CA1304103C - Base clamp - Google Patents

Abstract

ABSTRACT OF THE DISCLOSURE
The present invention relates to manually operable pro-pulsion unit for detachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair which allows the occupant of the wheelchair to propel the wheelchair by means of backwards and forwards motion of a hand lever in addition to the direct drive by means of the hand rail. In particular the invention provides a linkage means detachably attached to each hand rail on the wheelchair and connecting the hand rail with a hand lever pivot-ally mounted on base member means adapted to be detachably att-ached transversely at the frame of the wheelchair such that back and forwards motion of the hand lever in a vertical plane drives its associated wheel of the wheelchair via the attached hand rail, the base member means comprising a pair of base clamps adapted to be clamped on the frame of the wheelchair at trans-versely opposite sides thereof, each of the base clamps having a horizontally extending portion for pivotally mounting the hand lever.

Description

~3~4~C~3 The present invention relates to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair. In particular the present invention relates to a manually operable propulsion unit for the detachable attachment to such a wheelchair which allows the occupant of the wheelchair to propel the wheelchair by means of the backwards and forward motion of a hand lever in addition to the direct drive by means of the hand rails. The present invention also provid~s a converslon kit which on erection provides said unit as well as a wheelchair equipped with said unit.

The normal propulsion of a wheelchair is accomplished by pushing a hand rail attached to the main wheels, or using a hand lever device, or using an electric motor. The steering of the wheelchair is accomplished either by a steering mechanism, or by individually braking the motion of the two main wheels by hand and in such sequence as to change the direction of the wheelchair. Such wheelchairs are disclosed, for example ln V.S.
Patent No. 4,354 to Queen's University, issued 91 October 1982, U.S. Patent No., 4,560,181, issued December 24, 1985 to Design Loft Inc., U.S. Patent No. 3,189,368 to James F. Peterson, issued 15 June 1965, U.S. Patent No. 3,994,509, lssued 28 January 1986 to Jerome E. Schaeffer, U.S. Patent No. ~,453,729, issued 12 June 1984 to Wesley o. Lacken, Canadian Patent No. 1,202,554, issued 1 Apri]. 1986 to Akira Korosue and Canadlan Patent No. 1,026,662 issued 21 February 1978 to Permobilstiftelsen.

All previously known devices used to propel a wheelchair with handle bars are very cumbersome, complicated, very heavy and require that the wheelchair has to undergo extenslve and expensive alterations and changes to accommodate such devices or a completely new and special wheelchair has to be designed and manufactured at exorbitant cost in order to utilize the use of a hand lever propulsion system. The use of a hand ., ~

4~03 lever propulsion system is very desirable as it provides a substantial power to propel the wheelchair, eliminates the tremendous stress and jolting of the arms and especially the shoulders and shoulder joints of the wheelchair user. This is a very severe problem, as documented by the discomfort and inflammation of the shoulder ~oints experienced by Rick ~Ianson on his world tour. Many patients confined to a wheelchair do not have the physical strenyth to propel the wheelchair by pushing the hand rail ring by hand and must rely on the assistance of a person pushing their wheelchair. Electrically propelled wheelchairs which could solve some of the problems, are exorbitantly expensive, heavy, require constant service and are difficult to transpor-t.

The invention of applicant's copending application No.
583l5~ filed ~ugust 22, 1988 and entitled Detachable Manual Propulsion System provides a manually operable propulsion unit which is a self-contained unlt and can be detachably attached to any type of hand rail pushed chair without alterations of the chair very quickly requiring a minimum of tools. Thus the uni-t can be transported to any desired place and quickly mounted on the wheelchair so as to convert the ~hselchair so that it is propellable by the backwards and forwards motion of the hand levers of the propulsion unit in addition to being propellabl~
directly by the hand rails.

In applicant's copending application No.5~3~56 flled August 22, 1988 and entitled Detachable Manual Propulsion Unit the invention provides a linkage means detachably attached to each said hand rail on the wheelchair and connecting said hand rail with a hand lever pivotably mounted on base member means adapted to be detachably attached transversely of the frame of the wheelchair such tha-t back and forwards motion of the hand lever in a vertical plane drives its associated wheel of the wheelchair via the attached hand rail.

