CA1094466A - Wheeled, dual axle device having an axially movable brake - Google Patents
Wheeled, dual axle device having an axially movable brakeInfo
- Publication number
- CA1094466A CA1094466A CA303,182A CA303182A CA1094466A CA 1094466 A CA1094466 A CA 1094466A CA 303182 A CA303182 A CA 303182A CA 1094466 A CA1094466 A CA 1094466A
- Authority
- CA
- Canada
- Prior art keywords
- wheel
- brake
- upright
- braking
- axis
- 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
Links
Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62B—HAND-PROPELLED VEHICLES, e.g. HAND CARTS OR PERAMBULATORS; SLEDGES
- B62B5/00—Accessories or details specially adapted for hand carts
- B62B5/04—Braking mechanisms; Locking devices against movement
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62B—HAND-PROPELLED VEHICLES, e.g. HAND CARTS OR PERAMBULATORS; SLEDGES
- B62B5/00—Accessories or details specially adapted for hand carts
- B62B5/04—Braking mechanisms; Locking devices against movement
- B62B5/048—Hub brakes; drum brakes
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
- F16D2125/00—Components of actuators
- F16D2125/18—Mechanical mechanisms
- F16D2125/20—Mechanical mechanisms converting rotation to linear movement or vice versa
- F16D2125/34—Mechanical mechanisms converting rotation to linear movement or vice versa acting in the direction of the axis of rotation
- F16D2125/36—Helical cams, Ball-rotating ramps
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Braking Arrangements (AREA)
- Motorcycle And Bicycle Frame (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
Wheeled, dual axle device having a platform which is supported by an axle arrangement which provides a mechanical action for engaging and disengaging a brake when force or weight is applied to the platform/or the platform is tilted from a predetermined position. At least one wheel is mounted on a wheel bearing axle and the load receiving platform is mounted on a load bearing axle.
An upright connects the load and wheel bearing axles and is free to pivot relative to the axes of both axles. When weight is applied to the platform and the wheel is placed in contact with the resisting element, the upright rotates relative to the of the load and wheel bearing axles until it reaches an equilibrium position. Thereafter, the upright tends to remain in the equilibrium position notwithstanding rotation of the load receiving platform about the axis of the load bearing axle. Brake means are actuated in response to the rotation movement of the load receiving platform while the upright remains in the equilibrium position. If the upright is moved from the equilibrium position, force is generated by the upright as it attempts to restore itself under the influence of the weight to the equilibrium position. This force is used to operate the brake mechanism. In the preferred embodiment, an axially expanding brake mechanism is sensitive to the amount of weight on the platform and the degree of tilt of the 1.
platform. Upon engagement of the brake, thee rotating wheel mounted brake pad cooperates with the axially expanding brake mechanism to cause the upright to tend to move or create a force that increases the braking force in one direction of rotation (self-energizing braking) and decreases the braking force in the opposite direction of rotation. The de-acceleration force produced by braking also tends to influence the upright to move or decrease a force so as to control the self-energizing braking action to prevent brake lock-up.
Wheeled, dual axle device having a platform which is supported by an axle arrangement which provides a mechanical action for engaging and disengaging a brake when force or weight is applied to the platform/or the platform is tilted from a predetermined position. At least one wheel is mounted on a wheel bearing axle and the load receiving platform is mounted on a load bearing axle.
An upright connects the load and wheel bearing axles and is free to pivot relative to the axes of both axles. When weight is applied to the platform and the wheel is placed in contact with the resisting element, the upright rotates relative to the of the load and wheel bearing axles until it reaches an equilibrium position. Thereafter, the upright tends to remain in the equilibrium position notwithstanding rotation of the load receiving platform about the axis of the load bearing axle. Brake means are actuated in response to the rotation movement of the load receiving platform while the upright remains in the equilibrium position. If the upright is moved from the equilibrium position, force is generated by the upright as it attempts to restore itself under the influence of the weight to the equilibrium position. This force is used to operate the brake mechanism. In the preferred embodiment, an axially expanding brake mechanism is sensitive to the amount of weight on the platform and the degree of tilt of the 1.
platform. Upon engagement of the brake, thee rotating wheel mounted brake pad cooperates with the axially expanding brake mechanism to cause the upright to tend to move or create a force that increases the braking force in one direction of rotation (self-energizing braking) and decreases the braking force in the opposite direction of rotation. The de-acceleration force produced by braking also tends to influence the upright to move or decrease a force so as to control the self-energizing braking action to prevent brake lock-up.
Description
- 10~44~;6 `
BACKGROUND OF THE INVENTION
~ The present invention relates to wheeled devices in general and more, particularly, to a wheeled, dual axle device having a load receiving platform and an axle arrangement which provides a mechanical action for engaging and disengaging a brake mechanism when force or weight is applied to the platform and/or the platform is tilted from a predetermined position.
My co-pending Canadian application, Serial No. 301,209 filed April 17, 1978, discloses a wheeled, dual axle device having an actuator which is operated in response to the application of force or weight to a load receiving platform of the device andjor when the platform in tilted from a predetermined position.
