The use of bedsteads that include adjustable bed frames has long been known in the art, particularly in respect of so- called hospital beds. However, in recent times the use of adjustable bed frames has also become common in the home, even bed frames that include motorised frame-orientating devices. These bed frame arrangements include a fixed outer frame and a pivotal and displaceable inner bed frame. The pivotal and displaceable inner bed frame carries raisable and lowerable back and/or leg parts and enables the back and/or leg parts of the bed to be inclined in relation to the fixed outer bed frame. In this respect, it is usual to provide a guide rail in the outer bed frame and wheels on link arms connected to the inner bed frame are adapted to roll in the guide rails to effect movement of the inner bed frame in relation to the outer bed frame. It is often so that the wheels begin to squeak or rattle after the bed has been used for some time, either due to dirt in the grooves in the guide bar or due to poor wheel bearings. Deficient or mediocre wheel bearings also make it difficult for the wheels to roll in the grooves of respective guide rails, therewith making movement of the wheels and orientation of the movable inner bed frame difficult.

Accordingly, an object of the present invention is to provide a novel bed frame arrangement which is not encumbered with the aforesaid drawbacks and which provides long-term, prob-

lem-free movement of the inner bed frame when desiring to orient the frame in relation to the fixed outer bed frame.

The object of the invention is achieved with the aid of the inventive arrangement, in which the inner bed frame is dis- placeably mounted in the outer bed frame through the medium of elongate slide blocks on which a surface layer or coating of low-friction material is disposed on at least one side of said frame.

According to a preferred embodiment, the slide blocks are made of a composite material on which a slide layer of polytetrafluoroethylene, Teflon@, in the form of a slide plate let into respective slide blocks.

The invention will now be described in more detail with ref- erence to a non-limiting embodiment illustrated in the accom- panying drawings, wherein Fig. 1 illustrates a bed frame arrangement schematically from beneath; Fig. 2 illustrates schematically a slide block for use in the inventive bed frame arrangement ; Fig. 3 is a side view illustrating a par- ticular embodiment of a slide block; Fig. 4 is a cross- sectional view of the slide block taken on the line A-A in Fig. 3; and Fig. 5 is a longitudinal sectioned view of the slide block taken on the line B-B in Fig. 3.

As mentioned, Fig. 1 is an underside plan view of an inven- tive bed frame arrangement, which includes a fixed, outer frame 1 and a movable inner frame 2. Attached in the in- ner/movable bed frame 2 is a first mechanism 3 which includes a number of links, pivots and pivot shafts connected to fas- teners 4 for a divided bed bottom (not shown) and for inclin- ing a head-and-back part on the bed bottom. This first mecha-

nism 3 is connected by means of a link 5 to the fixed outer frame 1 in a manner such that the head and back parts will be respectively raised and lowered in response to commensurate displacement of the inner/movable frame 2 in relation to the fixed outer frame 1, so that the distance of said head and back parts from the adjacent short end of the fixed outer frame 1 will always remain generally constant.

The first mechanism 3 may be typically equipped with electric setting motors for bringing the head and back parts to a desired inclined position. An arm in the link 5 is fixedly connected to a transverse pivotal shaft 6 whose ends are mounted in the movable inner frame 2. The transverse pivotal shaft 6 is also connected to pivot arms that are, in turn, connected to the attachments 4 for the head and back part of the divided bed bottom and also for connection to a drive motor (when included) for adjustment of the orientation of the head and back parts, by rotation of the shaft 6.

Also attached in the movable inner frame 2 is a second mecha- nism 7 which includes a number of links, pivots and pivot shafts that are connected to the attachment 8 for the divided bed bottom (not shown) and for inclining the leg and foot part of the bed bottom. The arrangement will also conven- iently include a drive motor for bringing the leg and foot parts to a desired position, i. e. either a horizontal posi- tion or a position inclined upwards towards the foot end.

Mounted on the outer surface of each long side of the movable inner frame 2 are generally U-shaped guide rails 9 where the open end of the U-form faces towards the opposite inner sur- face of the long side of the fixed outer frame 1. Mounted on the inner surface of the long side of the fixed outer frame are slide blocks 10, the free longitudinally extending sur-

faces of which are surrounded generally by the U-shaped guide rails on the movable inner frame 2. Two such U-shaped guide rails 9 will preferably be disposed on each side of the mov- able inner frame 2 in mutually spaced relationship. Conse- quently, two slide blocks 10 will then be disposed on each side of the fixed outer frame 1 at corresponding distances apart. The U-shaped guide rails will conveniently be made of stainless steel against which the guide blocks 10 can slide readily.

Naturally, the arrangement of the slide blocks 10 and the U- shaped guide rails 9 may be the reverse of that described above, i. e. with the slide blocks 10 mounted on the movable inner frame 2 and the guide rails 9 mounted on the fixed outer frame 1.

No link is provided on the leg part and the foot part for displacing the movable inner frame 2, since raising/inclining said part requires no adjustment of the position of the mov- able inner frame 2 in relation to the fixed outer frame 1.

The guide blocks 10, of which one is shown in Fig. 2, are generally in the form of elongate, rectangular bodies that have slightly bevelled longitudinal edges 11. The bodies 10 include transversally through-penetrating holes 12 that en- able screw fasteners to be fastened in the inner side of the long side of the fixed outer frame 1 and therewith screw said blocks 10 firmly to said fixed outer frame 1. The blocks 10 are suitably made of a composite material, for instance from a polyamide that includes an admixture of 30% fibreglass.

With the intention of reducing the friction of the blocks against the inner surfaces of the U-shaped guide rails 9, there is conveniently applied a slide layer of polytetra-

fluoroethylene, Teflon@, particularly a Teflons composite, e. g. SKF POLYTETRAFLUOROETHYLENE having a friction coeffi- cient of 0.03-0.08. The polytetrafluoroethylene slide layer suitably has the form of a slide plate 13 let into the slide block in the manner evident from Figs. 3-5. Particles of polytetrafluoroethylene may also be integrated in the compos- ite material.

Because the slide blocks 10 have an outer shape that fits exactly in the U-shaped guide rails 9, the blocks are able to slide in said rails without risk of binding or jamming. In order to further reduce the risk of the blocks 10 jamming or wedging in the rails 9, respective blocks are provided with holes that accommodate coil springs 14 which press inserts 15 coated with polytetrafluoroethylene against the two inner surfaces of the U-shaped guide rails 9 other than the inner surface against which the slide plate 13 is situated.

The aforesaid preferred slide block material means that the risk of binding is minimal and that the conditions for prob- lem-free functioning of the slide blocks is far better than in the case of wheels or rollers that move in grooves, as in the case of hitherto known arrangements.

The aforementioned divided bed bottom may be of any type whatsoever of the various types that are commercially avail- able at present. However, an interior sprung mattress is preferred.