GB2048791A - Wheelchairs - Google Patents

Abstract

A wheelchair comprising a frame 10 with four wheels 15, 17 and a seat 36, 37 mounted on the frame 10 for forward and rearward adjustment in a horizontal plane by means of slides. The seat is mounted on a pivotal parallelogram linkage 22, 23, 24, 25. The seat comprises a tiltable backrest portion 37 and raisable arms 39. Auxiliary drive wheels 33 are driven by an electric motor. In an alternative embodiment, the seat is mounted on a scissor linkage for vertical movement. <IMAGE>

Description

SPECIFICATION Wheelchairs This invention relates to wheelchairs for use by invalids. Such a wheelchair comprises a four wheeled vehicle having a frame on which is mounted a seat.

There are a number of reasons why the conventional wheelchair is not convenient for use in all circumstances. One circumstance is that in which the wheelchair it to be used in a motor vehicle such as that described and claimed in my Patent Application No. 1 569/78. With this wheelchair, the mounting of the wheelchair may not bring the occupant into a convenient position for driving, this depending upon the stature of the person concerned. Other reasons why conventional wheelchairs are not always convenient include difficulty of mounting and dismounting from the chair and difficulties of positioning in relation to furniture such as tables or working surfaces.

The object of the invention is to provide a wheelchair which provides increased versatility of use by an occupant of the chair.

According to the invention a wheelchair comprises a frame on which are mounted four wheels, a seat carried on the frame, the seat being adjustable in a horizontal plane in forward and rearward directions.

The invention will now be described by way of example, with reference to the accompanying drawings, in which: Figure 1 is a side elevation view of a wheelchair constructed in accordance with the invention; Figure 2 is a rear elevation view thereof: Figure 3 is a diagrammatic representation of the frame of the chair; Figure 4 is a side elevation view of the same chair but with the seat reversed; Figure 5 is a side elevation view of an alternative construction having a seat which can be raised and lowered; Figure 6 is a side elevation view of an alternative form of chair showing additional equipment attached to it; Figure 7 is a side elevation view of the chair shown in Figure 6 with parts shown in different positions;; Figure 8 is a side elevation view of an alternative form of chair, and Figure 9 is a side elevation view of a still further form of chair.

Figures 1, 2 and 3 show a wheelchair having a frame of generally upright channel shape comprising two side piates 10, 11 and a floor 12.

Reinforcements may be included where required, the parts being made from sheet metal. The sides 10, 11 carry at their rear upper corners, respective axles 13, 14 for large rear wheels 1 5, 16. These are conveniently placed for manual propulsion by an occupant of the wheechair.

At the front of the frame are mountings 19 for swivellable small front wheels 17, 18 each mounted on a vertical caster swivel 21.

Carried on the floor 12 of the frame are two pairs of parallel links 22, 23, 24, 25 interconnected by a sub-frame 26. The links 22, 23, 24, 25 are pivotally connected to the floor and to a seat base 27. As illustrated in Figure 1 it is possible for the seat mounted on the base 27 to be raised and lowered and at the same time to move forward and back under the control of the parallelogram linkage formed by the links 22, 23, 24, 25. Such movement is furthermore controrred by hydraulic mechanism (not shown) which is actuated by a pump handle 28 and a release handle 29. This mechanism and the operation of the parallelogram linkage is described and claimed in Patent Application i 569/78.

At the front of the frame are fittings 31 to which can be attached adjustable and folding foots rests 32. However, the fittings 31 are also capable of accepting other equipment to which reference will be made later.

At the rear of the frame is mounted an auxiliary wheel unit comprising one or a pair of auxiliary wheels 33. These are driven by an electric motor 34 which is powered from a battery 35 carried on the floor of the frame beneath the seat. The auxiliary wheel unit is arranged to be raised and lowered by the seat. This auxiliary wheel unit is the subject of Patent Application No. 7913266.

The seat mounted on the seat base 27 comprises a seat portion 36, to the rear edge of which is pivoted a backrest portion 37. To this is slidably engaged a head rest or head restraint.

Also pivotally connected to the seat portion 36 about an axis nearly coincident with the axis of pivotal connection between the seat portion 36 and the backrest portion 37 are two arm rests 39, 40. The dotted lines indicated at 41 show the position to which the arm rests 39, 40 can be swung to allow side access to the seat portion, if required.

In many cases, this.can be convenient for a wheelchair occupant particularly where transfer from the wheelchair into another seat is to be accomplished.

The seat base 27 and the seat portion 36 are interconnected by parallel longitudinal horizontal slides 42, 43 which are shown in Figure 2. These slides enable the whole seat to move in a horizontal plane forward and back as indicated by the dotted lines 44 in Figure 1.

The wheelchair shown in Figures 1 and 2 is particularly suitable for use with apparatus of the kind described and claimed in Patent Application 7900057 (Serial 2009097) for mounting in a motor vehicle. The raising and lowering of the seat facilitates entry and leaving of the vehicle.