The actuator can be used to engage and disengage a suitable brake mechanism. Two examples of relatively simple brake mechanisms-are disclosed in said application Serial No. 301,209. Although these brake mechanisms are functionally sufficient, they do not provide all of the benefits that accrue from the dual axle configur-ation disclosed in said U.S. patent application. `
It is accordingly a general object of the present invention to provide an improved brake mechanism or dual axle wheeled devices.
It is a specific object of the invention to provide a brake mechanism for dual axle wheeled devices that produces a self-energizing braking action in one direction of wheel rotation and self-negating braking action in the ~ .
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opposite direction of wheel rotation.
~ It is anothèr object of the invention to limit the self-energiæing ; braking action in response to de-acceleration forces to prevent brake lock-up.
It is still another object of the invention to provide a brake mechanism that converts the rotational movement of a load bearing platform to an axial movement parallel to the axis of the wheel bearing axle of the device.
It is a feature of the invention that the brake mechanism can be ~3 . .,., ,~ ,........................... ,: ::
, : .. . ;
` - ~0944~;6 adjusted to control brake engagement as a function of platform tilt.
These objects and other objects and features of the present invention will best be understood from a detailed description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which:
Figures lA through 5A are vlews in side elevation showing the assembly sequence of the brake mechanism and dual axle wheel device of the present invention;
Figures lB through SB are views in rear elevation correspondlng to the - 10 views in Figures lA through 5A, respectively, showing the brake assembly for one of the wheels;
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¦ Figures 6A is an enlarged view of the brake operator, ¦jbrake disc and brake pad showing the brake mechanism in the disengaged position;
,' Figure 6B is a similar view to that of Figure 6A, but Illshowing the brake in the engagcd position;
Figures 7A and 7B are force diagrams illustrating thc energizing aspect of the brake mechanism; and, ¦¦ Figure 8 is a rear view showing the brake mechanism and ~dual axle assembly mounted on a chassis.
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- , ' , DETAILED DESCRIPTION OF A
PREFERRED EMBODIMENT
Turning now to the drawings, specifically to Figures lA through 5A and the corresponding Figures lB through SB, there is shown in side elevation and rear view, respectively, the assembly sequence for producing the wheeled, dual axle device and brake mechanism of the present invention. The wheeled device, indicated generally by the reference numeral 10 in Figures 5A and 5B, has a load receiving platform 12 on which is mounted a truck assembly 14 by means of fasteners 16. The lower portion of the truck assembly 14 has a downwardly depending and rearwardly extending load bearing axle support 18 having an axle receiving, transverse aperture 20. Positioned within a longitudinally extending slot 22 in the truck assembly 14 is a brake adjusting spanner 24 that extends transversely to the longitudinal axis of the truck assembly. The brake adjusting spanner 22 is threaded onto a longitudinally threaded member 26 that is secured to a brake adjusting knob 28. By rotating the adjusting knob 28 in either direction as shown by the arrows in Figure lB the longitudinal portion of the brake adjusting spanner 24 can be varied within slot 22 as indicated by the .
arrows in Figure LA.
- Referring now to Figures 2 and 2B, a pivotally mounted upright assembly ~- indicated generally by the reference numeral 30 has been mounted to the truck ` assembly shown in Figures lA and lB. The upright assembly 30 is pivotally secured to the truck assembly 14 by means of a load bearing axle 32 that is ~; fitted within truck assembly aperture 20 and upright assembly aperture 34. The plvotally mounted assembly 30 comprises a wheel axle 36 having a threaded end ~ portion 37, a male spline portion 38, a round 40 and a g :: ~
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~; ....... . . . . . : : . ~ .
0~466 li '-/shoulder 42 having an anti-friction coating (not shown) thereon.
'IThe round 40 can be of any diameter, but for simplicity of explanation, the round 40 is shown with the same diameter as the .
¦¦outside diameter of the spline portion 38. It can be seen from an ! inspection of Figure 2A that the upright assembly 30 is free to pivot around the axis of the load bearing axle 32 within the limits 'I.shown by the double ended arrow. This freedom of rotational movement for the upright assembly 30 permits the assembly to assume an equilibrium position when a load is placed on the load 'Ibearing axle 32 as explained in detail in my co-pending application Serial No. ~4;,~}
,~ Looking now at Figures 3A and 3B, a brake operator 44 with a slot 46 is mounted over the upri~ht assembly round 40 in contact with the anti-friction coating on thrust shoulder 42 and ~15 !i with slot 46 encompassing spanner 24. The brake operator 44 is l¦free to rotate about the axis of the wheel axle 36 subject to the ¦Iconstraint imposed by the hrake adjusting spanner 22 fltted within ¦jslot 46. The brake operator 44 has a plurality of ramped, hemi-,spherical radial ball tracks 48 within which are placed balls 50.
1'l The balls SO have substantially the same radius as the ramped ¦Ihemi-spherical radlal ball tracks 48. The balls 50 are free to rotate within the ball tracks 48 and the rotation of the ball causes it to roll ~p or climb the track ramp until further rotation is inhibited by the end of the ball track. The amount of I
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1O9L~4~;6 climbing for axial displacement of the ball is a function of the ramped angle of the ball track. The direction and angle of all of ! the ball tracks are substantially the same.
