GB2090564A - Modular wheelchair - Google Patents

Abstract

A wheel chair comprises an undercarriage comprising a chassis in the form of a sheet metal pan 1 having a pair of main bearer wheels 6 journalled in its side walls 3 at an upper point generally towards a rear end of the chassis. A pair of castor wheels 8 are mounted generally towards a front end of the chassis, and a seat mounting 10 is carried by the chassis and adjustable into a raised position above the chassis and into a folded position within the chassis. A seat structure is carried on the seat mounting, the interconnection between the seat structure and the seat mounting being such that the seat structure is adjustable fore and aft relative to the seat mounting and is also removable from the seat mounting and replaceable in fore and aft reversed position thereon, and also on the undercarriage support when the latter is inverted. <IMAGE>

Description

SPECIFICATION Modular wheelchair This invention relates to a wheelchair, primarily intended for propulsion by the occupant using a conventional hand-wheel at each side, but capable also of being propelled by conventional motor means.

The object of the invention is to provide an improved wheelchair which is so constructed as to be capable of a large number of adjustments and re-arrangements of its components so as to be able to fulfil different functions and requirements, particularly those of reversibility of the main seat structure relative to the undercarriage, removability of the seat structure to permit use as a medi-chair, and inversion of the undercarriage relative to the seat structure.

According to the present invention a wheelchair comprises an undercarriage with a rigid support having a pair of main bearer wheels journalled at an upper point generally towards a rear end of the support and a pair of castor wheels mounted generally towards a front end of the support, a seat mounting carried by the support and adjustable into a raised position above the support and into a folded position within the support, and a seat structure carried on the seat mounting, the interconnection between the seat structure and the seat mounting being such that the seat structure is adjustable fore and aft relative to the seat mounting and is also removable from the seat mounting and replaceable in fore and aft reversed position thereon and also on the undercarriage support when the latter is inverted.

The support of the undercarriage is advantageously in the form of a sheet metal pan with a base and side and front and rear walls, the main bearer wheels being journalled in the side walls, and the castor wheels being mounted on extensions of the side walls.

The seat mounting may be in the form of a collapsible "X" frame of which one arm is pivoted to the undercarriage support and to a seat slide, and the other arm is pivoted to the seat slide and is engaged in a runner guide on the undercarriage support to permit the whole to be adjusted between raised and stowed positions.

The seat structure comprises essentially a base and a backrest, to which there may optionally be added arm rests and footrests. The base of the seat is adapted to engage onto the seat slide and to be adjustable fore and aft of the wheelchair. It can also be removed entirely from the undercarriage structure to permit the seat structure to be used as a carrying chair. The seat base and the underside of the undercarriage support are also provided with co-operating means such that, if the undercarriage support is inverted, the seat base can then be engaged thereon and is likewise adjustable fore and aft of the wheelchair.

The backrest is preferably pivotably adjustable with respect to the base. Where arm rests are provided, these are advantageously pivoted in cantilever manner on the backrest, and are preferably movable into, and adjustable in, a forwardly projecting position in which they serve as arm rests, and a stowed position in which they lie adjacent to and aligned with the backrest.

The backrest may be provided with a pusher bar, and advantageously this is pivotably connected to the backrest so as to be capable of height adjustment, and also being stowed away in a position closed against the rear of the backrest.

The backrest may be provided with a headrest, and preferably this is adjustable for height and/or forward projection, for example by an eccentric cam mounting. Similarly, there may be provided a lumbar support at a lower point of the backrest, and adjustable in similar manner.

Where footrests are provided, these are preferably mounted on the front edge of the seat base, and are advantageously adjustable fore and aft, e.g. by pivoting with respect to the base. The footrests are preferably adjustable in length, and where foot plates are provided these are preferably pivotably adjustable with respect to the remainder of the footrest.

Where the undercarriage support is inverted as a whole, and the seat structure is then mounted on the inverted support, extension drop arms may be attached, or pivoted down on, the front end of the support to carry wheels, such as castor wheels so that the support is maintained in a generally horizontal (but higher) position with respect to the ground.

In order that the nature of the invention may be readily ascertained, an embodiment of wheelchair in accordance therewith is hereinafter particularly described with reference to the figures of the accompanying drawings, wherein: Figure 1 is a schematic side elevation to show generally the movements and adjustments possible with the various components; Figure 2a, 2b, 2c and 2d are schematic side elevations to illustrate possible relative positions of adjustment of the seat structure with respect to the undercarriage structure; Figures 3 and 4 show perspective views of the wheelchair in two different conditions of use.

Referring to Figure 1 , the undercarriage comprises a rigid support pan 1 with a base 2, side walls 3, rear wall 4, and front wall 5. The rear wall 4 serves as an "anti-tip" safeguard, in that it is placed close to the ground and prevents the wheelchair from tilting over backwards. Main bearer wheels 6 are journalled in the side walls 3, at 7. Front castor wheels 8 are mounted in casing 9 secured at the front wall 5.

A seat mounting 10 is composed of a pair of arms 11, 12, pivoted centrally at 13, the arrangement being identical to each side of the chair. The arm 12 is pivoted at 14 to the base 1 and at 1 5 to a seat slide (not shown, but positioned generally along the line 16). The arm 1 1 is pivoted at 1 7 to the seat slide, and is engaged at its other end at 1 8 in a runway 1 9 of the pan 1. Movement of the end 18 along the runway 1 9 permits the double "X" structure to move into the raised position shown, and also to collapse flat into the pan 1.

The seat structure is shown only in the form of its structural elements, and would in practice be upholstered. The seat structure comprises a seat base (not shown, but again lying substantially along the line 16) engaged in removable manner with the seat slide. The seat base is adjustable fore and aft along the seat slide. It can also be removed entirely, reversed end-for-end and reattached to the seat slide. On the seat base there is provided a pivot mounting 20 for a backrest 21.

