WO2000006416A1

WO2000006416A1 - Wheelchair auxiliary device

Info

Publication number: WO2000006416A1
Application number: PCT/US1999/016912
Authority: WO
Inventors: Marion E. Esposito
Original assignee: Sanders, Daniel, C.
Priority date: 1998-07-27
Filing date: 1999-07-27
Publication date: 2000-02-10

Abstract

The device (1) is used to transport a wheelchair over difficult terrain such as sand, mud, snow, gravel, and shallow water. The device (1) includes balloon-type tires (17-20), an engageable brake (23, 25), a releasable wheelchair securing means (8), and a stowable ramp (21) for loading the wheelchair.

Description

WHEELCHAIR AUXILIARY DEVICE Background of the Invention

The invention relates to wheelchair auxiliary devices used to transport persons, particularly handicapped persons, in their wheelchairs across terrain, particularly rough or difficult terrain, such as sand, gravel, snow or shallow water.

Wheelchairs in use at the present time are generally adapted for use on smooth surfaces such as tile, concrete, wood, asphalt and the like, found both indoors and outdoors. These wheelchairs have been either difficult or impossible to operate over such rough or difficult terrain as sand, gravel, snow or shallow water. U.S. Patent No. 5,634,650 describes an approach to solving this problem, involving a recreational wheelchair with oversized tires. This solution, however, requires the wheelchair user to move, or be moved, from the occupant's regular wheelchair to the recreational wheelchair. This is often inconvenient in practice. The occupant's regular use wheelchair must then be left behind as the recreational wheelchair is used. Another approach is taken by U.S. Patent No. 5,427,398, in which soft terrain wheel adapters are attached to the wheels of a regular wheelchair. Yet another example is provided by U.S. Patent No. 5,312,127, in which a self-propelling mechanism including a front drive wheel and rails is installed into a regular wheelchair, allowing the wheelchair user to move across terrain via a reciprocating motion of the arms. This device is not useful for wheelchair occupants who do not have the use of their arms. U.S. Patent No. 4,902,027 describes a dolly for wheeled devices. Wheelchairs could be lifted onto the dolly. This is often difficult or impossible if the wheeled device is loaded with a person. U.S. Patent No. 4,898,508 describes a low slung small self-propelled vehicle, which can be used to transport a wheelchair.

Summary of the Invention The invention provides a wheelchair auxiliary device which is used to transport persons, typically handicapped persons, in their regular wheelchairs, across difficult or rough terrain such as sand, gravel, snow or shallow water. The device comprises a non-motorized cart meant to be pushed or pulled by a force external to the device, for example by a second person. The device is equipped with a stowable ramp, to allow a wheelchair together with its occupant to be easily loaded onto the device. The device is also equipped with a means for securing a wheelchair (or other wheeled vehicle) to the device. The device is also equipped with an engagable brake, to ensure that the device does not roll down a slope unattended, or otherwise move when such motion is undesirable. The device is also equipped with steerable wheel assemblies, allowing the device to be easily maneuvered in tight spaces. The device provides high stability, good visibility for the occupant, good ground clearance, and ease of use, including pushing, loading, and maneuvering.

The invention provides a wheelchair auxiliary device for transporting a wheelchair (with or without its occupant) over difficult terrain. The device is meant to be propelled by a second person, who is not the wheelchair occupant . The device includes a planar horizontal wheelchair support which supports the wheels of a wheelchair, and which allows the wheelchair to be rolled into a securable position and removed from the securable position. The wheelchair support can be a planar surface with lateral edges, some of the edges having walls. The wheelchair support can also take the form of a pair of parallel mounted rails with side walls. The device also includes front and rear wheel assemblies, each wheel assembly including at least one freely rotatable wheel, an axle, and balloon tire. The wheel assemblies are supported by, and mounted onto, first and optionally second wheel assembly supports. In some embodiments, two of the wheel assemblies are made to be steerable wheel assemblies.

The device further includes at least one engagable brake which prevents the wheels from moving when engaged. This brake can take the form of a rod which interacts with the spokes of at least one of the wheels.

The device further includes a means for securing the wheelchair to the device, and can take the form of a rod which simultaneously passes through a part of the device and the spokes of the wheelchair wheel. If the wheelchair wheel lacks spokes, the means for securing the wheelchair can take the form of an adjustable strap which simultanteously passes through a part of the device and the frame of the wheelchair. The device further includes a stowable ramp for loading and unloading the wheelchair. The ramp attaches to the edge of the wheelchair support surface. The ramp is stowable on the device.

As used herein, the term "wheel assembly" refers to the part of the device, or a wheelchair to be transported by the device, which allows the device to be moved. Depending on the selected design, the wheel assembly can comprise a wheel, a tire and an axle passing through or partially through the wheel; a belt-shaped tread with associated wheels; or a wheel, tire, axle, forked member, shaft, head tube and capping member. A wheelchair wheel assembly generally includes the wheel, tire, spokes of the wheel and any associated parts of the wheel, for instance a circular hand grip. As used herein, the term "driver" refers to anyone or anything which is able to apply a force enabling the device of the invention to move. As used herein, the term "driving direction" refers to the direction in which the device is moved. The devices of the invention have a preferred front end and a preferred rear end. When viewed from the rear end of the device, "left" and "right", respectively, are determined in relation to a vertical plane defined by the points equidistant from the front or rear wheel assemblies. In devices of the invention, these planes will coincide. This convention applies as well to wheelchairs, which are used with the device of the invention.