I It was previously mentioned that the operator 44 is free S I to rotate about the axis of the wheel axle 36 within the constrant¦
jimposed by the spanner pin 24. Figure 3A illustrates in dashed ¦¦form the rotation of the operator relative to the axis of the ¦~wheel axle as the upright assembly pivots about the load bearing ~laxle 32. It can be seen that as the upright assembly pivots, llthere is a change in the relationship between a given point on the ¦I~operator and an adjacent point on the spline.
Looking now at Figures 4A and 4B, a brake disc has a ¦brake contact face 56 on one side and on the other side in the . 'preferred embodiment, a corresponding plurality of ramped, he~i-lS Ispherical radial ball tracks 58 of substantially the same format and radial placement as the ball tracks 48 in the brake operator.
¦jHowever, in this case the brake disc ball tracks 58 have ramps ¦,ascending in the opposite direction to the ramps of the ball tracks 148 on the brake operator 44.
¦¦ The brake disc 52 is free to slide axially back and forth on the male spline portion 38 but is not free to rotate about the ¦!jaxis of the wheel axle. Its ramped ball tracks 58 are positioned ith respect to the ball tracks of the brake operator 44 to contain¦
he balls 50 within the hemi-spherical tracks of the two components j ' l -;' I .
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I 10944~;6 For purposes of illustration, both ball tracks 48 and 58 have been generated radially such that the depth of the hemi-spherical ball tracks at the deepest portion is substantially one-half the l¦diameter of the balls 58. Therefore, with the brake operator 44, ¦¦ the balls 50 and the brake disc 52 assemblied as shown in Figures 4A and 4B, it can be seen that with the rotation of the upright ~iassembly 30, the brake operator 44 and brake disc 52 can be ¦irotated in relation to each other to locate the balls S0 in the ¦~deepest portion of each ball track. In this situation, the two o !i components are in substantial face-to-face contact with the ball lying in the deepest portion of each ball track.
j When the brake operator and brake disc are assembled on the pivotally mounted upright assembly shown in Figures 4A and 4B, ¦¦the brake adjustment knob 28 is rotated to move the spanner pin 24 IIThe movement of the spanner pin moves the brake operator ball ¦tracks in relation to the spline fixed brake disc ball tracks.
¦Thus, when the upright assembly with wheels 60 attached (Figures ; j5A and 5B) is placed on a resisting element such as, the ground, (Figure 8) and comes to a equilibrium position, the balls come to ~¦rest in the deepest portion of each track. This position of the balls represents the "rest" or brake disengaged position.
Referring to Figure 6A, it can be seen that with the brake components adjusted as described above, rotation of the ¦upright assembly 30 about the load bearing axle 32 causes relative Imovement bet~een the ball tracks of the brakc operator and brake !l 9.
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¦disc. As these two brake components move in opposite directions, !! the opposing ramped hemi-spherical ball tracks made contact with ¦¦the ball which begins to rotate and ascend the two ramps thereby ¦llcausing axial expansion of the two brake components as depicted S Ilin Figure 6B. Since the movement of the brake operator 44 is limited by thrust shoulder 42, the brake disc 52 is forced outward: Ly and axially to the left as viewed in Figures 4B and 6B. The out-¦ward position of the brake disc 52 in the braking position is 'lindicated by the dashed lines in Figure 4B.
il After mounting the brake disc 52, the wheel 60 and ,!associated components are fitted onto the wheel axle 36, as ~¦illustrated in Figures 5A and 5B. The wheel 60 has secured ¦Ithereto a wheel hub 62 to which is affixed an annular brake pad 64 ¦as best seen in Figures 5A-SB, 6A-6B and 8. The wheel itself is 15 ` ¦¦ rotatably mounted on the axle 36 by means of one or more press-¦fitted ball bearing assemblies 66. Finally, a locking nut 68 is thxeaded onto the threaded end portion 37 of the wheel axle.
¦ Referring to Figure 5B, it will be understood that the locking nut 68 prevents the wheel 60 from moving axially to the ¦lleft as viewed in the Figure. Thus, when the brake disc 56 ., expands axially outward to the left, it frictionally engages the wheel brake pad 64. ~his position is depicted in Figure 5B by the . dashed lined brake disc 56.
. 1I With the brake disc and brake pad frictionally engaged 1III 10.
,l 1094~66 il jlas shown in Figure 6B, the pad will rotate with the wheel in a counter-clockwise direction as the wheeled device rolls in a forwardly direction (to the left as viewed in Figures 1-7). ~he ,¦frictional engagement tends to force the splined brake disc also il in a counter-clockwise direction. This tendancy creates a torque around the axis of the wheel axle in the forwardly direction. The effect of this torque is to cause the upright assembly to pivot about the load bearing axle in the forwardly (counter-clockwise) lldirection i.e. the direction of increased braking (brake operator-llbrake disc axial expansion). Any additional counter clockwise movement of the brake disc will cause the balls to further ascend Ithe ball track lamps. This in turn further increases the braking ¦force exerted by the brake disc against the brake pad.
