GB1595702A

GB1595702A - Wheelchairs

Info

Publication number: GB1595702A
Application number: GB27163/77A
Authority: GB
Original assignee: Spastics Society
Current assignee: Spastics Society
Priority date: 1978-05-19
Filing date: 1978-05-19
Publication date: 1981-08-19

Description

(54) IMPROVEMENTS IN WHEELCHAIRS (71) We, THE SPASTICS SOCIETY, a British Company of 12 Park Crescent, London W1N 4EQ, do hereby declare the invention for which we pray that a patent may be granted to us and the method by which it is to be performed to be particularly described in and by the following statement: This invention relates to wheelchairs.

In one known construction of wheelchair comprising a chassis and a seat mounted on the chassis manually operable locking means is provided on the seat to secure the seat to the chassis. The locking means is engageable with a generally horizontal cross-bar on the chassis and is operable through a toggle linkage. The locking means depends beneath the seat portion of the seat and is therefore susceptible to damage when the seat is separated from the chassis. This is particularly true when it is necessary to separate the seat from the chassis in order to move an occupant to a location inaccessible to the wheelchair. The seat cannot be put down on a generally horizontal surface, for example the seat of a chair or a table, without damaging the locking means and therefore either the separated chassis must also be moved to the location or another chassis must be provided at the location.The first solution is inconvenient especially in the home where the required number of people available to move the seat plus occupant and the chassis are not available while the second solution is expensive.

A further dlsadvantage of providing the locking means on the seat is that it is difficult, especially when an occupant is in the seat, to locate the cross-bar on the chassis in the locking means on the seat.

According to the present invention we provide a wheelchair comprising a chassis and a seat mounted on the chassis, the chassis having manually operable locking means in engagement with the seat to secure the seat to the chassis, the seat being pivotal about the locking means to alter the angle of inclination of the seat relative to a horizontal plane and tilt adjuster means extending between the seat and chassis to lock the seat in a selected angular position, the locking means and tilt adjuster means being operable to allow the seat to be detached from the chassis.

Preferably the locking means comprises a pair of clamps in engagement with a crossbar provided on the seat. Convenientlv each clamp is operable through an associated toggle linkage and the toggle linkages have a common operator handle. Guide means may be provided on the chassis to facilitate location of the cross-bar in the clamps.

The cross-bar depends beneath the seat portion of the seat and is generally horizontal. Thus when the seat is detached from the chassis it can be put down on a generally horizontal surface, for example a chair or table, without risk of damage to the surface of the cross-bar. The weight of the seat and any occupant being transmitted through the cross-bar which also acts as a stop to prevent any movement of the seat.

Preferably the seat is of the fold-down type having a hinged handle with manually operable release means for controlling hinging movement. The seat may include a foot-rest which is adjustable to accommodate different leg lengths.

Preferably, the foot-rest is also angularly adjustable and includes manually operable adjuster means for locating the foot-rest in any one of a number of angular positions. In the folded-down position of the seat, the foot-rest is moved to a position in which it substantially overlies the seat portion of the seat, the hinged handle is then folded-down to a position in which it substantially overlies the foot-rest and the seat portion.

From a further aspect the present invention consists in a seat for a wheelchair of the kind comprising a chassis and a seat detachably mounted on the chassis, the chassis having manually operable locking means engageable with the seat to secure the seat to the chassis wherein the seat includes a member adapted to engage the locking means on the chassis for pivotal movement of the seat about the locking means to alter the angle of inclination of the seat relative to a horizontal plane.

A preferred emhodimcnt of the invention will now be describechnith reference to the accompan} ing drawings wherein: Ffteitre i is a pcrspective view of a wheelchair according to the present invention; Figure 2 is a perspective view of the seat shown in Figure 1. the seat. back and side members having been removed for clarity; Figure 3 shows one of the manuallv oper- able release means for controlling hinging movement of the handle in the assembled and folded-down positioIis;; Figure 4 is a section through the locking means for locking tlic foot-rest at any required extension, Figure 5 shows the manually operable adjuster means for controlling the angular position of the foot-r-es!; and Figure 6 shows the locking means of the chassis of the wheelchair shown in Figure 1.

