GB2269145A

GB2269145A - Wheelchair wheel with self-contained motor

Info

Publication number: GB2269145A
Application number: GB9315590A
Authority: GB
Inventors: Roy Higgins
Original assignee: Individual
Current assignee: Individual
Priority date: 1992-07-30
Filing date: 1993-07-28
Publication date: 1994-02-02
Also published as: GB9315590D0; GB9216210D0

Abstract

The wheelchair comprises a frame supporting a seat and has a pair of motor driven wheels 16 wherein the motor 32, 50, 132 for each wheel is mounted within the wheel. Pinions 42, 44 driven by the motor 32, Fig.2, mesh with a circular rack 46 formed in a compartment 30 in the wheel. The batteries 35 may be located adjacent the motor. Alternatively, Fig.4, the motor 50 is coupled to a 90 degree reduction gearbox 58 the final gear 60 of which meshes with a toothed belt 62 which drives a toothed ring 64 formed in the wheel compartment 68. In a further alternative, Fig.6, the final drive gear 140 meshes with an internal ring gear 142, which is part of the front plate 144 of the wheel. <IMAGE>

Description

Title: Improvements in and relating to wheelchairs DESCRIPTION This invention concerns improvements in and relating to wheelchairs.

Motorised wheelchairs have brackets fitted to their frame to support motors and batteries for driving main wheels of the wheelchair. Such motors and batteries are generally heavy and have to be removed before the wheelchair can be folded for storage in a vehicle boot or before being hoisted into a vehicle using a proprietary wheelchair hoist. Therefore, a disabled person will almost always require assistance at the beginning or end of a journey by vehicle, which can be restrictive.

An object of the present invention is to provide an improved wheelchair- that may overcome the abovementioned disadvantages.

According to the present invention there is provided a wheelchair comprising a frame supporting a seat and having a pair of motor driven wheels, wherein the motor for each wheel is mounted within the wheel.

The invention further comprehends a wheel for a wheelchair having a motor mounted within the wheel for driving same.

Preferably each said wheel has a motor that is fixed relative to an axle for the wheel which is itself fixed, wherein the motor is arranged to drive the wheel about the axle. The motor preferably has a drive shaft with means for engaging a wheel part for driving the wheel about the axle. That may be achieved in any suitable way.

In one preferred embodiment, the motor has a drive shaft with a pinion gear thereon that meshes with a circular rack formed within the wheel to drive the wheel.

In another preferred embodiment, the motor has a drive shaft with a gear driven thereby, which gear meshes with a toothed belt or chain which itself engages a complimentary toothed ring formed within the wheel to drive the wheel.

In yet another preferred embodiment the motor has a drive shaft with a gear driven thereby, which gear meshes with a ring gear formed within the wheel, such as of the type on a vehicle starter ring, to drive the wheel. Preferably the gear rotates about an axis parallel to the wheel axle and meshes with a circular internal ring gear of the wheel.

In any embodiment of the invention reduction gearing may be desirable or necessary between the motor and the drive gear, whereby the size of the motor required may be kept to a minimum. For the latter two preferred embodiments a 900 reduction gearbox may be advantageously used for that purpose.

The wheel motors will typically be battery powered. The batteries used are preferably of the rechargeable type. Gel-filled nickel cadmium batteries may be suitable for use in the invention.

It is further preferred that a motor and battery or batteries therefor be housed in a compartment within the wheel circumference and that the wheels be mounted to the wheelchair frame by quick-release mechanisms.

The wheels themselves are preferably made as slim as possible so that the wheelchair may be folded up in a conventional manner without the wheels having to be removed.

The wheelchairs of the invention will ideally have hand operated control means for the motorised wheels, such as of the joystick type, and the control means is preferably connected to the wheel motors by quick release couplings, such as of a bayonet type.

Battery charging circuitry is preferably also connectable to the wheels and hence the battery or batteries via the same couplings.

The wheelchairs of the invention will have a pair of conventional balancing wheels for stability usually in front of the drive wheels. Additionally means, such as additional wheels, may be provided at the rear of the wheelchairs of the invention to guard against tipping backwards of the wheelchair.

The invention will now be further described, by way of example only, with reference to the accompanying drawings, in which Figure 1 is a side view of a wheelchair according to the invention Figure 2 is a side view of a first drive arrangement for the wheelchair of Figure 1; Figure 3 is a section along a diameter of the wheel of Figure 2; Figure 4 shows a second drive arrangement for the wheelchair of Figure 1; Figure 5 shows a third drive arrangement for the wheelchair of Figure 1; and Figure 6 is a section along a diameter of the wheel of Figure 5.

Referring to Figure 1 of the accompanying drawings, a wheelchair 10 has a frame 12 which carries a seat 14, the frame being supported on two pairs of wheels 16 and 18. Rear wheels 16 are the drive wheels and are independently motorised as will be described later or may be rotated by hand using conventional circular hand rails 20 secured to the outside of the wheels. Front wheels 18 are freely rotatable and are provided for stability. The wheels 16 are shown having inflatable tyres 19 on wheel rims 21. The wheel rims 21 have spaced arcuate openings 23 near their peripheries in order to reduce weight.

