EP0297831A2

EP0297831A2 - Wheel chair

Info

Publication number: EP0297831A2
Application number: EP88305871A
Authority: EP
Inventors: John Charles Payne
Original assignee: Individual
Current assignee: Individual
Priority date: 1987-06-27
Filing date: 1988-06-27
Publication date: 1989-01-04
Also published as: EP0297831A3; GB8715149D0

Abstract

A wheel chair is made up of a wheeled chassis (11) and a seat (12) wherein the seat (12) and the chassis (11) are discrete, self supporting members and a demountable coupling (26, 27, 46) is provided linking the seat (12) to the chassis (11). The coupling (26, 27, 46) is operable between a first position where the coupling (36, 27, 46) secures the seat (12) to the chassis (11) and a second position where the coupling (26, 27, 46) releases the seat (12) from engagement with the chassis (11). A control linkage (39, 29, 37, 32) provides for regulating the operation of the coupling (26, 27, 46) at least from the first to the second position. A lifting point (44) is incorporated in the seat structure (40) to enable at least the seat (12) (with or without an occupant) to be lifted alone or combined with the chassis (11).

Description

This invention relates to a wheel chair.
A known type of wheel chair is made up of a frame mounted on wheels the frame being fitted with flexible seat and back support members to accommodate an occupant. Such chairs are frequently equipped for self propulsion with two relatively large wheels positioned for manipulation by the occupant. To allow the chair to be stowed within a vehicle or other storage volume the lateral width or some other significant dimension of the chair can be reduced by folding the frame which generally requires that the seat and back support members should be flexible.
According to the present invention a wheel chair comprising a wheeled chassis incorporating a seat is characterised in that: the seat and the chassis are discrete, self supporting members; a demountable coupling is provided linking the seat to the chassis, the coupling being operable between a first position where the coupling secures the seat to the chassis and a second position where the coupling releases the seat from engagement with the chassis; a control linkage provides for regulating the operation of the coupling at least from the first to the second position; and a lifting point is incorporated in the seat structure to enable at least the seat (with or without an occupant) to be lifted alone whether or not coupled to the chassis.
In a first preferred form of the present invention a wheel chair is characterised in that the seat and the chassis are provided with complementary alignment structure adapted so that on the juxtaposition of the separated seat portion with the chassis the complementary alignment means interact to urge the seat towards a predetermined final location of the seat relative to the chassis prior to or during transition of the coupling from the second to the first position. Typically the complementary alignment structure provides for alignment of the seat with the chassis in first and second directions at right angles, the first direction being coaxial with or parallel to the usual direction of travel of the wheelchair. Preferably the complementary alignment structure provides for alignment of the seat in the first direction to occur prior to alignment in the second direction.
A further preferred form of the present invention, or the first preferred form thereof, is characterised in that the coupling is adapted to automatically change from the second to the first position on the close approach of the seat to, or on its arrival at, the first position.
An exemplary embodiment of the invention will now be described with reference to the accompanying drawings of a wheel chair made up of a seat and a chassis.
Figures 1-3 are views of the chassis in which:

Figure 1 is a side elevation;
Figure 2 is a front elevation; and
Figure 3 is a plan view from direction III of Figure 2.

Figures 4-6 are views of the seat in which:

Figure 4 is a side elevation
Figure 5 is a sectional view on section V-V of Figure 4; and
Figure 6 is is a plan view from direction VI of Figure 4.