In a non-pivotally mounted upright design, the self-lenergizing braking action would soon result in a runaway self-servoing in which the brake disc and brake operator wedged them-selves between the thrust shoulder and the brake pad thereby lockilg the wheel. Skidding and locked wheels are undesirable in almost jlall applications. For the roller skate and skate board embodiment ~20 ¦lof the dual axle wheel, device, such brake lock-up is decidedly Illunsafe.
¦i However, in the present invention in which the upright assembly 30 is pivotally mounted with respect to the load receivinc platform or chassis 12, when the brake mechanism approaches this Idcgree of self-energization, the resultant braking force causes 11 ~
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" ` 109~466 significant de-acceleration which produces a de-acceleration force on the wheel axis in a rearwardly (clockwise) direction. The de-acceleration force in the rearwardly direction tends to rotate the upright assembly about the load bearing axle in a rearwardly (clockwise) brake disengaging direction. It will be appreciated that equilibrium will be reached when the self-energizing forces influencing the upright assembly into a brake engaged position create enough de-acceleration forces to negate further self-energization of the brake.
This substantially balanced condition is represented illustratively in the force diagrams of Figures 7A and 7B. Figure 7A shows the forces exerted on the load receiying platform or chassis 12, the rotational force of the wheel and the forwardmomentum of the chassis and truck assembly. In Figure 7B, the chassis 12 has been tilted in a rearward direction with a change in the downward force on the portion of the chassis located to the rear of the wheel axle axis. The upright assembly tends to remain in an upright i.e. equilibrium position despite the tilting of the chassis. The chassis tilting rotates the operator 44 through the rearward movement of the spanner pin 24. This rotation causes the balls 50 to ascend the ball track ramps thereby forcing the brake disc outwardly against the brake pad. At this point, there is no further relative rotation of the brake operator and the brake disc. Further tilting of the chassis forces the upright off of the vertical :....... ,. , i ,. , ~ .,.. , , . . , :
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¦or equilibrium position thereby creatin~ a restoring force as ! explained in detail in my previously mentioncd co-pending application Serial No. 7-~7,97~.
I¦ The counter-clockwise direction of the wheel rotation ,Iwhen the device 10 is going in a forwardly direction (to the left ¦las viewed in Figures) produces a self-energizing braking force as ijindicated by the solid counter-clockwise arrow in Figure 7B. As iexplained above, when sufficient de-acceleration forces are ¦produced, the upright assembly tends to move in a clockwise or Irearward direction as indicated by the dashed arrow in Fig~rc 7B.
¦ The preceding discussion has been directed to the ¦¦operation of the upright assembly and brake mechanism when the I ¦Iwheels 60 are rolling in a forward direction. If the wheels roll ¦¦in a backwardly direction (to the right as viewed in Figures 1-7) ~15 j¦the operation of the components is reversed, i.e. the clockwise ~ ~ Irotation of the brake pad drives the upright assembly 30 in a I ~ ¦rearwardly or brake disengaged direction. Thus, if the truck ¦assembly, upright assembly and brake mechanism are mounted on a skateboard, the rider can do 360 turns with one wheel essentially ¦locked in the brake ON position while the other wheel is free to rotate because it is rolling in the reverse direction.
I ¦ In addition to this feature, the present invention can b~
used with steerable trucks~ For purposes of simplicity a non-- Isteerable truck has been depicted in the drawings. However, it should be understood that conventional steerable trucks SUCil as I ~ O~ ~n~lc Ithe truck sold under the tradcna~ "Tracker".
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¦I Figure 8 illustrates a modification of the wheeled, and axle device 10 in which brake disc cooling fins 66 have been ladded to the brake disc 52. It can be seen from an inspection ¦of the cut-away portion of wheel 60 in Figure 8 that the brake Ihub 62 is exposed to cooling air between the hub and the wheel itself. This feature in conjunction with the coollng fins and the "heat sink" operation of the brake disc 52 maintain brake 'temperature within accepteable limits.
ll In addition to the cooling fins, Figure 8 illustrates a ;disc stop, detent adjustment for the brake spanner pin adusting ¦knob 28. $he knob rotates opposite a series of detent 68 and has ai mating projection 70 that engages the detent in a well known mannerl.
Having described in detail a preferred embodiment of my llinvention it will now be apparent to those skilled in the art that ¦!numerous modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
14.
BACKGROUND OF THE INVENTION
~ The present invention relates to wheeled devices in general and more, particularly, to a wheeled, dual axle device having a load receiving platform and an axle arrangement which provides a mechanical action for engaging and disengaging a brake mechanism when force or weight is applied to the platform and/or the platform is tilted from a predetermined position.
My co-pending Canadian application, Serial No. 301,209 filed April 17, 1978, discloses a wheeled, dual axle device having an actuator which is operated in response to the application of force or weight to a load receiving platform of the device andjor when the platform in tilted from a predetermined position.
The actuator can be used to engage and disengage a suitable brake mechanism. Two examples of relatively simple brake mechanisms-are disclosed in said application Serial No. 301,209. Although these brake mechanisms are functionally sufficient, they do not provide all of the benefits that accrue from the dual axle configur-ation disclosed in said U.S. patent application. `
It is accordingly a general object of the present invention to provide an improved brake mechanism or dual axle wheeled devices.