The wheelchair auxiliary device of the invention has several advantages over prior art devices. The device can travel easily over sand, snow, mud, gravel, shallow water and other difficult terrain. The steerable wheels allow easy maneuverability, including turning the device in an extremely tight space. In preferred embodiments, the wheelchair can be turned on its axis (the vertical axis passing through the center of the device) .

The device of the invention can be loaded and unloaded easily by one person using the ramp, and the ramp can be stored on the device to be transported with the device to desired destinations. This means that the wheelchair to be loaded does not need to be hoisted onto the device, or the wheelchair occupant be displaced from the wheelchair for loading purposes, as would be required by certain prior art devices.

The device can be braked, preventing the device from moving when on a slope, in windy conditions, or in any other situation in which movement of the device is not desired.

The device provides means of securing a wheelchair to prevent substantial movement of the wheelchair with respect to the framework of the device, providing enhanced stability for the device and enhanced security for the wheelchair occupant .

The method of transporting occupied or unoccupied wheelchairs provided by the invention also has distinct advantages over methods offered by prior art devices. The method does not require placing the wheelchair occupant into a new device.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention, suitable methods and materials are described below. All publications, patent applications, patents, and other references mentioned herein are incorporated in their entirety. In case of conflict, the present specification, including definitions, will control. In addition, the materials, methods and examples are illustrative only and not intended to be limiting.

Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.

Brief Description of the Drawings Fig. 1 is a perspective view of the relevant parts of a wheelchair mounted on the wheelchair auxiliary device of the present invention.

Fig. 2 is a closeup view of a particular embodiment of the engagable brake for use in a particular embodiment of the present invention.

Fig. 3 is a close up view of a particular embodiment of the releasable securing means for use in a particular embodiment of the present invention. Fig. 4 is a close up view of a particular embodiment of a steerable wheel assembly for use in a particular embodiment of the present invention.

Fig. 5 is a close up view of a particular embodiment of a stowable ramp for use in a particular embodiment of the present invention.

Fig. 6 is an overhead view of a particular embodiment of the device, showing how the stowable ramp can be stowed on the device. Fig. 7 is a side perspective view of a particular embodiment of a wheel support with an engagable brake.

Detailed Description An embodiment of the device of the invention is shown in Fig. 1. Device 1 includes right rail 2 having upwardly extending wall 3 at the outside lateral edge of right rail 2 and upwardly extending wall 4 at the inside lateral edge of right rail 2, and left rail 5 having upwardly extending wall 6 at the inside lateral edge of left rail 5 and upwardly extending wall 7 at the outside lateral edge of left rail 5. Each rail supports a rear wheel A and front wheel B of a wheelchair (entire wheelchair not shown) . The wheels A and B are secured to the rails by pins 8 which are inserted through holes 9 in the upwardly extending walls 3, 4, 6 and 7. The pins pass through spaces E and F between spokes C and D in wheels A and B, respectively. The rails are attached to front "C" -shaped cross member 10 and rear "C" -shaped cross member 11. Front "C" -shaped cross member 10 supports left front axle 12 and right front axle (not shown) . Rear "C" -shaped cross member 11 supports left rear axle 13 and right rear axle (not shown) . Mounted on the axles are left front wheel 14, left rear wheel 15, right front wheel 16, and right rear wheel (not shown) . Mounted on the wheels are left front tire 17, left rear tire 18, right front tire 19, and right rear tire 20. Forming part of the rails are ramp rails 21 with upwardly extending walls 22. Right brake rod 23, engagable by operating right brake rod handle 24, and left brake rod 25, engagable by operating left brake rod handle 26 are mounted on front "C" -shaped cross member 10. In other embodiments, the brake rods are mounted on the rear "C"- shaped cross member 11.

Wheelchair support

The auxiliary wheelchair device includes a wheelchair support, which is sized to allow all of the wheelchair wheel assemblies to find support on it. As a minimum, the dimensions of the wheelchair support are such that each of the points at which the wheelchair contacts the ground (for example, the wheels) , contacts the wheelchair support. Preferably, associated parts of the wheel are also within the dimensions of the wheelchair support. For example, the wheelchair support will preferably be wider than the distance between any circular handgrips which can be present on some wheelchairs. Preferably, it is wide enough to provide stability to the device and security to the wheelchair occupant, while minimizing bulk and weight and maximizing maneuverability. It is as least as long as the distance between the front and rear wheels of the wheelchair. Preferably, it is long enough to provide stability to the device and security to the wheelchair occupant while minimizing bulk and weight and maximizing maneuverability.

