GB2293797A - Wheelchair with a forward tilting or reclining seat, fixed front and castored rear wheels. - Google Patents

Abstract

A wheelchair comprising a frame 1 joined by perpendicular crosspieces, having large, fixed front wheels 6 and castored rear wheels 3. The seat 8 is pivotably attached to a backrest 14 and legrest 13 which are connected 17 to ensure that they rotate together. The seat is pivotably suspended from the top of the frame at 12 so that it and the rests are tiltable relative to the frame with the extent of the tilt restricted by a releasable strut 18 pivotably attached to the seat and releasably engaging a frame crosspiece 4. A pivoting block brake mechanism 24 is connected 27 to the seat so that the chair is immoble when the seat is tilted forwards. There is provision for an adjustable, counterbalancing spring 34 to be attached between the rear of the frame and a vertical extension of the suspending pivot point of the seat 33. <IMAGE>

Description

WHEELCHAIR This invention relates to a wheelchair for home use, and in particular to a wheelchair suitable for use in a home which has not been specially designed or adapted to accommodate wheelchairs of conventional construction.

Such a wheelchair will be of particular interest to disabled persons capable of looking after themselves in their own home.

In many houses the passages are not more than 915mm (36 inches) wide and the internal door openings are a standard 710mm (28 inches) wide. A conventional manually propelled wheelchair is approximately 1,070mm (42 inches) long and it is quite impossible to execute a 90 degree turn in a 915mm passage to go through a 710mm opening.

Furthermore, a conventional wheelchair does not allow the occupant full access to the units and worktops in a conventionally fitted kitchen, nor to normally fitted washbasins and sinks etc.. Accordingly, most houses will require considerable modification and re-fitting, at great expense, to accommodate a disabled person in a conventional wheelchair. Furthermore, if an able bodied person is to move into the house after the disabled person, further expense will be necessary in order to re-fit the house again to suit able bodied people.

With the aim of overcoming this problem, according ito the invention there is provided a wheelchair comprising a support frame carrying a pair of larger diameter wheels at the front and a pair of smaller diameter castor wheels at the back, a seat which has a backrest and a legrest connected to it and which is pivotally mounted on the support frame so that the seat is tiltable relative to the support frame, and means for restricting forward tilting of the seat when the occupier leans forward and operative to apply the major part of the occupier's weight to the front wheels.

In a conventional wheelchair the larger diameter wheels are at the rear and project considerably beyond the back of the frame, thereby contributing materially to the overall length of the wheelchair. In a wheelchair in accordance with the invention the larger diameter wheels are placed at the front and although they will project to a considerable extent in front of the frame they will not effectively increase the overall length of the wheelchair since the legrest and the occupant's legs will also project in front of the frame in the space between the front wheels.Accordingly, a wheelchair in accordance with the invention can be constructed with an overall length of 710mm (28 inches) - compared with the 1,070mm (42 inches) of a conventional wheelchair - and by keeping the width of the chair to not more than 610mm (24 inches) it will be possible for the chair to be turned through 90 degrees to go through a 710mm (28 inch) door opening from a 915mm (36 inch) passage.

This turning, and indeed steering of the wheelchair in general, is greatly facilitated by the pivotal mounting of the seat and the provision of the means for restricting forward tilting of the seat so as to apply the major part of the occupier's weight to the front wheels. Without this construction the occupier's weight would be applied more to the rear castors wheels, making manoeuvring exteremly difficult. With the weight applied mainly to the large front wheels, however, manoeuvring becomes very easy. Indeed, a 90 degree turn, pivoting about one wheel, can be executed when the chair is in motion merely by applying a thumb to the tyre of the said wheel.

Preferably the means for restricting forward tilting of the seat comprises a stop provided on a strut which is pivotally connected to the underside of the seat and hangs downwardly therefrom so that it rests against a member of the support frame between the front wheels and is slidable over the member as the seat tilts, forward tilting of the seat being prevented when the stop engages the member. Preferably the member is a cross-member which defines or interconnects the axles of the front wheels.

