Background of the Invention 1. Field of the Invention The invention relates generally to an apparatus for supporting a wheelchair which allows the wheelchair and occupant to move over ice surfaces under the control of the occupant. The wheelchair occupant can control the movement and direction of the platform by rotating the wheels of the wheelchair. The wheels of the wheelchair fit into slots formed by parallel frame rails. The wheels engage multiple rollers connected by a toothed gear wheel system that engages studded wheels which grip the surfaces for traction and provide directional movement on ice surfaces.

2. Description of Related Art Wheelchair conversion and platform devices are available to allow wheelchair occupants to climb stairs and to transverse rough terrain. With the emphasis on improved mobility and increased participation in recreational activities for persons confined to wheelchairs, there remains a need for an apparatus that is strong, light-weight, inexpensive, and simple to utilize for the efficient movement of the wheelchair and occupant across ice covered surfaces such as a skating rink.

Summary of the Invention It is an object of this invention to provide a platform that supports a wheelchair or scooter and which allows the occupant to move over ice.

It is a further object of this invention to provide an apparatus for supporting and cradling a wheelchair that is light-weight but rugged and simple in design.

It is a further and more particular object of this invention to provide an apparatus for supporting and cradling a wheelchair that allows for easy entry by the wheelchair and occupant from a ramp, curb, or similar structure.

These and other objects of the invention are accomplished by an apparatus comprising a substantially horizontal frame having an upper surface and a lower surface; a first slot defined by the upper surface of the frame; a second slot defined by the upper surface of the frame, the first and second slots being a spaced distance apart corresponding to the distance between the drive wheels of a wheelchair; a first roller and a second roller, the first and second roller each carried within said first slot, said second roller in communication with a drive means, the drive means in further communication with a drive roller wheel in communication with an opening defined by the lower frame surface; a third roller and a fourth roller, the third and fourth roller each carried within the second slot, the fourth roller in communication with the drive means, the drive means in further communication with a second drive roller wheel in communication with an opening defined by the lower frame surface; wherein when a wheelchair is carried by the frame, the spaced drive wheels of the wheelchair each engage a respective slot defined by the frame, each drive wheel supported by said respective rollers so that as an occupant of the wheelchair rotates said drive wheels of the wheelchair, each respective drive roller wheel is rotated thereby engaging the surface beneath the horizontal frame.

Each drive roller propelling wheel defines an exterior roller or wheel surface having a plurality of rounded or spiked projections that provide improved traction. The supporting platform also has connected to its underside at least one pivoting support member such as a wheel which protrudes downwardly to stabilize the platform and occupant.

Brief Description of the Drawings The above described features and other features, aspects, and advantages of the present invention will become better understood with regard to the following preferred embodiment, appended claims, and accompanying drawings where: FIG. 1 is a side-view of the platform onto which a wheelchair can be positioned;

FIG. 2 is a top-view of the platform's drive mechanism; FIG. 3 is a side-view of the platform's drive mechanism as seen in the direction of line 3-3 of Fig. 2; FIG. 4 is a side-view of the full length of the platform; FIG. 5 is a cross-section of the rear of the platform as seen in the direction of line 5-5 of Fig. 4; FIG. 6 is a cross-section of the rotating rollers located on the first rotating shaft as seen in the direction of line 6-6 of Fig. 4; and FIG. 7 is a cross-section of the rotating rollers located on the second rotating shaft, and the drive roller wheels extending below the platform, as seen in the direction of line 7-7 of Fig. 4.

Detailed Description The preferred embodiment of the invention, as seen in Figure 1, comprises a platform that provides for a frame 1 to support a wheelchair 50 and a seated occupant. As used herein, the term"wheelchair"is defined to include a scooter or other similar wheeled device that transports a physically challenged individual. The platform comprises a structure that is a substantially horizontal frame comprising a plurality of length-wise and cross-member structural beams, which are interconnected. Along either side of the upper frame surface 1, are a pair of opposing, parallel slots 3 and 3', with the center axis of each pair of parallel slots being separated by the approximate width of the drive wheels of a wheelchair. If desired, the size and position of the slots 3 and 3'may be adjusted by the relative movement of the supporting beams. This feature allows varying wheel configurations to be accommodated.

Reference is now made to a single slot 3 for convenience. However, it is understood that slot 3'has similar structural details and operation and corresponding structure is designated with the prime''"designation on the figures.

