PRIOR ART Several sofa beds are known from prior art. Swedish patent publication SE 98998, for example, describes a sofa bed, which can be made into a double bed by turning its seating section and backrest. Several patent publications also describe forming of an upper bed from a similar sofa like device. These include for example : FR 2553651, GB 1410440, DE 189525, US 3858254, US 4922561, GB 2372695, US 3736601, DE 881251 ja GB 1028036. None of the known publications present any simple and reliable sofa bed, which can be turned into a single bed or a double bed, when desired. Especially a simple and reliable sofa bed is not known, which sofa bed in double bed position would not need additional legs or the like arrangements to support a wide double bed.

BRIEF DESCRIPTION OF THE INVENTION It is an aim of the present invention to reduce or even eliminate the above- mentioned problems of the prior art.

It is an aim of the present invention especially to provide a sofa bed that is simple and reliable to use, and which can be turned into a single bed or a double bed. A further aim of the invention is to attain a sofa bed where additional supporting legs or the like mechanisms would not be required even in double bed position to support its structure that is wide compared to the sofa position. It is also an aim to attain a new sofa bed mechanism, which enables functioning of the sofa bed according to the invention.

In order to realise for instance the above mentioned objects, the sofa bed according to the invention is characterised by what is presented in the characterising part of the enclosed independent claim.

Typical sofa bed according to the invention comprises a frame, for example ends of the sofa and cross structures that connect them. A sitting section and a backrest section are attached to the frame supported by mainly horizontal axis of rotation in turnable manner in relation to the frame. The sitting section and the backrest section can be moved separately. Both the sitting section and the backrest section have two different sides. Usually, the sides differ at least in their cushions. Different sides of the sitting section and the backrest section are visible or invisible depending on whether the sofa bed is in sofa use, single bed use or double bed use.

Typically, a sitting side of the sitting section is facing upwards in sofa use, thereby acting as a sitting surface of the sofa. A bed side of the sitting section is facing upwards in the bed use, on which bed side a mattress suitable for sleeping can be arranged.

Typically, the backrest section is mainly in vertical position in the sofa use and in the single bed use. Thus, a backrest side of the backrest section is on front side of the backrest section, i. e. is mainly towards the front edge of the sofa, serving as a backrest surface. In the sofa use, a bed side of the back rest section is on the rear side of the back rest section, on which bed side a mattress suitable for sleeping can be arranged. The front side of the sofa bed is that side that is normally used when one is seated on the sofa. The back side of the sofa bed is that side where the backrest of the sofa is normally.

In a typical sofa bed according to the invention, an axis of rotation of the sitting section can be moved in relation to the frame, the axis of rotation being supported by its supporting arm. The supporting arm, in turn, can be turned supported by its own mainly horizontal axis of rotation. The said axis of rotation of the supporting arm is supported to the frame, typically close to the front edge of the frame. The

axis of rotation of the supporting arm is often supported to the frame of the sofa bed, underneath the sitting section which is in the sofa use, maybe even close to the floor level.

Typical supporting arm of the sitting section's axis of rotation according to the invention, and thereby also the axis of rotation of the sitting section can be moved between at least two firm positions. These two positions are a single bed position and a double bed position. Typically, also the sitting section moves when the supporting arm of the axis of rotation and the axis of rotation of the sitting section are moving.

In a typical single bed position, the axis of rotation of the sitting section is on backside of the axis of rotation of its supporting arm. In a double bed position, the axis of rotation of the sitting section is turned forwards, compared to the single bed position, so that the axis of rotation is on front side of the axis of rotation of its supporting arm. Thereby also the sitting section has moved forwards in regard to the single bed position, so that an empty space is formed behind it. Now the backrest section can be turned on the original place of the sitting section, or at least close to the original place of the sitting section, into a mainly horizontal position. Double bed is ready when the backrest section is turned around its own axis of rotation so that its bed side will turn upwards.

