GB2113988A

GB2113988A - Seat construction

Info

Publication number: GB2113988A
Application number: GB08301016A
Authority: GB
Inventors: Michael Eric Norman
Original assignee: WORKSHOPS FOR ADULT BLIND
Current assignee: WORKSHOPS FOR ADULT BLIND
Priority date: 1982-01-29
Filing date: 1983-01-14
Publication date: 1983-08-17
Also published as: GB8301016D0

Abstract

A seat construction for assisting the infirm to stand up on leaving the seat, comprises a seat 6 having a support board 8 pivoted at 9 to a chair frame 1. A block 10 fixed under the board 8 has an arm assembly 11 hinged thereto and the arm assembly carries a bar 13 to which springs 14 are anchored at one end, the springs being anchored at the other end to a cross member 15. The inclination of arm assembly 11 is adjustable by means of a nut 16 on a threaded shaft 17 to vary the effective length of a notional lever between the bar 13 and board 8. In an alternative embodiment (Fig. 2) the lever is provided by fixed brackets 28, 29 and the effective force is varied by tensioning the springs 31 by means of a shaft 24 and runner 33 pulling on the springs. <IMAGE>

Description

SPECIFICATION Seat construction This invention relates to seats, particularly seats for the elderly and disabled. The act of rising from a seat causes considerable difficulty to many elderly and disabled people. It is therefore desirable to provide some form of assistance to enable such people to rise from a seat and gain standing balance without their falling back or otherwise losing balance, and an object of the invention is to provide a seat construction which will provide such assistance.

According to the invention therefore, a seat construction includes a seat member pivotally mounted on a support, and resilient means urging the seat member into a raised position.

In a preferred embodiment of the invention, the seat member comprises a planar member such as a board, which can be upholstered or otherwise cushioned for comfort. The seat member is preferably hinged at its front edge to a chair frame.

An array of tension springs is disposed extending across the chair frame, and connected at one end to lever means mounted on the underside of the seat member.

To satisfy persons of different weight, it is desirable for the force exerted on the seat to tilt it to be variable, so that sufficient force is imparted to assist an occupant to his or her feet, without propelling the occupant forwards. This may be achieved by making the tension of the springs adjustable, or by altering the effective length of the lever means. The springs may be varied in tension by connecting them to a cross bar member having a threaded shaft parallel to the springs with a knob so that rotation of the knob will rotate the shaft and cause displacement of a complementary threaded runner on a member to which one end of the springs are attached to tighten or slacken the springs.

The springs act to pull the legs or brackets attached to the seat member away from the hinges, and by so doing urge the seat upwardly on the hinges. When a person is seated on the seat, the force of the springs is overcome, but when the person begins to rise, the springs pull the legs and thus raise the seat, giving a force assisting the person to rise.

In a preferred embodiment of the invention, the lever means is comprised by a block or arm rigidly attached below the seat, pivotally connected to an arm assembly extending towards the pivot of the seat, and carrying at its free end a cross bar to which one end of the array of springs is anchored.

The other end of the array of springs is anchored to the chair frame. Variation in the effective length of the notional lever extending between the seat pivot and the cross bar is effected by pivoting the arm assembly relative to the block towards or away from the seat.

Preferred embodiments of the invention will now be described by way of example with reference to the accompanying drawings wherein: Fig. 1 is a diagrammatic side view of a first more preferred embodiment of the invention; and Fig. 2 is a perspective view of a second embodiment of the invention.

Referring to Fig. 1 the more preferred embodiment of the invention comprises a chair having a frame 1 with front and back members 2 and 3, legs 4 and a back frame 5. A seat 6 comprises an upholstered pad 7 and a support board 8 and is pivoted by hinges 9 to the front member 2 of the frame. A block 10 is mounted below the board 8, some distance, e.g. 25 cm, from the hinge 9, and an arm assembly 11 is pivoted to the block 10 by a hinge 12 and extends in the general direction of the front frame member 2.

The arm assembly 11 may be a solid genera!ly planar member or comprise one, two or more separate arms.

