IE86876B1

IE86876B1 - A wheelchair drive mechanism

Info

Publication number: IE86876B1
Application number: IE20120203A
Authority: IE
Inventors: Cunningham Kevin; Canney Sean; Morrow Peter; Burke Michael
Original assignee: Folding Attic Stairs Ltd
Priority date: 2011-04-21
Filing date: 2012-04-23
Publication date: 2018-02-21
Also published as: GB201207099D0; IE20120203A1; GB201106805D0; GB2490579B; GB2490579A; IES86073B2

Abstract

A manually operable wheelchair drive mechanism (30) has a support plate (9) for attachment to a wheelchair frame (6). A drive pinion (14) is rotatably mounted on the support plate (9). The drive pinion (14) drivably connects through a freewheel unit (18) with a wheelchair wheel to drive the wheelchair wheel. A drive lever (31) has an arcuate arm (33) with fear teeth (34) which drivably engage an intermediate gear (16) which in turn drives the drive pinion (14) for moving the wheelchair wheel forward with each push stroke of the drive lever (31). Alternatively, the pivot (37) of the drive lever (31) can be mounted at a second mounting position on the support plate (9) such that he gear teeth (34) on the drive lever (31) directly engage the drive pinion for moving the wheelchair wheel forward with each pull stroke of the drive lever (31). <Figure 7>

Description

This invention relates to manually operable wheelchair drive mechanisms.

Background to the Invention Generally speaking, wheelchairs are driven either by an assistant pushing the wheelchair or by the occupant gripping and turning the wheels at each side of the wheelchair. However, many wheelchair users have limited physical strength and thus find it difficult to drive the wheelchair on their own. This can be very inconvenient, as an assistant is not always available to push the wheelchair on their behalf. Problems can also arise in maintaining control of the wheelchair on ramps and slopes.

A number of manually operable wheelchair drive mechanisms are known. For example, WO 2007/125341 discloses a manually operated wheelchair drive mechanism comprising a drive lever pivotally mounted at a side of a wheelchair with an arcuate drive chain segment at a lower end of the lever to drivably engage a drive sprocket connected to a rear wheel of the wheelchair. Pivoting the lever causes rotation of the drive sprocket and hence the wheel to drive the wheelchair forward. Various other lever operated wheelchair drive mechanisms are shown for example in BE 1013717, SU 1773402, CN 2920206 and JP 2007282870. It would appear that such lever operated wheelchair drive mechanisms have, to date, been somewhat unsatisfactory as they are not in widespread use. Possibly in some cases this is because their complexity makes them relatively expensive to manufacture. Also, they do not appear to be easily adaptable to the particular needs and comfort of different users.

The present invention is directed towards overcoming these problems. -2It is an object of the present invention to aid wheelchair users in manually driving and controlling a wheelchair on their own, even where such users may have limited physical strength.

It is a further object of this invention to provide a wheelchair drive mechanism of relatively simple construction which is reliable in operation and relatively economical to manufacture.

Summary of the Invention According to the invention there is provided a manually operated wheelchair drive mechanism, including; a support for attachment to a wheelchair; a drive pinion rotatably mounted on the support; the drive pinion drivably connecting through a freewheel unit with a wheelchair wheel mount; a drive lever pivotally mounted intermediate its ends on the support by a pivot, said drive lever having a handgrip at one side of the pivot and having an arcuate drive gear at an opposite side of the pivot; and means for pivotally mounting the drive lever on the support in one of a first drive lever mounting position and a second drive lever mounting position on the support, when in the first drive lever mounting position, said arcuate drive gear being drivably engagable with the drive pinion mounted on the support, and when in the second mounting position on the support, said arcuate drive gear being drivably engagable with an intermediate gear rotatably mounted on the support and drivably connecting between the arcuate drive gear and the drive pinion.

Thus, advantageously the drive lever may provide drive to the wheelchair wheel by -3either a pushing motion or a pulling motion on the drive lever, whichever is most comfortable for the user.

In one embodiment of the invention, the drive lever is adjustably mounted on the support for selective driving engagement with either the drive pinion or the intermediate gear.

In another embodiment, the arcuate drive gear is provided at a lower end of the drive lever.

In another embodiment the drive lever has a C-shaped crank at a lower end of the drive lever, said crank having an arcuate arm with an array of gear teeth extending along an outer face of the arm, a cylindrical boss at an inner end of the crank having a through-bore for reception of a pivot pin for pivotally mounted the drive lever on the support, a handle extending radially outwardly of the boss and terminating in a handgrip.