A footrest may be mounted on the legrest to keep the occupier's feet clear of the ground when the wheelchair is in motion, as in the case of a conventional wheelchair, but preferably the wheelchair in accordance with the invention is arranged with the seat at a height such that the occupier's legs will hang with the feet clear of the ground when the forward tilting stop is engaged with the frame member with which it co-operates to ensure manoeuvrability of the wheelchair. In this way the need for a footrest, which tends to be complicated and difficult to fit and operate, is obviated.

Increasing the height of the seat in this way in comparison with the seat height of a conventional wheelchair also improves the access of the occupier to worktops and sinks in a conventionally fitted kitchen, and this access can be further improved by arranging that the means for restricting forward tilting of the seat is releasable, for example by a hand operated control lever, to allow the seat to tilt forwards, and by providing the wheelchair with brakes which are engagable with the front wheels to prevent rearward movement of the wheelchair when the seat is tilted forwards. With the seat tilted fully forward the reach of a person occupying the chair can be increased by up to 200mm (about 8 inches), the torso of the person acting rather like the jib of a crane.The wheelchair is prevented from moving backwards by the brakes and the occupier cannot slide forwards out of the chair because the person's feet have been brought into contact with the floor and the knees will ; become braced against the cabinet facing the wheelchair.

Furthermore, if a detachable table is fitted to the wheelchair this will also help to hold the occupier safely in the chair when the seat is tilted forwards to improve the reach of the occupier.

A wheelchair in accordance with the invention can thus enable a disabled person to access, without getting out of the chair, most appliances and fittings (with the exception of high wall cupboards) in a conventionally fitted kitchen for able bodied persons, thus saving the expense of refurbishing the kitchen with fittings designed to suit disabled persons confined to a conventional wheelchair.

Preferably the brakes are linked to the seat so that the brakes are applied to the front wheels automatically when the seat is moved to a forwardly tilted position, and preferably they are arranged so that any tendency for the wheelchair to move rearwardly will cause the brakes to be applied even tighter to prevent rearward movement.

Preferably the seat is suspended from the support frame so that the seat is below the axis about which it tilts.

In this way the pivoting movement of the seat is gentler and easier to control, the seat acting more in the manner of a swing than a seesaw.

The forward tilting facility of the seat and automatic braking of the front wheels will also make it much easier for a disabled person to get into and out of the chair and to transfer between the chair and a bed, and if the weighting of the seat and the legrest and backrest connected thereto is such that the seat does not naturally adopt a forwardly tilted position when the chair is not occupied and the forward tilt restricting means is released, then the seat may be spring biased to adopt this position ready for occupation.

The wheelchair may also have means for restricting rearward tilting of the seat when the occupier leans back to relax. In this position the seat will preferably slope slightly downwards towards the rear and the occupier will be supported securely in a comfortable relaxed position.

The means for restricting the rearward tilting of the seat may be formed by a second stop provided on the strut which carries the stop for restricting forward tilting of the seat, the second stop being located at a position spaced along the strut from the first stop, and rearward tilting of the seat being prevented when the second stop engages the member against which the strut rests.

The wheelchair in accordance with the invention may also be arranged to support the occupier in a reclining position. For this purpose the means for restricting rearward tilting of the seat is releasable to allow the seat to tilt further rearwards, and preferably the wheelchair is provided with means, such as a chain connected to the seat and to the frame, for preventing rearward tilting of the seat beyond a predetermined maximum limit.

Advantageously the wheelchair may be provided with a counterbalance mechanism which helps the occupier to control rearward tilting of the seat beyond a predetermined position and to restore the seat to the predetermined position from a rearwardly tilted position.

Preferably this mechanism comprises a counterbalance spring which preferably acts substantially horizontally between the support frame and a rod which is pivotally suspended from the frame and is linked to the seat so that the rod is pulled against the action of the counterbalance spring when the seat is tilted rearwardly beyond the predetermined position.

