Background of the invention

In different types of nursing homes, such as old people's homes, homes for disabled persons, hospitals and the like, use is frequently made of conventional chairs which comprise a seat, a back and four legs, i.e. two front and two rear legs. The chairs are used primarily for patients sitting at table, for instance in connection with meals. Some patients are in such a bad condition that they are able only with great efforts, either by themselves or with the help of other persons, to sit down on or get up from a chair standing in a free space, but as soon as it comes to moving the chair forwards into a comfortable position at a table, the patient is incapable of managing himself. Thus, in order to place the patient correctly at the table, at least one or often two nurses will have to assist. Generally, this is done by a combination of lifting and pushing the chair with the sometimes heavy patient on it. From the ergonomic point of view, this work is condemnable. Thus, the nursing staff who have to carry out maybe hundreds of such working operations every day, are liable to serious injuries in the back and the shoulders as a result of the highly unsuitable working positions they are forced to assume, as at the same time considerable forces are required for displacing the chair. Another serious consequence of moving a chair with a person sitting on it, back and forth along the floor is that the legs of the chair after a short period of time will loosen or be otherwise damaged, which entails considerable costs for repairing or purchasing new chairs.

Brief description of the inventive concept

The present invention has for its object to overcome the above-mentioned drawbacks and provide for a simple

and convenient displacement of chairs, even with a person sitting on the chair. According to the invention, this _ is achieved by a device which, more specifically, is characterized in that each of the front legs of the chair is provided with a wheel bracket with at least one wheel which is rotatable about a shaft extending laterally with respect to the chair, but otherwise assumes a fixed position in relation to the pertaining leg of the chair, said wheel being located a short distance behind the rearward face of the pertaining front leg and having its lower peripheral surface located slightly below the plane which is common to four supporting sur¬ faces for the legs of the chair, namely, on the one hand, the lower end portions of the rear legs and, on the other hand, the lower portions of the wheel brackets of the front legs, whereby the chair, when the wheels are resting on a floor or the like supporting the chair, is pivotal but to a.limited extent about the axes of rotation of the wheels between a position in which the supporting surfaces of the rear legs are engaging the floor and a position in which the supporting surfaces of the front legs are engaging the floor or the like.

By means of the device according to the invention, it is possible, when the chair with a person sitting on it should be moved in a direction in underneath a table, easily to lift the chair at the rear legs a short distance off the floor, suitably by grasping the back of the chair, whereupon the chair can be conveniently rolled into the desired position at the table by means of the wheels. By the location of the wheels immediately behind the two front legs of the chair, the chair will be standing firmly when in its normal state, i.e. when supported by the wheels and the supporting surfaces of the rear legs of the chair which are spaced a sub- stantial distance from the wheels (i.e. with the centre of gravity of the chair situated approximately midway between the wheels and the supporting surfaces of the

rear legs). Also, the risk that the chair would uninten¬ tionally tilt and/or roll away has been minimized. In _ fact, if the person sitting on the chair should cause the chair to tilt forwards by accident, the chair will pivot about the wheels to a limited extent only until the supporting surfaces of the front legs engage the floor. This means that further tilting of the chair is counteracted and the chair is prevented from rolling away because of the frictional resistance exerted by said supporting surfaces against the floor.

Brief account of the prior art

US 3,691,590 and DE 2,040,320 disclose chairs with wheel brackets each of which comprises, apart from a wheel, a projection serving to counteract excessive tilting of the chair. These wheel brackets are however of the pivot type, i.e. are freely rotatable about a vertical shaft. Besides, all the supporting points of the chair consist of wheels. In actual practice, this means that the chairs may easily roll away in an uncon¬ trolled manner if the person sitting on the chair has difficulties in controlling his movements, as is the case for instance with disabled persons.

DE 135,177 discloses a chair for children in which the two rear legs are provided with wheels which project backwards from the rearward face of the legs and the lower peripheral surface of which is situated in the same plane as the underside of the legs. Normally, the load on the chair is supported by the legs of the chair and not by the wheels. The purpose of these wheels is to avoid tilting of the chair in a rearward direction such that, if a child sitting on the chair should push with the feet, e.g. against a table, the wheels will assume the load-bearing function of the rear legs and make the chair roll away a short distance, thus preventing it from falling over. However, these wheels are quite

useless for facilitating the displacement of a chair, provided with a back, in a direction in underneath a table.

Brief description of the accompanying drawings

In the drawings, Figs. 1 and 2 illustrate how a chair designed in accordance with the invention is used for properly placing a person at a table, Fig. 3 is a perspective view of a device according to the invention, and Figs. 4-7 are side and end views of two alternative devices according to the invention.