In a further embodiment the drive lever is cranked intermediate its ends.

Conveniently an adjustable handle is mounted at an upper end of the drive lever.

In another embodiment the handle is rotatably mounted at the upper end of the drive lever for adjustment of the handle, there being provided a locking mechanism for locking the handle in a selected position of use.

In a further embodiment the handle is cranked.

In another embodiment a wheel brake mechanism is provided.

In another embodiment, the wheel brake mechanism includes a brake actuator mounted on the drive lever and operably connected to a braking device mounted on the support.

In a further embodiment the brake actuator is a brake lever mounted on the drive -4lever.

In another embodiment the wheel brake mechanism comprises a brake disc on the wheel mount and having an associated calliper which is connected to the brake actuator element on the handle.

In another embodiment a parking brake is provided. Conveniently the parking brake is operable to releasably lock the wheel brake mechanism in a braking position.

In another aspect the invention provides a wheelchair incorporating a wheelchair drive mechanism of the type described herein.

Brief Description of the Drawings The invention will be more clearly understood by the following description of some embodiments thereof, given by way of example only, with reference to the accompanying drawings, in which: Fig. 1 is a perspective view of a wheelchair drive mechanism according to the invention; Fig. 2 is an elevational view of the wheelchair drive mechanism; Fig. 3 is an elevational view showing a wheel mounted on the drive mechanism; Fig. 4 is an elevational view, similar to Fig. 2, showing the wheelchair drive mechanism in another position of use; Fig. 5 is an elevational view similar to Fig. 4 showing the wheelchair drive mechanism in use; Fig. 6 is a perspective view of a wheelchair incorporating the wheelchair -5drive mechanism of the invention; Fig. 7 is a perspective view of another wheelchair drive mechanism according to the invention, shown mounted on the frame of a wheelchair; Fig. 8 is an elevational view of the wheelchair drive mechanism shown in Fig. 7; Fig. 9 is a detail perspective view of portion of a wheel brake mechanism incorporated in the wheelchair drive mechanism of Fig. 7; Fig. 10 is a perspective view of another wheelchair drive mechanism according to the invention; and Fig. 11 is a detail elevational view of an alternative brake lever arrangement for use with the wheelchair drive mechanism of the invention.

Referring to the drawings, and initially to Figs. 1 to 6 thereof, there is illustrated a wheelchair drive mechanism according to the invention indicated generally by the reference numeral 1. The wheelchair drive mechanism 1 is shown mounted on a wheelchair 2 in Fig. 6 for driving a wheel 3 of the wheelchair 2. Two of the wheelchair drive mechanisms 1 are provided for the wheelchair 2, one for driving each wheel 3 of the wheelchair 2. The wheelchair 2 has a seat 5 mounted on a metal frame 6 which is supported on the wheels 3 and an associated pair of front caster wheels 7 in the usual way.

The wheelchair drive mechanism 1 comprises a metal support plate 9 for attachment to the frame 6 of the wheelchair 2 as shown in Fig. 6. A drive lever 10 is pivotally mounted intermediate its ends by a pivot pin 11 on the support plate 9. In normal use with the wheelchair 2 standing on a horizontal surface the pivot pin 11 is substantially horizontal and thus the lever 10 is pivotally movable in a substantially vertical plane.

The drive lever 10 has an arcuate drive gear 12 at a lower end of the drive lever 10. -6A drive pinion 14 is rotatably mounted on the support plate 9 by an axle 15 which is parallel to the pivot 11 supporting the drive lever 10. An associated intermediate gear 16 is also mounted by a pivot shaft 17 on the support plate 9. The axle 15 and the pivot shaft 17 have parallel rotational axes. Together the drive gear 12, the intermediate gear 16 and the drive pinion 14 form a gear train as shown in Figs. 1 and 2 in one position of use.

It will be noted that the pivot 11 for the drive lever 10 is adjustably mounted on the support plate 9. Thus, the drive lever 10 can be mounted in a first position, as shown in Figs. 1 and 2 in which the drive gear 12 drivably engages the intermediate gear 16 which in turn drivably engages the drive pinion 14. Thus, the drive pinion 14 is rotated in the required direction by pushing on the drive lever 10 to drive the wheel 3 of the wheelchair 2 in a forward direction.