The predetermined position may correspond to the relaxed position as determined by the second stop, although if the strength and positional setting of the counterbalance spring are correctly matched to the weight of the occupier the second stop and also the maximum rearward tilt limiting means may become redundant. This is because, with the counterbalance spring adjusted correctly, the occupier will have complete control over the tilting of the seat rearwardly of the predetermined position, being able to increase or decrease the tilt very slowly or to stop it instantly simply by slightly shifting his or her centre of gravity, for example just by movement of the head or arms.

The backrest and the legrest are preferably each hingedly connected to the seat and are interconnected such that pivotal movement of either relative to the seat causes simultaneous pivotal movement of the other in the same rotational direction relative to the seat. With this arrangement, when the occupier leans back to tilt the seat into either the relaxed position or the reclining position, the backrest will also tilt rearwards relative to the seat. This causes the legrest simultaneously to pivot forwards and upwards a corresponding amount to counterbalance the backrest, and in this way a very comfortable and stable position can be achieved. This facility enables the occupier to relieve and change the pressure points occurring when sitting normally in the chair, and even allows the occupier to sleep comfortably for short periods without having to transfer to a bed.

Examples of a wheelchair constructed in accordance with the invention will now be described, by way of illustration, with reference to the accompanying 'sketch drawings, in which: Figure 1 is a side view of a first example of the wheelchair in a standby or access mode with the seat in a forwardly tilted position and the brakes engaged to prevent rearward movement of the wheelchair; Figure 2 is a side view of the wheelchair in a mobile mode with the seat substantially horizontal and prevented from tilting forwards; Figure 3 is a side view of the wheelchair in a relaxing mode with the seat tilted slightly rearwardly and prevented from tilting further rearwards; and Figure 4 is a side view of the wheelchair in a reclining mode with the seat tilted rearwards to its maximum limit.

Figure 5 is a view similar to Figure 3 but of a second, more preferred example of the wheelchair fitted with a counterbalance mechanism; and, Figure 6 is a side view of the second example in a reclining, pressure sore relief mode.

The wheelchair shown in Figures 1 to 4 comprises a support frame (1) formed by two identical substantially rectangular side frames (2) (only one of which can be seen in the drawings) which are of welded tubular construction and which are interconnected as described below. Each side frame (2) carries a rear castor wheel (3) at its rear lower corner mounted to swivel about a vertical axis, and a horizontal stub axle (4) fixed to the front upright (5) of the side frame for rotatably mounting a large diameter hand driven wheel (6) of the type conventionally used on wheelchairs.The front wheel stub axle (4) fixed to one of the side frames (2) is extended by a rod (not shown) axially towards the other side frame, and the front wheel stub axle of the other side frame is extended by a tube axially towards the first side frame, the rod fitting within the tube to interconnect the two side frames (2) in a manner which allows each side frame to move slightly relative to the other in the plane of the side frame. This is to cater for any uneveness in the floor or ground on which the wheelchair is standing or travelling. The side frames (2) may be further interconnected by one or more transverse tie rods, such as indicated at (7), which are fitted in a manner which does not affect the desired relative movement of the side frames (2).

The wheelchair also comprises a cushioned seat (8) having a rigid frame or base (9) which is suspended at each side from the upper member (10) of the respective side frame (2) by a link (11) which is fixed rigidly at its lower end to the seat base (9) and is pivotally connected at its upper end to a bracket (12) fixed to the underside of the upper member (10). The pivot axis of the link (11) at one side of the seat (8) is co-axial with that of the link (11) at the other side, and the seat (8) is thus able to tilt forwards and backwards relative to the support frame (1) about this common axis. The upper members (10) of the side frames (2) also serve as armrests.