Rcferring to the drawings. the eheclcllair shown comprises a chassis 1 and a seat 2 detachably mounted on the chassis. The seat 2 is of the fold-down type and comprises a collapsible seat fl-am 3 on which a seat member 4, back members 5, 6 and side members 7 incorporating respective arm rests 8 are secured. The members 4, 5, 6 and 7 each comprise a respective rigid panel covered in a durable material. for example a plastics material.The arm rests 8 each comprise a respective rigid panel padded with foamed plastics and covered in a durable material, for example, plastics material As shown in Figure 2 the seat frame comprises a first U-shaped member 9, bent to form a base element 10, a back element 11, and a handle 12, a pair of generally L-shaped members 13, each of which is connected to a respective one limb of the U-shaped member 9 to form a respective support for the arm rests 8 and a second J-shaped member 14, each limb of which is pivotally connected to a respective one of the L-shaped members 13.The second U-shaped member 14 is bent to form a support for a foot-rcst 1 5. A front crossmember 16 connects the L-shaped members 13 and a rear cross-membcr 17 connects the limbs of the back element 11. The front and rear cross-members 16 and 17 provide a support above the base element 10 for the seat member 4.

The seat frame 3 is further provided with a cross bar 18 depending beneath and extending between the limbs of the base element 10. Each end of the cross bar is connected to a respective one limb of the base element by an associated downwardly projecting member 19 mounted on the limb and adjustable thereon. The cross bar 18 is engageable with locking means 20 provided on the chassis 1 to secure the seat 2 to the chassis as will be described in more detail later.

Each limb of the handle 12 is connected to the associated limb of the back element 11 by respective hinge means 2 1 to allow the handle to be folded-down to a position in which it substantially overlies the seat member 4. One of the hinge means 21 is shown in Figure 3, the other hinge means is similar. Referring to Figure 3 the hinge means 21 comprises a pair of inserts 22, 23 hingedly connected to each other. One insert 22 is secured within the limb of the back element by any suitable means (not shown) and the other insert 23 is located within the limb of the handle.An axially extending slot 24 is formed in the limb of the handle adjacent to the free end thereof and an externally screw threaded bolt 25 secured to the insert 23 extends through the slot 24. Manually operable release means comprising a knob 26 mounted on the bolt 25 is adjustable to either engage the limb of the handle and prevent movement of the limb relative to the insert 23 or disengage the limb of the handle and allow movement of the limb relative to the insert 23 between first and second extreme positions defined by the engagement of the bolt 25 with a respective end of the slot 24. In the first extreme position the hinge connection between the inserts 22, 23 is located within the limb of the handle 12 while in the second extreme position the hinge connection is exposed.

Referring again to Figure 2 each limb of the second U-shaped member 14 comprises a pair of telescopic members 27, 28 provided with manually operable locking means 29 so that the foot-rest 15 can be adjusted to accommodate different leg lengths. Manually operable adjuster means 30 is provided for controlling the angular position of the second U-shaped member 14 so that the foot-rest can be adjusted to any one of a number of angular positions. One of the locking means 29 is shown in more detail in Figure 4 the other locking means is similar.

Referring to Figure 4 the locking means comprises a sleeve 31 mounted on the outer member 28 and housing a bolt 32 extending transversely of the members 27, 28. The bolt 32 has a head 32a and an externally screw threaded stem 32b. An element 33 is located on and slidable along the stem 32b.

As shown the bolt head 32a and element 33 are shaped to correspond to the outer surface of the inner member 27. A knob 34 is mounted on the bolt stem 32b. To lock the members 27, 28 at any desired extension the knob 34 is rotated so as to move the element 33 along the stem 32b until the bolt head 32a and the element 33 engage the inner member 27, whereby the latter is frictionally held in position.