It is a specific object of the invention to provide a brake mechanism for dual axle wheeled devices that produces a self-energizing braking action in one direction of wheel rotation and self-negating braking action in the ~ .
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opposite direction of wheel rotation.
~ It is anothèr object of the invention to limit the self-energiæing ; braking action in response to de-acceleration forces to prevent brake lock-up.
It is still another object of the invention to provide a brake mechanism that converts the rotational movement of a load bearing platform to an axial movement parallel to the axis of the wheel bearing axle of the device.
It is a feature of the invention that the brake mechanism can be ~3 . .,., ,~ ,........................... ,: ::
, : .. . ;
` - ~0944~;6 adjusted to control brake engagement as a function of platform tilt.
These objects and other objects and features of the present invention will best be understood from a detailed description of a preferred embodiment thereof, selected for purposes of illustration and shown in the accompanying drawings, in which:
Figures lA through 5A are vlews in side elevation showing the assembly sequence of the brake mechanism and dual axle wheel device of the present invention;
Figures lB through SB are views in rear elevation correspondlng to the - 10 views in Figures lA through 5A, respectively, showing the brake assembly for one of the wheels;
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¦ Figures 6A is an enlarged view of the brake operator, ¦jbrake disc and brake pad showing the brake mechanism in the disengaged position;
,' Figure 6B is a similar view to that of Figure 6A, but Illshowing the brake in the engagcd position;
Figures 7A and 7B are force diagrams illustrating thc energizing aspect of the brake mechanism; and, ¦¦ Figure 8 is a rear view showing the brake mechanism and ~dual axle assembly mounted on a chassis.
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- , ' , DETAILED DESCRIPTION OF A
PREFERRED EMBODIMENT
Turning now to the drawings, specifically to Figures lA through 5A and the corresponding Figures lB through SB, there is shown in side elevation and rear view, respectively, the assembly sequence for producing the wheeled, dual axle device and brake mechanism of the present invention. The wheeled device, indicated generally by the reference numeral 10 in Figures 5A and 5B, has a load receiving platform 12 on which is mounted a truck assembly 14 by means of fasteners 16. The lower portion of the truck assembly 14 has a downwardly depending and rearwardly extending load bearing axle support 18 having an axle receiving, transverse aperture 20. Positioned within a longitudinally extending slot 22 in the truck assembly 14 is a brake adjusting spanner 24 that extends transversely to the longitudinal axis of the truck assembly. The brake adjusting spanner 22 is threaded onto a longitudinally threaded member 26 that is secured to a brake adjusting knob 28. By rotating the adjusting knob 28 in either direction as shown by the arrows in Figure lB the longitudinal portion of the brake adjusting spanner 24 can be varied within slot 22 as indicated by the .
arrows in Figure LA.
- Referring now to Figures 2 and 2B, a pivotally mounted upright assembly ~- indicated generally by the reference numeral 30 has been mounted to the truck ` assembly shown in Figures lA and lB. The upright assembly 30 is pivotally secured to the truck assembly 14 by means of a load bearing axle 32 that is ~; fitted within truck assembly aperture 20 and upright assembly aperture 34. The plvotally mounted assembly 30 comprises a wheel axle 36 having a threaded end ~ portion 37, a male spline portion 38, a round 40 and a g :: ~
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~; ....... . . . . . : : . ~ .
0~466 li '-/shoulder 42 having an anti-friction coating (not shown) thereon.
'IThe round 40 can be of any diameter, but for simplicity of explanation, the round 40 is shown with the same diameter as the .
¦¦outside diameter of the spline portion 38. It can be seen from an ! inspection of Figure 2A that the upright assembly 30 is free to pivot around the axis of the load bearing axle 32 within the limits 'I.shown by the double ended arrow. This freedom of rotational movement for the upright assembly 30 permits the assembly to assume an equilibrium position when a load is placed on the load 'Ibearing axle 32 as explained in detail in my co-pending application Serial No. ~4;,~}
,~ Looking now at Figures 3A and 3B, a brake operator 44 with a slot 46 is mounted over the upri~ht assembly round 40 in contact with the anti-friction coating on thrust shoulder 42 and ~15 !i with slot 46 encompassing spanner 24. The brake operator 44 is l¦free to rotate about the axis of the wheel axle 36 subject to the ¦Iconstraint imposed by the hrake adjusting spanner 22 fltted within ¦jslot 46. The brake operator 44 has a plurality of ramped, hemi-,spherical radial ball tracks 48 within which are placed balls 50.
1'l The balls SO have substantially the same radius as the ramped ¦Ihemi-spherical radlal ball tracks 48. The balls 50 are free to rotate within the ball tracks 48 and the rotation of the ball causes it to roll ~p or climb the track ramp until further rotation is inhibited by the end of the ball track. The amount of I
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1O9L~4~;6 climbing for axial displacement of the ball is a function of the ramped angle of the ball track. The direction and angle of all of ! the ball tracks are substantially the same.