This wheelchair support can have any of numerous different configurations. Preferably, the wheelchair support provides a horizontally planar surface supporting all the wheels of the wheelchair. The substantially planar surface can have a regular or irregular shape. Preferred embodiments are rectilinear. If the wheelchair support surface is a square or rectangle, the device is configured so that two opposing edges are parallel to the direction of travel of the device (lateral edges) , and two opposing edges are perpendicular to the direction of travel of the device (leading and trailing edges) . If the wheelchair support is a single surface, the wheelchair support surface is between about 25 and 45 inches wide, preferably between about 28 and 40 inches wide. The wheelchair support surface is between about 28 and 50 inches long, preferably between about 32 and 40 inches long.

The wheelchair support surface need not be continuous. For economy of material and/or reduction in weight, portions of the planar surface can be omitted, as long as the wheelchair can be placed in a supported position on the wheelchair support, the strength of the remaining support surface is sufficient to support the wheelchair, and the wheels of the wheelchair can be rolled into position. Further, portions of the wheelchair support which do come into contact with the wheels can be partially omitted, in a mesh or grate pattern, for example. However, any interruption, omission, or discontinuity of wheelchair support material which substantially compromises functions of the wheelchair support such as strength or ability to be loaded, is to be avoided.

The device includes wheelchair lateral support members, which provide lateral security to the wheelchair and, preferably, loading guides. These support members can contribute to the structural strength of the device. When the wheelchair support takes the form of a substantially planar surface of rectilinear form, lateral support members may comprise at least two walls extending upwardly from the support surface. Two of the walls are situated in parallel to each other and when the surface is a quadrilateral, also parallel to the lateral edges of the wheelchair support. These walls may be fixed, for example, at the lateral edges of the wheelchair support, or adjustably spaced apart. One or more transverse walls situated parallel to the lateral or trailing edge of the wheelchair support can also be included. In preferred embodiments, such a wall is not present at the trailing edge, to facilitate rolling a wheelchair onto the wheelchair support over the edge which lacks a wall, by not requiring that a wall be traversed during loading. In preferred embodiments, such a wall is present at the leading edge to prevent the wheelchair from being rolled off of the wheelchair support during loading, before the wheelchair is secured to the device. This wall can also provide support for the propelling force during transport of the wheelchair. However, the support surface may include retaining bumps which can be traversed during loading of the device and which act to prevent undesirable free movement of a wheelchair from the support surface if the ground surface is not level, for example. Such bumps are distinct from substantially upwardly extending walls, and these may be present in a plurality on the rail surface, preferably at positions adjacent to the expected positions of the wheelchair wheels when in the supported position.

The lateral support members need not be continuous surfaces, but may be interrupted, or partially omitted. The substantially upwardly extending walls are sufficiently high to prevent the wheels of the wheelchair from easily sliding off of the surface, but not so high as to interfere with the ease of loading, securing or transporting the wheelchair on the device. For example, the wall cannot be so high that it contacts components associated with the wheels of some wheelchairs, for example a circular handgrip. A suitable height for the substantially upwardly extending walls is from about 1 inch to about 6 inches, preferably from about 2 inches to about 4 inches . In another embodiment, the wheelchair support consists of a pair of rails, mounted in parallel with each other, and parallel to the direction of travel of the device. This is shown in Fig. 1, in which the left and right rails are shown as 5 and 2, respectively. The rails are substantially planar rectangular horizontal surfaces with substantially upwardly extending walls on at least two of their edges. In Fig. 1, these walls are shown as 3 , 4, 6 and 7. The positioning and width of the substantially planar rectangular horizontal rail surface is sufficient to allow the wheelchair wheels to rest on the surface. The width of each rail can range from 2 to 8 inches, and is preferably from 3 to 6 inches.

The rails are preferably substantially planar and elongate in form. The edges of the rails are defined as above, i.e., lateral, leading and trailing edges. The substantially upwardly extending walls are preferably on the lateral and leading edges of each of the rails. It is preferred that the wheelchair be loaded so that a wall is not traversed by the wheelchair. The left and right rails are spaced apart by a distance which is sufficient to allow the wheel assemblies of a wheelchair to rest on the rails without substantial contact with the substantially upwardly extending walls. This distance is measured from the center line of each rail (which is parallel to the length of the rail) , and can be from about 28 to 45 inches, and is preferably from about 30 to 40 inches.

Materials suitable for use in construction of the wheelchair support include aluminum sheet. One of skill in the art will immediately recognize other potential building materials which combine strength, resistance to corrosion, ease of workability, cost, durability and light weight, as well as other considerations not listed here. The thickness of such building material will depend on its intrinsic strength. For example, when the building material is aluminum, the device is made from 1/4" aluminum sheeting. One of skill in the art will be able to use a different thickness depending on the material to be used.

