GB2193886A - Improved invalid chair - Google Patents

Abstract

An invalid chair for assisting an occupant in rising therefrom includes a support frame (2, 4, 6, 8) to the front transverse member 6 of which is hingedly mounted a seat having a base plate 10 whereby the seat can be pivoted upwardly about said frame member 6. Resilient means such as torsion springs 16 react between the frame of the chair and the underside of the seat to urge the seat upwardly from a first position located on the support frame towards a pivotally-displaced position, the upward force applied to the underside of the seat of the chair in its first position by the resilient means being adjustable by suitable operation of control means (30, 34, 36, 38) acting on said resilient means. <IMAGE>

Description

SPECIFICATION Improved invalid chair This invention relates to chairs and more particularly to such chairs incorporating means to facilitate an occupant rising therefrom.

Elderly, infirm and disabled people often find it difficult to rise from conventional chairs and it is known to provide invalid or orthopaedic chairs, known as high rise chairs, which provide assistance to the occupant when rising therefrom. Such known chairs commonly include a seat the front regions of which are hingedly mounted to the chair frame whereby the seat can be pivoted about said front regions from a substantially horizontal position seating on the chair frame to a displaced position in which the seat is angled upwardly with the rear regions thereof above the level of the front regions thereof.

The seat is urged towards said displaced position by, for example, a plurality of coil springs reacting between the fixed frame of the chair and the underside of the seat, the arrangement being such that, on initial rising from the chair such as to reduce the downward force of the occupant on the seat, and therefore on the springs, the previously compressed springs can begin to expand thereby urging the seat upwards and assisting the further rising of the occupant.

It will be appreciated, however, that the degree of assistance in rising from such a chair is dependent upon the strength and number of coil springs used, and, for a given chair, is of a fixed value. In practice, the weight of an occupant oan vary considerably, from, say, 4 to 5 stones up to of the order of 17 or 18 stones or more, and it is therefore quite clear that a given coil spring arrangement as detailed above cannot provide adequate assistance to occupants over this full weight range.

The number of springs used could be increased or decreased in dependence upon the weight of the occupant, but such alterations would require disassembly of the assistance mechanism, and is clearly not a practical possibility, particularly for infirm or elderly persons.

Alternative known high-rise chairs incorporate a lever-operated hydraulic mechanism for pivoting the seat of the chair upwards but, as with the spring-assisted arrangement, the force provided by such a mechanism is of a fixed value and, again, is not ideally suited to assisting occupants of widely-varying weights.

It would be desirable to be able to provide an invalid chair capable of giving adequate and effective assistance in rising therefrom to occupants regardless of their weight.

According to the present invention there is provided an invalid chair comprising a seat the forward regions of which are hingedly mounted to the frame of the chair whereby said seat can be pivoted about an axis extending transversely of the chair between a first position determined by abutment of the seat with the frame of the chair and a second position angled upwardly from said first position in which the rear regions of the seat are located above the level of the forward regions thereof, resilient means reacting between the frame of the chair and the underside of the seat to urge said seat upwardly from the first position towards the second position thereof, and control means operable to adjust the force applied by the resilient means to the underside of the seat when in said first position.

The resilient means may comprise one or more, and preferably two, torsion springs conveniently mounted with their longitudinal central axes extending transversely of the chair, one end extent of each spring reacting against the underside of the seat of the chair and the position of the other end extent of each spring being adjustable.

In a preferred arrangement, the springs are mounted on, to surround, a fixed fulcrum bar extending transversely of the chair below the seat of the chair whereby said springs can be rotated about the central longitudinal axis of said bar, the one end extent of each spring extending transversely of the chair and said one end extents being received in the opposed ends of, to carry thereon, a roller engaging the underside of the seat of the chair, said roller being rotatable about its central longitudinal axis defined by said one end extents of the springs.

Conventiently, the other end extents of the springs are each attached to a torsion bar extending transversely of the chair below the seat of the chair, said torsion bar being movable fore and aft of the chair to alter the positions of the other end extents of the springs relative to the fixed fulcrum bar.