Typically in the double bed position, the supporting arm of the sitting section's axis of rotation is arranged to be supported on the front part of the sofa bed frame for receiving the sitting section and stress directed on it. This supporting is typically arranged above the axis of rotation of the supporting arm. The frame, supporting arm and other parts subjected to stress will of course have to be robust enough in structure in order to resist the stress that they are subjected to by the bed that is formed of the sitting section and supported by them.

With the arrangement according to the invention, it is possible to attain a very simple sofa bed, which can be turned into a single bed or a double bed according to the need. With the supporting arm system according to the invention,

supporting legs or other special supporting systems would not necessarily be needed even in the double bed position for supporting the a that is placed even totally outside the sofa bed frame. The invention provides a sofa bed mechanism that is fast to use. In the sofa bed according to the invention bed sides of both the sitting section and the backrest section are hidden when it is in sofa use. Thus, it is easy to further fasten use of the sofa bed according to the invention by attaching all bedclothes readily on the bed sides. This attachment can be realised for example with elastic belts that are pulled over the bed sides or with a flexible net that covers the whole bed side.

In one sofa bed according to the invention, the axis of rotation of the sitting section is attached to the sitting section so that in sofa use, the axis of rotation is closer to the front edge of the sitting section than to the rear edge, whereby turning the sitting section from the sofa use to the bed use, the sitting section moves forward while the axis of rotation remains in the same place. Typically in the sofa use, a part of the sitting section is under the backrest section, whereby the entire depth of the sitting section is not available for sitting. When turning such sitting section according to the invention from the sofa use to the bed use, the sitting section moves a certain distance away from under the backrest. By means of this arrangement, in the single bed use, the bed arranged from the bed side of the sitting section can easily be made wider than the sitting section in the sofa use.

In one sofa bed according to the invention, a first path, such as a rail or a slot, is arranged in the frame. The path is typically arranged for example to the towards the beds arranged sides of the sofa bed end, for example in an armrest panel. The path is typically arranged to start from the front edge of the frame. This means, that when parts of the sofa bed, especially the sitting part, are turned, means fit for this path can be led to the path and led away from the path via the starting point of this path. Typically, at least one above-mentioned kind means, such as a pin, which is suitable for the path, supported by it and arranged to travel along it, is thus arranged to the axis of rotation of the sitting section or to its supporting arm for guiding and supporting the axis of rotation of the sitting section and its supporting arm when moving and turning the sitting section. By means of

such rails, slots or the like, turning of parts of the sofa bed is controlled and realised exactly as desired by the sofa bed designer.

In one sofa bed according to the invention, a second path, such as a rail or a slot, is arranged in the frame. The path is typically arranged for example to the towards the beds arranged sides of the sofa bed end, that is for example in the armrest panel. Also the second path is arranged to start from the front edge of the frame and is preferably arranged below the first path over its entire length. At least one means, such as a pin, which is suitable for the path, supported by it and arranged to travel along it, is typically arranged to the axis of rotation of the sitting section or to its supporting arm The second path makes the device even more easier to use and reliable.

In one sofa bed according to the invention in the sofa use position, there is a means, such as a pin, in the front edge of the sitting part, which means is supported by the first path in the sofa use, and by the second path in the single bed use. By means of these two paths, it is possible to guide the movement of the sitting part exactly as desired. Furthermore, by means of the design of the paths, for example by means of locking cavities, where the means of the sitting section's front edge barely fits, it is easy to arrange the sitting section to be locked in a detachable manner.

The supporting arm of the sitting section's axis of rotation according to the invention is typically shaped mainly in a form of letter L. Thereby, the axis of rotation of the supporting arm is at the end of the first branch of the letter L, and the axis of rotation of the sitting section is at the end of the second branch. The edge of the first branch of L that points upwards in the sofa use and in the single bed use, and the edge of the second branch that points forwards in the sofa use and in the single bed use, are typically mainly straight and at right angle in relation to each other.