First wheel assembly support

The wheelchair support is attached to and supported by a first front wheel assembly support and a first rear wheel assembly support . These first front and first rear wheel assembly supports may be the same or they may differ as set out below. The form of the first wheel assembly supports will depend on the form of the wheelchair support. For example, if the wheelchair support is in the form of a pair of parallel rails, as shown in Fig. 1, with substantially upwardly extending walls, the first wheel assembly support will act to indirectly connect the rails to each other. In this case, the first wheel assembly support extends substantially perpendicularly to the rails and is connected to the rails by known means of secure fixed connection. One suitable first wheel assembly support means for use with wheelchair support in the form of rails is an oblong rectangular cross member. The cross sectional view of such a cross member can be solid or hollow, can be of rectangular or can be "C" -shaped, "I"- shaped, "O" -shaped, or can simply be a sheet of material. As long as the first wheel assembly support member is able to provide structural stability to the device and/or provide a mount for the wheel assembly, the shape is not critical. In the embodiment shown in Fig. 1, the first wheel assembly supports comprise front and rear "C"- shaped cross members, shown as 10 and 11 respectively.

The cross members comprise at least two paralleledly positioned cross members. These are referred to as the "front" and "rear" cross members, front and rear being defined by the intended direction of travel of the device. If there are more cross members, these can be at least one "central" cross member (located between the front and rear cross members) , or "left front", "right front", "left rear" and "right rear" cross members. Not all of these last four need be present, for example, the functions of the left and right rear cross members could be combined into one rear cross member. The cross members are parallel to each other and are spaced apart a distance sufficient to provide stability to the device when loaded with a wheelchair. This can define the distance between the centerpoints of the front and rear wheel hubs ( "wheelbase" ) . This distance can be from about 22 to about 40 inches, and is preferably from about 25 to about 36 inches. Fig. 7 shows an end-on perspective of a cross member according to a preferred embodiment of the invention. In this preferred embodiment, rear cross member 11 is "C" -shaped, but other arrangements are possible, including a rectangular shape. The open end of the "C" may be facing in any direction, rather than downward as depicted in this particular embodiment. Axle 13 is shown attached to the corner of the interior of the "C" -shaped cross member. Also depicted is right brake rod 23, surrounded by brake rod housing 45. Alternatively, the first wheel assembly support can be a plurality of flanges attached to the wheelchair support. Such a first wheel assembly support can also be connected to a second wheel assembly support . In an example of such a case, the flanges would have holes adapted to allow passage of an axle through the flanges. In preferred embodiments of the invention, the first front and first rear wheel assembly supports are "C" shaped cross-members which are attached to the wheelchair support and have axles attached to them. The length of the cross-members will influence the width of the device as a whole. In preferred embodiments, the cross members are from about 28 to 50 inches long, preferably from about 29 to 45 inches wide. The front and rear cross members need not be equal in length. The device also possesses ground clearance (distance between the lowermost point on the device frame, generally the wheel assembly supports, to the ground) when loaded with a standard wheelchair and a 140 pound occupant of at least 3 1/2 inches, preferably at least 4 inches .

Second wheel assembly support

Either or both of the first wheel assembly supports can be attached to a second wheel assembly support . The means of connection for the front and rear first wheel assembly supports to the second wheel assembly supports need not be the same. The form of the second wheel assembly support will depend in the first instance on the form of the wheel assembly, as set out below. For example, if the wheel assembly comprises a wheel, a tire and an axle, the second wheel assembly support is generally absent, as the first wheel assembly support will serve to secure the wheel assembly to the wheelchair support .

Alternatively, if the wheel assembly comprises a tube and fork assembly (discussed below) , the second wheel assembly support can take the form of a rod or any other support member which can be attached to the head tube of a tube and fork assembly.

Wheel assemblies

The invention includes at least a pair of front wheel assemblies and at least a pair of rear wheel assemblies, each wheel assembly having balloon-type tires and being rotatably attached to the wheelchair support . The wheel assemblies include: a wheel, having a means for accommodating an axle, such as a hub, and a means for mounting a balloon-type tire, such as a rim; an axle; and a balloon-type tire. More than one wheel assembly can be mounted on a given axle. For example, in some embodiments, there can be more than one wheel assembly at 5 a given left or right, front or rear position (e.g., two left front wheel assemblies, "inner" and "outer"). Additionally, at least one of the wheels for use in the device of the invention includes at least one radially extending rib member. The radially extending rib member o comprises a surface against which a portion of a brake rod can rest, thereby substantially preventing movement of the wheel when the brake is engaged. Under these circumstances, the wheel is said to be locked. The radially extending rib member can take the form of spokes s or ribs in the wheel. Preferably, the wheels include a plurality of such radially extending rib members. Preferably at least two of the wheels include radially extending rib members. Preferably, at least the two rear wheels include a plurality of radially extending rib o members. Preferably, the radially extending rib members are present on the inner portion of the wheel, that is, the portion of the wheel not facing away from the device. The axle may be turningly connected to the wheel, in cases in which the axle is to remain fixed and the 5 wheel to turn. Alternatively, the axle may be fixedly connected to the wheel, in cases in which the axle is meant to turn. It is also possible to turningly connect the wheel to the axle and further turningly connect the axle to other parts of the device or wheel assembly, so 0 that both the wheel and the axle turn independently. In preferred embodiments of the invention, the axle is turningly connected to the wheel and fixedly connected to other parts of the device or wheel assembly.