Slot 3 is in communication with a first roller 5 and as seen carried upon a corresponding shaft 7 connected to the sidewalls which define slot 3. A second roller 9 is positioned along a shaft 11 at a spaced distance from roller 5. Roller 5 may be constructed of metal, hard rubber, or a rubber coated composite material. The center of roller 5 preferably defines a reduced circumference contact area adapted for engaging the drive wheel of a wheelchair. The position of roller 5 and shaft 7 may be adjusted within slot 3 by placement within additional attachment sites defined by or along the slot sidewalls. Alternatively, a rear portion of the frame can slide or telescope relative to the front frame whereby locking pins, bolts or other connecting means are used to resecure the frame halves.

Roller 9 is positioned in front of the first roller 5 providing a gap distance therebetween of approximately one- half the diameter of the driving wheel 60 of wheelchair 50.

As seen in Figure 2, a transmission is provided as seen by the second roller 9 which further defines a toothed gear wheel 13 that rotates in unison with second roller 9. The teeth of the first toothed gear wheel 13 are in contact and mate with the teeth of a second toothed gear wheel 15, carried by shaft 17. Shaft 17 carries sprocket 19 which uses chain 21 to engage a sprocket 23. Sprocket 23 is in communication with a drive roller through common shaft 27. A lower exterior surface of drive wheel 25 extends below the plane of the lower platform and engages the support surface below.

During operation, each drive roller wheel 25 is in contact with the ice surface. Traction is provided by a plurality of studs or cleats 29 imbedded into the exterior surface of each drive roller wheel. The connection of the wheelchair wheel 60, to rollers 5 and 9 allows the gear system to transfer in a proportional manner the occupant's movements of the wheelchair wheels to each of the drive roller wheels. The interconnected gear/drive mechanism translates the rotational movement of the occupant's vehicle

drive wheels to a respective forward or backward motion of the platform's drive wheels. A 1: 1.25 gear ratio has been found useful for electric wheelchairs. Ratios as high as 1: 2 have been evaluated but require a high torque output not found in standard electric wheelchairs.

The gear ratios can be varied as conditions warrant by the selection of various size sprockets 19 and 23. It is envisioned that a shifting system similar to a multiple speed bike derailleur can be used to vary the performance of the apparatus. As seen in Figure 2, drive roller wheel 25 includes on its exterior surface a traction enhancing surface such as a plurality of cleats or studs 29. Studs 29 can be provided by metal or rigid plastic spikes, cleats, or other similar design. Hollowed metal tubes have been found to provide effective studs in that the inner and outer edges of each tube provides a high traction gripping action. In the preferred embodiment, drive roller 25 has a resilient, elastomeric surface in which rolled metal studs 29 are embedded.

As best seen in Figure 4, the rear of the supporting platform is supported by at least one pivoting wheel 33, connected to the underside of the platform and protruding downward below the platform. Additional support wheels may be present. The support wheel or wheels provide for stable support of the platform when a wheelchair and occupant are positioned on the platform. The presence of only a single rear support wheel greatly increases the maneuverability and pivoting action of the frame.

The means for forward and lateral movement of the platform is provided by the wheelchair occupant's rotation of each wheelchair wheel, which are in communication with the rollers, gear wheels, drive chains, and drive roller wheels.

Preferably, electric wheelchairs are used which have been found to provide a continuous and coordinated engagement of the drive rollers. Manual engagement of the wheelchair drive wheels has been found difficult. However, variations in the gear ratio of the drive mechanism could be provided to

improve manual performance.

Control of the movement of the platform and braking are provided by the wheelchair occupant's control over the wheelchair wheels 60. The apparatus permits the independent control of each wheelchair wheel in a respective forward, stopped, or reverse rotation. In operation, the wheelchair occupant has much greater maneuverability in executing tight turns and spins than is provided by an unassisted wheelchair.

Access to the platform can be provided by locating the platform near an access ramp or step at the edge of the ice surface. Once the wheelchair is positioned on and between the parallel positioning slots 3, the platform is controllable by the wheelchair occupant. Exit from the platform is a reverse process where the wheelchair and platform is located by the occupant next to an access ramp or step, which allows the wheelchair occupant to move the wheelchair wheels off the platform.

Although the present invention has been described in considerable detail with reference to a preferred embodiment, many variations in materials and design are possible. For example, the platform frame may be constructed from metal, fiberglass, plastic, or similar components. Further, the frame may be provided as a substantially unitary structure.

The frame itself need not be limited to a rectangular outer dimension, but could be in a variety of shapes such as a circle. Alternate shapes may be safer or more efficient when the platforms are used in competitive team sports such as hockey.

Many variations will undoubtedly become apparent to one skilled in the art upon a reading of the above specification with reference to the drawings. Such variations, however, are within the spirit and scope of the invention as defined by the following appended claims.