The backrest can pivot between the inclined position of use seen in this figure, and a stowed position in which it lies substantially parallel across the seat base. On the backrest, at each side, there is provided a cantilever arm rest 22 mounted by a pivot 23 for movement adjustably into the position of use shown, and into a stowed position illustrated at 22a in chaindotted line.

On the rear of the backrest 21 there is provided a pusher bar 24 which can be adjusted between the position of use shown, and a stowed position against the rear of the backrest.

At the upper end of the backrest 21 there is provided a headrest 25 which is adjustable, as an eccentric, about a pivot point 26. At a lower point of the backrest there is provided a lumbar support 27 which is adjustable in similar manner about a pivot point 28.

At the forward end of the seat base there is pivoted a pair of identical leg rests 29 each of which includes an extensible portion 29a for length adjustment. At the tip of each extension there is pivotably mounted a foot plate 30 adjustable about a pivot axis 31.

The position of the backrest 21, when the seat structure as a whole is reversed, is shown in dotted line at 21 a, and the position of the leg rests is shown at 29b.

Referring now to Figures 2a-2d, Figure 2a shows the wheelchair schematically with the seat structure 1 6-31 in the position of use, relative to the undercarriage 1-1 9, corresponding to that shown in fill lines in Figure 1. The seat proper is adjustable, by means of the slide at 16, fore and aft of the wheelchair to the extent shown by the lines 1 6a-1 Sb.

Referring to Figure 2b, the wheelchair is shown with the seat structure 1 6-31 in the end-for-end reversed condition, relative to the undercarriage 1-19, corresponding to the broken line position seen in Figure 1. The seat is again adjustable fore and aft to the extent shown at 1 6a-1 6b.

Referring to Figure 2c, the wheelchair is shown again in the condition of Figure 2b, and the extent of raising and lowering of the seat structure 1 6-31 with respect to the undercarriage 1-1 9 is indicated by the lines 1 6c-1 Sd.

Referring to Figure 2d, the wheelchair is shown in the condition in which the undercarriage 1-1 9 has been inverted, the front castor wheels 8 now being mounted on long drop arms 32, and the seat structure 16-31 being carried on the underside (now uppermost) of the base pan 1 , the same fore and aft adjustment still being available for the seat structure.

The wheelchair of this invention is accordingly extremely versatile as regards adjustment to suit the individual needs of a patient, and to be used in the various manners set forth. in particular, it permits reduction of the dimensions of the wheelchair to the extent that it can be inserted as a whole in a vehicle and used as a set for the patient when driving the vehicle.

Claims (14)

1. A wheelchair comprising an undercarriage with a rigid support having a pair of main bearer wheels journalled at an upper point generally towards a rear end of the support, and a pair of castor wheels mounted generally towards a front end of the support, a seat mounting carried by the support and adjustable into a raised position above the support and into a folded position within the support, and a seat structure carried on the seat mounting, the interconnection between the seat structure and the seat mounting being such that the seat structure is adjustable fore and aft relative to the seat mounting and is also removable from the seat mounting and replaceable in fore and aft reversed position thereon, and also on the undercarriage support when the latter is inverted.

2. A wheelchair as claimed in Claim 1, wherein the support has the form of a pan of a sheet material, having a base, side walls, and front and rear walls.

3. A wheelchair as claimed in Claim 1, wherein the bearer wheels are journalled in the pan side walls.

4. A wheelchair as claimed in any one of Claims 1 to 3, including a pivotably adjustable backrest.

5. A wheelchair as claimed in any one of Claims 1 to 4, including a pusher bar, and means for adjusting the height of the pusher bar.

6. A wheelchair as claimed in any one of Claims 1 to 5, including a headrest, and means for adjusting the height and/or the forward displacement of the headrest.

7. An undercarriage for a wheelchair, comprising a chassis having a pair of castors mounted generally towards a first end thereof, and a pair of main bearer wheels, journalled at a first point generally towards a second end thereof, the chassis being provided with a second journalling point for main bearer wheels, the second journalling point being spaced vertically from the first journalling point, whereby the main bearer wheels may be removed and replaced by an alternative pair of main bearer wheels, having a diameter different from that of the first-mentioned pair of bearer wheels, whilst retaining the general orientation of the undercarriage with respect to the ground.

8. An undercarriage as claimed in Claim 7, wherein the chassis is in the form of a pan of a sheet material, the said journalling points being provided in the side walls of the pan.

9. An undercarriage as claimed in Claim 7 or Claim 8, including a motor for driving the main bearer wheels.

10. An undercarriage as claimed in Claim 9, wherein the motor is arranged to drive at least one of the main bearer wheels at a point spaced radially from the wheel centre.

11. An undercarriage as claimed in Claim 10, including two alternative pairs of main bearer wheels, having different diameters, the diameters of the main bearer wheels and the arrangement of the respective journalling points being such that each pair is alternatively capable of being journalled at its respectively journalling point, and driven from a single drive shaft.

12. An undercarriage for a wheelchair, comprising a chassis in the form of a pan of a sheet material having side walls, a front wall, and a back wall, a pair of castors mounted generally towards a first end thereof, a pair of main bearer wheels journalled at a point generally towards a second end thereof, and a seat mounting adjustable into an upper position for supporting a seat in a working position, and a lower position, in which the seat support is stowed within the pan.

13. An undercarriage for a wheelchair substantially as hereinbefore described with reference to, and as illustrated by the accompanying drawings.

14. A wheelchair incorporating an undercarriage as claimed in any one of Claims 7 to 13.

1 5. A wheelchair substantially as hereinbefore described with reference to, and as illustrated by the accompanying drawings.