I It was previously mentioned that the operator 44 is free S I to rotate about the axis of the wheel axle 36 within the constrant¦
jimposed by the spanner pin 24. Figure 3A illustrates in dashed ¦¦form the rotation of the operator relative to the axis of the ¦~wheel axle as the upright assembly pivots about the load bearing ~laxle 32. It can be seen that as the upright assembly pivots, llthere is a change in the relationship between a given point on the ¦I~operator and an adjacent point on the spline.
Looking now at Figures 4A and 4B, a brake disc has a ¦brake contact face 56 on one side and on the other side in the . 'preferred embodiment, a corresponding plurality of ramped, he~i-lS Ispherical radial ball tracks 58 of substantially the same format and radial placement as the ball tracks 48 in the brake operator.
¦jHowever, in this case the brake disc ball tracks 58 have ramps ¦,ascending in the opposite direction to the ramps of the ball tracks 148 on the brake operator 44.
¦¦ The brake disc 52 is free to slide axially back and forth on the male spline portion 38 but is not free to rotate about the ¦!jaxis of the wheel axle. Its ramped ball tracks 58 are positioned ith respect to the ball tracks of the brake operator 44 to contain¦
he balls 50 within the hemi-spherical tracks of the two components j ' l -;' I .
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I 10944~;6 For purposes of illustration, both ball tracks 48 and 58 have been generated radially such that the depth of the hemi-spherical ball tracks at the deepest portion is substantially one-half the l¦diameter of the balls 58. Therefore, with the brake operator 44, ¦¦ the balls 50 and the brake disc 52 assemblied as shown in Figures 4A and 4B, it can be seen that with the rotation of the upright ~iassembly 30, the brake operator 44 and brake disc 52 can be ¦irotated in relation to each other to locate the balls S0 in the ¦~deepest portion of each ball track. In this situation, the two o !i components are in substantial face-to-face contact with the ball lying in the deepest portion of each ball track.
j When the brake operator and brake disc are assembled on the pivotally mounted upright assembly shown in Figures 4A and 4B, ¦¦the brake adjustment knob 28 is rotated to move the spanner pin 24 IIThe movement of the spanner pin moves the brake operator ball ¦tracks in relation to the spline fixed brake disc ball tracks.
¦Thus, when the upright assembly with wheels 60 attached (Figures ; j5A and 5B) is placed on a resisting element such as, the ground, (Figure 8) and comes to a equilibrium position, the balls come to ~¦rest in the deepest portion of each track. This position of the balls represents the "rest" or brake disengaged position.
Referring to Figure 6A, it can be seen that with the brake components adjusted as described above, rotation of the ¦upright assembly 30 about the load bearing axle 32 causes relative Imovement bet~een the ball tracks of the brakc operator and brake !l 9.
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¦disc. As these two brake components move in opposite directions, !! the opposing ramped hemi-spherical ball tracks made contact with ¦¦the ball which begins to rotate and ascend the two ramps thereby ¦llcausing axial expansion of the two brake components as depicted S Ilin Figure 6B. Since the movement of the brake operator 44 is limited by thrust shoulder 42, the brake disc 52 is forced outward: Ly and axially to the left as viewed in Figures 4B and 6B. The out-¦ward position of the brake disc 52 in the braking position is 'lindicated by the dashed lines in Figure 4B.
il After mounting the brake disc 52, the wheel 60 and ,!associated components are fitted onto the wheel axle 36, as ~¦illustrated in Figures 5A and 5B. The wheel 60 has secured ¦Ithereto a wheel hub 62 to which is affixed an annular brake pad 64 ¦as best seen in Figures 5A-SB, 6A-6B and 8. The wheel itself is 15 ` ¦¦ rotatably mounted on the axle 36 by means of one or more press-¦fitted ball bearing assemblies 66. Finally, a locking nut 68 is thxeaded onto the threaded end portion 37 of the wheel axle.
¦ Referring to Figure 5B, it will be understood that the locking nut 68 prevents the wheel 60 from moving axially to the ¦lleft as viewed in the Figure. Thus, when the brake disc 56 ., expands axially outward to the left, it frictionally engages the wheel brake pad 64. ~his position is depicted in Figure 5B by the . dashed lined brake disc 56.
. 1I With the brake disc and brake pad frictionally engaged 1III 10.
,l 1094~66 il jlas shown in Figure 6B, the pad will rotate with the wheel in a counter-clockwise direction as the wheeled device rolls in a forwardly direction (to the left as viewed in Figures 1-7). ~he ,¦frictional engagement tends to force the splined brake disc also il in a counter-clockwise direction. This tendancy creates a torque around the axis of the wheel axle in the forwardly direction. The effect of this torque is to cause the upright assembly to pivot about the load bearing axle in the forwardly (counter-clockwise) lldirection i.e. the direction of increased braking (brake operator-llbrake disc axial expansion). Any additional counter clockwise movement of the brake disc will cause the balls to further ascend Ithe ball track lamps. This in turn further increases the braking ¦force exerted by the brake disc against the brake pad.
In a non-pivotally mounted upright design, the self-lenergizing braking action would soon result in a runaway self-servoing in which the brake disc and brake operator wedged them-selves between the thrust shoulder and the brake pad thereby lockilg the wheel. Skidding and locked wheels are undesirable in almost jlall applications. For the roller skate and skate board embodiment ~20 ¦lof the dual axle wheel, device, such brake lock-up is decidedly Illunsafe.