However, when the occupant has entered the vehicle in the wheelchair by means of that apparatus, he may not be in a convenient position for driving the vehicle. This depends very much upon the stature of the occupant and also upon any disabilities. It is therefore possible to adjust the position of the seat in relation to the frame and wheels of the wheelchair by means of the slides 42, 43. A locking mechanism (not illustrated) is provided for releasing and locking the slides 42, 43 as required. This may be separate from, or incorporated in mechanism for permitting tilting of the backrest portion 37 of the chair as indicated by the dotted lines 45 in Figure 1.

Figure 4 shows the same wheelchair but having the seat mounted on the seat base 27, the opposite way round. With this configuration the rear large wheels 1 5, 1 6 are at the front and the small swivellable wheels 17, i 8 8 are at the rear.

Such a configuration is convenient for an amputee. Provision is made for forward and back adjustment of the seat portion 36 and therefore the whole seat in relation the seat base 27, by means of the same arrangement of slides 42, 43 as shown in Figure 2. The locking mechanism, however, must be so positioned as to be accessible to the wheelchair occupant whichever mode of seat mounting is adopted.

In Figure 5 there is again shown the same wheelchair but the seat base 27 is connected to the upper ends of the links 22,23,24,25 by scissor links 48, 49 which permit additional lift of the seat in relation to the frame. The seat portion 36 is mounted on the seat base 27 by means of the slides 42, 43, as in the construction previously described. Hydraulic or mechanical linkage is provided for allowing actuation of the scissor linkage 48, 49 to control raising and lowering of the seat.

Figure 6 shows an alternative form of wheelchair having the same frame but in place of the large rear wheels, are small wheels 51. The same small swivellable front wheels 1 7 are provided as in the other construction.

In place of the parallelogram linkage however a fixed support structure comprising legs 52, 53 is provided for supporting the seat base 54. The seat portion 55 is mounted on the seat base by means of slides (not illustrated) equivalent to those shown in Figure 2.

One of the legs 52 has a fitting 56 to accept handles 57. Fittings 58 at the front of the vehicle carry foot rests 59 and also a detachable table 61.

Forward and back sliding movement of the seat can therefore be accomplished in relation to this table 61. To drive the wheelchair is an electric motor 62 which is provided with power from a battery 63 on the frame. Since this wheelchair is intended substantially only for electric drive, or hand pushing and since it does not have a seat capable of being raised and lowered, a larger storage battery or more than one such battery 63 can be accommodated in the frame.

In Figure 7 the wheelchair of Figure 6 is shown with the alternative large wheels 64 at the rear.

Furthermore,this shows the seat portion 55 moved to the forwardmost position and it also shows the arm rests 65 in the raised position. An alternative form of table 66 is also illustrated.

In Figure 8 there is shown a further form of wheelchair having the same frame but in this case in inverted position. The sides 67 depend from a platform 68 which forms the floor in the other versions and there is a further platform 69 spanning the sides 67 so that the frame takes up a closed box configuration. The large rear wheels 71 shown are mounted at the lower rear corners of the sides 67 and the swivellable smaller front wheels 72 are on longer supports so that the frame stands higher from the floor.

The seat is mounted directly on the platform 68 through runners (not illustrated) allowing forward and back adjustable movement. The seat comprises a seat base 73 which is itself mounted on the platform 68 and to this is fixed the seat portion 74. This seat is also shown having a fixed backrest 75.

In Figure 9 a similar construction is shown but the hollow box frame contains a removable toilet unit 76 which may be slid outwards rearwardly from the wheelchair.

This construction also shows, mounted on fittings 77, the foot rests 78 and a toilet or vanity unit 79 including such items as mirror 81 and a storage drawer 82. The sliding adjustment of the seat in the forward and rearward directions is accomplished in the same manner as the construction in Figure 8.

Claims (14)

1. A wheelchair comprising a frame on which are mounted four wheels, a seat carried on the frame, the seat being adjustable in a horizontal plane in forward and rearward directions.

2. A wheelchair as claimed in claim 1 in which the seat is mounted on the frame through slides.

3. A wheelchair as claimed in either of claims 1 and 2 in which locking means is arranged to secure the seat relatively to the frame in any selected position.

4. A wheelchair as claimed in any one of the preceding claims wherein the seat is also capable of adjustment in a vertical direction relatively to the frame.

5. A wheelchair as claimed in any of the preceding claims wherein the frame has alternative mounting means for wheels at front and rear ends thereof.

6. A wheelchair as claimed in any one of the preceding claims wherein the frame has provision for electrical drive at least one wheel on the frame.

7. A wheelchair as claimed in any one of the preceding claims wherein the frame has means for mounting of a table, relatively to which the seat is adjustable.

8. A wheelchair substantially as hereinbefore described with reference to and as shown in Figures 1,2 and 3 of the accompanying drawings.

9. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 4 of the accompanying drawings.

10. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 5 of the accompanying drawings.

11. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 6 of the accompanying drawings.

12. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 7 of the accompanying drawings.

13. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 8 of the accompanying drawings.

14. A wheelchair substantially as hereinbefore described with reference to and as shown in Figure 9 of the accompanying drawings.