A padded legrest (13) is hinged to the front edge of the seat (8), and a padded backrest (14) fitted with a height adjustable padded headrest (15) is hinged at its lower edge to the rear edge of the seat (8). A rigid stay (16) is fixed substantially centrally to the rear of the backrest (14) so that the stay extends downwardly from the lower edge of the backrest between the two side frames (2), and at its lower end the stay (16) is pivotally connected to a pair of push rods (17) (only one of which can be seen) which extend forwards in a V-shaped and are pivotally connected to the rear of the legrest (13). The stay (16) and the two push rods (17) therefore interconnect the backrest (14) and legrest (13) so that pivotal movement of the backrest (14) relative to the seat (8) in a particular direction will cause simultaneous pivotal movement of the legrest in the same rotational direction relative to the seat (8). In other words, if the backrest (14) pivots rearwards and downwards relative to the seat, the legrest will pivot forwards and upwards, and vice versa.

Pivotally connected to the underside of the seat (8) near the middle of its front edge is a strut (18) which extends downwards and rearwards so that it normally rests under the action of gravity against the frame cross-member formed by the telescoped rod and tube interconnecting the front wheel axles (4). If preferred, the strut (18) may be spring biased against the cross-member in order to ensure contact therewith at all times except when positively retracted therefrom as described below.Towards its lower end the strut (18) has an elongate notch (19) cut in its edge which faces the front wheel axle cross-member, and further up the strut (18) a chain (20) connects the strut to one end of a cranked control lever (21) which is pivotally mounted on the underside of the seat (8) and has an operating handle (22) positioned at one side of the seat so that a slight push on the handle will pivot the control lever (21) so as to pull the chain (20) and thereby retract the strut (18) away from the front wheel axle cross-member.

The wheelchair is also provided with a brake (23) for each front wheel (6), the brakes being arranged to engage the wheels (6) automatically when the seat tilts forwardly to prevent the wheelchair from moving backwards while in this condition. Each of the brakes (23) comprises a block (24) which is pivotally mounted on the outside of the lower side frame member (25) to the rear of the tyre of the respective wheel (6).At its end furthest from the wheel the block (24) is connected by a coil spring (26) and a chain (27) to the side of the seat (8) near its rear edge, and the arrangement is such that when the seat tilts forward and its rear edge rises, the block (24) is rocked about its pivot axis to bring its forward end into engagement with the tyre of the wheel (6), any tendency of the wheel (6) to move rearwardly only serving to cause the block (24) to bite even tighter into the tyre to prevent the rearward movement. When the seat is tilted back to a substantially horizontal position the pull on the rear end of the brake block (24) via the chain (27) and spring (26) is relaxed and the block is free to pivot under gravity out of engagement with the wheel, thereby releasing the brake.

Finally, each side frame (2) has a chain (28) fixed to it near its upper rear corner, the other end of the chain being fixed to the rear edge of the seat (8). These chains (28) serve to limit the maximum extent to which the seat can be tilted rearwardly.

When the wheelchair is not in use it will normally be left in the standby or access mode shown in Figure 1, in which the seat (8) is tilted forwardly and the brakes (23) are applied to the front wheels (6) to prevent rearward movement of the wheelchair. If necessary, a spring may be provided, for example between the seat (8) and the lower member (25) of one or both of the side frames (2) as shown at (29) in Figure 1 only, in order to bias the seat into this position. If the seat is prevented from tilting forwards by engagement pf the notch (19) with the front axle cross-member as mentioned below, a slight forward push on the control handle (22) will retract the strut (18) to disengage the notch from the cross-member and allow the seat (8) to move into the forwardly tilted position.This is the position which is used when a person wishes to get into or out of the chair, and generally also when working at a desk or work bench, eating at a dining table, or using a sink, hob or worktop in the kitchen. As mentioned earlier, in this position the wheelchair is locked against rearward movement by the brakes (23), although the brakes will allow additional forward movement if necessary.

