EP0161922B1

EP0161922B1 - User-assisting seat

Info

Publication number: EP0161922B1
Application number: EP85303321A
Authority: EP
Inventors: Thornton Wear Smith
Original assignee: Newcastle upon Tyne Metropolitan District Council Workshops for adult blind
Current assignee: Newcastle upon Tyne Metropolitan District Council Workshops for adult blind
Priority date: 1984-05-11
Filing date: 1985-05-10
Publication date: 1989-04-12
Also published as: EP0161922A3; EP0161922A2; DE3569329D1; GB8412080D0; ATE42035T1

Abstract

A seat designed to give assistance to the user in rising from a seated position is hinged to the seat frame at or adjacent to one edge of the seat and is urged to lift pivotally about the hinge by at least one coil spring, adjustment means being provided to vary the tension in the spring by tightening or slackening the coil. In a preferred form, two such coil springs together carry a roller at one of their ends, which roller is disposed to bear upon the underside of the seat, and together carry a rod or bar at their other ends, which rod or bar may be moved to vary the tension in the coils.

Description

The present invention is a seat having the facility of assisting the user to rise when he wishes to leave it.
It is a recurring problem for persons of limited agility that they have difficulty raising themselves from a comfortable sitting position when wishing to leave the seat. The problem is aggravated when the seat is a relatively low one. It is undesirable and restricting for a user to have to seek assistance in rising from a seat and therefore it has previously been suggested that a seat may incorporate some mechanical means of such assistance. However no wholly satisfactory seat of this type is available.
One disadvantage of previously available such seats is that they do not adequately cater for a range of users of different weights and physical strengths. Another is that some such prior seats are not able to withstand the repeated wear entailed in regular daily use.
One example of such available seats is shown in AU-A-520008, where the adjustment means, namely the eccentrically mounted block, affords only a limited number of step-wise adjustments.
It is therefore an object of the present invention to provide a seat which adapts to give adequate assistance in rising to a wide range of different users and which may be made in a simple but robust construction which can survive regular repeated use.
According to the present invention, a seat to give assistance in rising to the user comprises a seat hinged to the supporting frame at or adjacent to one edge of the seat, lifting means to urge said seat to lift relative to the frame by pivotting about the hinge, and adjustment means to vary the lifting force, said lifting means comprising two coil torsion springs characterised in that said springs carry between them a roller at one end of each said spring, said roller being disposed to bear upon the underside of said seat, and in that said adjustment means comprises a first rod or bar carried by the springs between their other ends, an elongated rod threadedly engaging said first rod or bar at one end of said elongated rod, and adjustment means associated with said supporting frame for rotating said elongated rod.
Apart from the assisted-rising feature, the seat may in all other respects resemble a conventional chair. If desired, the feature may be incorporated in a settee, with one or more of the seats thereof being modified according to the invention, such seat or seats being individually adjustable as described.
Two coil torsion springs are provided to urge the seat to lift about the hinge. The point of action of the springs upon the seat will vary as the seat rises. For this reason, the ends of the springs which abut the seat carry a roller between them.
To allow the seat to adapt to the differing needs of different users, means are provided to vary the pressure of the springs by tightening or slackening the coils. For this purpose, a threaded mechanism is provided to enable continuous varying of the position of the end of the coil remote from the seat itself.
In a particularly preferred form of the invention, a locking means is provided to retain the seat in its down position. The locking means preferably is designed to engage automatically when the seat approaches that position. The locking means may be remotely operated so that it can be released manually from a point which is accessible to the user when seated. Conveniently a manual release control may be provided for the user, linked to the locking means by a flexible link such as a Bowden cable.
Other features of the present invention, and possible variations thereof, will become apparent from the following description with reference to the accompanying drawings, in which:

Fig. 1 is a perspective view from the rear of the operating mechanism of one form of seat according to the present inventon;
Fig. 2 is a plan view of the seat of Fig. 1 with the seat portion itself removed; and
Fig. 3 is a vertical sectional view from the side of the seat illustrated in Figs. 1 and 2.

