GB2210589A

GB2210589A - Improvements in foldable electric wheelchairs

Info

Publication number: GB2210589A
Application number: GB8723416A
Authority: GB
Inventors: James Francis Slasor; John Michael Singleton
Original assignee: Spastics Society
Current assignee: Spastics Society
Priority date: 1987-10-06
Filing date: 1987-10-06
Publication date: 1989-06-14
Also published as: GB8723416D0

Abstract

An electric wheelchair foldable to a compact folded condition has opposed main side frames 10 each mounting a front castor wheel 17 and a rear wheel 28 driven by a respective electric motor 30 positioned inboard of the wheel 28 and powered by a respective battery housed in a panier 33 mounted between upper and lower cross members 13, 14 of the side frame 10. The side frames 10 are connected by links 44, 45, Fig 2, at the front and rear which permit the side frames 10 to be brought into close proximity on folding with the batteries in situ and a respective back member 16 extending upwardly from each side frame 10 is pivotal about pin 57 rearwardly of the side frame 10 to reduce the overall height of the wheelchair in the folded condition. <IMAGE>

Description

IMPROVEMENTS IN FOLDABLE ELECTRIC WHEELCHAIRS This invention concerns improvements in foldable electric wheelchairs.

It is already known to provide wheelchairs having a foldable frame. It is also known to provide electrically powered wheelchairs having foldable frames mounting at least two driven ground engaging wheels, each such driven wheel having an associated electric motor for controlled drive of the wheel through a controller connected to an electric power source comprising at least one battery.

In such electrically powered wheelchairs there are difficulties in folding the wheelchair to a sufficient compact size for useful portability. Some difficulties arise from the arrangement of the electric motors relative to the wheels and frame as the motors project or protrude a fixed distance and thereby limit clearance for folding proximity. Other difficulties arise from the limitations in the frame design and arrangements for supporting the power source battery or batteries.

It is an object of this invention to provide an improved electric wheelchair which has a special design of frar;L and rotor drIve to enable thc aheelz > .air te bo folded to a particular compact condition.

It is a further object of this invention to provide an electric wheelchair having a special construction of frame for folding the wheelchair.

Other objects of this invention include providing an electrically powered wheelchair which is simple to fold and/or erect and which is of lightweight design.

Further objects of this invention will be made apparent later herein with reference to an exemplary embodiment of the invention.

According to this invention we provide an electrically powered wheelchair having two main side frames connected together by foldable links, each side frame mounting a front caster wheel and a rear driven wheel with an electric motor associated with said rear driven wheel mounted inboard of the wheel and having its major axis extending parallel to the plane of rotation of the wheel, each side frame further supporting one of two a side mounted batteries arranged for connection to the respective motors through a controller mounted on one side frame for access and use by the user, the two side frames being also connected together by a seat panel of flexible material that is arranged to fold between the side frames when the links are folded, each side frame having pivotally connected thereto a rearwardly extending back member arranged for folding movement rearwardly of the associated side frame with a back panel of flexible material extending between said back members that is also arranged to fold between the back members when folded rearwardly of of the side frames and when the side frames are moved towards each other on closing of the foldable links.

B this arrangement of the invented electrically powered wheelchair, the overall height of the wheelchair can be reduced on folding by the rearward movement of the back members into the folded rearward position, and the two side frames are brought into close proximity on folding movement of the links with the respective electric motors being adjacent to each other inboard of their associated driven wheels. As the batteries are each mounted on a side frame, these can be maintained in situ on folding movement or, if desired can be removed for transport or storage of the wheelchair in the folded condition.

In a preferred construction of the invented wheelchair, there is a foldable back link extending between the back members with the back link being arranged to maintain the link secure in the extended position when the wheelchair is in the erected condition.

Such back link provides a support to maintain the wheelchair in the elected condition and ensures that the back members are held in the correct attitude relative to each other. Conveniently, such back link may be arranged as two arms, each pivotally connected at one end to a back member with the other ends being pivotally connected together for relative folding with an over-centre action to maintain the two arms secure when in the extended condition.

Preferably, the foldable links connecting the side frames include a rear foldable link also having two arms of which one end of each are pivotally connected to a rear member of a respective side frame with the other ends of the arms being pivotally connected together for relative folding with an over-centre action to maintain the two arms secure when in the extended condition. In addition to the rear foldable link, there is preferably a front link connected between forward portions of the two side frames and the front link would also comprise two pivotally mounted connected arms with an over-centre action. The front link is for maintaining the forward portion of the wheelchair in a stable condition in the erected condition.