Having sat on the seat (8) in the standby or access position, a slight lean back by the occupier will cause the seat to swing forwards towards a horizontal position and then start to tilt rearwards. During the course of this movement the strut (18) slides upwards on the front axle cross-member until the member enters the notch (19) and is engaged by a stop (30) formed by the lower end of the notch. This prevents further rearward tilting of the seat (8). A slight forward lean of the occupier will then cause the seat to tilt forwards and the strut (18) to move downwards until the front axle cross-member is engaged by a stop (31) formed by the upper edge of the notch (19).In this position, which is the mobile position shown in Figure 2, further forward tilting of the seat (8) is prevented by the engagement of the stop (31) on the front axle cross-member and, with the occupier leaning forward, the major part of the occupier's weight is tranferred through the strut (18) and the stop (31) to the front wheel cross-member and hence to the front wheels (6) themselves. This greatly facilitates the propulsion and manoeuvring of the wheelchair by the occupier.

Having propelled the wheelchair to where the occupier wishes to be and the access position is required, a simple push on the control lever (22) disengages the stop (31) from the front axle cross-member and allows the seat (8) to tilt forwards as desired under the control of the occupier merely by appropriately shifting the position of his or her body. On the other hand, if the occupier wishes to relax, a slight lean back in the chair is all that is necessary. This will cause the seat (8) to tilt towards the rear until the stop (30) engages under the front wheel cross-member to prevent further tilting. The backrest (14) will also tend to pivot slightly rearwards, causing the legrest (13) to rise simultaneously until a comfortable balanced position is reached. Figure 3 illustrates the wheelchair in this mode.

If a fully reclining position as shown in Figure 4 is required, a further slight push on the control lever (22) releases the stop (30) from the front axle cross-member and allows the seat (8) to tilt rearwardly until 1 the limit chains (28) are pulled taut and prevent further tilting. The backrest (14) will also pivot further rearwards while at the same time further raising the legrest (13) until the occupier achieves a comfortable balanced position.

It will be noted that when the seat (8) tilts rearwards into the relaxing position of Figure 3 and in particular to the reclining position of Figure 4, the seat itself swings towards the front of the wheelchair as a result of it being pivotally suspended on the support frame (1), thereby acting to shift the centre of gravity of the seat assembly and the occupier further forwards to increase the stability and safety of the wheelchair in these positions.

In order to be able to fit a small table or tray to the wheelchair if required, each of the armrests formed by the tubular upper members (10) of the two side frames (2) is arranged to house a support rod (32) which can be pulled out to support the tray or table and pushed back out of the way when the table is removed and no longer required.

The second example of the wheelchair illustrated in Figures 5 and 6 is similar in many respects to the first example, and those parts of the second example which are identical to parts of the first example have been given the same reference numeral.

The main difference between the two examples is that the second example is provided with a counterbalance mechanism which is operative when the seat (8) is tilted rearwardly from the relaxed mode position shown in Figure 5. Essentially, the counterbalance mechanism comprises, at each side of the support frame (1), a rod (33) which is pivotally suspended at its upper end from the bracket (12) from which the seat (8) is suspended, a strong tension spring (34) which is connected between the rod (33) and the upright rear member (35) of the respective side frame (2) and exerts a force on the rod (33) tending to pull it towards the rear upright (35) until the lower end of the rod (33) engages a stop member (36) fixed to the lower member (25) of the side frame, and a chain (37) which links the lower end of the rod (33) to the front region of the seat (8).In this example the stop member (36) is positioned so that the rod (33) is substantially vertical and parallel to the rear upright member (35) of the side frame (2) when the lower end of the rod (33) abuts the stop member (36), and the chain (37) is of a length such that it is slack, thereby allowing the spring (34) to pull the lower end of the rod (33) against the stop (36), whenever the seat is in a tilted position which is forward of the relaxed mode position, but is taut, thereby rendering the counterbalance mechanism operative, when the tilt of the seat (8) ,is at or rearward of the relaxed mode position as shown in Figure 5.