Preferabiy the torsion bar is provided with a diametrical, screw-threaded bore therein through which passes a correspondinglythreaded portion of a shaft extending fore and aft of the chair and rotatable by means of a handle mounted on one end of the shaft, conveniently at the rear of the chair.

Lateral movement of the springs on the fulcrum bar is conveniently prevented by means of pins extending through diametrical bores in the fulcrum bar and engaging the associated ends of the coiled body portions of the springs.

By way of example only, an embodiment of the invention will now be described in greater detail with reference to the accompanying drawings of which: Figure 1 is a rear end view of the resilient means and the control means of an invalid chair according to the invention; Figure 2 is a side view of the means of Fig.

1 showing the seat of the chair in the second position thereof, and Figure 3 is a plan view from above of the means of Figs. 1 and 2.

Referring to the drawings, the illustrated chair comprises a frame including a pair of opposed seat supporting members 2, 4 extending fore and aft of the chair and a pair of opposed seat-supporting members 6, 8 extending transversely of the chair. The base plate 10 of the seat of the chair is hingedly mounted at 12 to the front tranverse frame member 6 as seen in Fig. 2 so that the seat of the chair can be pivoted upwardly about its front regions thereof from a substantially horizontal position seating on the frame members 2, 4, 6, 8 to a displaced position shown in dotted lines in Fig. 2 in which the rear regions of the seat are located above the level of the front regions thereof.

The illustrated chair further comprises means for effecting said upward pivoting movement of the seat to the position of Fig. 2, said means being adjustable whereby the extent of said pivoting movement and therefore the degree of displacement of the seat from its position sitting on the frame, can be varied.

More particularly, a fulcrum bar 14 extends transversely of the chair below the seat, said bar 14 being secured to the inside faces of the side frame members 2, 4. A pair of torsion springs indicated generally at 16 are mounted on the bar 14 with their coiled body portions 18 surrounding the bar 14, cylindrical nylon bushes 20 being interposed between the springs 16 and the bar 14. The springs are rotatable on the bar 14 but are prevented from moving laterally along the bar by pins 22 extending diametrically through bores in the bar 14 and reacting against the ends of the coiled body portions 18 of the springs 16.

One end portion 24 of each spring 16 extends rearwardly from the fulcrum bar 14 and is bent inwardly of the chair to extend parallel with the bar 14, the two end portions 24 terminating adjacent to, but spaced from, one another and carrying thereon a cylindrical roller 26 which is rotatable on said end portions 24 of the springs 16.

The other end portions 28 of the springs 16 are hooked onto opposed end regions of a torsion bar 30 extending transversely of the chair in front of and below the level of the fulcrum bar 14. Again, pins 32 passing through diametrical bores in the torsion bar 30 prevent lateral movement of the end portions 28 of the springs on the bar 30.

The torsion bar 30 is formed with a diametrical, screw-threaded bore centrally therethrough, through which passes a correspondingly-threaded front portion 34 of a shaft 36 extending fore and aft of the shaft 36 passing through the rear frame member 8 and having a handle 38 attached thereto whereby said shaft 36 can be rotated. It will be appreciated that, on rotation of the shaft 36, the torsion bar 30 is moved fore and aft of the chair whereby the end portions 28 of the springs 16 are moved away from and towards the fulcrum bar 14 respectively.

With the torsion bar 30, and consequently the end portions 28 of the springs 16, in the foremost position, the body portions 18 of the springs 16 are located on the fulcrum bar 14 such that the end portions 24 of the springs are positioned substantially horizontally and below the level of the base plate 10 of the seat of the chair which can therefore sit unimpeded on the frame of the chair.

As the shaft 36 is rotated to draw the torsion bar 30 rearwardly, the end portions 28 of the springs 16 move therewith such that the body portions 18 of the springs 16 are pivoted, in a clockwise direction as viewed in Fig. 2, on the fulcrum bar 14. Thus, the end portions 24 of the springs 16 are raised towards the position shown in Fig. 2 such that the roller 26 engages the underside of the base plate 10 and raises the seat of the chair about the hinges 12. The position of the torsion bar 30 on the shaft 36 determines the amount by which the roller 26 raises the seat of the chair.