The connection of the axle to other parts of the 5 device or wheel assembly can take a number of forms . For example, the axle could pass through at least two vertically depending flanges on the underside of the wheelchair support. The axle could be either fixedly or turningly connected to these flanges.

The axle is fixedly or turningly connected to at least a first wheel assembly support intermediate the axle and the wheelchair support, as described above.

The axles can be mounted inside the cross members for example in an inside corner of the cross members as shown in Fig. 7, or can be mounted in an inside surface of the cross members, if they are hollow. The axles can also be mounted on the outside surface of the cross members. The axles are preferably stationary axles. The mounting can be by U-bolt, for example, thereby not allowing the free rotation of the axle. Welding can be employed to secure the axle to the wheel assembly support. In another method of mounting the axles, a hole is made through the diameter of the axle and a corresponding hole is made through the cross member, and a bolt or any other suitable retaining means is placed through these holes and secured. These approaches could be combined in any plausible manner to fix the axle.

The axles must extend far enough from the ends of the wheel assembly supports to allow the axles to pass through the wheels. Thus the minimum extension of the axles from the wheel assembly supports is determined by the width of the wheels and additional length needed to provide for attachment of the wheels. The axles must also extend into or onto the wheel assembly supports far enough to sufficiently minimize the strain on the axle- wheel assembly support connection. Moreover, the combined length of the wheel assembly support and the exposed axles must be that which will provide suitable width to the device. This width must be at least as wide as a wheelchair and is preferably wider than a wheelchair to be transported. However, excessive widths can make the device cumbersome to navigate in tight quarters. The preferred width of the device as a whole (outer edge of left wheels to outer edge of right wheels) is from about 40 to about 70 inches, and is more preferably from about 50 to about 65 inches. In certain preferred embodiments to be discussed herein, the vehicle further comprises steerable wheels, involving a different axle-wheel assembly support configuration.

The axle can extend completely through the wheel assembly support, or can terminate within or on the wheel assembly support. Thus, each axle can support a single wheel (e.g., front left axle supporting front left wheel) or an axle can support a pair of wheels (e.g., rear axle supporting left rear and right rear wheels) . The axles include a means for securing the wheels, and the means can include a hole bored through the diameter of the axle, near its outer end, so that after mounting of the wheel, a cotter pin or other commonly used means for securing wheels can be used well known to those in the art . 0 The wheels are preferably wide enough to support the mounting of a tire adapted to travel over soft terrain. This will generally require a flange which can support the tire as it expands under the combined pressure of a load and uneven terrain. The wheels are 5 made of a variety of materials. The wheels can have ball bearings to provide increase efficiency. Preferably, the ball bearings are made of a material that does not corrode easily. Preferably, the ball bearings are isolated from the external environment. This isolation o provides increased resistance to sand and grit. The wheels can be provided in a large range of diameters, for example from about 3 inches to about 24 inches, or any desired diameter.

Tires to be mounted on the wheels are those which 5 are adapted to be used over uneven terrain. These tires are preferably low pressure (20 psi or less) , so that they can flex under load to flatten substantially from its unloaded shape, and continue to flatten as the load increases. The tires provide an enlarging contact area between their outer diameter surface and any underlying soft or irregular surface. As a result, rolling friction is reduced. For these reasons, the tires will stretch to deform substantially when encountering and rolling over obstacles under load. Tires suitable for use in the device of the invention can be made of elastomeric material such as thermoplastics, including polyurethane and other thermoplastics well known to those in the art. Suitable wheels with premounted tires are commercially available under the name of ROLEEZ^® (Roleez Wheel System, Inc . Norfolk VA) . In preferred embodiments of the invention, the device is equipped with a pair of 17 inch diameter wheels, and a pair of 12 inch diameter wheels (tires included in diameter) .

The wheel assemblies can further comprise a means for rotating the wheel and its associated tire about a vertical axis. This feature allows easy steerability of the device. One means of allowing the rotation of a wheel assembly is with a tube and fork construction, similar to that found on a standard bicycle front wheel . A specific embodiment of a tube and fork construction is depicted in Fig. 4, which shows a particular embodiment of such a tube and fork assembly. This assembly comprises wheel 14 (not shown) , tire 17 mounted on the wheel, axle 12 passing partially or fully through the wheel, forked member 30 attached to the axle, shaft 31 attached to the forked member, head tube 32 substantially cylindrically surrounding the shaft, and capping member 33, acting to maintain the surrounding relationship between shaft and head tube. Shaft 31 is held in a constant vertical position in head tube 32 by retaining means known in the art . The head tube permits free rotation of the shaft, and thus, free rotation of the wheel about a vertical axis. In this case a relatively short axle 12 passes through the wheel. It need only be long enough to pass through wheel 14 and provide for secure attachment to fork element 30. Attachment of axle to fork is accomplished by cotter pin 35. In other embodiments, axle 12 can be threaded and fork 30 attached to the axle by washers and nuts.

