The invention concerns an adjustment device for beds and other reclining or sitting furnitures, wherein the article of furniture has two or more mutually adjustable, articulated members which together form the frame of the article, and wherein the frame is mounted in a support member by means of transverse axles or axle journals.

There are a number of different kinds of beds and other reclining and sitting furnitures currently on the market equipped with adjustment devices for setting different angles between the back member, the intermediate member or seat member and the foot member in order to provide the article with alternative user positions. The most common examples are adjustable chairs, where the back member and seat member can be set at an angle in relation to each other in order to provide a position of rest or a more active sitting position. Similar solutions have been developed for beds, offering the possibility of assuming a position which is more suitable for reading in bed, etc.

Such adjustment facilities for beds and chairs are employed not only for reasons of comfort, but are particularly important in nursing and illness situations, such as in hospital or in nursing institutions where the user has to stay for lengthy periods, e.g. in a bed, or in connection with therapeutic chairs for dentists, doctors, etc.

Examples of adjustable beds and other reclining or sitting furniture can be found in US patent 4751754 and FI patent 89867, both of which disclose adjustable hospital beds, as well as in DK 125771 and DK 145563, both of which disclose examples of adjustable frames for installation in beds. To some extent these previously known constructions have a relatively complicated design. They offer the possibility of different angular adjustments for both the back member, seat member and foot member of the surface of a bed. In previously known designs a change in the sitting angle will result in a relatively radical change in the angle between the seat surface and the back surface, since the surfaces are rotated about fixed axles. Due to the fact that the foot member is connected tc ⁺ he seat member and is slidingly guided in the frame ofthe bed, it will be raised above the surface of the bed in the knee area, which is not always desirable. Alternatively, special joint constructions or additional surface elements have been employed.

The object of the present invention is to provide an adjustment device which permits the desired changes in angular adjustment between the seat and the back member, or between the back member, the seat member and the foot member of the frame of an article of furniture. The adjustment device should be simple in design and relatively inexpensive to manufacture, while at the same time it should be possible to perform the angular adjustment either manually or by simple operating means, and preferably with only one single exercise of force.

This object is achieved with an adjustment device of the type mentioned in the introduction, which is characterized by the features presented in the patent claims.

In the invention special consideration is given to a three-part bed, mattress, sofa, divan or bench frame, or a two-part chair frame where the individual parts are hinged to one another and mounted in a supporting frame. The back member is pivotally mounted in a fixed horizontal transversal axis or by means of axis journals a short distance above the hinge or the joint which connects the back member to the seat member. The seat member is pivotally mounted in a fixed horizontal transversal axis or with axis journals and mounted in a mounting or guide which permits movement of the transversal axis slidably in an approximately straight line or approximately parallel in relation to the back's suspension axis. The foot/leg member is pivotally mounted in a preferably movable horizontal transversal axis or by means of axis journals which are mounted on a mounting which moves the transversal axis slidably in an approximately straight or approximately parallel line in relation to the back's and the seat's suspension axes. In the case of chairs there are no foot/leg members. If desired, the chair can be extended with a separate stool or the like.

According to a feature of the invention, the lower part of the back, which extends from the mounting axis to the articulation with the seat member can be equipped with a lever which can be influenced by a force, possibly from an actuator or gas spring. In order to achieve further angular adjustments according to the floor area, according to a further feature of the invention the bed frame can be combined with a tilting device which can tilt the support frame about a desired smaller angle, e.g. +/- 12°.

By means of the invention it may be said that adjustable sitting furniture is supplied with the advantages which adjustable beds have, and that adjustable beds are provided with the same advantages which exist in adjustable sitting furniture. The adjustment device according to the invention offers the possibility of adjusting back members of furniture in an angular range from 0 to 75°, the seat member between 0 and 15° and the leg/foot member from 0 to 22°. In addition, as mentioned above, a tilting effect can be exercised of the order of +/- 12 ⁰ . The possibility is thereby obtained of adjusting angles between the back and the seat member from 180°, which means that the back and seat members are located on the same plane, to an angular adjustment of 90° between the parts. The seat member and the leg member can be angularly adjusted between 180° and -37°. The previously known adjustable beds are normally also hinged or articulated between the individual parts or sections and are usually constructed with heavy, complicated and expensive fittings which by means of manual operation, gas springs or actuators will lift the various parts into the desired angles. With the adjustment device according to the invention a simpler, lighter and more reasonably priced adjustment concept is provided, in which only one external force may be employed to perform the required adjustments.

The invention will now be described in more detail by means of the embodiment which is illustrated in the drawings, in which:

fig. 1 is a schematic drawing illustrating a bed design with the adjustment device according to the invention,

figs. 2 and 3 show a detail of the drawing in fig. 1 illustrating the operating mechanism during angular adjustment between the back and seat members,

figs. 4-6 are views illustrating the principles of the design during angular adjustment between the seat member and the foot member,

fig. 7 is a drawing corresponding to fig. 1 illustrating the adjustment device according to the invention for a chair design, fig. 8 is a perspective view illustrating the furniture frame and support member, intended for mounting in a bed frame, and

fig. 9 is a similar perspective view illustrating a second design, where the support member is designed as a chassis.