Ibe position of the foot-rest 15 is therefore quickly and easily adjusted by rotating the knobs 34 of the locking means to release the members 27 allowing the members 27 to he moved relative to the members 28 to the required position. The foot-rest 15 is then fixed in position by rotating the knobs 34 in the opposite direction so that the bolt heads 32a and elements 33 engage and frictionally retain the members 27 in position.

The adjuster means 30 is shown in more detail in Figure 5 and includes a pair of connector rods 35, 36 pivotally mounted on a bar 37 extending between the limbs of the U-shaped member 14 and engageable with locking means 38 mounted on the seat frame 3. The locking means 38 comprises a tube 39 extending between downwardly pl ojccting extensions of the L-shaped members 13 and housing a fixed insert 40 connected to one L-shaped member and an adjustable insert 41 connected to the other L-shaped member. The tube 39 has a cylindrical extension (not shown) of reduced cross erection the inner end of which acts as a stop for the adjustable insert 41 and the outer free end of which is located in an opening in the adjacent L-shaped member.

The adjustable insert 41 has an externally threaded portion 41a which passes through the extension and has an operator knob 42 mounted on the free end. Each insert is formed with a respective hole 43, 44 and the tube is formed with two pairs of relatively spaced opposed apertures (not shown). In the assembled position shown one pair of opposed apertures is aligned with the hole 43 in the fixed insert and the connector rod 35 extends t'nerethrough and, the other pair of opposed apertures is aligned with the hole in the adjustable insert and the connector rod 36 extends therethrough.

To lock the foot-rest 15 in any desired angular position the knob 42 is rotated to mox C the adjustable insert 41 relative to the tube 39 so that the hole 44 and the opposed apertures in the tube are no longer aligned and the connector rod 36 is frictionally held in position. Further rotation of the knob 42 causes the adjustable insert 41 and the tube 39 to move together relative to the fixed insert 40 so that the hole 43 and opposed apertures in the tube are no longer aligned and the connector rod 35 is frictionally held in position. The connector rods 35, 36 are released simply by rotation of the knob 42 in the opposite direction to re-align the holes 43, 44 in the inserts with the associated apertures in the tube.

To fold down the seat 2 illustrated in Figure 1 the foot-rest adjuster means 30 is released allowing the connector rods 35, 36 o be disengaged and the foot-rest 15 is , iwri-co upwards to a position in which it overlies the seat member 4. The handle release means is then released and the handle 12 raised relative to the back element 11 until both hinge connections 21 are exposed whereupon the handle 12 is pivoted forwards to a position in which it overlies the foot-rest 15. The above described seat is easy to assemble and to fold down since all the necessary control means are easily accessible.

The chassis 1 comprises a sprung frame 45 mounted on a pair of rear wheels 46 and a pair of front swivel castors 47. The chassis further includes the manually operable locking means 20 for securing the seat 2 to The chassis and a manually operable brake system 48 for locking the rear wheels 46 against rotation.

The locking means 20 is shown in more detail in Figure 6 and comprises a pair of clamps 49 mounted on a cross-member 50 secured to the chassis frame 45. Each clamp is similar and comprises a spring loaded jaw 49a and a movable jaw 49b pivotally mounted on the cross-member 50. Each movable jaw is operable by a respective toggle linkage 51. Each toggle linkage is similar and comprises a connector link Slo. and an operator link 51b. The connector link 51a is pivotally connected to the movable jaw 49b and to the operator link. The operator link 51b is pivotally mounted at a point 52 intermediate its ends on a bracket 53 secured to the cross member 50. The free ends of the operator links are connected together to form an operator handle 54 to allow simultaneous opening and closing of the clamps 49.The clamps are shown in an intermediate position in Figure 5. Upward movement of the handle 54 fully opens the clamps 49 and downward movement fully closes the clamps 49. Closing movement of the clamps 49 is limited by respective adjustable stops 55 mounted on each of the brakets 53.