130~ 3 According to a particular embodiment of the invention of the copending applicatlon there is provided a manually operable propulsion unit for de-tachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outwardly from the wheels of the chair comprising a pair of rigid support members each adapted to be detachably attached to one said hand rail within the periphery thereof, a rigid elongated base member means adapted to be detachably attached transversely of the frame of said wheelchair, a pair of hand levers pivotally mounted about the horizontal axis of said base member at either side of the wheelchair, a pair of mounting means each on one said rigid support member and a pair of rigid linkages each pivotally mounted at one end to one said mounting means at a point off-center from the center of the hand rail and to an intermediate point on said hand lever whereby the back and forwards motion in a vertical plane of each said hand lever drives its associated wheel of the wheelchair via its attached hand rail. Suitably the rigid support members are straight bars or other shaped cross-bars, such as Y-shaped and X-shaped depending on the type of the wheelchair and the location of the connections between the handrail and the wheel of the wheelchair.

In a particularly desirabl~ embodiment of the invention of the copending application there is provided a manually operable propulsion unit for detachable attachment to a wheelchair in which the wh els are arranged -to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheel of the wheelchair comprising a pair of crossbars each adapted to he detachably attached diametrically across one said hand rail, a basebar adapted to be detachably attached across the frame of said wheelchair, a palr of mounting means on each one of said crossbars extending across said hand rail and a pair of connectlng bars each pivotably mounted at either end to said mounting means at a point off-, ~3~ )3 centre from the centre of the hand rail and to an intermediatepoint on said hand lever bar whereby back and forwards motion in a vertical plane of each of said hand lever bars drives its associated whPel of the wheelchair via its attached hand rail.
Suitably the mounting means is a plate fixedly attached to the crossbar extending across the hand rail. The crossbars adapted to be detachably attached diametrically across the hand rail include adjustment means therein so as to be able to force fitted across internal faces of the hand rail by the adjustment means, which adjustment means preferably comprises a thread and nut means, which adjustment means preferably comprlses a thread and nut means in the crossbar for varying its length. In particular the adjustment means desirably comprises a threaded ad~ustment bolt which slides into a hole drilled lengthwise into the center of the crossbar and an adjustment in length is made by turning the nut on the bolt. Alternatively a right and left turn thread is afixed to the adjustment nut to lengthen or shorten the crossbar to fit securely into a position across the inside of the hand rail. The crossbar suitably has a length of 1 1/2 to 2 feet and is a 1 1/2 to 2 inches square bar of aluminum or steel and has a thread and nut for adjustment to the diameter of the hand rail of the chair. Suitably the ends of the bar are semi-circularly recessed to accommodate the hand rail and more desirably one side of each end of the bar has a round dovetail so as to slide onto the bolts which attach the hand rail to the wheel of the wheelchair which prohibits the tendency of the bar to slide around the hand rail.

The mounting means is suitably a plate located at the centre of the crossbar having a mounting hole *or the end of the connecting bar at a distance from the centerpoint of the wheel and thus the hand rail which is concentric therewith. It is desirable that the plate has several holes at different distances from the centerpoint of the wheel, this gives stroke and leverage adjustment as desired by the occupant of the wheelchair. The lower end of the connecting bar is suitably attached to the plant ~.3~41~3 by a bol-t and bushing.

In a further embodiment of the invention of the copending application the hand lever bar has means for attaching the connection at differe~t points intermediate the end of the bar to provide for stroke lenyth adjustment. Thus the hand lever bar which is suitably about 3 feet in length and 1 1/2 inch square made o aluminum or steel bar is connected to the basebar by a plastic bushing or roller bearing for easy manoeuvreability.
The len~th of the ~oint is usually 2 to ~ inches. The hand lever bars desirabl~ include handles which are adjustable to extend vertically or horizontally from said lever bar. The handles on top of the hand lever bars are suitably plastic with a metal screw and each can be changed to vertical to horizontal operating positio~ by either screwing it on vertically or sideways as desired. The hand lever bars are attached to a basebar suitably at the base at the front wheelchair frame in front of the big wheels and behind the small wheels. The basebar acts as a stabilizer to ensure stability of a folding wheelchair and acts on both sides as a base connection o~ the lever bar. The basebar is detachably clamped to the wheelchair frame, which clamps suitably have wing nuts for easy removal and mounting.