Conveniently, the invented wheelchair may be provided with footrest assembles for detachable support on the front or forward end of each side frame, and these assemblies can be removed to reduce the overall size and weight of the wheelchair in the folded condition.

The invented wheelchair may also include arm rest assemblies which are mounted on each side frame and each arm rest assembly includes a support arm that extends between the forward end of the respective side frame and the associated back member remote from the pivotal connection to the rear member of the side frame. Such support arm may be detachably mounted to the side frame and the back member for removal when the wheelchair is folded, and the support arm may also be arranged to provide stability to the wheelchair when in the erected condition.

Other preferred features of the invented wheelchair will be described later herein with reference to an exemplary embodiment of the invention, but it should be noted that such features do include the detachable support of the controller and an electrical harness arranged with quick-fit connectors for the electrical power drive and control.

An exemplary embodiment of the invention will now be described with reference to the accompanying drawings wherein: - FIGURE 1 is an elevation of one side of an exemplary wheelchair shown in the erected condition; FIGURE 2 is a front elevation of the erected wheelchair as shown in Figure 1; FIGURE 3 is a further elevation on the other side of the erected wheelchair as shown in Figure 1; FIGURE 4 is a rear elevation of the erected wheelchair as shown in Figure 1; FIGURE 5 is a top plan view of the erected wheelchair as shown in Figure 1; and FIGURE 6 is a detail enlarged view showing the inboard mounting and arrangement of one driven wheel of the exemplary wheelchair.

FIGURES 7, 8, 9 and 10 are detail views of detachable parts of the exemplary wheelchair being, respectively, one arm rest assembly, the other arm rest assembley with controller a footrest assembly and a battery pannier.

FIGURE 11 is a side elevation of the wheelchair with the detachable parts removed and depicting the rearward folding of the back members.

FIGURE 12 is a top plan view of the exemplary wheelchair in the compact folded condition; FIGURE 13 is a side elevation of the wheelchair in the compact folded condition as shown in Figure 12; and FIGURE 14 is a rear view of the wheelchair in the compact folded condition as shown in Figure 12.

FIGURE 15 is a rear view of the wheelchair with detachable parts removed and depicted in the closed frames condition with the links folded; and FIGURE 16 is a front view of the wheelchair as shown in Figure 15.

The exemplary wheelchair as shown in the various Figures comprises two main side frames 10 which are similar. Each side frame 10 has a front member 11 and a rear member 12 that are connected together by upper and lower cross members 13,14. A hinge block 15 is mounted on the upper portion of each rear member 12 and connected to this are back members 16 arranged either to extend contiguously with the associated rear member 12 in the erected condition of the wheelchair as shown in Figure 1, or to be folded rearwardly relative to the associated rear member in the compact folded condition of the wheelchair as depicted in Figures 11, 12, 13 and 14.

The front member 11 of each side frame 10 has a dependent front caster wheel 17 supported therefrom.

Each front member 11 also mounts a detachable footrest assembly 18 having a quick release bracket 19 at one end of a stem 20 with the other end of the stem supporting a footplate 21 mounted by a rotatable tube 22 for adjustable and swivelling or adjusting movement of the footplate 21 relative to the stem 20 and bracket 19.

As best shown in Figure 6, the rear member 12 of each side frame 10 supports a wheel plate 23 connected to the associated rear member 12 by a bracket 24 with a resilient bushing 25 for resilient spring support from the frame 10. Each wheel plate 23 is similar and has a rear extension 26 mounting an anti-tip wheel 27. Each wheel plate 23 supports a ground engaging wheel 28 that extends outboard of the wheel plate 23 and which has a drive coupling (not shown) to a gearbox 29 integral with an electric motor 30 arranged for power driving of the vileel 2 . The major awis 30x of the electric motor extends parallel to the plane of rotation of the wheel but is inboard of the wheel.

By such an arrangement, the electric motors 30 on each side of the wheelchair do not protrude outwardly of the wheelchair and the motors only protrude inboard of the wheel plate 23 by a short distance which is less than in other forms of such electric drives in which the electric motors have their major axis aligned with the axis of rotation of the driven wheel.

Each electric motor 30 is connected to an electric wiring harness 31 having quick release couplings 32 of known kind. The power source for the motors 30 is provided by two batteries (not shown). Each battery is housed and mounted in a respective panier 33 detachably mounted between respective upper and lower cross members 13,14 of the associated side frame 10.

With particular reference to Figure 10, the panniers 33 are each similar and comprise a box-like base 34 and a removable lid 35. Metal straps 36,37 are connected to the front and rear walls of the base 34 and extend upwardly to be joined together by a grab handle 38 by which the pannier may be lifted with the battery inside. At the upper end of each strap 36,37 there are connectors 39,40 for respective detachable connection to bosses on the associated side frame 10.

