GB2191683A - Seat unit - Google Patents

Abstract

A seat unit comprises a base 1 and a seat 2 connected to the base 1 by a linkage 3 of crossed legs 4, 5. The seat 2 can be raised and lowered relative to the base 1, with the rearward part of the seat 2 being lifted to a greater extent than the forward part when the seat is raised, to tip the seat occupant forwardly towards a standing position. A spring 15 urges the seat toward its raised position. The seat may further comprise handles to provide further support for assistance for a person using the seat and moving between sitting and standing positions. The seat may take the form of a toilet seat. <IMAGE>

Description

SPECIFICATION Seat unit The present invention relates to a seat unit which is intended for example to enable disabled or elderly persons to sit down in and stand up from the seat, more easily.

It is well-known that in particular disabled and/or elderly persons but also persons suffering from various kinds of physical infirmity such as injury, often find it difficult to sit down in and stand up from the seat, without the assistance of another person.

That frequentiy happens because the muscles of the person wishing to sit down or stand up are insufficiently strong, or cannot be satisfactorily controlled, to lower and raise the person's body underfull control over the whole range of movements between the sitting and the standing positions.

According to the present invention, there is provided a seat unit comprising: a base means; a seat portion for a person using the seat to sit upon; a linkage means interconnecting the base means and the seat portion and operable to provide for displacement of the seat portion relative to the base means between a first position constituting a normal seat position for the person using the seat, with the seat portion lowered towards the base means, and a second position in which the seat portion is raised from the base means to provide assistance for the person using the seat to stand up therefrom, the linkage means also being operable to cause the rearward part of the seat portion to be raised to a greater distance from the base means than the front part of the seat portion whereby the seat portion in moving from said first position to said second position lifts away from said base means and also tilts forwardly of the seat; and means urging said seat portion towards said second position.

In a preferred feature of the unit, the linkage means comprises a scissor-type assembly, the respective lengths of the legs constituting the scissor-type assembly being so adjusted as to produce the simultaneous upward and forwardly tilting movement of the seat portion relative to the base means. More preferably still, the linkage means comprises a first pair of legs and a second pair of legs, with the first and second pairs being in crossed relationship and pivotally connected together in such a way that the lengths of the leg portions of each pair at one side of the pivot connection are smaller than the lengths of the leg portions of each pair at the other side of said pivot connection, thereby producing said forwardly tilting movement of the seat portion as it moves towards said second position.

Each pair of legs may be part of a frame arrangement of generally rectangular configuration, with the legs of one pair being closer together than the legs of the other pair whereby one of said rectangular frame assemblies is disposed within the other of the rectangular frame assemblies.

The means for urging the seat portion towards the second position desirably comprise a spring, preferably a torsion spring which is carried on pivot means of the linkage assembly and which has elongate leg portions urging the seat portion towards its said second position.

The seat unit may further comprise a device for holding the seat portion latched or locked to the base means in the first position of the seat portion, while handles may further be provided on the seat portion or another part of the seat unit, to provide further support and assistance for the person using the seat in moving between the sitting and the standing positions.

The seat unit may be in various forms, for example an upholstered seat unit, a toilet seat unit and so forth.

Embodiments of a seat unit according to the present invention will now be described by way of example with reference to the accompanying drawing in which: Figure lisa diagrammatic side view of the seat unit in a raised position, Figure 2 is a side view of the linkage assembly and spring of the Figure 1 unit, and Figure 3 is a plan view of the assembly shown in Figure 2.

Referring firstly to Figure 1, a seat unit as shown therein comprises a base structure as indicated generally at 1, which is such that it can be placed on any suitable support structure such as a leg arrangement, a toilet bowl or the like. The seat unit illustrated is in the form of a toilet seat which is thus arranged to be mounted on the rim of a WC bowl.

The seat unit further includes a seat portion as indicated generally at 2, which will be of a nature suited to the kind of seat, for example being an upholstered or cushioned portion if the seat is in the form of an armchair-like seat, while in the case of the illustrated embodiment which constitutes a toilet seat, the seat portion 2 is of a generally conventional toilet seat configuration, being produced for example by a standard moulding process of for example ABS.

Operatively disposed between the base structure 1 and the seat portion 2 is a linkage assembly which is generally indicated at 3. As can be seen from the drawing, the linkage assembly comprises pairs of legs 4 and 5 which are disposed in crossed relationship, with the legs 5' and 5" of the pair 5 being disposed within the legs 4' and 4", as can be most clearly seen from Figure 3. It will further be seen from Figure 3 that each pair of legs 4 and 5 forms part of a respective generally rectangular frame structure, such that the legs 4' and 4" form long side portions of a rectangular frame structure, with cross bar portions 6 and 7 shown in Figure 3.