The position of the counterbalance spring (34) on the rod (33) and rear frame member (35) is adjustable to suit the weight of the occupier of the wheelchair. For this purpose, in the present example the front end of the spring (34) is attached to the rod (33) by a friction lock (38) formed by two L-shaped plates (39) which extend one each side of the rod (33) and are rigidly interconnected by two cross pins (40) positioned one in front and one behind the rod (33) and spaced apart by a distance slightly greater than the thickness of the rod (33).These cross pins (40) bracketing the rod (33) are located on one leg of the L-shaped plates (39), and the forward end of the spring (34) is secured to the free end of the other leg of the plates (39) so that the tensile force exerted by the spring (34) causes the L-shaped plates (39) to adopt a skew position on the rod (33) such that the cross pins (40) jam against the front and rear sides of the rod (33) to lock the plates frictionally in position on the rod. At its rear end the spring (34) is secured to a pair of plates (41) which extend one each side of the rear frame member (35) and between which a wheel or roller (42) is rotatably mounted so as to be freely movable over the rear surface of the rear member (35).With this arrangement, the position of the spring (34) on the rod (33) and rear member (35) is infinitely adjustable, with any adjustment of the position of the forward end being followed automatically by the rearward end as a result of the wheel (42) rolling correspondingly up or down the rear frame member (35). Adjustment of the position of the front end of the spring (34) is effected either by pushing down on the rear end of the friction lock (38) if the spring is to be moved further down the rod (33) in order to increase the counterbalancing force, or by lifting the front end of the friction lock (38) if the spring (34) is to be moved further up the rod (33) in order to decrease the counterbalancing force.

A further difference between the second example and the first example as shown in Figures 1 to 4 lies in the way in which the legrest (13) is pivotally connected to the seat (8) and the push rods (17). In the second example, the legrest (13) is connected to the seat (8) by means of a pair of parallel rigid links (43) which are pivotally connected at one end (44) to the underside of the seat (8) adjacent its front edge, and are pivotally connected at their other end (45) to the back of the legrest (13) at a position approximately midway between its upper and lower edges. In turn, the push rods (17) are pivotally connected to the links (43) at positions (46) approximately midway between their two ends (44) and (45). The effect of this arrangement is clearly illustrated in Figure 5, and will be described below in more detail.Although this arrangement is not shown in Figures 1 to 4, it is to be understood that it would in fact be generally preferred to use this arrangement in the first example as well.

The only other difference between the first and second examples is that the chain (28) which limits the rearward tilting of the seat (8) is made slightly longer so that the maximum rearward tilt of the seat is increased in order to allow the chair to recline even further than the position shown in Figure 4 to adopt the position which is shown in Figure 6 and which is termed the pressure sore relief position.

The operation of the wheelchair shown in Figures 5 and 6 is identical to that of the first example when in the access, mobile and relaxed modes as shown in Figures 1, 2 and 3, and when moving between these modes, the counterbalance spring (34) remaining inoperative. As shown in Figure 5, however, in the relaxed mode position the chain (37) is taut, and when the control lever (22) is operated to disengage the stop (30) from the cross-member (4) to allow the seat (8) to tilt rearwardly towards the reclining position, such tilting will displace the front edge of the seat forwards and upwards and cause the chain (37) to pull the lower end of the rod (33) away from the stop member (36) against the action of the counterbalance spring (34), which thus resists the rearward tilting movement.If the position of the counterbalance spring (4) has been correctly set by appropriate adjustment of the friction lock (38), the spring force acting through the rod (33) and chain (37) to resist the rearward tilting of the seat (8) will exactly counter the rearward tilting force applied to the seat (8) by the occupier sitting in a relaxed position on the seat. The seat will thus be in balance and no movement will occur.A slight push against the armrests (10) or lifting the arms to shift the centre of gravity of the occupier slightly more to the rear will, however, just overcome the counterbalance spring force and cause the seat (8) to tilt very slowly rearwards until the occupier wishes to stop, for example in a reclining position corresponding to that of Figure 4, at which point the occupier simply stops pushing on the armrests or lowers his arms to restore equilibrium with the counterbalance spring (34) and thereby stop the seat in this position. The seat can be restored equally slowly and under the same control to the relaxed mode position by exerting a slight pull on the armrests (10) or by moving to shift the centre of gravity slightly forwards, for example simply by moving the hands and/or the head slightly forwards.