The frame 12 also has a pair of handles 22 by which the wheelchair may be pushed, if desired. A pair of trailing wheels 24 are also provided to prevent the wheelchair from tipping backwards.

The driven rear wheels 16 are controlled by a joystick control 26 conveniently located at one end of one of a pair of arm rests 28 for the wheelchair. The joystick control 26 is adapted to control speed and direction of the wheelchair. Turning of the wheelchair around corners is achieved by differential speeds of rotation of the drive wheels 16. Speed of forwards and reverse movement of the wheelchair is controlled rheostatically.

The drive wheels 16 may be of the type shown in Figures 2 and 3, in Figure 4 or in Figures 5 and 6 of the accompanying drawings. In Figures 2 and 3 each wheel 16 is provided with a compartment 30 about its axis. The compartment 30 contains a 24 volt motor 32 coupled to a fixed spindle 34 along the axis of the wheel. A pair of 12 volt rechargeable batteries 35 are fitted either side of the motor to provide electrical power therefor. The batteries and the motor are actually mounted on base plate 36 within the compartment rigidly fixed to the spindle.

The motor 32 has a drive shaft 40 extending from opposite ends of the motor. On one end of the drive shaft 40 is a drive pinion 42 and on its other end is an idle pinion 44. Both pinions 42, 44 mesh with a circular rack 46 formed at the periphery of one side 47 of the compartment 30. In order to be able to -use the smallest motor possible, reduction gearing is provided between the motor and the drive pinion but is not shown here. The other side of the compartment is provided by a removable cover plate 38. The side 47 of the wheel may be open to facilitate making electrical connections direct to the base plate 36 for the motor and/or batteries The arrangement is such that when the motor is switched on its shaft rotates to turn the wheel around the spindle. Bearings 48, 49 are shown between the spindle 34 and the front and back faces of the compartment 30.

The wheels 16 are intended to be attached to the frame of the wheelchair by quick release mechanisms which will include connection means for control unit 26 and for battery recharging, such as a bayonet type connector In Figure 4 there is shown an alternative drive means for the wheels 16, wherein a motor 50 and batteries 52 are again fixed to a base plate 54 rigidly attached to a fixed spindle 56 forming the axle for the wheel. The motor has a drive shaft (not shown) that is coupled to 900 reduction gearbox 58. The gear box 58 has a final gear 60 that meshes with a toothed belt 62 which in turn meshes with a toothed ring 64 formed on a wall 66 of compartment 68 of the wheel.

Thus, as the gear 60 is rotated by the motor, the toothed belt is driven and that in turn drives the wheel round.

As an alternative to the embodiment of Figure 4 of the drawings, instead of acting on a toothed belt, a gear connected to the reduction gearbox may act on a ring gear coaxial with the wheel, for example, similar to that on a vehicle starter ring is shown in Figures 5 and 6 of the accompanying drawings.

Referring to Figures 5 and 6 of the accompanying drawings, each wheel 16 is provided with a compartment 130 about its axis. The compartment 130 contains in one part a 24 volt motor 132 coupled to a back plate 134 which is itself fixedly mounted on a fixed spindle 136 that is attached to the wheelchair frame. In another part of the compartment is fixed a battery (not shown) for powering the motor 132.

The motor 132 has a drive shaft 138 on which is mounted a drive gear 140. The drive gear 140 meshes with a circular internal ring gear 142 fitted to or formed as part of front plate 144 of the wheel which is freely rotatable about spindle 136. Reduction gearing is provided between the motor and the drive gear 140.

The arrangement is such that when the motor is switched on it rotates the gear 140 which in turn drives the wheel 16 around the spindle 136 by means of ring gear 142.

In other respects the wheel of Figures 5 and 6 is similar to that of- Figures 2 and 3.

The illustrated wheelchair drive arrangements may have several advantages over known arrangements. An important feature of the drive wheels 16 for the wheelchair 10 is that the motor and batteries are concealed within the wheels rather than mounted under the wheelchair. By careful selection of the components for such as system weight can be controlled so as not to reduce manoeuvrebility unduly. Furthermore, wheelchairs including the illustrated drive arrangements may be aesthetically pleasing, as motors, batteries and control gear are hidden rather than being visibly mounted on brackets etc attached to the wheelchair frame Sec Secondly, one of the constraints have of other arrangements is that the motor and batteries to be removed before a wheelchair can be loaded into the boot of a motor vehicle. For a disabled person that can be extremely difficult and usually requires an assistant.

That is true of the illustrated arrangements but at least only the wheels have to be removed, although a fit person could probably lift the complete wheelchair.