Figs. 4 and 5 show the pivot 11 mounted in an alternative position on the support plate 9 such that the drive gear 12 directly engages the drive pinion 14 to rotate the drive pinion 14 in the required direction to drive the wheelchair 2 forward by means of a pulling action on the drive lever 10. Thus, advantageously the drive mechanism 1 can be set up on the wheelchair 2 so that the user of the wheelchair 2 can drive the wheelchair 2 by either a pushing motion or a pulling motion on the drive lever 10, whichever is the most comfortable for the particular user.

An adjustable handle 20 is mounted by a pivot mount 21 at an upper end of the drive lever 10. This pivot mount 21 is operable so that the handle 20 can be pivotally moved into the most comfortable operating position for the user of the wheelchair 2 as shown by arrow A in Fig. 4 and then locked in the chosen position of use.

It will also be noted that the handle 20 is cranked having an inner portion 23 pivotally mounted by pivot mount 21 on the drive lever 10 and an outer portion 24 angled outwardly of the inner portion 23. The handle 20 can be reversed on the pivot mount 21 to provide further adjustment. In this regard a first orientation of the handle 20 is shown in Fig. 1 and a second orientation of the handle is shown in Fig. 4. -7ln use, a pair of the wheelchair drive mechanisms 1 are mounted one at each side of the wheelchair 2 on the frame 6, the mounting plates 9 being attached to the frame 6 in any suitable fashion. When fitting the wheelchair drive mechanism 1 to the wheelchair 2, the drive lever 10 is positioned as required on the support plate 9 in engagement with either the intermediate gear 16 or the drive pinion 14 so that in use the drive lever 10 will provide drive during either a pushing or pulling motion on the drive lever 10 as required. A user then sitting in the wheelchair 2 simply grips the handles 20 to manipulate the drive levers 10 back and forth to provide forward drive to the main wheels 3 of the wheelchair 2. The freewheel unit 18 disengages the drive on each return stroke of the drive lever 10 whether it is set up for drive by a pushing or pulling motion.

While in the drawings, the wheels 3 of the wheelchair 2 are shown as being independently driven by wheelchair drive mechanisms 1 of the invention, it is envisaged that in some cases, it may be desirable to interconnect the wheelchair drive mechanisms 1 at each side of the wheelchair 2.

It will be appreciated that various different configurations and arrangements of drive lever and drive gears may be provided within the scope of this invention.

It is also envisaged that the wheelchair drive mechanism 1 of the invention can be either retro-fitted to an existing wheelchair 2, or could be built into a wheelchair 2 during manufacture, in which case the support 9 could be an integral part of the wheelchair frame 6. The construction and design of the support 9 may change as required to accommodate different wheelchair 2 designs.

Referring now to Figs. 7 to 9, another wheelchair drive mechanism according to a second embodiment of the invention is shown and indicated generally by the reference numeral 30. Parts similar to those described previously are assigned the same reference numerals. In this case the wheelchair drive mechanism 30 has a drive lever 31. The drive lever 31 has a lower end formed by a C-shaped crank 32 having an arcuate arm 33 on an outer face of which is a drive gear formed by gear teeth 34 for drivably engaging the intermediate gear 16. A cylindrical boss 36 at an -8upper end of the crank 32 is pivotally mounted by a pivot pin 37 on the support plate 9. A handle 38 projects outwardly from the boss 36 and terminates in a hand grip 39.

In this case also a braking mechanism is provided comprising a brake lever 40 pivotally mounted at the hand grip 39 and operably connected via a brake line 42 with an associated calliper 43 mounted on the support plate 9. This calliper 43 is mounted at a complementary brake disc 45 which is connected to a wheel of the wheelchair, to allow braking of the wheel of the wheelchair. The brake lever 40 operates a master hydraulic cylinder 46 which communicates through the hydraulic brake line 42 with an associated slave cylinder in the calliper 43 for actuating the calliper 43 to clamp the brake disc 45 to provide the braking action.

A parking brake 50 is also provided on the hand grip 39 for locking the brake lever 40 in a braking position if desired. The parking brake has a spindle 51 biased downwardly by a spring 52 against an outwardly projecting finger 53 at an inner end of the brake lever 40. To apply the parking brake 50, the brake lever 40 is squeezed moving the brake lever 40 upwardly towards the hand grip 39. The spindle 51 engages in a notch 54 formed between the finger 53 and the brake lever 40 to hold the brake lever 40 in a braking position. To release the parking brake 50, the brake lever 40 is simply squeezed and released to cause the spindle 51 to disengage from the notch 51 and allow the brake lever 40 to return to the released position.

