The present application claims priority to Canadian Application No. 2,560,637 filed Sep. 22, 2006, which is incorporated herein in its entirety by reference.
This invention relates to wheelchairs and in particular to a wheelchair adapted for climbing a step, curb, or the like.
Persons using wheelchairs are limited in their ability to travel by curbs, steps, and the like. Where sloped curbs are not provided at street intersections, wheelchair occupants may be able to maneuver down from the sidewalk curb onto the street, but to climb the curb once the street has been crossed is often not possible, forcing the wheelchair to travel down the street in order to find a driveway, alley, or like sloped access to the sidewalk.
Various stair and step climbing wheelchairs have been developed. See for example U.S. Pat. No. 6,554,086 to Goertzen et al., U.S. Pat. No. 4,222,449 to Feliz, and U.S. Pat. No. 4,119,163 to Ball. Also it is known to mount a ramp on a wheelchair for mounting curbs, such as is disclosed in U.S. Pat. No. 3,976,152 to Bell.
It is an object of the present invention to provide a method of operating a wheelchair and a wheelchair apparatus adapted for climbing steps, curbs, and the like that overcomes problems in the prior art.
The present invention provide, in a first embodiment, a step climbing wheelchair apparatus comprising right and left axles extending out from rotational axes of corresponding right and left rear wheels of a wheelchair, and right and left lift alms, and a longitudinal slot defined in a middle portion of each lift arm, and a handle on a front end of each lift arm. The right and left axles extend through the slots defined by corresponding right and left lift arms, and a fastener is attached to secure each lift arm on the corresponding axle such that each lift arm can slide longitudinally substantially perpendicular to the axle from an extended position, where the axle is located at a front handle end of the slot, to a retracted position where the axle is located at an opposite rear step end of the slot. The lift arms are configured such that when in the extended position rear step ends of the lift arms are located rearward of the outer rim of the rear wheel, and the handles are located generally forward of the outer rim of the rear wheel. A front lift mechanism comprises a lift wheel and a lift lever operative to push the lift wheel downward to raise the front caster wheels of the wheelchair.
The present invention provides, in a second embodiment, a method of climbing a step with a wheelchair, the wheelchair having right and left axles extending out from rotational axes of corresponding right and left rear wheels of the wheelchair. The method comprises providing right and left lift arms with a longitudinal slot defined in a middle portion of each lift arm, and a handle on a front end of each lift arm; attaching the right and left lift arms to corresponding right and left rear wheel axles of the wheelchair by inserting the right and left axles extend through the slots, and attaching a fastener to secure each lift arm on the corresponding axle such that each lift arm can slide longitudinally substantially perpendicular to the axle from an extended position, where the axle is located at a front handle end of the slot, to a retracted position where the axle is located at an opposite rear step end of the slot, and wherein the lift arms are configured such that when in the extended position rear step ends of the lift arms are located rearward of the outer rim of the rear wheel, and the handles are located generally forward of the outer rim of the rear wheel; providing a front lift mechanism comprising a lift wheel located forward of front caster wheels of the wheelchair, and a lift lever operative to push the lift wheel downward to raise the front caster wheels of the wheelchair; occupying the wheelchair and maneuvering the wheelchair in a rearward direction such that the rear wheels are adjacent to the step; moving the lift alms to the extended position such that the rear step ends are rearward of the outer rims of the rear wheels above the step; lifting the handles of the lift arms to move the rear step ends down to bear against a top of the step and moving the handles upward to exert a force upward and rearward on the axles to roll the rear wheels upward and rearward onto the top of the step; exerting a force on the rear wheels to roll the rear wheels rearward to move the wheelchair rearward until front caster wheels of the wheelchair are adjacent to the step; manipulating the lift lever to push the lift wheel downward and raise the front caster wheels; exerting a force on the rear wheels to move the wheelchair rearward until the front caster wheels of the wheelchair are on the top of the step; moving the lift arms and front lift mechanism to a stored position.
The wheelchair is maneuvered in a rearward direction such that the rear wheels are adjacent to the curb and then manipulates the lift arms to raise the rear wheels onto the curb or step, and then rolls the rear wheels back until the front wheels are at the curb, then manipulates the lift lever to raise the front wheels up so the rear wheels can be rolled back until the front wheels are on the curb. The lift arms and front lift mechanism are moved to a stored position, where they do not interfere with conventional operation of the wheelchair, until required again.
While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:
In operation the wheelchair 5 is maneuvered in a rearward direction such that the rear wheels 11 are adjacent to the step to be climbed, illustrated as a curb 19, as in
As the occupant moves the handles 15 of the lift arms 3 upward the arms 3 pivot about the axles 9, and exert a force F upward and rearward on the axles 9, and the axles 9 move upward and rearward rolling the rear wheels 11 up through the intermediate position of
As seen in the schematic drawings, the lift arms 3 move from a shallow slope upward from their rear ends 13 when first engaging the curb 19 as seen in
In
In any event when needed the lock is released to allow the lift wheel 23 to move down onto the ground as shown in
The apparatus 1 provides a simple mechanism that can be adapted to existing wheelchairs to provide them with the ability to climb a curb or step.
The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention.
Number | Date | Country | Kind |
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2560637 | Sep 2006 | CA | national |
Number | Name | Date | Kind |
---|---|---|---|
3573877 | Locke | Apr 1971 | A |
3976152 | Bell | Aug 1976 | A |
4119163 | Ball | Oct 1978 | A |
4222449 | Feliz | Sep 1980 | A |
4455029 | Taylor | Jun 1984 | A |
5228709 | Kao | Jul 1993 | A |
6554086 | Goertzen et al. | Apr 2003 | B1 |
Number | Date | Country | |
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20080073863 A1 | Mar 2008 | US |