However, where a vehicle is fitted with a wheelchair hoist, which will load a wheelchair when folded, the illustrated wheelchair arrangements allow the wheelchair to be folded in the normal manner, so that a disabled person does not necessarily require travel assistance

Claims

CLAIMS 1. A wheelchair comprising a frame supporting a seat and having a pair of motor driven wheels, wherein the motor for each wheel is mounted within the wheel.
2. A wheelchair as claimed in claim 1, wherein each wheel has a motor that is fixed relative to an axle for the wheel which is itself fixed, wherein the motor is arranged to drive the wheel about the axle.
3. A wheelchair as claimed in claim 1 or 2, wherein the motor has a drive shaft with means engaging a wheel part for driving the wheel about the axle.
4. A wheelchair as claimed in claim 3, wherein the motor has a drive shaft with a pinion gear thereon that meshes with a circular rack formed within the wheel to drive the wheel.
5. A wheelchair as claimed in claim 3-, wherein the motor has a drive shaft with a gear driven thereby, which gear meshes with a toothed belt or chain which itself engages a complimentary toothed ring within the wheel to drive the wheel.
6. A wheelchair as claimed in claim 3, wherein the motor has a drive shaft with a gear driven thereby, which gear meshes with a ring gear formed within the wheel.
7. A wheelchair as claimed in claim 6, wherein the gear rotates about an axis parallel to the wheel axle and meshes with a circular internal ring gear of the wheel.
8. A wheelchair as claimed in any one of claims 1 to 7 including reduction gearing between the motor and the drive gear.
9. A wheelchair as claimed in claim 8, wherein reduction gearing is provided by a 900 reduction gearbox.
10. A wheelchair as claimed in any one of claims 1 to 9, wherein the motors are battery powered.
11. A wheelchair as claimed in claim 10, wherein the batteries are rechargeable.
12. A wheelchair as claimed in claim 11, wherein the batteries are gel-filled nickel cadmium batteries.
13. A wheelchair as claimed in any one of claims 1 to 12, wherein the motor and a battery therefor are housed in a compartment within the wheel circumference.
14. A wheelchair as claimed in any one of claims 1 to 13, wherein the wheels are mounted the frame by quickrelease mechanisms.
15. A wheelchair as claimed in any one of claims 1 to 14 further comprising hand operated control means for the motorised wheels.
16. A wheelchair as claimed in claim 15, wherein the control means is of a joystick type.
17. A wheelchair as claimed in claim 15 or 16, wherein the controls means is connected to the wheel motors by quick-release couplings.
18. A wheelchair as claimed in claim 17, wherein the quick-release couplings are of the bayonet type.
19. A wheelchair as claimed in any one of claims 1 to 18 further comprising a pair of balancing wheels for stability.
20. A wheelchair as claimed in claim 19, wherein the balancing wheels are in front of the drive wheels.
21. A wheelchair as claimed in any one of claims 1 to 20, further comprising additional wheels at the rear of the wheelchair.
22. A wheelchair substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3, Figures 1 and 4 or Figures 1, 5 and 6 of the accompanying drawings.
23. A wheel suitable for a motorised wheelchair, wherein the motor is mounted within the wheel.
24. A wheel as claimed in claim 23, wherein the motor is fixed relative to an axle for the wheel which is itself fixed, wherein the motor is arranged to drive the wheel about the axle.
25. A wheel as claimed in claim 23 or 24, wherein the motor has a drive shaft with means engaging a wheel part for driving the wheel about the axle.
26. A wheel as claimed in claim 25, wherein the motor has a drive shaft with a pinion gear thereon that meshes with a circular rack formed within the wheel to drive the wheel.
27. A wheel as claimed in claim 25, wherein the motor has a drive shaft with a gear driven thereby, which gear meshes with a toothed belt or chain which itself engages a complimentary toothed ring within the wheel to drive the wheel.
28. A wheel as claimed in claim 25, wherein the motor has a drive shaft with a gear driven thereby, which gear meshes with a ring gear formed within the wheel.
29. A wheel as claimed in claim 28, wherein the gear rotates about an axis parallel to the wheel axle and meshes with a circular internal ring gear of the wheel.
30. A wheel as claimed in any one of claims 23 to 29 including reduction gearing between the motor and the drive gear.
31. A wheel as claimed in claim 30, wherein reduction gearing is provided by a 900 reduction gearbox.
32. A wheel as claimed in any one of claims 23 to 31, wherein the motors are battery powered.
33. A wheel as claimed in claim 32, wherein the batteries are rechargeable.
34. A wheel as claimed in claim 33, wherein the batteries are gel-filled nickel cadmium batteries.
35. A wheel as claimed in any one of claims 23 to 34, wherein the motor and a battery therefor are housed in a compartment within the wheel circumference.
36. A wheel as claimed in any one of claims 23 to 35, wherein the wheel is mountable on a frame by a quickrelease mechanism.
37. A wheel suitable for a wheelchair substantially as hereinbefore described with reference to and as illustrated in Figures 1 to 3, Figures 1 and 4 or Figures 1, 5 and 6 of the accompanying drawings.