In a particularly desirable embodimen-t of the invention of the copending application in the lower rear frame of the wheelchair another basebar is clamped to provide cross stability, this having particularly good results with collapsible wheelchairs. The front and rear stabilizer basebar may have a centre joint and two side ~oints and appropriate stabilizer clamps and thus will be foldable with the chair without the necessity of detaching the propulsion unit of the present invention. Alternatively the rear stabilizer basebar is suitably a longitudinally adjustable bar suitably by means of screw means therein which is located between the hubs of the large rear wheels of the chair. Alternatively the front basebar may have its central portion between the frame bars of the wheelchair similarly longitudinally extendable by screw means, the ends of the central portion between the frame bars of the wheelchair being removably located in socket end portions of the outer por-tions of the front basebar. Thus, the centre portion can be removed for collapse of the wheelchair. The folding joints suitably have wing nuts for easy removal and moun-ting.

The upper end of the connecting bar suitably extends into an in~slot in the middle of the hand lever bar and desirably a number of holes, suitably three or four holes, are located approximately 1 1/2 to 2 inches apart to allow for stroke length adjustment. The connec-ting bar, is suitably a flat crossbar, and is inserted and secured by a bolt into the selected hole ln the slot in the lever bar for the desired stroke length. The crossbar is suitably of solid aluminum or steel of a 1/4 inch thickness and 1 1/2 inches width and approximately 1 3/4 to 2 feet in length.

Thus, the invention of the copending application provides a manually operatable propulsion unit for detachable attachment to any type of hand rail pushed wheelchair without alterations to the wheelchair in a very few minutes, usually less than 5 minutes, no tools are required, unless for convenience a simple wrench may be used. The unit is light weight weighing approximately about 4 lbs. and adds only a small amount, such as an inch, to the width of the chair and therefore poses no problems in getting!through normal door openings or operating in confined spaces. The propulsion unit is of utmost simplic~ty and reliability and virtually maintenance free. The unit in kit form can easily be taken on journeys, by plane or bus, etcO, by carrying it in a light plastic ~arrying bag approximately one tenth the size of a golf bag. The wheelchair can be left at the beginning of the journey and any other similar wheelchair can take its place at the end of the trip. Upon arrival at the travel destination the unit can be easily attached to any rented or otherwise provided hand rail driven wheelchair by simply ~04~3 changing the length o~ the basebars and the adjustable length of the crossbar. The steering works on the same princlple as manoeuvring a conventional wheelchair pushing the hand rail.
Especially elderly and weaker patients can use the unit easily and without assistance. secause of the very easy and continuous forward and backward rnovement of the lever bars this provldes constant gentle exercise to -the arm and shoulder muscles. This is of great therapeutic value. The marked improvement in the independence and mobility of the patient through use of this unit will have a very positive effect on the psycological welfare of the patient. The handles can be positioned straight upward or level to the left or right to supply a grip position for th0 hands and, at the same time, can provide a resting support for the hands. The device propels the wheelchair forward and backward and steering the wheelchair by holding back or accelerating the movement of the lever bars, or halting the movement of the hand lever bars completely to stop the wheelchair. The unit is very simple and does not require any service or maintenance.

It has now further been found according to the present invention that the basebar which extends across the frame of the wheelchair and upon the ends of which hand levers are pivotally mounted in the propulsion unit of the copending application may be replaced with advantage by a pair of base clamps adapted to be clamped on the frame of the wheelchair at transversely opposite sides thereof, each of the base clamps having a horizontally extending portion for pivotably mountlng on the hand lever.
These base clamps eliminate the necessity for having the basebar and also the stabilizer bar and thus significantly simplify the structure of the unit and with the absence of the basebar and the stabilizer bars the wheelchair folds wihtout the necessity for removal and reattachment of such bars. Furtherr the unit may be attached to and removed *rom the wheelchair much more easily and quickiy with the presence of these base clamps instead of the basebar.