The base 34 has an opening 41 (see Figure 4) through which the cable of the wiring harness 31 extends.

The operation of the motors 30 for controlled driving of the wheelchair is through a joystick 42 with associated control box 43 that is connected to the wiring harness 31 in known manner.

The two side frames 10 are connected together by a iront link 44 and a rear lirk 45. tach of these links 44,45 is foldable and of known form comprising two opposed arms, each arm having one end pivotally connected to the associated opposed side frames with the other ends being pivotally connected together for folding movement. The front link 44 has secondary arms 44a pivotally extending over the main link arms to provide a scissor action locking arrangement. In the rear link 45 the link arms have a slight offset or crank so that the pivot axis at the centre of the link is not aligned with the opposed outer pivot centres.

When the arms of this rear link 45 are in the extended condition, then the link 45 is maintained in the extended over-centre position to preclude inadvertent folding movement.

The back members are also connected together by a back link 46 which is of two-armed type similar to the rear link 45 with an over-centre action to preclude inadvertent folding movement.

A seat panel 47 is stretched and extends between the upper members 13 of each side frame 10, and a back panel 48 is stretched between each back member 16.

Each of these panels 47,48 is of flexible material, and may be wrapped around each frame member to secure the opposed marginal edges of the panels thereto. In addition, an optional tray panel 49 is depicted which extends between the lower members 14 of each side frame 10, and this is of similar material and can be used as a parcel or like shelf when the wheelchair is in the erected condition.

Detachably mounted on each side frame is an arm rest assembly 50. Each arm rest assembly 50 is similar as depicted best in Figures 7 and 8, and comprises a rest 51 and a side panel 52 which are secured to & support bar 53. The upper end of the front member 11 of the side frame 10 provides a socket to receive the forward end of the support bar 53. The rear end of the support bar 53 is connected to the back member 16 by a pin 54 and slot 55 connection. The support bar 53 is detachable from the side frame 10 by lifting the forward end of the bar and then sliding the rearward end of the bar until the pin 54 projecting from the back member 16 is disengaged from the specially shaped slot 55.

The control box 43 with joystick 42 may be mounted to the support bar and/or the upper cross member of the associated side frame for detachment therewith when required and as shown in Figure 8. The panel 52 may be relieved or recessed to provide a clearance for the box 43.

As will now be appreciated, the support bar 53 of each arm rest assembly 50 extends between the back member 16 and the front member 11 so as to hold the back member 16 securely in the upright or erected position as shown in Figure 1, and the support bar 53 provides extra rigidity to the wheelchair when erected.

When the respective support bars 53 are connected to the associated front members 11 of the frame and the associated back members 16, then the back members 16 cannot be folded about the hinge block 15 into the rearwardly folded position as shown in Figures 11,12, 13 and 14.

Each back member 16 is connected to the hinge block 15 by a rearwardly extending lug 56 through which a pivot pin 57 extends. The upper end of the rear member of the frame 10 provides an open end for receiving a sliding locking tube (not shown) received within the adjacent end of the back member and which is located for sliding movement by a pin 58 projecting through a slot 59 in the back member 16. To hold the back member 16 in the erected or upright position such as shown in Figure 1, the locking tube is received within the open top of the rear member 12 to locate the two members together in alignment.To release the connection, the pin 58 with locking tube is moved to the other end of the slot 59 and then the locking tube is lifted clear of the rear member 12 so that the back member 16 can be swung about the pivot pin 57 in a rearward direction as shown by the arrow in Figure 11 after the support bar 53 has been disengaged as previously described.

The rearward movement of the back members 16 after removal of the arm rest assembly reduces the overall height of the wheelchair, and for some purposes this may be sufficient. However, the wheelchair may be folded further by closing the two side frames 10 towards each other.

For such inward folding of the wheelchair as shown in Figures 15 and 16, the back link 46 and the rear and front links 45,44 are each folded so that the side frames 10 can be pushed together to reduce the overall width of the wheelchair. The seat, tray and back panels 47,49,48 fall into a folded state between the members to which they are connected due to the flexible nature of the material of which the panels are made.

The two main side frames 10 can be pushed into close proximity as shown in either Figure 14 or Figure 15 with the electric motors 30 lying closely adjacent to each other inboard of the wheels 28.

As will be appreciated in some cases, the back members 16 may not be required to be folded rearwardly, and all that may be needed is to inwardly fold the wheelchair to reduce its width, for example to negotiate a narrow doorway or aisle.