¦i However, in the present invention in which the upright assembly 30 is pivotally mounted with respect to the load receivinc platform or chassis 12, when the brake mechanism approaches this Idcgree of self-energization, the resultant braking force causes 11 ~
Il` . I
. Il I
j ' 11. I
" ` 109~466 significant de-acceleration which produces a de-acceleration force on the wheel axis in a rearwardly (clockwise) direction. The de-acceleration force in the rearwardly direction tends to rotate the upright assembly about the load bearing axle in a rearwardly (clockwise) brake disengaging direction. It will be appreciated that equilibrium will be reached when the self-energizing forces influencing the upright assembly into a brake engaged position create enough de-acceleration forces to negate further self-energization of the brake.
This substantially balanced condition is represented illustratively in the force diagrams of Figures 7A and 7B. Figure 7A shows the forces exerted on the load receiying platform or chassis 12, the rotational force of the wheel and the forwardmomentum of the chassis and truck assembly. In Figure 7B, the chassis 12 has been tilted in a rearward direction with a change in the downward force on the portion of the chassis located to the rear of the wheel axle axis. The upright assembly tends to remain in an upright i.e. equilibrium position despite the tilting of the chassis. The chassis tilting rotates the operator 44 through the rearward movement of the spanner pin 24. This rotation causes the balls 50 to ascend the ball track ramps thereby forcing the brake disc outwardly against the brake pad. At this point, there is no further relative rotation of the brake operator and the brake disc. Further tilting of the chassis forces the upright off of the vertical :....... ,. , i ,. , ~ .,.. , , . . , :
. .
., . ~ . : , ~ : : ~ :: :
:,: : ' ~
:
11 l 1l 109~66 Il'l .
¦or equilibrium position thereby creatin~ a restoring force as ! explained in detail in my previously mentioncd co-pending application Serial No. 7-~7,97~.
I¦ The counter-clockwise direction of the wheel rotation ,Iwhen the device 10 is going in a forwardly direction (to the left ¦las viewed in Figures) produces a self-energizing braking force as ijindicated by the solid counter-clockwise arrow in Figure 7B. As iexplained above, when sufficient de-acceleration forces are ¦produced, the upright assembly tends to move in a clockwise or Irearward direction as indicated by the dashed arrow in Fig~rc 7B.
¦ The preceding discussion has been directed to the ¦¦operation of the upright assembly and brake mechanism when the I ¦Iwheels 60 are rolling in a forward direction. If the wheels roll ¦¦in a backwardly direction (to the right as viewed in Figures 1-7) ~15 j¦the operation of the components is reversed, i.e. the clockwise ~ ~ Irotation of the brake pad drives the upright assembly 30 in a I ~ ¦rearwardly or brake disengaged direction. Thus, if the truck ¦assembly, upright assembly and brake mechanism are mounted on a skateboard, the rider can do 360 turns with one wheel essentially ¦locked in the brake ON position while the other wheel is free to rotate because it is rolling in the reverse direction.
I ¦ In addition to this feature, the present invention can b~
used with steerable trucks~ For purposes of simplicity a non-- Isteerable truck has been depicted in the drawings. However, it should be understood that conventional steerable trucks SUCil as I ~ O~ ~n~lc Ithe truck sold under the tradcna~ "Tracker".
i Il .
11 13.
Ii . .
¦I Figure 8 illustrates a modification of the wheeled, and axle device 10 in which brake disc cooling fins 66 have been ladded to the brake disc 52. It can be seen from an inspection ¦of the cut-away portion of wheel 60 in Figure 8 that the brake Ihub 62 is exposed to cooling air between the hub and the wheel itself. This feature in conjunction with the coollng fins and the "heat sink" operation of the brake disc 52 maintain brake 'temperature within accepteable limits.
ll In addition to the cooling fins, Figure 8 illustrates a ;disc stop, detent adjustment for the brake spanner pin adusting ¦knob 28. $he knob rotates opposite a series of detent 68 and has ai mating projection 70 that engages the detent in a well known mannerl.
Having described in detail a preferred embodiment of my llinvention it will now be apparent to those skilled in the art that ¦!numerous modifications can be made therein without departing from the scope of the invention as defined in the appended claims.
14.
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A wheel braking apparatus comprising:
(1) a load receiving means;
(2) an upright mcans pivotally mounted with respect to said load receiving means, said upright means including (i) a wheel axle means for rotatably mounting a wheel at one end thereof and (ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof; and, (3) means responsive to the rotational movement of said load receiving means with respect to said upright means for axially moving said wheel braking means along the wheel axle means toward the wheel mounting end thereof to brake the wheel.
15.
Serial No. 797,337
(1) a load receiving means;
(2) an upright mcans pivotally mounted with respect to said load receiving means, said upright means including (i) a wheel axle means for rotatably mounting a wheel at one end thereof and (ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof; and, (3) means responsive to the rotational movement of said load receiving means with respect to said upright means for axially moving said wheel braking means along the wheel axle means toward the wheel mounting end thereof to brake the wheel.