To mount the seat 2 on the chassis 1 the clamps 49 are fully opened, the cross bar 18 on the seat is then located between the jaws 49a, 49b of the clamps and locked in position by lowering the handle 54 to close the jaws of the clamps. Guide means (not shown) may be provided on the chassis to facilitate location of the cross-bar 18 between the jaws of the clamps. By adjusting the stops 55 the clamps 49 can be set to accommodate cross-bars of different dimensions so that the chassis 1 can be used with a number of different seats in which the sizes of the cross-bars vary. The spring loaded jaws 49a allow any slight maladjustment of the stops 55, resulting in the clamps 49 either being set too tightly straining the linkage or not being set tight enough leaving the seat frame 3 loose of the chassis 1, to be compensated for.

As shown in Figure 1 the wheelchair further includes tilt adjuster means 56 for controlling the angular position of the seat 2 comprising a pair of telescopic tubes 57, 58 and a butterfly lock nut 59 for locking the tubes at an', required extension. One end of the assembly is pivotally connected to a cross member 60 on the seat and the other end has a clamp 61 operable through a toggle linkage 62 connected to a cross member 63 on the chassis.

To adjust the position of the seat the butterfly lock nut 59 is released, the cross-bar 18 engaged in the locking means 20 is free to pivot about the locking means which acts as a fulcrum so that the angular position of the seat can be adjusted. At the desired angle of tilt the butterfly lock nut 59 is tightened to secure the seat in position. The tilt adjuster means 56 is normally locked to prevent inadvertent tilting of the seat 2 and must be released to allow the seat 2 to be detached from the chassis 1. The seat 2 normally occupies the position shown in Figure 1 in which a respective outwardly directed lug 64 provided on a downward extension of each L-shaped member 13 engages the chassis so that the weight of the seat cind any occupant is more evenly distributed on the chassis.

The above described wheelchair may be modified in a number of ways, for example the locking means on the chassis may comprise one clamp only having movable and fixed jaws of suitable dimensions to engage the cross bar on the seat or any number of clamps may be provided as appropriate.

The clamp or each clamp may be operated by any suitable means for example the clamps may be tightened by screw means but it will be appreciated that the above described toggle linkages have the advantages of being both quick and easy to operate.

The or each clamp may comprise a pair of fixed jaws at least one of which is resiliently biassed to allow insertion and removal of the cross bar on the seat.

The foot-rest adjuster means may comprise one rod only pivotally connected to the foot-rcst and engaging the friction means on tlie seat. Furthermore the foot-rest adjuster means may be replaced by any other suitable means, for example a spring loaded detent on the seat engaging in one of a series of notches in a slot or a series of spaced apertures in a rod pivotally connected to the foot-rest, known to those skilled in the art.

The seat, back and side members may be padded with a suitable resilient material or the seat may be formed as an integral body by moulding from a suitable plastics material.

It will be appreciated from the foregoing that the invention is not limited to the particular chassis and seat described and illustrated but applies to any type of chassis provided with locking means to engage a cross bar or similar member provided on any type of seat.

It will also be appreciated that the invention is applicable both to manual and to electrically driven wheelchairs. In an electrically driven wheelchair suitable controls for operating power means to drive a pair of wheels are provided on the seat and a releasable connection is provided between the controls and the power means to facilitate separation of the seat from the chassis.

Finally the chassis illustrated and described forms the subject matter of our co-pending U.K. Patent Application No.

27162/77 (accepted and published under No. 1 575 354) of even date titled 'Improvements in Chassis for Wheelchairs'.

WHAT WE CLAIM IS: 1. A wheelchair comprising a chassis and a seat mounted on the chassis, the chassis having manually operable locking means in engagement with the seat to secure the seat to the chassis, the seat being pivotal about the locking means to alter the angle of inclination of the seat relative to a horizontal plane and tilt adjuster means extending between the seat and chassis to lock the seat in a selected angular position, the locking means and tilt adjuster means being operable to allow the seat to be detached from the chassis.

2. A wheelchair according to claim 1 wherein the locking means comprises a clamp in engagement with a member on the seat.

3. A wheelchair according to claim 2 wherein the clamp has a fixed jaw and a movable jaw and the member is held between the fixed and movable jaws.