Before or after such folding of the wheelchair, the batteries in their respective panniers 33 can be removed after uncoupling the connections 32 of the wiring harness 31 where appropriate. The footrest assemblies 18 can be removed from the front members 11 of the side frames 10, and the controller 43 can also be removed after uncoupling the connections 32 of the wiring harness 31 where appropriate.

Such removed and uncoupled component assemblies or parts can be handled, moved or stored separately whilst the wheelchair in the very compact folded form can be lifted by strap handles 60 provided on the upper frame members 13 or can be manouvred upon its own ground engaging caster and driving wheels.

In known manner, the frame members may be of light alloy and be tubular. The panniers for the batteries may be of lightweight plastics material and the footrest assembly can also be of light alloy.

The arrangement for the drive transmission to the driven wheels from the associated motors may include a right-angle drive through a worm gear to the gearbox which is coupled to a drive shaft of the driven wheel.

Means for uncoupling or de-clutching the connection between the gearbox and the drive shaft of each wheel may be provided. In known manner, steering of the wheelchair when in use may be achieved by differential control of the drive to each wheel through the joystick controller.

Under certain conditions of use, some of the removable or detachable component parts or assemblies may be received for transport or storage within the folded portion of the seat panel extending between the side frames.

From the foregoing description of the invented foldable wheelchair, those skilled in this field will appreciate the advantages and merits of the design and construction of the wheelchair and the advantages achieved thereby.

Claims

Claims:

1. An electrically powered wheelchair having two main side frames connected together by foldable links, each side frame mounting a front castor wheel and a rear driven wheel with an electric motor associated with said rear driven wheel mounted inboard of the wheel and having its major axis extending parallel to the plane of rotation of the wheel, each side frame further supporting one of two side mounted batteries arranged for connection to the respective motors through a controller mounted on one side frame for access and use by the user, the two side frames being also connected together by a seat panel of flexible material that is arranged to fold between the side frames when the links are folded, each side frame having pivotally connected thereto an upwardly extending back member arranged for folding movement rearwardly of the associated side frame with a back panel of flexible material extending between said back members that is also arranged to fold between the back members when folded rearwardly of the side frames and when the side frames are moved towards each other on closing of the foldable links.

2. A wheelchair according to Claim 1 wherein the foldable links comprise a rear link and a front link.

3. A wheelchair according to Claim 2 wherein each rear link comprises two arms, each pivotally connected at one end to a respective one of the side frames with the other ends pivotally connected together for relative folding with an over-centre action to maintain the two arms secure when in the extended condition.

4. A wheelchair according to Claim 2 wherein each front link comprises two main arms, each pivotally connected at one end to a respective one of the side frames with the other ends pivotally connected together for relative folding and two secondary arms pivotally extending over the main arms to provide a scissor action locking arrangement when in the extended condition.

5. A wheelchair according to any one of the preceding Claims wherein the back members are connected together by a foldable back link.

6. A wheelchair according to Claim 5 wherein the back link comprises two arms, each pivotally connected at one end to the associated back member with the other ends pivotally connected together for relative folding with an over-centre action to maintain the two arms secure when in the extended position.

7. A wheelchair according to any one of the preceding Claims wherein the front or forward end of each side frame carries a detachable footrest assembly.

8. A wheelchair according to any one of the preceding Claims wherein each side frame mounts an armrest assembly.

9. A wheelchair according to Claim 8 wherein each armrest assembly is detachable.

10. A wheelchair according to Claim 8 or Claim 9 wherein each armrest assembly includes a support arm that extends between the forward end of the associated side frame and back member.

11. A wheelchair according to any one of the preceding Claims wherein each battery is housed and mounted in a respective panier detachably mounted between upper and lower cross members of the associated side frame.

12. A wheelchair according to Claim 11 wherein each panier comprises a box-like base and a removable lid.

13. A wheelchair according to any one of the preceding Claims wherein each driven rear wheel and associated motor is supported by a respective wheel plate resiliently mounted on the associated side frame.

14. A wheelchair according to Claim 13 wherein each wheel plate has a rear extension mounting an anti-tip wheel.

15. A wheelchair according to any one of the preceding Claims including means for uncoupling or de-clutching the drive connection between each rear wheel and the associated motor.

16. A wheelchair according to any one of the preceding Claims wherein the controller includes a joystick for controlling the drive to each driven rear wheel.

17. A wheelchair according to any one of the preceding Claims wherein the controller is detachable.

18. A wheelchair according to any one of the preceding Claims including a wiring harness releasably connected to the batteries, motors and controller.

19. A wheelchair according to any one of the preceding Claims including a foldable panel of flexible material extending between the side frames beneath the seat panel.

20. An electrically powered wheelchair substantially as hereinbefore described with reference to the accompanying drawings.