~3~ 1D3 According to the invention therefore there ls provided a manually operable propulsion unit for detachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair comprising base member means adapted to be detachably attached transversely of the frame o~ said wheelchair, a pair of hand levers pivotably mounted about a horizontal axis of said base member means at either side of the wheelchair, a pair of linkage means each detachably connected between one said hand rail and said hand lever such that back and forward motion in a vertical plane of each of said hand levers drives its associated wheel of the wheelchair via its attached hand rall, said base member means comprising a pair of base clamps adapted to be clamped on the frame of the wheelchair at transversely opposite sides thereof, each said base clamps having a horizontally extending portion for pivotally mounted said hand lever.

The present invention also provides a conversion kit for erection of a manually operable propulsion unit for detachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair, said kit comprising base member means adapted to be detachably attached transversely of the frame of said wheelchair, a pair of hand levers adapted to be pivotally mounted about a horizontal axis on said base member each adapted to be detachably connected between one said hand rail and said hand lever such that back and forwards motion in a vertical plane of each of said hand levers in the unit drives its associated wheel of the wheelchair via its attached hand rail, said base member means comprising a pair of base clamps adapted to be clamped on the frame of the wheelchair at transversely opposite sides thereof, each said base clamps having a horizontally extending portlon for pivotally mounting said hand lever.

'13~ 3 In a preferred embodimen-t oE the presenk invention each of the base clamps is adapted to be clamped between a pair o tubes on the frame of the wheelchair. Desirably each of the base clamps is adapted t~ be clamped between a pair of vertlcally spaced adjacent tubes on the frame of the wheelchair.

In a particular embodiment of the present invention each of the base clamps is L-shaped with an obtuse angle between the leg and foot portions with the leg and foot portions each being adapted to be clamped to one of the tubes of the frame of the wheelchair, the foot portion having a bearing for pivotably mounting the hand lever extending outwardly transversely therefrom. Suitably each of the base clamps is longitudinally split into a pair of symmetrical parts, each of the parts having on its inner surface recesses for accommodating the tube of the frame of the wheelchair and screw means for clamping the parts together around the tubes of the frame of the wheelchair.
Preferably -the screw means are wing bolts. However, it will be realized that the shape of the base clamp will depend on the particular structure of the frame of the wheelchair and the clamp may be of other shapes such as straight or L-shape.

The present invention will be further illustrated by way of the accompanying drawings, in which:-Figure 1 is a perspective view of a wheelchairincluding the manually operable propulsion unit including a base clamp according to a preferred embodiment of the present invention; and Figure 2 is an exploded side elevation of the bas~
clamp as shown in Figure 1.

Referring to the Figures, the manually operable propulsion unit comprises a pair of vertically extending hand lever bars 1, each lever bar 1 pivotably mounted at its bottom ~.3(~4~1)3 end to the end of a base clamp 40 mounted in the frame 3 of the wheelchair 4 such that the occupant of the wheelchalr 4 can provide back and forwards mo-tion in a vertical plane of the hand lever bars 1. As seen particularly from ~'igure 2 each the ba~e clamp 2 has at its end a spigot 5 on which a sleeve 6 on the end of each lever bar 1 rota-tes. Sleeve 6 is held by spring cotter pin (not shown), its rotation facilitated by a plastic bushing extending the full length of the sleeve 6. A washer is located on each side oE the sleeve 6. The upper end of each lever bar 1 has a rubber grip handle 20.
As shown in Fig. 2 the base clamp 40 is of L-shaped configuration and is longitudinally split to a pair of symmetrical members 41 having recesses 42 on the Eacing surfaces ad~acent the ends thereof to accommodate the tubes of the frame 3 of the wheelchair 4. The symmetrical members 41 are clamped together over vertically ad~acent tubes of the frame 3 of the wheelchair 4 by means of wing bolts 43 such that the spigots 5 extend outwardly transversely of the frame 3 of the wheelchair 4 and are suitably in alignment. While the base clamp 40 is shown as L-shaped with an obtuse angle between the leg and foot por-tions depending on the structure of the frame 3 of the wheelchair 4, the base clamp may be of o-ther shapes so as to be clamped between adjacent tubes of -the frame 3 of the wheelchair 4 and may, for example, be straight or of T-shaped configuration and may, of course, be clamped between more than two tubes of the frame 3 of the wheelchair 4.

Each base clamp ~0 is clamped to the wheelchalr frame 3 in front of the big wheels and behind the small wheels. There are approximately 5 inches of frame 3 on which the base clamp 40 can be moved forwardly and backwardly thereby adjusting the handle position and the stroke length of the lever bar 1.

Extending across the circular handrail 11 of the wheelchair 4 by which the wheels 12 of the wheelchair 4 are ~3~4~
normally drlven is a Y-shaped bar 13. The Y-shaped bar 13 is securely fastened by turning a nut of an extension bolt 14 in the bar 13. The bar 13 has a mounting plate 15 fixedly attached thereto having a moun-ting hole therein which is off-center from the hub of the wheel 12 of the wheelchair 4 and also from the handrail.

Extending between the lever bar 1 and the mounting plate 15 is a connecting bar 16. A sliding connecting clamp 17 is attached to the lever har 1 and the connecting bar 16 is attached into a receiving slot of the connecting clamp 17 and is held in place by a bolt. The connecting clamp 17 can be moved up and down the lever bar 1 thereby adjusting the stroke length and leverage to any desired position re~uired by the occupant of the wheelchair 4. The connecting bar 16 can move freely as required by the circumference of the circle described by the mounting plate 15 of the Y-shaped bar 13. The distance of the point of attachment of the connecting bar 16 to the mounting plate 15 on th~ U-shaped bar 13 from the center of the wheel 12 and the off-center distance of the point of attachment in relation to the imaginary center crosslines are of vital importance as the particular position produces the zero leverage distance which the propulsion unit has to overcome to approximat.ely 1 inch instead of approximately 6 inches necessary if the connecting bar 16 were attached directly to ths Y-shaped bar 13 and not off-center. It will be recognized that the propulsion unit has a mirror image structure on each side of the wheelchair 4 and that each of the hand lever bars 1 can be operated lndependently of the other and thus the wheelchair 4 can be guided by the mode of the operation of the hand lever bars 1. It will be further recognized that the propulsion of the present invention can be attached to any standard handrail driven wheelchair 4 and thus the structure of the wheelchair does not form a critical part of the present invention can be used with both foldlng and permanently expanded wheelchairs. However, for use with folding wheelchairs it is not necessary to remove the propulsion unit of the present invention ~3 [)~ 3 in order to fold the wheelchair. It is only desirable to remove the propulsion unit of the pr0sent lnvention when it is desired to transport it to another location to a-ttach it to another wheelchair.

For wheelchairs with air tires there are usually more than four bolts holding the handrail 11 to the main wheel 12.
For such wheelchairs, as shown in Figure 1, the bar 13 may be Y-shaped and this generally covers any and all known handrail lo designs. Alternatively it can be X-shaped.
To remove the whole unit from the wheelchair 4, only two wing bolts 42 on each side have to be taken off to remove the base clamps 40. Then the extension bolts 14 on the two Y-Cross bars 13 have to be loosened to remove the whole propulsion unit from the wheelchair 4. No tools are required, because everything is adequately secured by hand tightening. This has also reduced the weight of the unit. The removal and reattachment time has been reduced to a maximum of 3 minutes.

Claims (19)

1. A manually operable propulsion unit for detachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair comprising base member means adapted to be detachably attached transversely of the frame of said wheelchair, a pair of hand levers pivotably mounted about a horizontal axis of said base member means at either side of the wheelchair, a pair of linkage means each detachably connected between one said hand rail and said hand lever such that back and forward motion in a vertical plane of each of said hand levers drives its associated wheel of the wheelchair via its attached hand rail, said base member means comprising a pair of base clamps adapted to be clamped on the frame of the wheelchair at transversely opposite sides thereof, each said base clamps having a horizontally extending portion for pivotally mounted said hand lever.

2. A unit according to claim 1, in which each of the base clamps is adapted to be clamped between a pair of tubes on the frame of the wheelchair.

3. A unit according to claim 2, in which each of the base clamps is adapted to be clamped between a pair of vertically spaced adjacent tubes on the frame of the wheelchair.

4. A unit according to claim 3, in which each of the base clamps is L-shaped with an obtuse angle between the leg and foot portion with the leg and foot portions each being adapted to be clamped to one of the tubes of the frame of the wheelchair, the foot portion having bearing for pivotably mounting the hand lever extending outwardly transversely therefrom.

5. A unit according to claim 4, in which each of the base clamps is longitudinally split into a pair of symmetrical parts, each of the parts having on its inner surface recesses for accommodating the tube of the frame of the wheelchair and screw means for clamping the parts together around the tubes of the frame of the wheelchair.

6. A unit according to claim 5, in which the screw means are wing bolts.

7. A unit according to claim 1, in which each linkage means includes a bar means adapted to extend across the hand rail and detachably attached to the hand rail within the periphery thereof, a mounting means on the bar means and a rigid linkage pivotably mounted on one end of the mounting means at a point off-centre from the centre of the hand rail and to an intermediate point of the hand lever.

8. A unit according to claim 7, in which the bar means is a Y-shaped bar.

9. A wheelchair equipped with a propulsion unit according to claim 1, 2 or 3.

10. A wheelchair equipped with a propulsion unit according to claim 4, 5 or 6.

11. A wheelchair equipped with a propulsion unit according to claim 7 or 8.

12. A conversion kit for erection of a manually operable propulsion unit for detachable attachment to a wheelchair in which the wheels are arranged to be driven by circular hand rails fixedly attached to, concentric with and laterally spaced outside the wheels of the wheelchair, said kit comprising base member means adapted to be detachably attached transversely of the frame of said wheelchair, a pair of hand levers adapted to be pivotally mounted about a horizontal axis on said base member each adapted to be detachably connected between one said hand rail and said hand lever such that back and forwards motion in a vertical plane of each of said hand levers in the unit drives its associated wheel of the wheelchair via its attached hand rail, said base member means comprising a pair of base clamps adapted to be clamped on the frame of the wheelchair at transversely opposite sides thereof, each said base clamps having a horizontally extending portion for pivotally mounting said hand lever.

13. A unit according to claim 12, in which each of the base clamps is adapted to be clamped between a pair of tubes on the frame of the wheelchair.

14. A unit according to claim 13, in which each of the base clamps is adapted to be clamped between a pair of vertically spaced adjacent tubes on the frame of the wheelchair.

15. A unit according to claim 14, in which each of the base clamps is L-shaped with an obtuse angle between the leg and foot portion with the leg and foot portions each being adapted to be clamped to one of the tubes of the frame of the wheelchair, the foot portion having bearing for pivotably mounting the hand lever extending outwardly transversely therefrom.

16. A unit according to claim 15, in which each of the base clamps is longitudinally split into a pair of symmetrical parts, each of the parts having on its inner surface recesses for accommodating the tube of the frame of the wheelchair and screw means for clamping the parts together around the tubes of the frame of the wheelchair.

17. A unit according to claim 16, in which the screw means are wing bolts.

18. A unit according to claim 12, in which each linkage means includes a bar means adapted to extend across the hand rail and detachably attached to the hand rail within the periphery thereof, a mounting means on the bar means and a rigid linkage pivotably mounted on one end of the mounting means at a point off-centre from the centre of the hand rail and to an intermediate point of the hand lever.

19. A unit according to claim 18, in which the bar means is a Y-shaped bar.