As mentioned earlier, the second example allows the occupier of the wheelchair to recline the seat and backrest further than in the first example to a pressure relief mode as shown in Figure 6. In this mode it will be seen that the legrest (13) is separated from and raised above the seat (8) as a result of the arrangement of the links (43) and push rods (17). This lifts the back of the thighs clear of the seat (8) to relieve any pressure soreness which may have occurred as a result of occupying the other modes for too long.

Reclining to the pressure relief mode (and also recovery therefrom) is still under the control of the counterbalance spring (34), and the occupier can therefore stop in any position as desired. Accordingly, the tilt limiting chains (28) could be dispensed with, but for safety reasons it will generally be preferred to retain them. Similarly, the stop (30) on the strut (18) for holding the seat in the relaxed mode position may also be dispensed with since the counterbalance spring (34) will come into play in this position and will serve to hold the position until the occupier wishes to alter it. Again, however, it may be preferred to keep the stop (30) in order to provide a lock which will prevent any unwanted reclining movement as a result of inadvertent movement by the occupier.

The present invention also envisages that the counterbalance mechanism as described above in relation to the second example shown in Figures 5 and 6 may be applied to reclining chairs which are not wheelchairs, and in which the legrest and backrest may also be hinged to the seat and interconnected as described herein.

Claims (30)

1. A wheelchair comprising a support frame carrying a pair of larger diameter wheels at the front and a pair of smaller diameter castor wheels at the back, a seat which has a backrest and a legrest connected to it and which is pivotally mounted on the support frame so that the seat is tiltable relative to the support frame, and means for restricting forward tilting of the seat when the occupier leans forward and operative to apply the major part of the occupier's weight to the front wheels.

2. A wheelchair according to claim 1, in which the seat is suspended from the support frame so that the seat is below the axis about which it tilts.

3. A wheelchair according to claim 1 or claim 2, in which the means for restricting forward tilting of the seat is releasable to allow the seat to tilt forward, and the wheelchair is provided with brakes which are engageable with the front wheels to prevent rearward movement of the wheelchair when the seat is tilted forwards.

4. A wheelchair according to claim 3, in which the brakes are linked to the seat so that the brakes are applied to the front wheels automatically when the seat is moved to a forwardly tilted position.

5. A wheelchair according to claim 3 or claim 4, in which the brakes comprise a pair of blocks, one for each front wheel, which are pivotally mounted so that each is applied to its wheel by being rocked into engagement with the wheel and so that the engagement will be tightened by any tendency of the wheel to move rearwardly.

6. A wheelchair according to any one of claims 3 to 5, in which the seat is spring biased to adopt a forwardly tilted position when the chair is not occupied and the restricting means is released.

7. A wheelchair according to any one of the preceding claims, in which the means for restricting forward tilting of the seat comprises a stop provided on a strut which is pivotally connected to the underside of the seat and hangs downwardly therefrom so that it rests against a member of the support frame between the front wheels and is slidable over the member as the seat tilts, forward tilting of the seat being prevented when the stop engages the member.

8. A wheelchair according to claim 7, in which the member is a cross-member which defines or interconnects the axles of the front wheels.

9. A wheelchair according to any one of the preceding claims, including means for restricting rearward tilting of the seat when the occupier leans back.

10. A wheelchair according to claim 9, in which the means for restricting rearward tilting of the seat is releasable to allow the seat to tilt further rearwards.

11. A wheelchair according to claim 9 or claim 10 when dependent on claim 7 or claim 8, in which the means for restricting rearward tilting of the seat comprises a second stop provided on the strut at a position spaced along the strut from the first stop, rearward tilting of the seat being prevented when the second stop engages the member.