4. A wheelchair according to claim 3 wherein the fixed jaw is resiliently biassed.

5. A wheelchair according to claim 3 or claim 4 wherein the clamp has an adjustable stop for limiting closing movement of the movable jaw.

6. A wheelchair according to any one of claims 2 to 5 wherein the clamp is operable through a toggle linkage.

7. A wheelchair according to any one of claims 2 to 6 wherein the locking means comprises a pair of relatively spaced clamps mounted on a cross member secured to the chassis frame.

8. A wheelchair according to claim 7 wherein the member on the seat in engagement with the locking means comprises a generally horizontal bar which depends beneath the seat and extends transversely thereof between the spaced clamps.

9. A wheelchair according to claim 7 in combination with claim 6 wherein the toggle linkages of the clamps are connected by and operable through a common operator handle.

10. A wheelchair according to any one

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Claims

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comprising a pair of telescopic tubes 57, 58 and a butterfly lock nut 59 for locking the tubes at an', required extension. One end of the assembly is pivotally connected to a cross member 60 on the seat and the other end has a clamp 61 operable through a toggle linkage 62 connected to a cross member 63 on the chassis.

To adjust the position of the seat the butterfly lock nut 59 is released, the cross-bar 18 engaged in the locking means 20 is free to pivot about the locking means which acts as a fulcrum so that the angular position of the seat can be adjusted. At the desired angle of tilt the butterfly lock nut 59 is tightened to secure the seat in position. The tilt adjuster means 56 is normally locked to prevent inadvertent tilting of the seat 2 and must be released to allow the seat 2 to be detached from the chassis 1. The seat 2 normally occupies the position shown in Figure 1 in which a respective outwardly directed lug 64 provided on a downward extension of each L-shaped member 13 engages the chassis so that the weight of the seat cind any occupant is more evenly distributed on the chassis.

The above described wheelchair may be modified in a number of ways, for example the locking means on the chassis may comprise one clamp only having movable and fixed jaws of suitable dimensions to engage the cross bar on the seat or any number of clamps may be provided as appropriate.

The clamp or each clamp may be operated by any suitable means for example the clamps may be tightened by screw means but it will be appreciated that the above described toggle linkages have the advantages of being both quick and easy to operate.

The or each clamp may comprise a pair of fixed jaws at least one of which is resiliently biassed to allow insertion and removal of the cross bar on the seat.

The foot-rest adjuster means may comprise one rod only pivotally connected to the foot-rcst and engaging the friction means on tlie seat. Furthermore the foot-rest adjuster means may be replaced by any other suitable means, for example a spring loaded detent on the seat engaging in one of a series of notches in a slot or a series of spaced apertures in a rod pivotally connected to the foot-rest, known to those skilled in the art.

The seat, back and side members may be padded with a suitable resilient material or the seat may be formed as an integral body by moulding from a suitable plastics material.

It will be appreciated from the foregoing that the invention is not limited to the particular chassis and seat described and illustrated but applies to any type of chassis provided with locking means to engage a cross bar or similar member provided on any type of seat.

It will also be appreciated that the invention is applicable both to manual and to electrically driven wheelchairs. In an electrically driven wheelchair suitable controls for operating power means to drive a pair of wheels are provided on the seat and a releasable connection is provided between the controls and the power means to facilitate separation of the seat from the chassis.

Finally the chassis illustrated and described forms the subject matter of our co-pending U.K. Patent Application No.

27162/77 (accepted and published under No. 1 575 354) of even date titled 'Improvements in Chassis for Wheelchairs'.