In a typical sofa bed according to the invention - between the supporting arm of the sitting section's axis of rotation and the frame and/or, - between the backrest section and the frame, there has been arranged a spring means, such as a coil spring, gas spring or hydraulic cylinder. By means of the spring means, moving of some parts is lightened in order to easier change the position of the sofa. On the other hand, it is possible to decelerate the movement between some parts for preventing unnecessary knocks and movements. One advantageous spring means is arranged between the frame and a central part of the supporting arm of the sitting section's axis of rotation, which is mainly in form of letter L. Hence, the supporting arm can be handled especially smoothly.

The sofa bed according to the invention may further comprise an upper bed that can be turned supported by its mainly horizontal axis of rotation between a mainly vertical closed position and a mainly horizontal upper bed position.

Thereby, an easy and reliable additional bed can be attained in the one and same arrangement. If the upper bed and its axis of rotation is supported to the same frame together with the rest of the sofa bed, a sofa bed is attained, which can provide even three beds without special additional supporting legs or other supporting structures.

More advantages of the invention as well as preferred embodiments of the invention and their advantages are presented in the enclosed figures and their description.

BRIEF DESCRIPTION OF THE FIGURES The invention is described in more detail below with reference to the enclosed schematic drawing, in which Fig. 1 shows a side-view and partial cross-sectional view of a sofa bed according to the invention in the sofa use, Fig. 2 shows the sofa bed of the Figure 1 in a single bed position, Fig. 3 shows the sofa bed of the Figure 1 in a double bed position,

Fig. 4 shows the sofa bed of the Figure 1 in a 3-bed position, Fig. 5 shows the situation of the Figure 1 seen from the front, and Fig. 6 shows the situation of the Figure 4 seen from the front.

DETAILED DESCRIPTION OF THE EMBODIMENTS OF THE DRAWINGS Figures 1-6 show an advantageous sofa bed 1 according to the invention. Figures 1-4 show the sofa bed 1 from the side so that structures of only one end are visible. Mechanisms and structures at the second end of the sofa bed 1 of the Figures are at least mainly similar. The sofa bed 1 comprises a frame, for example ends 2 of the sofa and cross structures that connect them. A sitting section 5 and a back rest section 6 of the sofa are attached to the frame 2 supported by mainly horizontal axis of rotation 3 and 4 in turnable manner in relation to the frame 2.

The sitting section 5 and the backrest section 6 can be moved separately. Both the sitting section 5 and the backrest section 6 are covered on both sides. Both sides comprise two sides varying in their cushions, which sides are visible or hidden according to whether the sofa bed 1 is in sofa use as shown in Figure 1, in a single bed use as shown in Figure 2 or in a double bed use as shown in Figures 3 and 4.

Sitting side 7 of the sitting section 5 is facing upwards in the sofa use, thereby acting as a sitting surface of the sofa. In the single bed position or in the double bed position, the bed side 8 of the sitting section 5 is facing upwards, on which bed side 8 is arranged a mattress suitable for sleeping and also preferably bed clothes that are not shown in the figures. Bedclothes can be attached to the bed side 8 for example with bands or a net.

The backrest section 6 is mainly in vertical position in the sofa use as shown in Figure 1 and in the single bed use as shown in Figure 2. Thus, a backrest side 10 of the backrest section is on the front side of the backrest section 6, that is mainly towards the front edge 9 of the sofa, serving as a back rest surface of the sofa. A bed side 11 of the backrest section is in sofa use on the rear side of the backrest section 6, on which bedside typically a mattress suitable for sleeping and also preferably bed clothes are arranged.

In the sofa bed 1 according to the Figures, the axis of rotation 3 of the sitting section can be moved in relation to the frame 2 supported by its supporting arm 12. The supporting arm 12, in turn, can be turned supported by its own mainly horizontal axis of rotation 13. The said axis of rotation 13 of the supporting arm is supported to the frame 2, typically close to the front edge 9 of the frame. The axis of rotation of the supporting arm 13 in the Figures is supported to the frame 2 of the sofa bed, close to the floor, underneath the sitting section 5 that is in the sofa use and shown in Figure 1.