The legs 5' and 5" similarly form long side portions of the second frame structure which is completed by cross bar portions 8 and 9, also as shown in Figure 3. The transverse width of the rectangular frame structure formed by the legs 5' and 5" and the cross bar portions 8 and 9, is less than that of the other frame structure so that the legs 5' and 5" are thus disposed inwardiy of the legs 4' and 4" respectively, as is clearly visible in Figure 3. The respectively adjacent legs 4', 5' and 4", 5", are connected by suitable spindles or shafts as diagrammatically indicated at 10 in Figure 3 and also as indicated in Figure 2.

It will be seen from Figure 1 that the ends of the legs 4' and 4" which are towards the left in Figure 1, being therefore joined to the cross bar portion 7 of the corresponding rectangular frame structure (Figure 3) are pivotally connected by means not shown in the drawing to the base structure 1, at the location indicated at 11 in Figure 1.

The other ends of the legs 4' and 4" are slidably connected to the end part of the seat portion 2, which is towards the right in Figure 1 and which therefore constitutes the rearward part of the seat portion 2. These ends of the legs 4' and 4" are thus slidable lengthwise of the seat portion 2, at the underside thereof.

The ends of the legs 5' and 5" which are towards the left in Figure 1 are pivotally connected to the corresponding end part of the seat portion 2, being therefore the forward end part of the seat portion 2.

Similarly, the other ends of the legs 5' and 5" are in sliding contact with the end part of the base structure 1 which is towards the right in Figure 1, for which purpose the base structure 1 has slide surfaces with a slight ramp configuration, of which one is shown at 12 in Figure 1. Disposed at the ends of the slide surfaces 12 towards the left in Figure 1 are hooks of which one is shown at 13, the hooks 13 being such as to be capable of accommodating respective laterally projecting end parts 14 of the cross bar portion 8 of the frame structure which includes the legs 5' and 5".When the end parts 14 are thus engaged with the respective hooks 13, the seat portion 2 with the linkage means 3 cannot therefore tilt forwardly away from the base structure 1, which could constitute a dangerous situation for the person using the seat, in the course of standing up or sitting down.

The seat unit also includes a spring assembly as indicated generally at 15 in Figure 1. The assembly comprises a torsion spring at each side of the respective pairs of legs 4 and 15, each spring thus consisting of at least one annular portion or spring turn which is carried on each of the respective mounting spindles or shafts 10 which are indicated at Figures 2 and 3. The positions of the annular spring portions or spring turns can clearly seen from Figure 1 in side view while Figure 3 in plan shows that the spring turns are disposed between adjoining legs 4' and 5', 4" and 5". Each spring 15 further includes first and second legs 16 and 17.The free end of the leg 16 bears against the cross bar portion 8 or a respective one of the end parts 14 projecting thereform, while the other leg 17 of the spring 15 bears against the cross bar portion 6 or against a suitable part of the rectangular frame structure to which the cross bar portion 8 belongs, or alternatively against a part of the seat portion 2 at the underside thereof. The springs 15 are operable to urge the seat unit into the configuration shown in Figure 1, with the seat portion 2 raised and tilted forwardly, relative to the base structure 1.

Reference 18 indicates a pivot mounting shaft to permit the toilet seat to be lifted up by a pivot movement in the usual fashion.

The mode of operation of the illustrated seat unit is as follows: Assuming that the seat unit is in the configuration shown in Figure 1, a person wishing to use the seat simply sits on the seat portion 2 and the weight of that person thus causes the seat portion 2 to move downwardly until it comes to rest in a stable position upon the support structure 1. The springs 15 resist the downward movement of the seat portion 2 but are insufficiently strong to prevent that movement from taking place. Indeed, the upward force generated by the springs 15 is such as to assist with upward movement of the seat portion 2, when initiated and promoted by the muscles of the person sitting on the seat, but is not sufficient to lift the seat portion 2 and occupant, on its own.

In the course of the downward movement of the seat portion 2 towards the base structure 1, the ends of the legs 5' and 5", which are towards the right in Figure 1, will come out of engagement with the hooks 13 and slide along the slide surfaces 12 as the linkage assembly 4 and 5 collapses beneath the seat portion 2, by pivotal movement of the legs about the spindles or shafts 10. A similar sliding movement will also take place at the right-hand ends of the legs 4' and 4", at the underside of the right-hand end part of the seat portion 2.

When then the person sitting in the seat wishes to stand up, that person uses his or her own muscular strength to initiate the upward movement of the body, and that will be further assisted by the upward force of the springs 15. As the seat portion 2 moves upwardiy away from the base structure 1 as the person moves increasingly towards the standing position, the nature of the linkage assembly 4 and 5 will cause the rearward part of the seat portion 2 to rise at a greater rate, thus, not only lifting the person bodily but also tending to tilt the person forwardly so that the person can then more readily stand up, so-to-speak by virtue of being tipped forwardly on to the person's own feet. That tilting movement thus overcomes the problem of an infirm person seeking to stand on his or her own feet, from a seat which is still in a flat position.