The wheel assembly thus defined is connected to a wheel assembly support by means known in the art . In preferred embodiments of the invention (continuing reference to Fig. 4), the second front wheel assembly support comprises rod 34 which attaches to the head tube of a tube and fork assembly and the first front wheel assembly support which is a "C" -shaped cross member, and the second rear wheel assembly support is absent. Any number of the wheel assemblies may be steerable wheel assemblies. For example, all the wheel assemblies may be steerable. In some preferred embodiments, only the rear wheel assemblies are steerable. In other preferred embodiments, only the front wheel assemblies are steerable.

Device braking

The wheelchair auxiliary device of the invention also includes at least one engagable means for braking the device, referring to preventing at least one wheel from substantially rotating. The braking means is engagable when the device is not moving, and is intended to prevent the device from moving, for example, when the device is being loaded or when the device is on a slope.

In one embodiment, the means for braking the device comprises a rod, bolt or similar element which engages at least one of the wheels. The method of engagement can be by sliding the rod outwardly, or by swinging the rod in a radial arc, for example. The manner of engagement of the rod with the wheel can be for example, insertion of the rod into spaces between the spokes of at least one of the wheels. In this particular embodiment, it is important to dimension the rod to be able to fit between the spokes of at least one of the wheels. If this fit is too tight, the brake will be difficult to engage and will require undue precision in the placement of the wheel to align the spokes and rod for insertion. If this fit is too loose, the weight of the wheelchair or occupied wheelchair could cause rotation of the wheel to the extent that undue stress is put on the wheel by the rod, or vice versa, causing temporary or permanent failure of the brake, or breakage of the wheel spokes . The means for braking the device is preferably proximate the wheel which is to be braked. Thus, the means for braking can be located on or in the wheel assembly support, on or in the wheel assembly itself, or on or in the wheelchair support . In a preferred embodiment, the means for braking the device comprises a rod which slides along the length of the wheel assembly support to which it is mounted. This mounting may be within the wheel assembly support, or on the surface of the wheel assembly support. As shown in Fig. 2, in a particular embodiment of the invention, left brake rod 25 (shown in the engaged position) , actuated by left brake rod handle 26, is engaged between spokes 40 of wheel 14. Brake rod 25 is housed in brake rod housing 45. More than one means for braking the device can be included, each preventing the substantial rotation of at least one wheel . In one of the preferred embodiments of the invention, a means for braking the device comprising a pair of rear brake rods engagable between the spokes of two of the rear wheels is provided. The brake rods can also be mounted on the front wheel assembly support. The double-headed arrow in Fig. 2 indicates the direction in which the brake rod handle must be operated in order to engage and disengage the brake rod.

Wheelchair securing

The wheelchair auxiliary device of the invention also includes means for securing a wheelchair on the device when it is loaded. This feature prevents substantial movement of the wheelchair, contributing to the stability of the device, and providing increased security to the occupant of the wheelchair. The means for securing a wheelchair can take the form of any releasable securing means. A clamp can be used, and such clamps are available in many different configurations. In embodiments in which the invention is designed to secure a wheelchair having spoked wheels, the means for securing a wheelchair to the device preferably comprises a rod, bolt or similar element which engages with the spoked wheel of a wheelchair. This is a particularly inexpensive wheelchair securing means. The rod passes through holes in the substantially upwardly extending walls of the wheelchair support means and through the spokes of a wheelchair. The rod must be long enough to pass through both holes and is from 4 to 8 inches long. Fig. 3 shows pin 8 which can be inserted into holes 9 in the upwardly extending walls 6 and 7 of left rail 5. Pin 8, when inserted in both holes 9, also passes through a space F between spokes D of the wheelchair wheel B, thereby securing the wheelchair wheel . Another preferred embodiment uses a 6 inch hitch pin with a tension lock. Preferably more than one wheelchair wheel is so secured, most preferably, all wheelchair wheels are thus secured. Other embodiments of the invention are adapted to secure wheelchairs not having spoked wheels, but instead having solid wheels. In this case, the means for securing the wheelchair can take the form of a strap which is secured to the device and passes over or through the wheelchair. The strap can be fastened in place, for example, by providing hooks at either end of the strap which can engage correspondingly sized holes or slots in, for example, the rail walls in certain embodiments. Then the strap can be tightened by adjusting its length with a tightening means, for example, a ratcheted tightening device .

Ramp

The wheelchair auxiliary device of the invention also includes a stowable ramp for loading the device with a wheelchair. A stowable ramp is translatable to a ramping position and removably secured in this position to prevent slippage. The ramp attaches to the edge of the means for supporting a wheelchair, forming a continuous substantially planar surface between the ground and the means for supporting a wheelchair. The ramp is stowable on the device when not in use, and is thereby available for unloading at desired destinations. The ramp has side edges, a lower edge and an upper edge. The side edges are meant to define the sides of the ramp, and the wheelchair is not meant to traverse the side edges. The ramp preferably includes substantially upwardly extending walls on the side edges, which guide the wheelchair up the ramp, preventing the wheelchair from falling from the ramp. The upwardly extending walls also provide greater structural integrity to the ramp. The height of the substantially upwardly extending walls should be sufficient to prevent a wheelchair from being driven or pushed off the ramp, but not so great that it interferes with the operation and convenience of the wheelchair. This height can vary between about 1 inch and about 8 inches, or preferably, between about 2 inches and about 6 inches .