Operation of the wheelchair drive mechanism 30 is similar to the wheelchair drive mechanism described previously. In this case however, it will be appreciated that the braking mechanism provides additional control of the wheelchair, for example when travelling down slopes, or indeed for locking the wheelchair in a desired position by actuating the parking brake mechanism 50.

Referring now to Fig. 10 there is shown the wheelchair drive mechanism 30 in another position of use. In this case, the drive lever 31 is located at a second drive lever mounting position on the support plate 9. The intermediate gear has been omitted and the gear teeth 34 on the crank 32 directly engage and drive the drive pinion 14. Thus, the drive lever 31 can be operated by means of a pulling motion to -9drive the wheelchair forward.

Fig. 11 shows an alternative brake lever assembly for use with the wheelchair drive mechanisms of the invention, said brake lever assembly being indicated generally by the reference numeral 60. The brake lever 60 has a body 61 with a clamp 62 for attachment of the brake lever assembly 60 to the handgrip 39 of the drive lever 31. A brake lever 63 is pivotally mounted by a pivot pin 64 on the body 61. A brake cable 65 is connected to the brake lever 63. Cable tension can be adjusted if required by means of a cable adjuster 66. A parking brake is provided by a locking button 67 which can be pressed into the body 61 to retain the brake lever 63 in a squeezed braking position applying tension to the brake cable 64.

The invention is not limited to the embodiments hereinbefore described which may be varied in both construction and detail within the scope of the appended claims.

Claims

1. A manually operated wheelchair drive mechanism, including: a support for attachment to a wheelchair; a drive pinion rotatably mounted on the support; the drive pinion drivably connecting through a freewheel unit with a wheelchair wheel mount; a drive lever pivotally mounted intermediate its ends on the support by a pivot, said drive lever having a handgrip at one side of the pivot and having an arcuate drive gear at an opposite side of the pivot; and means for pivotally mounting the drive lever on the support in one of a first drive lever mounting position and a second drive lever mounting position on the support, when in the first drive lever mounting position, said arcuate drive gear being drivably engagable with the drive pinion mounted on the support, and when in the second mounting position on the support, said arcuate drive gear being drivably engagable with an intermediate gear rotatably mounted on the support and drivably connecting between the arcuate drive gear and the drive pinion.

2. The wheelchair drive mechanism as claimed in claim 1, wherein the drive lever is adjustably mounted on the support for selective driving engagement with either the drive pinion or the intermediate gear.

3. The wheelchair drive mechanism as claimed in claim 1 or claim 2, wherein the arcuate drive gear is provided at a lower end of the drive lever.

4. The wheelchair drive mechanism as claimed in any preceding claim wherein the drive lever has a C-shaped crank at a lower end of the drive lever, said crank having an arcuate arm with an array of gear teeth extending along an -11 outer face of the arm, a cylindrical boss at an inner end of the crank having a through-bore for reception of a pivot pin for pivotally mounted the drive lever on the support, a handle extending radially outwardly of the boss and terminating in a handgrip.

5. The wheelchair drive mechanism as claimed in any preceding claim wherein the drive lever is cranked intermediate its ends.

6. The wheelchair drive mechanism as claimed in any preceding claim wherein the handgrip comprises an adjustable handle mounted at an upper end of the drive lever.

7. The wheelchair drive mechanism as claimed in claim 6 wherein the handle is rotatably mounted at the upper end of the drive lever for adjustment of the handle, there being provided a locking mechanism for locking the handle in a selected position of use.

8. The wheelchair drive mechanism as claimed in claim 6 or claim 7 wherein the handle is cranked.

9. The wheelchair drive mechanism as claimed in any preceding claim wherein a wheel brake mechanism is provided.

10. The wheelchair drive mechanism as claimed in claim 9 wherein the wheel brake mechanism comprises a brake disc on the wheel mount and having an associated calliper which is connected to a brake actuating element on the handle.

11. The wheelchair drive mechanism as claimed in claim 9 or claim 10, wherein a parking brake is provided which is operable to releasably lock the wheel brake mechanism in a braking position.

12. A wheelchair incorporating a wheelchair drive mechanism as claimed in any preceding claim.