The adjustment device according to the invention will now be explained in more detail in connection with the schematic illustration presented in fig. 1 of the drawing. The drawing illustrates in a side view the invention in connection with a bed design, where the furniture frame or the bed frame consists of three sections or parts, R which is the back member, S which is the seat member and F which is the foot or leg member of the bed frame. Each of these three parts is equipped with a transverse axis or axis journals, as illustrated in figs. 8 and 9. The axis journals for the back member R are designated by 2, the axis journals for the seat member are designated by 3 and the axis journals for the leg member F are designated by 5. The parts of the frame are hinged or linked to one another by means of hinged joints which again are best illustrated in figs. 8 and 9, in which they are designated by 1 and 4 respectively.

During angular adjustment of the parts R, S and F in relation to one another, the parts will rotate about the linkage points 1 and 4, while the axis journal connection to the support member remains located in the same plane. In figs. 8 and 9 the support member is designated by A and B respectively, and the attachment or displacement areas for the axis journals are designated by 1 1 , 12 and 13. It can be seen from figs. 8 and 9 that the axis journals 3 and 5 have displacement possibilities in the slot-shaped openings, while the back member's axis journal 2 has a fixed mounting.

The distance between axis journals, i.e. the fulcrum for the individual parts and the articulation between the parts determines the relative pattern of movement between the parts. These distances, i.e. the ratio between the distances between fulcrum and linkage point for back member R and seat member S are selected in such a manner that an infinitely variable adjustment of between 180° and 90° can be performed of the angle between seat member and back member.

These two extreme positions are illustrated in fig. 1 , the position illustrated by a broken line showing an angular adjustment of 90° between the parts R and S. By means of this movement from the position which is illustrated by solid lines to the position illustrated by broken lines the mounting point 2 for the back member will remain fixed, while the mounting point for the seat member will be moved towards the back member, while at all times remaining located in the plane of the bed frame. This adjustment is illustrated

in more detail in figs. 2 and 3. Here it can be seen that the mounting points 2 and 3 remain located on the same plane.

By means of this displacement of the back member to an upright position the seat member S via the joint 4 will also influence the leg member F, which will be pulled along by the movement of the seat member. The joint 4 will thereby be pulled in the direction towards the back member and lifted slightly above the bed plane. At the same time the mounting 5 will move in the groove 13, also in the direction towards the back member, thereby controlling the angular movement of the foot member. The length ratio between the slots 12 and 13 is preferably selected so that the foot member or the leg member will fall about an angle between 4 and 22°, depending on where on the leg or foot member the suspension point 5 is located. In fig. 1 and 4-6 this movement is indicated very prominently for illustrative reasons, but it may, of course, also be different to that which is shown in the figure. The movement mechanism for the foot member is illustrated on a larger scale in figs. 4-6.

In order to perform the angular adjustment of the back member in the simplest possible way, on the underside of the back member R there is rigidly fastened an arm piece or a lever 6, which is also illustrated in figs. 8 and 9. Between this lever and a point on the support member or another attachment point there may be provided a pneumatic cylinder or an electrical actuator which via the lever 6 provides for the angular adjustment and the locking of the back member R and thereby normally of all parts of the construction.

Fig. 7 illustrates the adjustment device for the invention employed in a chair. The design differs only from that illustrated in fig. 1 in that, the leg member F has been removed.

Figs. 8 and 9 illustrate the use of two different support members, fig. 8 showing a support member A which is intended for mounting in a bed frame or the like while fig. 9 illustrates a design where the support member B is equipped with legs, i.e. designed as a chassis. In the design in fig. 8 it will be the support member A with the parts R, S and F which are tilted. In a design with legs, as illustrated in fig. 9, it will also be possible to establish a tilting function. The tilting function will be particularly relevant, e.g. in connection with hospital or nursing home beds.

Fig. 1 also illustrates in a purely schematic form the said tilting movement for the support member, where the whole bed can be tilted, e.g. between the positions 8 and 9 in relation to the normal position 7, the settings 8 and 9 corresponding to angular adjustments of -/+12°. It should be pointed out that the angular range may be both smaller and greater, and also different in the two directions, e.g. only + 12°.

In the drawings the invention is only illustrated by means of principle drawings, and it should be quite obvious that it will be possible to design the individual parts of the frame in many different ways, with many different types of support elements. These features do not constitute components of the actual invention and are therefore not illustrated in more detail. The use of different possibilities for variation will be obvious to a person skilled in the art. Joint and axle mounting are also indicated purely in principle. It will be possible for a person skilled in the art to vary these elements too, e.g. by introducing an extra degree of freedom for one or more axles. It may also be conceivable that a frame of this kind may be designed with more parts, and this too will fall within the scope of the invention.