion of each of said motor/drive wheel combinations relative to said frame (12) to a respective one of said anti-tip wheels (42).
- The wheelchair of claim 8, wherein each said anti-tip wheel (42) moves relative to said frame (12) together with its associated motor/drive wheel combination and independently of the other motor/drive wheel combination.
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
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US4197397P | 1997-04-15 | 1997-04-15 | |
US41973P | 1997-04-15 | ||
PCT/US1998/007543 WO1998046184A1 (en) | 1997-04-15 | 1998-04-14 | Curb-climbing front wheel drive power wheelchair |
Publications (2)
Publication Number | Publication Date |
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EP0973475A1 EP0973475A1 (en) | 2000-01-26 |
EP0973475B1 true EP0973475B1 (en) | 2005-07-06 |
Family
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP98918220A Expired - Lifetime EP0973475B1 (en) | 1997-04-15 | 1998-04-14 | Curb-climbing power wheelchair |
Country Status (7)
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EP (1) | EP0973475B1 (en) |
AT (1) | ATE299007T1 (en) |
AU (1) | AU733470B2 (en) |
CA (1) | CA2283355C (en) |
DE (1) | DE69830787D1 (en) |
GB (1) | GB2334244B (en) |
WO (1) | WO1998046184A1 (en) |
Families Citing this family (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6601863B1 (en) | 1997-10-06 | 2003-08-05 | Invacare Corporation | Mid-wheel drive wheelchair with rigid front wheel anti-tip stabilizer |
US5848658A (en) * | 1997-10-06 | 1998-12-15 | Invacare Corporation | Adjustable front wheel stabilizer for power wheelchair |
AU5487299A (en) * | 1998-08-14 | 2000-03-06 | Sunrise Medical Hhg Inc. | Resilient suspension system for a wheelchair |
US6070898A (en) * | 1998-08-14 | 2000-06-06 | Sunrise Medical, Inc. | Suspension system for a wheelchair |
GB9905305D0 (en) | 1999-03-09 | 1999-04-28 | Sunrise Medical Ltd | Improvements in vehicles |
SE520868C2 (en) * | 1999-03-17 | 2003-09-09 | Permobil Ab | Wheelchair tip protection |
US6554086B1 (en) | 2000-10-27 | 2003-04-29 | Invacare Corporation | Obstacle traversing wheelchair |
SE523203C2 (en) * | 2001-03-09 | 2004-03-30 | Margana Ag | Apparatus for facilitating operation with a walker and a walker provided with such a device |
US7040429B2 (en) | 2001-10-10 | 2006-05-09 | Invacare Corporation | Wheelchair suspension |
US7066290B2 (en) * | 2001-10-19 | 2006-06-27 | Invacare Corp. | Wheelchair suspension having pivotal motor mount |
US11213441B2 (en) | 2002-10-25 | 2022-01-04 | Invacare Corporation | Suspension for wheeled vehicles |
US7293801B2 (en) | 2003-08-18 | 2007-11-13 | Invacare Corporation | Self-stabilizing suspension for wheeled vehicles |
TW583968U (en) * | 2003-06-13 | 2004-04-11 | Pihsiang Machinery Mfg Co Ltd | Suspension structure of independent front guide wheel for wheelchair |
AU2005100261B4 (en) * | 2005-03-27 | 2005-08-18 | Zhang, Dongning Mr | Mobility solution |
US7896394B2 (en) | 2005-08-18 | 2011-03-01 | Sunrise Medical Hhg, Inc. | Midwheel drive wheelchair with independent front and rear suspension |
CA2566551C (en) | 2006-10-31 | 2009-04-07 | Volodymyr Ivanchenko | Apparatus for transporting an invalid |
ATE493960T1 (en) | 2007-02-08 | 2011-01-15 | Invacare Corp | WHEELCHAIR SUSPENSION |
DE602008006167D1 (en) | 2007-02-14 | 2011-05-26 | Invacare Corp | STABILITY CONTROL SYSTEM |
EP3238682A3 (en) | 2009-10-09 | 2018-01-10 | Invacare Corporation | Wheelchair suspension with opposite movement of anti-tip arms |
US8851214B2 (en) | 2010-07-15 | 2014-10-07 | Permobil Ab | Electric mid-wheel drive wheelchair |
CA2864124C (en) | 2012-02-15 | 2022-03-01 | Invacare Corporation | Wheelchair suspension |
US11419774B2 (en) * | 2018-07-06 | 2022-08-23 | Pride Mobility Products Corporation | Mobility vehicle |
Family Cites Families (11)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
SE381563B (en) | 1973-03-19 | 1975-12-15 | Stiftelsen Teknisk Hjelp At Ha | HAND-DRIVEN WHEELCHAIR |
FR2399822A1 (en) * | 1977-08-09 | 1979-03-09 | Dupont Lit Sa | Folding wheel chair for handicapped people - consists of frame on two drive wheels, with seat mounted by parallel arms raised and lowered by jack |
US4387325A (en) | 1981-04-15 | 1983-06-07 | Invacare Corporation | Electric wheelchair with speed control circuit |
SE431393B (en) | 1982-05-03 | 1984-02-06 | Permobil Ab | STEERABLE, ENGINE DRIVE WHEEL |
SE438960B (en) | 1982-05-04 | 1985-05-28 | Permobil Ab | Wheelchair footrest device |
US5094310A (en) | 1988-11-17 | 1992-03-10 | Invacare Corporation | Powered wheelchair having transversely mounted drive mechanism |
US5145020A (en) | 1990-11-14 | 1992-09-08 | Invacare Corporation | Suspension for seat of powered wheel chair |
FR2689003A1 (en) * | 1992-03-31 | 1993-10-01 | Long Shine Enterprise Co Ltd | Motorized chair on wheels. |
US5366037A (en) | 1992-11-23 | 1994-11-22 | Invacare Corporation | Powered wheelchair having drive motors integrated into driven wheels |
DE4420877C2 (en) | 1994-06-15 | 2001-09-20 | Invacare Deutschland Gmbh | wheelchair |
CA2181439C (en) * | 1994-11-18 | 2007-02-20 | Andre Degonda | Wheel-chair for transporting or assisting the displacement of at least one user, particularly for a handicapped person |
-
1998
- 1998-04-14 DE DE69830787T patent/DE69830787D1/en not_active Expired - Lifetime
- 1998-04-14 AU AU71184/98A patent/AU733470B2/en not_active Expired
- 1998-04-14 CA CA002283355A patent/CA2283355C/en not_active Expired - Fee Related
- 1998-04-14 AT AT98918220T patent/ATE299007T1/en not_active IP Right Cessation
- 1998-04-14 WO PCT/US1998/007543 patent/WO1998046184A1/en active IP Right Grant
- 1998-04-14 EP EP98918220A patent/EP0973475B1/en not_active Expired - Lifetime
- 1998-04-14 GB GB9913770A patent/GB2334244B/en not_active Expired - Lifetime
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ATE299007T1 (en) | 2005-07-15 |
EP0973475A1 (en) | 2000-01-26 |
WO1998046184A1 (en) | 1998-10-22 |
AU7118498A (en) | 1998-11-11 |
GB2334244B (en) | 2001-10-10 |
CA2283355C (en) | 2001-04-03 |
CA2283355A1 (en) | 1998-10-22 |
GB2334244A (en) | 1999-08-18 |
GB9913770D0 (en) | 1999-08-11 |
AU733470B2 (en) | 2001-05-17 |
DE69830787D1 (en) | 2005-08-11 |
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