GB2159794A - Elevating attachment for wheelchair - Google Patents

Abstract

A wheelchair elevating a wheelchair to sit at varying attachment enables the occupant of heights. The attachment comprises a first frame 2 and a second frame 22 movable vertically with respect to the first frame. The second frame has means e.g. blades 52 for engagement with the wheelchair e.g. in slideways 88. Means are provided e.g. screw 60 and nut 64 to raise or lower the second frame with respect to the first frame. The horizontal spacing of blades 52 may be adjustable. The elevator may only be operable when blades 52 are latched into slideways 88. <IMAGE>

Description

SPECIFICATION Attachment for a wheelchair This invention relates to wheelchairs, and is particularly concerned with means for elevating such chairs.

Wheelchairs for the use of invalids or partially disabled persons are well-known and generally comprise a chair-like seat mounted conveniently on or within a wheeled frame.

The frame and seat are frequently constructed such that they may be folded or collapsed for easy storage or stowage, e.g. within a car boot.

One disadvantage of the conventional wheelchair is that the height of the seat from floor-level is generally fixed. Although the height chosen may be on the level of a normal chair and therefore acceptable for most purposes, it very often happens that that user needs to be at a level considerably higher than normal, e.g. for activities performed at a kitchen work surface, or at a drawing board.

Wheelchairs are known which have a builtin elevating device whereby the seat portion is raisable with respect to the frame, but such chairs are expensive, heavy to manipulate and are generally not collapsible for ready stowage.

This invention seeks to provide a device which can be readily attached to a wheelchair to enable the entire wheelchair to be raised and lowered to the required height when desired, but which can be detached from the chair when it is not needed, enabling the chair to be used in normal fashion, there being only very little modification necessary to the conventional chair.

According to the invention, a wheelchair elevating attachment comprises a first frame, a second frame movable vertically with respect to the first frame, means attached to the second frame being engageable with at least one component of a wheelchair, and means for raising or lowering the second frame with respect to the first frame.

In one aspect of the invention, a first frame carries a jack which is actuatable to raise and lower a second frame when means attached to the second frame are engaged with a wheelchair.

There will now be described an embodiment of the invention by way of example only with reference to the accompanying drawings in which: Figure 1 is a side elevation of the device, parts of a wheelchair being shown in chain line, Figure 2 is a front view of the device, Figure 3 is a section view of parts of the raising and lowering mechanism of the device, Figure 4 is an exploded view of one of the frames of the attachment, and Figure 5 is a section view on the line V-V of Fig. 1 As seen in the drawings the wheelchair elevating attachment comprises a main frame 2 formed with a vertical post 4 and a base 6 having outriggers 8, 10 each being provided with feet 12, 14. An extension 1 6 carries a roller 1 8 and a handle 20 pivoted to the base 6 is provided for ease of movement of the attachment for storage or stowage.

Vertically movable with respect to the post 4 is a second frame 22 comprising a rigid plate 24 to which is joined, e.g. by welding, a U-section box member 26 having cheek plates 28 which lie on either side of the post 4.

Rollers 30, 32 extending between the plates 28 engage with the post. A similar, but smaller U-section box member 34 having a roller 36 is positioned above the member 26 and is attached to a vertical hollow member 38 which in turn is fixed to the cheek plates 28.

At the top and the bottom of the plate 24 are secured horizontal bars 40, 42 respectively and adjustably mounted on those bars are short box-shaped members 44, 46, these members being connected by vertical bars 48, 50. The lower members 46 have secured thereto by welding, a pair of forwardly extending blades 52.

Mounted between a pair of lugs 54 on the base 6 is a screwjack 56 actuated by an electric motor 58 and comprising a lead screw 60 within a housing 62. The lead screw is raised or lowered by a captive nut 64 having worm teeth on its periphery and rotated through a worm 66 which is formed on a shaft 68 driven by a worm and wheel unit 70 secured to the motor 58 and to the housing 62. The lead screw is prevented from rotating by a key 72 in an upwardly extending part of the housing 62 slideably engaged in a keyway 74 in the screw. A vertically upwards extension of the lead screw is unthreaded and is slideable within a sleeve 76, the topmost end of the extension being secured by a pin 78 to a block 80 and to the sides of the hollow member 38.