In the sofa bed 1 according to the Figures, the axis of rotation 3 of the sitting section is attached to the sitting section 5 so that in the sofa use, as shown in Figure 1, the axis of rotation 3 is closer to the front edge 14a of the sitting section than to the rear edge 14b. Thus, by turning the sitting section 5 from the sofa use of the Figure 1 to the bed use of the Figure 2, the sitting section 5 moves forward while its axis of rotation 3 remains in the same place. When in the sofa use, part of the sitting section 5 is under the back rest section 6, whereby the entire depth of the sitting section 5 is not available for sitting.

A first path, that is a slot 17, is arranged to the sides of the sofa bed end 2, the sides being towards the beds. The slot 17 starts from the front edge 9 of the frame, at the point 18. A pin 19 that fits the said slot 17 and is arranged to travel along it, is arranged at the end of the axis of rotation 3 of the sitting section. It is marked only in the Figure 2, in other Figures the reference number 3 of the sitting section's axis of rotation shows the location of the pin 19. Also a second slot 20 is arranged at the end 2 of the sofa bed. Also the second slot 20 starts from the front edge 9 of the frame, at point 21, and it travels beneath the first slot 17 over its entire length. When parts of the sofa bed 1, especially the sitting section 5, are turned, means fit in the slots 17 and 20 can be led to the slot 17 via the starting points 18 and 21 of the slot, or they can be led away from the slots 17 and 20 via the starting points 18 and 21. In the sofa use position shown in the Figure 1, the pin 19 kind of a pin 22 is arranged to the sitting section 5, on the upper edge of the sitting section's 5 front edge 14a. It fits in both slots 17 and 20.

Design of the slots has great effect on the functioning of the sofa bed 1 mechanism. For example, a cavity has been arranged to the bottom edge of the slot 17, which is most visible in Figure 2, close to the starting point 18 of the slot.

In the sofa use according to the Figure 1, the pin 22 is placed into the cavity 23 and the sitting section 5 is thus locked in its position. In sofa use, also the pin 19 that is in the slot 17, rolls 15 and 16, back rest section 6 hold the sitting section 5 in its place.

When changing from the situation of the Figure 1 to the situation of the Figure 2, the pin 22 is first detached from the cavity 23 with a slight twitch. Now the sitting section 5 is moved away from under the backrest section 6. At the same time, the pin 22 removes from the slot 17. In sofa use, the sitting section 5 leans on the rolls 15 and 16 that are attached to the frame 2 in a rotatable manner and facilitate pulling of the sitting section 5 from under the backrest section 6. When moving the sitting section 5, the supporting arm 12 turns supported by its axis of rotation 13, until it reaches a point where the sitting section 5 can be turned around supported by its axis of rotation 3. The pin 19 has moved in the slot 17 towards the front edge 9 of the frame, but remains still in the slot 17. Now the sitting section is started to be moved backwards. The pin 22 is guided to the second slot 20 via the opening 21. The pin 22 is pushed all the way to the bottom of the slot 20. Pins and slots guide the sitting section 5 automatically into the right single bed position shown by the Figure 2.

The pin 22 that in the situation of the Figure 2 is at the upwards directed end of the slot 20, the pin 19 that is in the slot 17 and the sitting section that leans on the upper edge 24 of the frame's front part shown in the Figure 5 lock respectively the sitting section 5 into this position.

The supporting arm 12 of the sitting section's axis of rotation, and thereby also the axis of rotation 3 of the sitting section can be moved between at least two firm positions. These two positions are the single bed position shown in the Figure 2 and the double bed position shown by the Figures 3 and 4. Typically, also the

sitting section 5 moves when the supporting arm 12 and the axis of rotation 3 are moved. As mentioned above, and as can be seen in the Figures 1 and 2, the supporting arm 12 and the axis of rotation 3 are in the single bed position in the same position as in the sofa use.