It will be appreciated that the higher the seat of the chair is raised above the frame of the chair, the greater is the force required to return the seat of the chair, against the bias of the springs 16, to its position sitting on the frame, and, correspondingly, with the seat of the chair sitting on the frame, the greater is the upward force exerted by the springs 16 on the underside of the seat urging the seat towards its raised position.

This described arrangement can be readily adapted to provide controlled assistance in rising from the chair to occupants of widely differing weights. For example, for relatively light people, or where little assistance in rising is required, the handle 38 can be rotated such that the torsion bar 30 is in a relatively forward position on the shaft 36,with the roller 26 projecting only slightly above the level of the frame comprising the members 2, 4, 6, 8.

More assistance for such relatively light people, or the equivalent assistance for heavier people, can be achieved by rotating the shaft 36 to draw the torsion bar 30 rearwardly, raise the roller 26 and therefore increase the torsion in the springs 16 with the seat of the chair sitting on the frame.

Clearly, the desired degree of assistance is under the control of the user of the chair and can be chosen merely by appropriate rotation of the handle 38 prior to using the chair. Thus a single chair is capable of providing effective and variable assistance in rising therefrom to occupants of widely differing weights.

Conveniently the assistance mechanism comprising the components 10 to 36 is housed in an enclosed container with only the roller 26 projecting therefrom to engage the underside of the seat.

Although two coiled torsion springs are shown as providing the variable resilient force on the seat of the chair, other arrangements incorporating other than two springs may be used. Other modifications are variations from the illustrated arrangement will be apparent to those skilled in the art.

Claims (8)

1. An invalid chair comprising a seat the forward regions of which are hingedly mounted to the frame of the chair whereby said seat can be pivoted about an axis extending transversely of the chair between a first position determined by abutment of the seat with the frame of the chair and a second position angled upwardly from said first position in which the rear regions of the seat are located above the level of the forward regions thereof, resilient means reacting between the frame of the chair and the underside of the seat to urge said seat upwardly from the first position towards the second position thereof, and control means operable to adjust the force applied by the resilient means to the underside of the seat when in said first position.

2. An invalid chair as claimed in claim 1 in which the resilient means comprise one or more torsion springs.

3. An invalid chair as claimed in claim 2 and comprising two coiled torsion springs mounted with their longitudinal central axes extending transversely of the chair, one end extent of each spring reacting against the underside of the seat of the chair and the position of the. other end extent of each spring being adjustable.

4. An invalid chair as claimed in claim 3 in which the springs are mounted on, to surround a fixed fulcrum bar extending transversely of the chair below the seat of the chair whereby said springs can be rotated about the central longitudinal axis of said bar, the one end extent of each spring extending transversely of the chair and being received in the opposed ends of, to carry thereon, a roller engaging the underside of the seat of the chair, said roller being rotatable about the central longitudinal axis defined by said one end extents of the springs.

5. An invalid chair as claimed in claim 4 in which the other end extents of the springs are each attached to a torsion bar extending transversely of the chair below the seat of the chair, said torsion bar being movable fore and aft of the chair to alter the positions of the other end extents of the springs relative to the fixed fulcrum bar.

6. An invalid chair as claimed in claim 5 in which the torsion bar is provided with a diametrical, screw-threaded bore therein through which passes a correspondingly threaded portion of a shaft extending fore and aft of the chair and rotatable by means of a handle mounted on one end of the shaft.

7. An invalid chair as claimed in any one of claims 4 to 6 in which lateral movement of the springs on the fulcrum bar is prevented by means of pins extending through diametrical bores in the fulcrum bar and engaging the associated ends of the coiled body portions of the springs.

8. An invalid chair substantially as described with reference to and as illustrated by the accompanying drawings.