A given component has the same reference numeral in each figure in which it appears. Items frequently associated with a wheel chair, such as foot rests, are omitted to improve the comprehensibility of the drawings.
The wheel chair has as major components a structurally discrete chassis 11 and a structurally discrete seat 12.
Referring to Figures 1 to 3 the chassis 11 comprises side frames 15, 16 linked by upper transverse bars 17, 18 and lower transverse bars 19, 20. Each lower corner of the chassis 11 is equipped with a castor action wheel 14 to allow for the combined chassis and chair (or the chassis on its own) to be propelled and manoeuvred.
The chassis 11 includes part of a complementary alignment structure made up of: a crutch 21 providing for fore-and-aft alignment; triangular projections 22, 23 on the transverse bar 17 and projections 24, 25 on the transverse bar 18 which projections all provide for lateral alignment. The function of the alignment structure will be described hereafter with reference to longitudinal axis X. The arrow F indicates the normal forward direction of the wheel chair when in use.
There is further provided on the chassis 11 a coupling whereby the seat 12 can be retained on and released from the chassis. The coupling includes four pads 26A, 26B. 27A, 27B. Each pad 26A, 26B is mounted on an arm 28 which is secured to bar 29. The bar 29 is mounted for rotation about axis 30 beneath upper transverse bars 17, 18. In a similar manner each pad 27A, 27B is mounted on an arm 31 which is secured to bar 32. The bar 32 is mounted for rotation about axis 33 beneath upper transverse bars 17, 18. In mounting the pads in this way rotation of the bars 29, 32 results in the associated pads being displaced along an arc of a circle centred on axis 30 or 33. The ends of bars 29. 32 are provided with, respectively, off- set plates 34, 35. Plate 35 is pivotably coupled by pin 36 (parallel to but off-set from axis 33) to one end of link 37 whose other end is pivotably coupled by pin 38 to plate 34. Pin 38 is parallel to but offset from axis 30). Handle 39 is secured to bar 29 and can be used to rotate the bar 29 and simultaneously, by virtue of the connection provided by link 37, rod 32. The arrangement of the link 37 and the off- set plates 34, 35 ensure that the bars 29, 32 rotate in an opposite handed way on using handle 39.
Referring to Figures 4-6 the seat 12 is made up of a tube frame with a back section 40 and a squab section 41. The back section 40 incorporates a manoeuvering handle 42, rest pad 43 and a lifting sleeve 44. Cross-bar C forms the lower part of the back section 40 and the rear of the squab section 41. The squab section 41 has mounted on it a seating pad 45 (in this case in the form of a commode seat). The side tubes of the squab section 41 S are provided with four stubs 46 each positioned in plan in a square pattern corresponding to disposition of the pads 26A, 26B, 27A, 27B.
The seat 12 is a discrete substantially rigid structure which can be supported by a lift arm attached to the seat by way of sleeve 44. In this way the seat 12 supports the weight of an occupant when separated from the chassis. Having engaged lifting sleeve 44 with a hoist the occupant of the seat or an assistant can operate the hoist controls to safely lift or lower the seat (and so the occupant) either with the seat 12 separate from, or even with it attached to, the chassis 11.
To recombine the chassis 11 and seat 12 the seat is positioned above and clear of the chassis 11 and aligned so that stubs 46 are approximately vertically above the pads 26A, 26B, 27A, 27 with the seat facing in the direction of arrow X. On lowering the seat 12 in the direction of the arrow L onto the chassis 11 the seat is caused to firstly take up a correct fore and aft position by the initial contact of the cross-bar C with crutch 21. The crutch 21 has upwardly facing jaws of sufficient width in the direction of axis X to enable a fair degree of misalignment between seat and chassis to be compensated for and ensure the subsequent satisfactory fore-and-aft alignment of the seat relative to the chassis. Further lowering results in side rails of squab section 41 either dropping directly into place on the chassis or contacting the top of triangular projections 22-25 with the result that the seat is deflected laterally. The deflection will be such as either to ensure that each side rail of the squab section lies outside its associated pair of projections 26A, B or 27A, B so providing for lateral alignment of the seat relative to the chassis or it will result in a palpable mis-alignment ensuring that the seat is raised to enable a more accurate initial alignment of the seat with the chassis (such as by a slight movement of the chassis) to ensure that a further lowering attempt will result in correct lateral alignment.
On completion of the lowering operation of the now aligned seat the lower edge U (Figure 5) of each stub 46 will strike the upper surface of one of the pads 26A, B and 27A, B. As a consequence the pads 26A, B and 27A, B will be displaced outwardly allowing the squab side frames to seat on the transverse bars 17, 18. Once this occurs the pads 26A, 26B, 27A, 27B are biassed to restore themselves to a position in which the lower edge of the pads 26A, B and 27A, B engage with upper sides of the stubs 46 to lock the seat 11 on the chassis 12. The combination of the pad and stub engagement and the alignment maintained by interaction of the seat frame with the crutch 21 and the triangular projections 22, 23, 24, 25 ensures that the combination is rigidly secured. The engagement occurs automatically on lowering the seat. Handle 39 can be used to release this engagement when it is desired to separate the seat from the chassis. This involves a positive intention and action on the part of the operator and cannot arise from an inadvertent action.

Claims

1 A wheel chair comprising a wheeled chassis incorporating a seat characterised in that:
the seat (12) and the chassis (11) are discrete, self supporting members;
a demountable coupling (26, 27, 46) is provided linking the seat to the chassis; the coupling being operable between a first position where the coupling (26, 27, 46) secures the seat (12) to the chassis (11) and a second position where the coupling (26, 27, 46) releases the seat (12) from engagement with the chassis (11);
a control linkage (39, 29, 37, 32) provides for regulating the operation of the coupling (26, 27, 46) at least from the first to the second position; and
a lifting point (44) is incorporated in the seat structure (40, 41) to enable at least the seat (12) (with or without an occupant) to be lifted alone if not when combined with the chassis (11).

2 A wheel chair as claimed in Claim 1 characterised in that the seat (12) and the chassis (11) are provided with complementary alignment structure (21-25) adapted so that on the juxtaposition of the separated seat (12) with the chassis (11) the complementary alignment structure (21-25) interact to urge the seat (12) towards a predetermined final location of the seat (12) relative to the chassis (11) prior to or during transition of the coupling from the second to the first position .

3 A wheel chair as claimed in Claim 2 wherein the complementary alignment structure (21-25) provides for alignment of the seat (12) with the chassis (11) in first (X) and second directions at right angles, the first direction (X) being coaxial with or parallel to the usual direction of travel of the wheelchair.

4 A wheel chair as claimed in Claim 4 characterised in that the complementary alignment structure (21-25) provides for alignment of the seat (12) in the first direction (X) occurs prior to alignment in the second direction.

5 A wheel chair as claimed in Claim 2, Claim 3 or Claim 4 characterised in that the coupling (26, 27, 46) is adapted to automatically change from the second to the first position on the close approach of the seat (12) to, or on its arrival at, the final location on the chassis (11).