Referring to the drawings, the seat consists essentially of a box frame composed of sides 4 and 5, back 6 and front 7, together with a seat portion 8, which forms a "lid" to the box frame. The seat portion 8 is hinged to the frame front 7 by means of hinges 9.
Extending between the sides 4 and 5, close to the front 7 of the frame is a cross-bar 10, about which a pair of coil springs 11 and 12 are mounted. At their upper ends, the coil springs 11 and 12 carry a nylon roller 13, which bears upon a rigid plate 14, for example of "Formica" (Registered Trade Mark), secured to the underside of the seat portion 8. Thus normal pressure of the springs urges the seat portion to pivot upward and forwards on the hinges 9. When the user of the seat wishes to rise from his sitting position, his lifting action is assisted by the upward pressure of the seat portion under the influence of the springs 11 and 12.
It will be understood that different users of the seat will differ in weight and also in the degree of assistance required. Adjustment of the seat to accommodate these different needs is afforded as follows.
The lower ends of the springs 11 and 12 carry between them a tension bar 15, to which they are secured. Extending between the rear frame member 6 and the bar 15 is a tension-adjusting rod 16, which is threadedly engaged at one end with the bar 15 and carries a knurled knob 17 at its other end. Thus, when the knob 17 is turned in a clockwise direction, the threaded rod 16 is screwed further into the bar 15 and pulls it towards the rear frame member 6, thereby increasing the tension in the coil springs 11 and 12 and enhancing the upward pressure on the seat portion 8. In this way, the person rising from the seat is given increased assistance.
An optional, but highly advantageous, further feature of the illustrated form of the invention is a locking means which operates to retain the seat closed. The locking means takes the form of a sprung latch 18 (Fig. 3) mounted on a cross-member 19 of the seat frame and arranged to engage a socket 20 on the underside of the seat portion 8. The seat would normally be held down by the weight of the user upon it but, in order to permit setting of the springs 11, 12 to afford strong assistance to the user in rising, while at the same time leaving him comfortable when seated, the locking means retains the seat securely closed until the assistance in rising is required. Spring operation of the latch 18 ensures that the seat locks automatically when it is lowered, as by the user sitting upon it.
The latch 18 may be withdrawn from engagement with the socket 20 by means of a Bowden cable 21, operated by a release lever 22 mounted on the underside of the arm (not shown) of the seat, in a position readily accessible to the seated user. Thus when the user wishes to rise, he merely operates the release lever 22 and thereby disengages the latch 19 to gain the help in rising afforded by the springs 11 and 12.
As will be seen, the seat according to the present invention may be made in a simple but robust form and is adapted to adjust to the needs of different users. In laboratory tests, we have found that a seat in the form illustrated in the accompanying drawings gave adequate assistance to users weighing from 45 to 95 kg (from 7 stone to 15 stone) and that the seat mechanism survived 100,000 cycles of lifting and lowering without failure.

Claims

1. A user-assisting seat comprising a supporting frame (4, 5, 6, 7), a seat (8) hinged to said frame at or adjacent to one edge of said seat, lifting means to urge said seat to lift relative to the frame by pivotting about the hinge (9), and adjustment means (15, 16, 17) to vary the lifting force, said lifting means comprising two coil torsion springs (11, 12), characterised in that said springs carry between them a roller (13) at one end of each said spring, said roller (13) being disposed to bear upon the underside of said seat (8), and in that said adjustment means comprises a first rod or bar (15) carried by the springs (11, 12) between their other ends, en elongated rod (16) threadedly engaging said first rod or bar (15) at one end of said elongated rod (16), and rotation means (17) associated with said supporting frame for rotating said elongated rod (16).

2. A user-assisting seat as claimed in claim 1, wherein said rotation means (17) is manually operable.

3. A user-assisting seat as claimed in either of the preceding claims, having locking means (18) to retain the seat in its down position, said locking means (18) being designed to engage automatically when the seat approaches said down position and being manually releasable from a point accessible to the user when seated.

4. A user-assisting seat as claimed in claim 3, wherein said locking means is linked to a manual release control by a Bowden cable.