15.
Serial No. 797,337
2. A wheel braking apparatus comprising:
(1) a load receiving means;
(2) an upright means pivotally mounted with respect to said load receiving means, said upright means including:
(i) a wheel axle means for rotatably mounting a wheel at one end thereof;
(ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof (iii) brake operator means rotatable mounted on said wheel axle means (iv) means for translating rotational movement of the brake operator means into axial movem?
of said wheel braking means along the axis of the wheel axis means;
(3) means for rotating said brake operator means in response to the rotation of the load receiving means with respect to the upright means to move said wheel braking means axially to brake the wheel.
16.
(1) a load receiving means;
(2) an upright means pivotally mounted with respect to said load receiving means, said upright means including:
(i) a wheel axle means for rotatably mounting a wheel at one end thereof;
(ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof (iii) brake operator means rotatable mounted on said wheel axle means (iv) means for translating rotational movement of the brake operator means into axial movem?
of said wheel braking means along the axis of the wheel axis means;
(3) means for rotating said brake operator means in response to the rotation of the load receiving means with respect to the upright means to move said wheel braking means axially to brake the wheel.
16.
3. The apparatus of Claim 2 wherein said means for translating rotational movement of the brake operator means into axial movement of the wheel brake means comprises a ramp located on one of said means and a ramp follower located on the other of said means.
4. The apparatus of Claim 3 wherein said ramp comprise hemi-spherical ball track and wherein said ramp follower comprise a ball located in said ball track.
5. The apparatus of Claim 2 further comprising means for preventing axial movement of said brake operator means in at least one direction along the axis of said wheel axle means.
6. The apparatus of Claim 2 further comprising a wheel mounted on said wheel axle means and means for preventing axial movement of said wheel along said wheel axle means.
7. The apparatus of Claim 2 further comprising means for preventing said wheel braking means from rotating about the axis of said wheel axle means.
8. The apparatus of Claim 7 wherein said wheel axle means includes a spline portion and said wheel braking means rotation preventing means comprises a mating spline portion.
17.
17.
9. A wheeled braking apparatus comprising:
(1) a load receiving means;
(2) an upright means pivotally mounted with respect to said load receiving means, said upright means including:
(i) a wheel axle means for rotatably mounting a wheel at one end thereof;
(ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof;
(iii) brake operator means rotatable mounted on said wheel axle means (iv) means for preventing axial movement of said brake operator means in at least one direction along the axis of said wheel axle means;
(v) means for translating rotational movement of the brake operator means into axial movement of said wheel braking means along the axis of the wheel axis means;
18.
(3) a wheel rotatably mounted on said wheel axle means;
(4) means for preventing the axial movement of said wheel along the axis of said wheel axle means; and, (5) means for rotating said brake operator means in response to the rotation of the load receiving means with respect to the upright means to move said wheel braking means axially to brake the wheel.
19.
(1) a load receiving means;
(2) an upright means pivotally mounted with respect to said load receiving means, said upright means including:
(i) a wheel axle means for rotatably mounting a wheel at one end thereof;
(ii) wheel braking means mounted on said wheel axle means for movement along the axis thereof;
(iii) brake operator means rotatable mounted on said wheel axle means (iv) means for preventing axial movement of said brake operator means in at least one direction along the axis of said wheel axle means;
(v) means for translating rotational movement of the brake operator means into axial movement of said wheel braking means along the axis of the wheel axis means;
18.
(3) a wheel rotatably mounted on said wheel axle means;
(4) means for preventing the axial movement of said wheel along the axis of said wheel axle means; and, (5) means for rotating said brake operator means in response to the rotation of the load receiving means with respect to the upright means to move said wheel braking means axially to brake the wheel.
19.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US79733777A | 1977-05-16 | 1977-05-16 | |
| US797,337 | 1985-11-12 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1094466A true CA1094466A (en) | 1981-01-27 |
Family
ID=25170557
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA303,182A Expired CA1094466A (en) | 1977-05-16 | 1978-05-12 | Wheeled, dual axle device having an axially movable brake |
Country Status (4)
| Country | Link |
|---|---|
| JP (1) | JPS5416070A (en) |
| CA (1) | CA1094466A (en) |
| DE (1) | DE2820935A1 (en) |
| FR (1) | FR2391396A1 (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| NL9400865A (en) * | 1994-05-26 | 1996-01-02 | Ligtvoet Products Bv | Hub brake and axle assembly including such a hub brake. |
| DE29505464U1 (en) * | 1995-04-06 | 1996-07-04 | Boisch, Richard, Prof. Dr., 26723 Emden | Brake device for roller skates |
-
1978
- 1978-05-12 DE DE19782820935 patent/DE2820935A1/en not_active Withdrawn
- 1978-05-12 CA CA303,182A patent/CA1094466A/en not_active Expired
- 1978-05-12 FR FR7814282A patent/FR2391396A1/en not_active Withdrawn
- 1978-05-15 JP JP5748178A patent/JPS5416070A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5416070A (en) | 1979-02-06 |
| DE2820935A1 (en) | 1978-12-07 |
| FR2391396A1 (en) | 1978-12-15 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |