WHEELCHAIR PROPULSION KIT

Abstract: A hand or manual propulsion assembly (30, 130) for use with a wheelchair (10) which includes a lever arm (36) journaled to the axis (14, 114) of each of the large wheels (18, 20, 118, 120) on the wheelchair (10) and a crank handle (62) at the end of the lever arm (36, 136) associated with friction pads (58, 60, 158, 160) for engaging the hand rail (26, 126) of the large wheel. When the occupant of the wheelchair (10) rotates and pushes forward or rearward on the crank handles (62, 162) the friction pads (58, 60) come into contact with the hand rail and allows the wheelchair to be propelled forward or rearward.

Description: WHEELCHAIR PROPULSION KIT Technical Field The present invention relates to wheelchairs and more particularly to hand or manual propulsion accessories to enable a wheelchair occupant to more readily propel the wheelchair in forward or rearward directions. Backσround Art Although several hand propulsion devices have been developed for conventional wheelchairs, most wheelchairs are still propelled by the occupant driving the circular hand rail attached to the side of each wheel. The reason appears to be the complexity of operating most such prior art devices. Devices such as shown in U.S. Patents 3,189,368 Petersen 1965; 3,869,146 Bulmer 1975 and 5,263,729 Watwood 1993 are all representative of devices that must engage the periphery of the respective wheel. It is evident that the wheels of a wheelchairs are subject to wear, thereby creating adjustment problems for most of these prior art devices, as well as the fact that the periphery of the wheels collect dirt as well as road salt causing further problems in the operation of these mechanisms.. U.S. Patent 3,877,725 Barroza 1975 and 4,354,691 Saunders et al 1982, describe hand propulsion devices that at least in part engage the hand rail attached to the respective wheels on the wheelchair. Saunders et al includes a complicated structure requiring a specially designed hand rail with a series of openings provided therein to cooperate with a lever arm having a bracket with a lug that must engage the openings in the hand rail when the lever is pressed outwardly and then drives the wheelchair when the lever is pushed forwardly. The Barroza device is somewhat simpler and includes upper and lower pads that jam against the hand rail to push forward or rearward the wheelchair. A brake pad engages the periphery of the wheel. Many older people develop physical handicaps at a late stage in their lives requiring that they adapt them- selves to the confines of a wheelchair and learn how to propel and navigate the wheelchair. Although hand propulsion devices according to the prior art can increase the mechanical advantage and thereby reduce the force that such occupants must exert to propel a wheelchair equipped with such devices, the relatively complicated manipulations required to operate the prior art devices, deters from their use. In practically all prior art hand propulsion devices, the installation of such devices requires alterations to the wheelchair. In many cases, such as Saunders et al, a special hand rail is necessary. Few if any prior art devices can be easily retrofitted to existing wheelchairs. Disclosure Of The Invention It is an aim of the present invention to provide an improved hand propulsion apparatus that can be mounted to existing conventional wheelchairs without modifications to the wheelchair. It is a further aim of the present invention to provide an improved hand propulsion apparatus for a wheelchair that is simpler to operate by the occupant than the devices suggested by the prior art. It is a still further aim of the present invention to provide a manual propulsion kit that is simpler in construction and requires fewer parts than the known hand propulsion devices. A construction in accordance with the present invention comprises a manual propulsion kit for a wheelchair wherein the wheelchair includes a frame with two large wheels on either side of the frame and journaled to axles on the frame, each of the large wheels mounting a circular hand rail, the kit including a pair of manual propulsion assemblies wherein each assembly includes a lever arm adapted to be journaled to the axle for rotational movement within a predetermined angular sector determined by a substantially vertical position and a position forward of the frame, a crank handle having a crank web member pivoted for rotation, at the end of the lever arm adjacent the hand rail when the lever arm is mounted to the axle, about an axis coincident with the lever arm such that the crank member defines an arc and moves between a forward position forward of the lever arm, at a tangent to the hand rail, and a reverse position extending rearward of the lever arm and at a tangent to the hand rail, a crank handle grip mounted to the crank web member, friction means associated with the crank web member adapted to engage the hand rail when pressure is applied to the crank handle grip, when the crank handle is in one of the forward and reverse positions whereby the manual propulsion assembly can be utilized to propel the wheelchair forwardly or rearwardly. More specifically the friction means is in the form of at least a friction pad mounted to a backing plate that is fixedly mounted to the crank handle grip but underneath the crank web and the backing plate with the crank handle grip are journaled to the crank web so that the at least one friction pad can engage the hand rail whether the crank handle is in the forward or reverse position. In another embodiment of the present invention the friction means includes a bracket that is pivotally mounted to the lever arm adjacent and below the crank handle and the bracket includes a forward component extending forward of the lever arm and a rearward component extending rearwardly thereof and both components extend in a plane tangential to the hand rail, and friction pads are mounted to the bracket components adapted to engage the hand rail when pressure is applied to the crank handle in one of the forward and reverse positions. Brief Description Of The Drawings Fig. 1 is a perspective view of a wheelchair incorporating the present invention; Fig. 2 is a side elevation of the wheelchair shown in Fig. 1; Fig. 3 is an enlarged perspective fragmentary view of the present invention ; Fig. 4 is an end elevation of the embodiment shown in Fig. 3 in an inoperative position. Fig. 5 is a top plan view of the embodiment shown in Fig. 4; Fig. 6 is a side elevation of the embodiment shown in Figs. 4 and 5; Fig. 7 is a fragmentary cross-section taken along lines 7-7 of Fig. 5; Fig. 8 is a fragmentary vertical cross-section taken along lines 8-8 of Fig. 5; Fig. 9 is a side elevation showing the present invention in different operable positions; Fig. 10 is a perspective view similar to Fig. 3 showing a different embodiment of the present invention. Fig. 11 is a side elevation of the embodiment shown in Fig. 10 in an operable position; Fig. 12 is a fragmentary cross-section taken along lines 12-12 of Fig. 11; Fig. 13 is a fragmentary top plan view of the embodiment shown in Figs. 10 through 12 but in an inopera- tive position; Fig. 14 is a radial cross-section taken along lines 14-14 of Fig. 13; and Fig. 15 is a side elevation of the embodiment shown in Figs. 13 and 14. Mode For Carrying Out The Invention Referring now to Figs. 1 and 2 there is shown a wheelchair 10 having a frame 12, and axles 14 extending on the either side of the frame to mount large wheels 18 and 20. As on conventional wheelchairs small caster wheels 22 and 24 are located on the front of the frame 12. The large wheels 18 and 20 both mount a circular hand rail 26. Since both sides of the wheelchair are mirror images, only wheel 18 will be described. Thus, wheel 18 has a peripheral rubber tire 28. As seen in Figs. 1 and 2, and more specifically in Fig. 3, a manual propulsion assembly 30 is provided. The manual propulsion assembly 30 is journaled to the axle 14 as shown in Figs. 3 and 4 and is maintained by thrust bearings 40 and 42. A washer 32 is fixed to the axle 14, and may be tack welded to the head 14a of the axle 14. An angular segment 34 is cut out in the washer 32 to accommodate a pin 38 mounted to the lever 36. As will be seen, the cut out portion 34 will limit the rotational travel of the lever 36. A pin 38 on lever arm 36 will travel in cut out portion 34 and will come into contact with the ends of the cut out portion 34 limiting the rotation of lever arm 36. The angular sector defined by the cut out portion 34 is preferably 35°. The top of the lever arm 36 as shown in Figs. 3 to 6 is provided with a platform 44 at an angle of 90° to the plane of the lever arm 36. The platform 44 intersects the plane of the hand rail 26 as shown in Fig. 7. A pivot pin 46 is mounted on the lever arm 36 below the platform 44 to mount rocker bracket 48 which is allowed to rotate about the pivot pin 46. The rocker bracket 48 includes a pair of wings 50 and 52. As shown in Fig. 6, a spring 54 urges the rocker bracket 48 to a neutral position. The wings 50 and 52 are angled and their axial components extend over the hand rail 26 as shown in Fig. 8. Both wings 50 and 52 are provided with rubber pads 58 and 60 respectively. For instance the rubber pad 58 includes an axial component 58a and a radial component 58b mounted within the wing 50 of the rocker bracket 48. Likewise, rubber pad 60 includes an axial component 60a and a radial component 60b. It is clear that any pressure which is ultimately applied to wing 50 or wing 52 will cause the pad component 58 or the pad component 60 to frictionally engage the hand rail 26 as will be described further. Mounted to the platform 44 is a crank handle 62 having a crank web 70. A pivot pin 64 mounts the crank web 70 for rotational movement about the axis X as shown in Fig. 3. A handle grip 68 is journaled to the crank web 70. A spring mounted detent 66 projects below the handle grip 68 and crank web 70. The crank web 70, in this particular embodiment, is a flat strap of spring steel. The wings 50, 52 each include a slot 72 or 74 and recesses 76, 78, respectively. For instance, when (Fig. 9) the handle grip is grasped by an occupant in the wheelchair and pushed forward relative to the frame the detent 66 enters the slot 74 and engage the recess 78. Further force applied forward on the grip 68 will cause rocker bracket 48 to rotate and the pad 60a to engage the hand rail 26, and entrain the hand rail to move forward, thereby moving the wheel 18. When the lever arm has reached its forward limit, the pressure on the grip 68 is released and the crank handle 62 and lever arm 36 are returned to the almost vertical position shown in Fig. 2, and the action is repeated. If both propulsion assemblies 30 are simultaneously operated in this manner, the wheelchair will advance. If it is required to reverse the movement of the wheelchair the hand grip 68 and web 70 can be rotated about the axis X until the detent 66 engages in the slot 72 and recess 76 on the wing 50. Further downward pressure will bend the crank web 70 and thus rotate the rocker bracket to frictionally press the pad 58a against hand rail 26. Further rearward force by the occupant simultaneously on both propulsion assemblies 30 will cause the hand rails 26 to move and thus entrain the wheels 18 and 20 to rotate rearwardly moving the wheelchair rearwardly. Then the pressure is released and this action is repeated. If it is required to turn the wheelchair the propulsion mechanisms can be operated in an inverse direction, that is with one hand grip being moved forwardly while the other hand grip is rotated and moved rearwardly. In order to apply the brakes to the wheelchair the handle grips 68 are moved inwardly towards the wheelchair 10 so that the friction pads 58b or 60b come into frictional engagement with the hand rail 26. Referring now to Figs. 10 through 15 there is shown another embodiment of the present invention. All the elements which are similar to elements in the embodiment of Figs. 1 to 9 have been designated by similar reference numerals but have been raised by 100. Fig. 10 shows the manual propulsion assembly 130 including a lever arm 136 journaled to the axle 114. A washer 132 having an angular segment 134 cut out therein is provided for limiting the rotation movement of the lever arm 136. This movement is limited by the interaction of rib 138 in the cut out segment 134. The washer 132 is fixed to the axle 114, and as shown in Figs. 14 and 15 thrust bearings 140 and 142 maintain the lever arm 136 in a proper radial plane relative to the axle 114. The top of the lever arm 136 is provided with a platform 144 which extends at 90° from the lever arm 136, over the hand rail 126. In fact in the present embodiment, the hand rail 126 may be a circular flange extending outwardly of the rim of wheel 118. In the event the manual propulsion assembly is integrated in the manufacture of the wheelchair, a hand rail per se may not be necessary but the — o — flange 126 will be required in order to cooperate with the manual propulsion assembly as will be described. The platform 144 has a short upwardly extending flange 147 which will act as a stopper as will be described. As shown in Figs. 10 through 15, a crank web 170 is pivotally mounted by pivot pin 164 to the platform 144 to allow the crank web 170 to rotate about an axis X and to form an arc between two positions, one forward of the lever arm and one rearward thereof, where the web 170 is somewhat tangential to the hand rail 126. The flange 147 will limit this arc to 180°. In the present embodiment, the hand grip 168 is mounted to a shaft 169 (as shown in Fig. 13) which in turn is journaled to the web 170 allowing the hand grip 169 to swivel relative to the crank web 170. A bracket 145 is fixedly mounted to the shaft 169 below the web 170 such that the bracket 145 will rotate in unison with the handle grip 168 relative to the crank web 170. The bracket 145 mounts a friction pad 159, which may be a rubber pad, with an axial component 159a and a radial component 159b. A bump 139 is located on the underside of crank web 170 and will engage either recess 141 or 143 in platform 144 when the crank web 170 is in either the forward or rearward position. In operation, when it is required to advance the wheelchair 10, the handle grip 168 is moved forwardly of the lever arm 136 by rotating the hand grip 168, and thus the crank web 170 about the pivot pin 164 to the point where the hand grip 168 is over the hand rail 126 as shown in Fig. 11. By pushing forward on the hand grip 168 the spring steel crank web 170 will bend slightly, allowing the friction pad 159a to come into contact and frictionally engage the hand rail 126. By pushing further on the hand grip 168 towards the dotted lines position shown in Fig. 11, the hand rail 126 will be entrained and thus the wheel 118 and the wheel- chair will move forward. This is similar to the operation of the embodiment shown in Figs. 1 to 9. An abutment 161 is provided on the bracket 145 to engage the sides of web 170 and limit the rotation of the bracket 145 to 180°. In order to reverse the direction of the wheel- chair, the handle grip 168 is rotated away from the hand rail 126 through its reverse arc as shown in Fig. 13 to the position shown in dotted lines where it is over the hand rail 126 but rearward of the lever arm 136. Pressing downwardly or rearwardly on the hand grip 168 will cause the web 170 to give a little, where the friction pad 159 on the bracket 145 will come into contact with the hand rail 126 and further rearward force on the hand grip 168 will entrain the hand rail 126 and therefore the wheel 118 rearwardly, thereby moving the wheelchair in a rearward direction. If it is necessary to apply the brakes it is merely necessary to move the hand grips 168 inwardly towards the occupant whereby the radial component of the friction pad 159b will come into contact with the sides of the hand rail 126, and this whether the hand grip is in a forward or rearward position. The bracket 145 must be maintained in an aligned position so that it contacts the hand rail 126 properly. However, the width of the bracket 145 will ensure that, when the hand grip 168 is moved towards the hand rail, it will align itself in the same radial plane as the hand rail 126.

Claims: CLAIMS 1. A manual propulsion kit for a wheelchair when the wheelchair includes a frame with two large wheels on either side of the frame journaled to axles on the frame, each of the large wheels mounting a circular hand rail, the kit including a pair of manual propulsion assemblies wherein each assembly includes a lever adapted to be journaled to one of the axles for rotational movement within a predetermined angular sector determined by a substantially vertical position and a position forward of the frame, a crank handle having a crank web member pivoted for rotation, at the end of the lever arm adjacent the hand rail when the lever arm is mounted to the axle, and about an axis coincident with the lever arm such that the crank member defines an arc and moves between a forward position forward of the lever arm at a tangent to the hand rail, and a reverse position extending rearwardly of the lever arm and at a tangent to the hand rail, a crank handle grip mounted to the crank web member, friction means associated with the crank web member adapted to engage the hand rail when pressure is applied to the crank hand grip when the crank handle is in one of the forward and reverse positions whereby the manual propulsion assembly can be utilized to propel the wheelchair forwardly or rearwadly. 2. A manual propulsion kit as defined in claim 1, wherein the crank web is a flexible member. 3. A manual propulsion kit as defined in claim 2, wherein the friction means comprises at least a friction pad mounted to a backing plate which is fixedly mounted to the crank handle grip, underneath the crank web, such that the backing plate and the crank handle grip are journaled to the crank web whereby the at least one friction pad can engage the hand rail when the crank handle is in one of the forward and reverse positions and pressure is applied by the occupant of the wheelchair to manually propel the wheelchair by applying further rotational force to the crank handle when the friction pad is in contact with the hand rail. 4. The manual propulsion kit as defined in claim 3, wherein the backing plate is in the form of an angle bracket and the friction pad is an elastomeric pad having an axial component and a radial component wherein the axial component of the friction pad is mainly utilized when the occupant applies force on the handle grip to propel the wheelchair, and the radial component is mainly utilized when the occupant applies lateral inward force to the handle grips such that the radial component of the friction pad presses against the hand rail to brake the movement of the wheelchair . 5. The manual propulsion kit as defined in claim 3, wherein the lever arm includes a platform at the free end thereof adjacent the hand rail and the platform extends at a right angle intersecting the radial plane of the hand rail, and the crank web is pivotally mounted to the platform and stop means are provided on the platform to limit the arc of rotation of the crank member to 180°. 6. The manual propulsion kit as defined in claim 5, wherein the backing plate is provided with a stop member to engage the crank web and limit the rotation of the handle grip and backing plate relative to the crank web to 180°. 7. The manual propulsion kit as defined in claim 4, wherein the elastomeric pads are rubber. 8. The manual propulsion kit as defined in claim 3, wherein the friction means includes a bracket which is pivo- tally mounted to the lever arm for rotation about an axial axis parallel to the axle, the bracket is adjacent and below the crank handle and includes a forward component extending forward of the lever arm and a rearward component extending rearwardly thereof, and both components extend in the plane tangential to the hand rail, friction pads are mounted to the bracket forward and rearward components and are adapted to alternatively engage the hand rail when pressure is applied to the crank handle in one of the forward and reverse positions. 9. The manual propulsion kit as defined in claim 8, wherein spring means extend between the bracket and the lever arm to maintain the bracket out of contact with the hand rail when pressure is not being applied to the bracket by the crank handle. 10. The manual propulsion kit as defined in claim 8, wherein the bracket has a radial component and each of the forward and rearward components includes axial flanges intersecting the radial plane of the hand rail, the friction pads are mounted to the flanges and to the radial portion of the forward and rearward components of the bracket, the flanges are provided with crank arm receiving seats whereby when the crank arm is rotated to one of the forward and rearward components a detent on the crank arm will engage the respective seats whereby when the occupant of the wheelchair applies pressure to the handle grip the pressure is transmitted from the flexible crank web to one of the forward and rearward components of the bracket to press the axial friction pad against the hand rail whereby further force applied to the handle grip will propel the wheel. 11. The manual propulsion kit as defined in claim 9, wherein the crank web is flexible. 12. The manual propulsion kit as defined in claim 10, wherein the friction pads are rubber. 13. The manual propulsion kit as defined in claim 10, wherein the lever arm and its ends opposite from the axle includes a platform extending at right angles to the axis of the arm, the platform intersecting the radial plane of the hand rail and the crank handle is pivotally mounted to the platform on the lever arm and limit means are provided on the platform for limiting the rotational arc of the crank handle to 190°. 14. A wheelchair comprising a frame with two large wheels, one on either side of the frame, and journaled to axles on the frame, each of the large wheel mounts a circular hand rail, a pair of manual propulsion assemblies one associated with each wheel and each assembly including a lever arm journaled to the respective axle for rotational movement in a radial plane within a predetermined angular sector determined by a substantially vertical position and a position forward of the frame, characterized by a crank handle having a crank web member pivoted for rotation at the end of the lever arm adjacent the hand rail, the crank web member rotating about an axis coincident with the lever arm such that the crank member defines an arc and moves between a forward position forward of the lever arm at a tangent to the hand rail and a reverse position extending rearwardly of the lever arm and at a tangent to the hand rail, a crank handle grip mounted to the crank web member, friction means associated with the crank web member adapted to engage the hand rail when pressure is applied to the crank handle grip when the crank handle is in one of the forward and reverse positions whereby the manual propulsion assembly can be utilized to propel the wheelchair forwardly of rearwardly.

Inventors: MITCHELL RAYMOND L, MITCHELL, RAYMOND, L.
Applicants: MITCHELL RAYMOND L, MITCHELL, RAYMOND, L.
Application year: 1997
Main classification: A61G5
IPC codes: A61G5