Detailed description of some embodiments of the invention As shown in Figs. 1 and 2, the chair comprises, in a conventional manner, a seat 1, a back 2 and four legs, viz. two front legs 3 and two rear legs 4 (of which legs only one of each pair is visible). In accordance with the invention, wheel brackets generally designated 5 are associated with the two front legs 3. The wheel brackets are schematically illustrated in Figs. 1 and 2 and shown in detail in Figs. 3-7. It should also be noted that the rear legs 4 have no such wheel brackets.

The wheel bracket 5 illustrated in Fig. 3 comprises a bottom plate 6 and two spaced-apart side members 7, 7' (of which only one is visible). The side members 7, 7' are interconnected by an intermediate plate 8 to be mounted against the rearward face of the leg. A wheel 9 is mounted between the side members and is freely rotatable on a shaft 10 extending laterally with respect to the chair. In actual practice, the wheel 9 may advantageously consist of plastic and/or rubber. At a distance from the plate or wall 8, there is provided a pin 11, for instance in the form a tube, which rises vertically from the bottom plate 6 and which is fixed to the plate by welding or the like. The pin is formed with a threaded through hole 12 for receiving a screw 13 via a hole 14 in the wall 8. More specifically, the

screw 13 (which may be a metal screw) is passed through the hole 14 and, by a bore provided in the leg 3, is _ advanced to the threaded hole 12 in which it is screwed. In this manner, the wheel bracket will be solidly anchored to the leg of the chair.

At its forward end, the bottom plate 6 has an exten¬ sion 6' which projects forwardly of the front face of the leg 3 and is terminated by a rounded downwardly convex portion 6 ¹¹ . The bottom plate 6 or, in this case, more precisely its forward portion 6'' forms a lower supporting surface of the associated leg 3. In accordance with the principle of the invention, the lower peripheral surface of the wheel 9 is located at least slightly below an imaginary plane extending through the supporting surfaces of the front legs 3 of the chair and the sup¬ porting surfaces or lower ends of the rear legs 4. In practice, the wheel 9 may project downwards about 2-4 mm below said plane.

Function and use of the invention

When a person is sitting on the chair as illustrated in Fig. 1, the chair normally remains steady in its posi¬ tion since the centre of gravity will be located in the region between the wheels 9 and the rear legs 4, whereby the latter will be held in engagement against the floor 15 with a force, produced by the weight of the user, which guarantees that the chair will not roll away unin¬ tentionally. A physically handicapped person may therefore sit down on the chair without any risk of it rolling away. Then, when the person on the chair should be moved to the vicinity of a table 16, a nurse will easily be able to move the chair with the person sitting on it, by taking hold of the back 2 and lifting the rear legs 4 a short distance, such that the entire load of the chair will be assumed by the wheels 9, whereupon the chair can be conveniently rolled in towards the table. In this manner, the nurse may carry out the necessary operations of

displacement without any major effort and without having to assume any ergonomically unsuitable working positions.: In practice, the chair can be moved by simply pushing the chair with one knee from behind. The presence of the forwardly projecting extension 6 ^r will further prevent the chair both from unintentional excessive tilting in the forward direction and from roll¬ ing away in an uncontrolled manner when in a forwardly tilted state, since the front portion 6' of the bottom plate 6 will engage the floor by frictional contact as soon as the chair is pivoted about the wheels in the for¬ ward direction through a certain, relatively small angle.

Figs. 4 and 5 illustrate an alternative embodiment in which the wheel 9 is carried by a wheel bracket 5' which, like the wheel bracket earlier described, comprises a bottom plate 6, two side members 7, 7' and an inter¬ mediate plate or wall 8 common to said side members. In this case, the side members 7, 7' have a considerably greater length than those earlier described, the wall 8 being fixed at the front face of the leg 2, for instance by means of screws (not shown) . In this case, too, the bottom plate has an extension 6 ^! projecting forwardly of the leg.

In the embodiment shown in Figs. 6 and 7, the bottom plate 6 is inclined with respect to the longitudinal extension of the leg.

Possible modifications of the invention

Naturally, the invention is not restricted only to the embodiments described above and shown in the drawings. Thus, it is possible, for instance, to provide the two front legs of the chair with two wheels each in order to reduce the surface pressure against the floor. Further, it is conceivable to dispose the wheels in a laterally offset position with respect to the associated leg, such that several chairs can be stacked on each other in a per se known way.