GB2124480A - Chairs - Google Patents

Abstract

A chair comprises two frames (10, 11), the first frame (10) including the rear ground support and an upward extension therefrom, the second frame (11) including the front ground support and seat (14), and the two frames being interconnected (12) for pivotal movement between two predetermined positions in a first one of which the first frame is generally upright for normal use of the chair, and in a second one of which the first frame is inclined rearwardly from a ground-engaging position beneath the seat for use of the chair as evacuation equipment. The ground-engaging position is preferably forward of the normal centre of gravity of the chair when occupied, the pivotal movement is suitably in the range 15 DEG to 40 DEG , and the two frames are preferably releasably locatable in the first position. In a preferred form the rear ground support has wheels or the like (18) to engage the ground in the second position, but not the first position, the wheels preferably being unidirectionally rotatable for rearward movement of the first frame. <IMAGE>

Description

SPECIFICATION Chairs This invention concerns chairs and more particularly chairs suitable for evacuating disabled people in the event of fire or other emergency.

Fires or other emergencies requiring rapid evacuation in homes catering for disabled people are rare events. Nevertheless equipment has to be provided for such an emergency otherwise the difficulties of evacuation can result in loss of life.

However, space, particularly in institutions, is usually limited and special evacuation equipment cannot always be easily stored at a location sufficiently accessible for ready use in an emergency.

One attractive possibility for meeting this last difficulty is to modify or design items of furniture or the like to serve a normal every day use and also as evacuation equipment. This possibility has been pursued, particularly for hospitai usage, in respect of mattresses and sheets, but such items do not suit all circumstances.

The present invention also results from pursuing this last possibility and provides a chair comprising two frames, the first frame including the rear ground support and an upward extension therefrom, the second frame including the front ground support and seat, and the two frames being interconnected for pivotal movement between two predetermined positions in a first one of which the first frame is generally upright and in a second one of which the first frame is inclined rearwardly from a ground-engaging position beneath the seat.

In normal usage the chair is used with the first frame in its first position and is preferably releasably lockable in this position for reasons of safety.

For emergency use the first frame is released for movement towards its second position, this position preferably being such as to effect rear ground support forward of the centre of gravity of the chair when occupied, with the rotation suitably being between 15 and 400 and determined by a stop mechanism. This second position facilitates use of the chair, when occupied, as evacuation equipment by rearward dragging as will be explained below.

The ground support parts of the chair are preferably of splayed form to enhance stability when in normal use. Also those same parts of the first frame can have wheels or the like which engage the ground in the second position, but not the first, to facilitate evacuation usage further.

However such wheels or the like are preferably unidirectionally rotatable to allow only rearward movement of the first frame.

The second frame also preferably includes the back as well as the seat of the chair.

A fuller understanding of the present invention will be gained from the following further description with reference to the accompanying drawings, in which: Figure 1 respectively diagrammatically illustrates at (a) and (b) for a normal chair, and at (c) for a chair according to the invention, forces acting during rearward dragging, and Figure 2 illustrates one presently preferred embodiment of a chair according to the invention.

Figure 1 (a) shows the usual disposition of forces acting on a normal chair when occupied and dragged rearwardly. The chair usually tilts so that frictional forces F act only on the rear legs, but with the weight W stili acting forwardly thereof. The dragging force P is accordingly constrained to be predominantly horizontal to counterbalance the weight and to overcome the frictional force.

This is not convenient to the person dragging who will normally prefer to pull in the direction of an inclined arm.

If the chair is tilted to the point where the weight acts behind the rear legs, the situation is as shown in Figure 1(b). The weight is now counterbalanced by the vertical component Pv of the dragging force, while the frictional force is overcome by the horizontal component PH. This situation is in fact not readily achieved or sustained. Increased tilting of the chair increases the effort required to balance the weight as compared to overcoming friction, and at the same time the occupant of the chair is moved from a normal seated position.

If, however, the chair accords with the present invention having a rear leg frame 1 which can be pivoted from a normal upright position as shown in broken line to that in full line relative to a seat/front leg frame 2 as in Figure 1(c), the situation is significantly improved. The pivotal movement, plus slightly tilting to lift the front legs from the ground, aligns the rear frame to suit the person dragging the chair, moves the rear leg ground contact forward of the centre of gravity, but to a lessee extent than in Figure 1 (b) so that a lesser proportion of force P is required for counterbalancing, and the occupant is seated more normally.

The embodiment of Figure 2 comprises a tubular metal first frame 10 and second frame 11 pivotally interconnected at their sides at 1 2.

Frame 10 incorporates the rear legs and an upward extension therefrom, this extension having an upper cross-member below which a latch mechanism 1 3 is mounted.

Frame 11 incorporates the front legs and subframes for a seat and back, the last two elements being provided as a one-piece moulding 14 of plastics material upon which may be located, in turn, cushioning 1 5.

The extension of frame 10 normally abuts behind the back sub-frame of frame 11, the latter having a cross-member 1 6 with which the latch 13 cooperates to lock the frames together for normal use. However, the latch is releasable by movement against a spring 17, whereupon the frame 10 can be pivoted to the position shown in broken outline where the rear legs abut the back sub-frame. This position corresponds to that of Figure 1 (c) with the rear leg ground contact being below the seat and in fact forward of the normal centre of gravity, denoted at W, when the chair is occupied. This will of course tilt the chair rearwardly and facilitate use for evacuation by dragging as described above.

The use is additionally facilitated by the provision of wheel 1 8 adjacent the feet of the rear legs, these wheels normally being out of ground contact but engaged by pivoting of frame 1 0.

These wheels are preferably unidirectionally rotatable to allow rotation only when the chair is dragged rearwardly.

In the case of chairs for children or lightweight adults the provision of wheels is not necessary, but it may be preferred to employ rear leg feet of low friction material such as nylon or PTFE.

The chair of Figure 2 is designed to be stackable, which is advantageous when a number are used for evacuation to a limited space as well as for normal storage requirements. The legs are splayed outwardly, and the front legs have feet of high friction material, to afford stability in use by disabled people. Also the seat is formed in such a way as to drain naturally, and the seat and back cushions are of separate, but like form for economy of manufacture.

Naturally, although a presently preferred form, the embodiment of Figure 2 is only one example of the present invention.

Claims (11)

1. A chair comprising two frames, the first frame including the rear ground support and an upward extension therefrom, the second frame including the front ground support and seat, and the two frames being interconnected for pivotal movement between two predetermined positions in a first one of which the first frame is generally upright, and in a second one of which the first frame is inclined rearwardly from a groundengaging position beneath the seat.

2. A chair according to claim 1 wherein said ground-engaging position is forward of the normal centre of gravity of the chair when occupied.

3. A chair according to claim 1 or 2 wherein said pivotal movement is in the range 1 50 to 400.

4. A chair according to claim 1, 2 or 3 wherein said frames are releasably lockable together in said first position.

5. A chair according to any preceding claim wherein said rear ground support has wheels or the like which are engaged with the ground by said pivotal movement but are otherwise normally out of contact with the ground.

6. A chair according to claim 5 wherein said wheels or the like are unidirectionally rotatable to allow rearward movement of the first frame thereon.

7. A chair according to any one of claims 1 to 4 wherein said rear and front ground supports respectively have low and high friction groundengaging elements.

8. A chair according to any preceding claim wherein said rear and front ground supports are outwardly splayed in said first position.

9. A chair according to any preceding claim of stackable form.

10. A chair according to any preceding claim wherein said second frame also includes a back.

11. A chair substantially as herein described with reference to the accompanying drawings.