As will thus be appreciated, the force of the springs 15 is such as to give the person using the seat substantiai assistance in raising him or herself towards the standing position, while however requiring that person to apply some physical effort in attempting to stand up. The requirement for the user of the seat to apply a physical force in order to move into a standing position constitutes a safety margin in that the springs are not sufficiently strong to 'catapult' the occupant of the seat into the standing position, with possibly disastrous consequences. The fact that the user of the seat has to apply a physical force in attempting to stand up also has a therapeutic effect in that the seat occupant does not become totally dependent on the power of the seat when seeking to stand, but is still required to exercise muscular force.

It will be seen therefore that the force of the springs 15 will desirably be adjusted to the bodyweight of the occupant, for example by fitting springs of a given force according to bodyweight, although other forms of adjustment of the spring force could also be envisaged.

In regard to the position of the connecting points 10 relative to the lengths of the respective legs 4', 4", 5' and 5", it has been found that it is desirable for the lengths of the leg portions which are to the left of the connecting point 10 in Figure 1 forexampleto be half the lengths of the corresponding leg portions which are towards the right of the connecting point 10 in Figure 1. Thus the length of the leg portion from the bottom left-hand pivot mounting 11 along the leg 4 to the pivot connection 10 is half the length from the pivot connection 10 along the same leg to the top right-hand end thereof. That arrangement thus gives the appropriate tilting movement of the seat portion 2.

To assist the occupant of the seat in using same, the seat will desirably be provided with handles at suitable locations. The handles may also be positioned in such a way as to discourage the occupant of the seat from resting hands or fingers on parts of the mechanism such as the base structure 1 or the linkage legs 4 or 5, with the possibility of injury in the event of the seat portion 2 coming down towards the base structure and consequently trapping fingers therebetween. Guard devices may be specifically provided to prevent entrapment of fingers and hands and like injury.

Although the seat unit described and illustrated herein is shown in the form of a toilet seat, it will be appreciated that it may also be in other forms, for example as an easy chair, a dining chair, or a wheelchair.

The seat unit may be made of any suitable materials, for example the leg structures 4 and 5 may be made of cold drawn BMS, with plating and wax injection, while the seat portion 2 may be for example of moulded ABS, all of which contributes to increased hygiene and ease of cleaning.

It is also possible to provide a suitable locking or catch device on appropriate parts of the seat, for holding the seat portion 2 in the closed position of the seat unit, that is to say, with the seat portion 2 closely adjacent to and preferably actually resting on the base structure 1.

It will be appreciated that other modifications and variations may be made in the above-described embodiment of the seat unit without thereby departing from the scope of this invention. For example it would be possible to use different forms and numbers of springs, and/or a different form of linkage assembly interconnecting the seat portion 2 and the base structure 1 while still providing for the combined upward/downward movement and pivotal or tilting movement.

Claims (10)

1. A seat unit comprising: a base means; a seat portion for a person using the seat to sit upon; a linkage means interconnecting the base means and the seat portion and operable to provide for displacement of the seat portion relative to the base means between a first position constituting a normal seat position for the person using the seat, with the seat portion lowered towards the base means, and a second position in which the seat portion is raised from the base means to provide assistance for the person using the seat to stand up therefrom, the linkage means also being operable to cause the rearward part of the seat portion to be raised to a greater distance from the base means than the front part of the seat portion whereby the seat portion in moving from said first position to said second position lifts away from said base means and also tilts forwardly of the seat; and means urging said seat portion towards said second position.

2. A seat unit according to claim 1 wherein the linkage means comprises a scissor-type assembly, the respective lengths of the legs constituting the scissor-type assembly being so adjusted as to produce the simultaneous upward and forwardly tilting movement of the seat portion relative to the base means.

3. A seat unit according to claim 2 wherein the linkage means comprises a first pair of legs and a second pair of legs, with the first and second pairs being in crossed relationship and pivotally connected together in such a way that the lengths of the leg portions of each pair at one side of the pivot connection are smaller than the lengths of the leg portions of each pair at the other side of said pivot connection, thereby producing said forwardly tilting movement of the seat portion as it moves towards said second position.

4. A seat unit according to claim 3 wherein each pair of legs is part of a frame arrangement of generally rectangular configuration, with the legs of one pair being closer together than the legs of the other pair whereby one of said rectangular frame assemblies is disposed within the other of the rectangular frame assemblies.

5. A seat unit according to any one of the preceding claims wherein the means for urging the seat portion towards the second position comprise a spring.

6. A seat unit according to claim 5 wherein said spring is a torsion spring which is carried on pivot means of the linkage assembly and which has elongate leg portions urging the seat portion towards its said second position.

7. A seat unit according to any one of the preceding claims and further comprising a device for holding the seat portion fixed with respect to the base means in the first position of the seat portion.

8. A seat unit according to any one of the preceding claims and further including handles to provide further support and assistance for the person using the seat in moving between the sitting and the standing positions.

9. A seat unit according to any one of the preceding claims which is in the form of a toilet seat unit.

10. A seat unit substantially as hereinbefore described with reference to the accompanying drawing.