WHAT WE CLAIM IS: 1. A wheelchair comprising a chassis and a seat mounted on the chassis, the chassis having manually operable locking means in engagement with the seat to secure the seat to the chassis, the seat being pivotal about the locking means to alter the angle of inclination of the seat relative to a horizontal plane and tilt adjuster means extending between the seat and chassis to lock the seat in a selected angular position, the locking means and tilt adjuster means being operable to allow the seat to be detached from the chassis.
2. A wheelchair according to claim 1 wherein the locking means comprises a clamp in engagement with a member on the seat.
3. A wheelchair according to claim 2 wherein the clamp has a fixed jaw and a movable jaw and the member is held between the fixed and movable jaws.
4. A wheelchair according to claim 3 wherein the fixed jaw is resiliently biassed.
5. A wheelchair according to claim 3 or claim 4 wherein the clamp has an adjustable stop for limiting closing movement of the movable jaw.
6. A wheelchair according to any one of claims 2 to 5 wherein the clamp is operable through a toggle linkage.
7. A wheelchair according to any one of claims 2 to 6 wherein the locking means comprises a pair of relatively spaced clamps mounted on a cross member secured to the chassis frame.
8. A wheelchair according to claim 7 wherein the member on the seat in engagement with the locking means comprises a generally horizontal bar which depends beneath the seat and extends transversely thereof between the spaced clamps.
9. A wheelchair according to claim 7 in combination with claim 6 wherein the toggle linkages of the clamps are connected by and operable through a common operator handle.
10. A wheelchair according to any one

of claims 1 to 9 wherein the chassis has guide means arranged to facilitate location of the seat in the locking means.
11. A wheelchair according to any one of claims 1 to 10 wherein the seat is foldable to a collapsed position to facilitate storage when the seat is detached from the chassis.
12. A wheelchair according to claim 11 wherein the seat comprises a seat frame having a base element, a back element and a handle, the handle being mounted for hinging movement relative to the back element so that in the collapsed position the handle overlies the base element.
13. A wheelchair according to claim 12 wherein the back element comprises a pair of relatively spaced members and the handle comprises a U-shaped member, each limb of which is connected to a respective back member by respective hinge means.
14. A wheelchair according to claim 13 wherein each hinge means comprises a pair of hinged inserts, one insert being secured within the associated back member and the other insert being located within the associated limb of the handle and the handle is movable relative to said back member between a first position in which the hinge connection is located within the limb of the handle preventing hinging movement and a second position in which the hinge connection is exposed allowing hinging movement.
15. A wheelchair according to Claim 14 wherein each hinge means includes respective manually operable release means comprising a projection on said other insert extending through a slot in the associated limb of the handle and a knob mounted on the projection and adjustable to frictionally engage the limb of the handle to prevent relative movement between the limb of the handle and the associated back member.
16. A wheelchair according to any one of Claims 12 to 15 wherein the seat has a foot-rest mounted for hinging movement relative to the seat frame so that in the collapsed position the foot-rest overlies the base element and the handle overlies the foot-rest and the base element.
17. A wheelchair according to Claim 16 wherein the foot-rest is adjustable to accommodate different leg lengths.
18. A wheelchair according to Claim 16 or Claim 17 wherein the foot-rest is adjustable through a range of angular positions relative to the seat frame and angle adjuster means extending between the foot-rest and seat frame is adjustable to lock the foot-rest in a selected position.
19. A wheelchair according to Claim 18 wherein the angle adjuster means comprises friction means on the seat frame in engagement with a rod pivotally connected to the foot-rest and the friction means is operable through a control knob to release the rod to allow adjustment.
20. A wheelchair according to claim 19 wherein the foot-rest has a pair of said rods, each rod being in engagement with respective friction means on the seat and the friction means being operable through a common control knob.
21. A wheelchair according to any one of claims 12 to 20 wherein the seat frame has a pair of relatively spaced side elements and detachable seat, back and side members are secured to the base, back and side frame elements respectively.
22. A wheelchair according to any one of the preceding claims wherein the chassis has a pair of front swivel castors and a pair of rear wheels.
23. A wheelchair according to claim 22 wherein the chassis has a manually operable brake system for locking the rear wheels against rotation.
24. A wheelchair substantially as herein described with reference to the accompanying drawings.
25. The seat of the wheelchair as claimed in any one of the preceding claims wherein the seat has a member to engage the locking means on the chassis for pivotal movement of the seat about the locking means to alter the angle of inclination of the seat relative to a horizontal plane.