Arm assembly 11 carries on its free end a cross bar 13 to which are anchored ends of eight helical springs 14. Springs 14 are disposed in two groups of four, to each side of the arm assembly 11 so as not to foul the arm assembly and/or block 10. The other ends of the springs are mounted on a cross strut extending between lateral side members frame 1.

The arm assembly 11 may be pivoted between for example the-extreme broken line portions 1 la and 11 b shown in Fig. 1, the lower surface of block 10 being shaped to allow the arm assembly 11 to occupy an attitude above the portion parallel to board 8. This pivoting varies the length of the effective notional lever between the anchorage of the springs 14 on bar 13 and the board 8, thereby varying the mechanical advantage through which the spring force is transmitted to the seat 6 and thus the lifting force exerted on the seat 6. The movement can be varied by a factor of greater than 2:1 so that occupants with body weights in a range of, for example, 6 stones to 13 stones (i.e.

approximately 38 kg to 83 kg) can have the lifting force properly adjusted for them.

Adjustment is effected by a nut 1 6 on a threaded shaft 1 7 extending through the arm assembly 11, and fixed in the seat 6. Nut 1 6 has a handle 1 8 for manipulation. The effective force applied to the seat is reduced by tightening the nut 16 up towards the seat, moving the arm assembly towards the position 11 a, thereby shortening the effective lever. Conversely the lifting force can be increased by allowing the arm assembly to drop towards the portion 11 b by slackening the nut 16, thereby lengthening the effective lever.

In the less preferred embodiment of Fig. 2, a seat member 21 is hinged by hinges 22, 23 to the front side 24 of a frame also comprised by side members 25, 26 and a rear side 27. Triangular brackets 28, 29 are mounted one at each side on the underside of the seat member 21 towards the front hinged end. A bar 30 connects the apices of the brackets 28, 29, and six for example cylindrically coiled tension springs 31 are anchored each at one of their ends to the bar 30.

The other ends of the spring 31 are anchored to a further bar 32 connected at each end to a bow member 33. A threaded shaft 34 extends through an aperture in the bar 32 and cooperates with a counter threaded aperture in the bow member 33 which acts as a runner on the shaft 34. The end of the shaft 34 passes through an aperture in the rear side 27 of the frame and carries a knob or handle 35 for turning the shaft 34.

The handle 35 turns shaft 34, and rotation of the shaft displaces the runner formed by the bow member 33 and the bar 32 as also pulled by the bow member 33. The tension on the springs 31 can thus be increased or diminished depending on the sense of rotation of the shaft.

The bow member 33 is preferably resilient, e.g.

of spring steel, and contributes to the total spring loading effect.

Claims

1. A seat construction including a seat member pivotally mounted along one edge on a support structure, and resilient means urging the said seat member into a raised position.

2. A seat construction according to claim 1 wherein the seat member comprises a planar member such as a board hinged at its front edge to a chair frame, an array of tension springs being disposed extending across the chair and connected at one end to lever means mounted on the underside of the board.

3. A seat construction according to claim 2 wherein the lever means comprises a block or arm rigidly attached below the seat pivotally connected to an arm assembly extending towards the pivot of the seat and carrying at its free end a cross bar to which one end of the array of springs is anchored, the other end of the array of springs being attached to the chair frame, variation in the effective length of the notional lever being effected by pivoting the arm assembly relative to the block towards or away from the seat.

4. A seat construction according to claim 3, wherein adjustment of the pivotal portion of the arm assembly is effected by a nut bearing on the underside of the arm assembly and running on a threaded shaft extending through the arm assembly and mounted on the seat to project downwardly therefrom.

5. A seat construction according to claim 2 wherein the tension of the springs forming the array of springs is variable, the other ends of the springs being connected to a cross bar having a threaded shaft extending in the axial direction of the springs, said shaft passing through one side of the frame and provided with a knob on the outerside so that turning of the knob rotates the shaft and causes displacement of a complementary threaded runner connected to the cross bar member.

6. A seat construction according to claim 5 wherein the runner is formed as a resilient bow member connected at each end to the cross bar.

7. A seat construction substantially as hereinbefore described, with reference to and as illustrated in Fig. 1 or Fig. 2 of the accompanying drawings.