In single bed position, the axis of rotation 3 of the sitting section is on backside of the axis of rotation 13 of its supporting arm. When changing to the double bed position, the supporting arm 12 is started to turn supported by its axis of rotation 13. Also the sitting section 5 moves forwards. At some point of the movement, the pins 19 and 22 exit from the slots 17 and 20. Finally, the axis of rotation 3 of the sitting section is turned forwards, compared with the single bed position, so that the axis of rotation 13 is on front side of the axis of rotation 3 of its supporting arm.

In the double bed position, the sitting section 5 has moved forwards in regard to the single bed position, so that an empty space is formed behind it. The sitting section 5 that is in double bed position in the example of the Figures 3 and 4, has moved approximately a distance of its length compared to when in the sofa use as shown by the Figure 1. Now the backrest section 6 can be turned to the original place of the sitting section 5, into a mainly horizontal position. Double bed is ready when the backrest section 6 is turned around its own axis of rotation 4 so that its bedside 11 will turn upwards.

Movement of the supporting arm 12 of the sitting section's axis of rotation stops in the double bed position when it reaches the front part 25 of the sofa bed's 1 frame seen in the Figure 2. This is typically arranged above the axis of rotation 13 of the supporting arm. The frame 2, supporting arm 12 and other parts subjected to stress will of course have to be robust enough in structure in order to resist the stress that they are subjected to by the bed formed of the sitting section 5.

The supporting arm 12 of the sitting section's axis of rotation according to the Figures is typically shaped mainly in a form of letter L. The axis of rotation 13 of the supporting arm is at the end of the first branch 26 of the supporting arm 12, and the axis of rotation 3 of the sitting section is at the end of the second branch 27. The edge 28 of the first branch 26 of L that points upwards in the sofa use and

in the single bed use, and the edge 29 of the second branch 27 that points forwards in the sofa use and in the single bed use, are typically mainly straight and at substantially in right angle in relation to each other.

A coil spring 30 is placed between the central part of the supporting arm 12 of the sitting section's axis of rotation and the end 2 of the sofa bed for assisting and slowing down the turning movements of the sitting section 5. For the same reason, a gas spring 31 is placed between the backrest section 6 and the end 2 of the sofa bed. The gas spring 31 is attached to the backrest section 6 via a short supporting arm that is attached to the axis of rotation 4 of the backrest section 6.

Also an upper bed 32 is shown in the Figures. The upper bed can be used totally apart from the lower beds. The upper bed 32 has a mainly horizontal axis of rotation 33, supported by which it can be turned between a mainly vertical closed position shown in the Figure 3 and a mainly horizontal upper bed position shown in the Figure 4. Figures 5 and 6 show the manner in which the upper bed 32 is connected to the ends 2 of the lower bed with vertical structure beams 34. Figures 1-4 show schematically the beams 34 only by a line 34. By means of a double- deck sofa bed that is combined to the one and the same frame, it is possible to provide even three full size and readily made beds with one bed structure and without special additional supporting legs or other supporting structures. The upper bed 32 is not necessary for the functioning of the inventive sofa bed 1. The upper bed 32 can be separate from the lower sofa bed, and supported only to a wall, for example. Figure 5 shows an opening handle 35 for the closed upper bed.

Figure 6 shows a supporting bar 36 for the edge of the upper bed 32.

The invention is particularly well suitable to be used in ships, hotel rooms and the like where solutions that can be made fast and that save space are of particular importance.

It is feasible, that the sofa bed mechanism according to the invention making it possible to choose freely between the following positions: sofa, sofa and upper

bed, single lower bed, double bed, bunk bed made of two single beds, bunk bed made of a double bed and a single upper bed, can also be realised by means of a mechanism that differs somewhat from the one described above.

Figures show preferred embodiments according to the invention. Facts of secondary importance regarding the main idea of the invention, facts known as such or apparent for a man skilled in the art, such as support structures possibly required by the invention, are not separately shown in the figures. It is apparent to the man skilled in the art that the invention is not limited exclusively to the examples described above, but that the invention can vary within the frames of the claims presented below. The dependent claims present some possible embodiments of the invention, and they are not to be considered to restrict the scope of protection of the invention as such.