An arm 82 extends from the member 38 and carries a flexible extension 84 leading to a push-button switchbox 86. Cables from the switchbox lead to a control box (which is omitted from the drawings for clarity) and to a battery within a suitable covered box mounted conveniently on the base 6, but also omitted from the drawings.

To adapt a conventional wheelchair for use with the above-described elevating device, a pair of slideways 88 are secured to the wheelchair framework 90, either by permanently welding or by removably bolting them thereto, that being the only adaptation required, the blades 52 being adjusted widthwise to align with the slideways.

In use, the occupant first propels the wheel chair, in reverse direction, until the blades 52 fully enter the slides 88, the wheelchair being in its normal out-of-use position. A first button on the box 86 is then depressed which, through the control box, not shown, actuates the screwjack in a sense to raise the frame 2 slightly to lift the base 6 and feet 12, 14 off the ground. The chair can then be propelled to any desirable location in the normal way, carrying with it the elevating attachment.

On reaching the point where the occupant wishes to work, a second button is depressed which actuates the electric motor 58, and, through the worm drives, the screwjack to cause the lead screw to ascend. This raises the members 38 and 28, the plate 24, bars 40, 42 and blades 52 thereby lifting the wheelchair through its attachment by the slideways 88 to the blades. The user merely releases pressure on the button when he desired height is reached, but an over-ride arrangement can be provided to automatically switch off the motor at a predetermined elevation.

To lower the chair, the first button is again depressed which derives the screwjack in reverse direction, a further over-ride arrangement causing automatic cut-off when the wheelchair reaches floor level and the elevating device has been raised slightly off the ground.

Although not shown in the drawings, a latch arrangement is provided and is engaged by part of the slideways 88 to prevent the wheelchair becoming undesirably detached from the elevating device, particularly when in it elevated position. A further electrical interlock arrangement is incorported in the latching system to ensure that the electric motor drive will not operate unless the latch is fully engaged by the slideways.

The use of a double worm and wheel reduction gearing unit makes it possible to use a normal readily available motor car battery to drive the electric motor.

The elevating attachment according to the invention has been found to be comparatively inexpensive to manufacture, operate and maintain. Its design makes the chair stable in use and readily adaptable for almost all existing makes of wheelchairs.

Although the example shown and described includes an electrically operated screwjack, other means may conveniently be provided for elevating the wheelchair engaging blades 52, for example, a hydraulic or pneumatic jack actuated by a suitable hand-operated pump or an electric pump can replace the screwjack.

Claims (9)

1. A wheelchair elevating attachment comprising a first frame, a second frame movable vertically with respect to the first frame, means attached to the second frame engageable, in use, with at least one component of a wheelchair and means for raising or lowering the second frame with respect to the first frame.

2. A wheelchair elevating attachment according to claim 1, wherein the means for raising or lowering the second frame with respect to the first frame comprises a jack carried by the first frame actuatable to raise or lower the second frame with respect to the first frame.

3. A wheelchair elevating attachment according to claim, 1, wherein the jack is electrically operated.

4. A wheelchair elevating attachment according to claim 1, 2 or 3, wherein the means for raising or lowering the second frame with respect to the first frame is controlled by a manually operable switch box mounted on said attachment so as, in use, to be accessible to an occupant of the wheelchair.

5. A wheelchair elevating attachment according to any one of the preceding claims wherein the means attached to the second frame engageable with the wheelchair comprises a pair of substantially horizontally extending blades adapted to engage the sides of the wheelchair.

6. A wheelchair attachment according to claim 5, wherein the horizontal spacing between the blades is adjustable.

7. A wheelchair elevating attachment according to claim 5 or 6, wherein the blades extend forwardly and are adapted to be recieved in slideways provided on the sides of the wheelchair.

8. A wheelchair elevating attachment according to claim 7 wherein a latch arrangement is provided to lock the blades in the slideways, the means for raising or lowering the second frame with respect to the first frame being adapted to operate only when the latch is engaged.

9. A wheelchair elevating attachment substantially as shown in the accompanying drawings and described herein with reference thereto.