12. A wheelchair according to claim 11, in which the strut has an elongated notch in its side which rests against the member, one end of the notch forming the first stop and the other end of the notch forming the second stop.

13. A wheelchair according to any one of claims 7, 8, 11 and 12, in which a hand operated control lever is pivotally mounted on the frame or the seat and is connected to the strut so that moving the lever in one direction is operative to move the strut away from the member and thereby disengage the stop or stops from the member to allow further tilting of the seat.

14. A wheelchair according to any one of the preceding claims, having means for preventing rearward tilting of the seat beyond a predetermined maximum limit.

15. A wheelchair according to claim 14, in which the means for preventing rearward tilting of the seat beyond said predetermined limit comprises a chain connected to the seat and to the frame.

16. A wheelchair according to any one of the preceding claims, including a counterbalance mechanism which helps the occupier to control rearward tilting of the seat beyond a predetermined position and to restore the seat to the predetermined position from a rearwardly tilted position.

17. A wheelchair according to claim 16, in which the counterbalance mechanism comprises a spring.

18. A wheelchair according to claim 17, in which the counterbalance spring acts substantially horizontally between the support frame and a rod which is pivotally suspended from the frame and is linked to the seat so that the rod is pulled against the action of the counterbalance spring when the seat is tilted rearwardly beyond the predetermined position.

19. A wheelchair according to claim 18, in which the rod is urged by the counterbalance spring against a stop member when the seat is tilted forward of the predetermined position, and is pulled away from the stop member by its link to the seat when the seat is tilted rearwardly of the predetermined position.

20. A wheelchair according to claim 19, in which the portion of the frame to which the counterbalance spring is attached is substantially vertical, and the rod is substantially parallel thereto when the rod is in engagement with the stop member.

21. A wheelchair according to any one of claims 18 to 20, in which the counterbalance spring is adjustable in position on the frame and the rod.

22. A wheelchair according to claim 21 when dependent on claim 20, in which the position of the counterbalance spring is infinitely adjustable, the spring being attached to the rod by a friction lock which can be released manually to adjust its position on the rod, and being attached to the frame by. means including a wheel which runs on the frame so that adjustment of the spring position on the frame automatically follows adjustment of its position on the rod.

23. A wheelchair according to any one of claims 18 to 22, in which the rod is linked to the seat by a chain.

24. A wheelchair according to any one of the preceding claims, in which the backrest and the legrest are each hingedly connected to the seat and are interconnected such that pivotal movement of either relative to the seat causes simultaneous pivotal movement of the other in the same rotational direction relative to the seat.

25. A wheelchair according to claim 24, in which the backrest and legrest are interconnected by a stay which is fixed rigidly to the backrest and projects downwards therefrom, and a push rod which is pivotally connected at one end to the lower end of the stay and at the other end to the legrest.

26. A wheelchair according to claim 25, in which the legrest is connected to the seat by a rigid link which is pivotally connected at one end to the seat and at its other end to the legrest at a position between the upper and lower edges of the legrest, and the push rod is pivotally connected to the link at a position between the ends of the link.

27. A wheelchair according to any one of the preceding claims, in which the backrest carries an adjustable headrest.

28. A wheelchair according to any one of the preceding claims, in which the support frame has means for removably attaching a table thereto.

29. A wheelchair according to claim 1, substantially as described with reference to Figures 1 to 4 or Figures 5 and 6 of the accompanying drawings.

30. A reclining chair comprising a support frame, a seat which has a backrest and a legrest connected to it and which is pivotally suspended from the support frame so that the seat is tiltable relative to the frame, and a counterbalance mechanism which helps the occupier to control rearward tilting of the seat beyond a predetermined position and to restore the seat to the predetermined position from a rearwardly tilted position, the counterbalance mechanism comprising a counterbalance spring which acts substantially horizontally between the support frame and a rod which is pivotally suspended from the frame and is linked to the seat so that the rod is pulled against the action of the counterbalance spring when the seat is tilted rearwardly beyond the predetermined position.