The lower edge of the ramp is meant to substantially contact the ground and allow the wheelchair to be driven or pushed onto the ramp. The upper edge of the ramp is meant to substantially contact the wheelchair support means, and allow the wheelchair to be driven or pushed onto the device proper. The contact between the upper edge of the ramp and the wheelchair support means is preferably a positive contact, so that any slight movement of the ramp or vehicle does not diminish the contact and endanger the wheelchair or its occupant. Such positive contact can be established by, for example, a tab and slot connection. The ramp may have a tab depending from the lower side of the upper edge, which is inserted into a correspondingly sized and shaped slot in the wheelchair support. Preferably, such a slot is located near the edge of the wheelchair support, and can be located at either the leading or trailing edge of the wheelchair support. Alternatively, a plurality of such tabs and slots can be employed. Positive contact could also be made by any number of means including clips, buckles, hook and loop type fasteners, and many other contacting means known to those skilled in the art.

Fig. 5 shows a particular embodiment of the ramp and its connection to the wheelchair support. Ramp rail 21 including upwardly extending walls 22 is shown with a downwardly depending tab 40 which fits through correspondingly sized slot 41 (not shown) at the edge of the wheelchair support, here shown as right rail 2 with upwardly extending wall 3.

Alternatively, the ramp could include a groove along one or both of its walls, into which are positioned correspondingly sized pins which are found on the undersurface of the wheelchair support. In this arrangement, the ramp slides from a position underneath the wheelchair support into a ramping position. Upon loading or unloading, the ramp is slid back to a stowed position. In an alternative configuration, the ramp could be permanently and hingedly attached to the edge of the wheelchair support, so that after the loading operation is complete, the ramp can be stowed in a vertical position by lifting the lower end of the ramp and raising it, preferably to form a means by which the device may be pushed or pulled.

The ramp is sufficiently wide to allow the wheels of the wheelchair to substantially continuously contact the ramp during loading. The ramp is sufficiently long to minimize the effort needed to load the cart, but not so long as to make storage or transportation cumbersome. In preferred embodiments, the ramp is from about 30 to about 50 inches long, preferably from about 35 to about 45 inches long. The ramp itself need not be a continuous surface, but portions thereof can be omitted as long as the strength of the resulting ramp is such that the wheelchair and its occupant can be safely loaded.

After loading, the ramp is stored on the device to be transported to desired destinations, so that the wheelchair can be unloaded from the device at those destinations. The ramp can be removable, i.e., physically separable, from the device. The ramp can be stored by laying it across the wheel assembly support and fastened to them by a number of means including hook and loop type fasteners, clips, buckles, and a wide variety of other fastening means known in the art .

Fig. 6 shows a particular embodiment of the invention, in which the ramp takes the form of ramp rails (described below) . The ramp rails are removable from the device and are stowed on top of the wheel assembly supports. Ramp rail 21 is shown in the stowed position on the left side of device 1, attached to front wheel assembly support 10 and rear wheel assembly support 11. The means of attachment of the ramp in the stowed position is by means of pieces of hook and loop fastener 42 which are attached to the wheel assembly supports as shown. The arrow in Fig. 6 indicates the preferred direction of travel of the device, denoting front and rear directions. Alternatively, the ramp can be stored under the wheel assembly support and fastened to them by any of the means alluded to above. Alternatively the ramp can be suspended below the wheel assembly support by brackets or eyehooks . In embodiments in which the ramp is a pair of ramp rails, each rail can be stored by laying it on top of one side of the wheel assembly support. Fastening is provided by hook and loop fasteners, for example.

In one embodiment, the ramp is a substantially planar rectilinear surface with substantially upwardly extending walls on the side edges. Positive contact between the upper edge of the ramp and the wheelchair support means is established between downwardly depending tabs on the lower surface of the upper edge of the ramp, and correspondingly sized and shaped slots in the wheelchair support means.

In another embodiment, the ramp is a pair of ramp rails. The ramp rails are oblong rectangular surfaces forming a bottom surface and which have substantially upwardly extending walls. The rails make positive contact with the device through downwardly depending tabs on the lower surface of the upper edges of the ramp rails. Correspondingly sized and shaped slots in the wheelchair support means accept the tabs to form the ramp and allow for loading. The ramp rails are wide enough to allow the wheels to easily be guided onto the bottom surfaces. Preferably, the ramp rails, if removable, are interchangeable with each other without any change in the performance of the ramp.

The materials for the wheelchair support, all wheel assembly supports, ramp are preferably sheet metal, more preferably aluminum sheet metal . The engagable brake can be made of solid metal stock, preferably solid aluminum stock. The means for securing the wheelchair to the device can be made of any rigid material, but is preferably solid metal stock. The devices of the present invention are fabricated according to known methods of construction. General methods of working sheet metal (bending, cutting, finishing, etc.) and attaching parts to each other (with welds, rivets, screws, bolts, etc.), will allow one of ordinary skill in the art to construct the device as substantially described herein.

Method of transporting a wheelchair

The invention also provides a method of transporting a wheelchair across soft, uneven, or otherwise difficult terrain using the wheelchair auxiliary device of the invention. The method includes providing a wheelchair auxiliary device substantially as described above, braking the device, loading a wheelchair onto the device by putting the ramp in place, driving or pushing the wheelchair up the ramp onto the wheelchair support means, securing the wheelchair, removing the ramp from a ramping position and stowing it, disengaging the device brake, and pushing or pulling the device. The wheelchair can also have an occupant . It is to be understood that while the invention has been described in conjunction with the detailed description thereof, the foregoing description is intended to illustrate and not limit the scope of the invention, which is defined by the scope of the appended claims. Other aspects, advantages, and modifications are within the scope of the following claims. The present invention has been designed and built to support a wheelchair; however, it is contemplated that similar devices would support other wheeled devices such as baby carriages, and similar vehicles.

Claims

What is claimed is:

1. A wheelchair auxiliary device for transporting a wheelchair over difficult terrain, said device comprising : s a) a planar, horizontal wheelchair support for supporting the wheels of a wheelchair including means by which a wheelchair can be rolled into and removed from a securable position; b) at least one front wheel assembly comprising at o least one freely rotatable wheel and a balloon-type tire; c) at least one rear wheel assembly comprising at least one wheel and a balloon-type tire; d) at least one first front wheel assembly support attached to said wheelchair support, and upon which said s front wheel assembly is mountable; e) at least one first rear wheel assembly support attached to said wheelchair support, and upon which said rear wheel assembly is mountable; f) at least one engagable brake for locking at 0 least one of said wheel assemblies; g) at least one releasable securing means for locking said wheelchair to said wheelchair support; and h) a ramp for loading the device with a wheelchair, wherein the ramp attaches to the wheelchair 5 support, and wherein the ramp is stowable on the device when not in use, wherein the device is propellable in a direction of travel by a orce external to the device .

2. The device of claim 1, further comprising at least 0 one second front wheel assembly support intermediate said at least one first front wheel assembly support and said at least one front wheel assembly, and at least one second rear wheel assembly support intermediate said at least one first rear wheel assembly support and said at least one rear wheel assembly.

3. The device of claim 1, wherein said wheelchair support comprises at least one substantially planar surface having lateral edges, a leading edge and a trailing edge, wherein said surface is aligned so that the lateral edges of the surface are substantially parallel to the direction of travel of the device, and the leading and trailing edges of the surface are substantially perpendicular to the direction of travel of the device, wherein said surface has at least two substantially upwardly extending walls, and wherein said stowable ramp attaches to the trailing edge of the wheelchair support for loading the device.

4. The device of claim 3, wherein the two lateral edges of the planar surface have parallel and substantially upwardly extending walls.

5. The device of claim 4, further comprising substantially upwardly extending walls on the leading edge of the planar surface .

6. The device of claim 1, wherein said wheelchair support comprises left and right rails mounted in parallel, said rails having upwardly extending walls on their lateral edges, wherein the rails are spaced sufficiently far apart to allow the left and right sets of wheelchair wheels to contact the left and right rails, and wherein the rails are sufficiently wide to allow the wheelchair wheels to rest on the rail surface.

7. The device of claim 1, wherein the front wheel assembly further comprises an axle passing through the wheel, a forked member attached to the axle, a shaft attached to the forked member, a head tube cylindrically surrounding the shaft, and a capping member maintaining the cylindrically surrounding relationship between the shaft and head tube, wherein the shaft is substantially freely rotatable within the head tube.

8. The device of claim 1, wherein the engagable brake is mounted immediately proximate a wheel assembly.

9. The device of claim 8, wherein at least one wheel assembly comprises radial support members.

10. The device of claim 9, wherein the engagable brake comprises a brake rod that engages at least one of the wheel assemblies by inserting between radial support members of the wheel assembly.

11. The device of claim 4, wherein the releasable securing means is mounted immediately proximate the wheelchair support .

12. The device of claim 11, wherein the wheelchair to be secured has spoked wheels, and at least one substantially upwardly extending wall of the wheelchair support is provided with at least one hole.

13. The device of claim 12, wherein the releasable securing means passes through the at least one hole in the substantially upwardly extending walls of the wheelchair support and the spokes of the wheels of the wheelchair.

14. The device of claim 1, wherein the ramp consists of left and right ramp rails having bottom surfaces, lateral edges and substantially upwardly extending walls on their lateral edges, wherein the ramp rails are spaced sufficiently far apart to allow the left and right sets of wheels of the wheelchair to contact the left and right ramp rails, and wherein the ramp rails are sufficiently wide to allow the wheelchair wheel assemblies to rest on the bottom surfaces of the ramp rails.

15. The device of claim 1, wherein the force external to the device is a person pushing the device.