WO2016171612A1

WO2016171612A1 - Sofa bed and associated frame construction

Info

Publication number: WO2016171612A1
Application number: PCT/SE2016/050354
Authority: WO
Inventors: Per Nilsson; Stefan HÅKANSSON
Original assignee: Ikea Supply Ag
Priority date: 2015-04-24
Filing date: 2016-04-22
Publication date: 2016-10-27
Also published as: SE1550493A1

Abstract

A frame construction (10) for a sofa bed (100) is provided. The frame construction (10) comprises an outer framework structure (11) defining the width of the sofa bed (100), a transformable framework structure (12) transformable between a sofa state in which the sofa bed acts as a sofa and a bed state in which the sofa bed acts as a bed, the transformable framework structure (12) comprising a number of interconnected parts (121, 122, 123, 124), and at least one support member (13), each support member (13) being rigidly connected to the outer framework structure (11), wherein the at least one support member (13) is arranged to support a first end part (121) of the number of interconnected parts when the transformable framework structure (12) is in the bed state whereby said first end part (121) is configured to be guided by said at least one support member (13) from a position along the bottom part (112) of the outer framework structure (11), when the transformable framework structure is in the sofa state, upwards and towards a backrest area of the outer framework structure (11) for reaching said bed state.

Description

SOFA BED AND ASSOCIATED FRAME CONSTRUCTION

TECHNICAL FIELD

The present invention relates to a sofa bed and its associated frame construction.

BACKGROUND

Sofa beds being transformable between a first sofa state and a second bed state are well known. For natural reasons sofa beds provide for a two-in-one solution, where the sofa bed is used in the sofa state as a sofa e.g. during the daytime, and a

transformable construction within the sofa bed may be extracted to provide for a bed surface in the bed state, e.g. during night-time.

Sofa beds are particularly used at locations where the space available is limited, e.g. in flats in large cities as well as in vacation homes. Accordingly, there is an inherent aim of trying to optimize the construction framework of sofa beds such as to provide the least space consuming or compact solution while maintaining an adequate and comfortable sofa and bed size.

In the past the comfort in the bed state has been down prioritized in view of the compactness aspects.

In view of the commonly known solutions, there is still a need to improve the comfortability as well as the sofa bed construction framework for optimizing the required space of the sofa bed.

SUMMARY

The sofa bed construction according to the embodiments of the present invention provides for a solution to the problems mentioned above being associated with the prior art.

A sofa bed is a sitting furniture which may be convertible into a bed. A sofa bed thus includes multi-seats sofas as well one-seat sofas, i.e. chairs.

According to an aspect a frame construction for a sofa bed is provided. The frame construction comprises an outer framework structure defining the width of the sofa bed. The frame construction further comprises a transformable framework structure transformable between a sofa state in which the sofa bed acts as a sofa and a bed state in which the sofa bed acts as a bed, the transformable framework structure comprising a number of interconnected parts. Furthermore, the frame construction comprises at least one, preferably two, support members, each support member being rigidly connected to the outer framework structure. The at least one support member is arranged to support a first end part of the number of interconnected parts when the transformable framework structure is in the bed state. Additional support members provide an increased stability of the frame construction.

Each support member may comprise a first support part being arranged essentially horizontal in use, wherein the first support part supports the first end part when the transformable framework structure is in the bed state. A planar support thus prevents the first end part from moving unintentionally.

Each support member may comprise a second support part being inclined in relation to the horizontal plane in use, wherein the second part guides the first end part when the transformable framework structure is in transition between the bed state and sofa state and vice versa. This greatly reduces the force required for moving from the bed state to the sofa state.

The first end part is guided relative the support member by means of a guide means. Sliding guidance may e.g. be achieved by a roller running along a track, or using low-friction surfaces. The guide means may be formed by a guide rail provided along the extension of the support member and a guide member, such as a wheel, of the first end part movably engaging with the guide rail.

A first position at which the support member is attached to the outer framework structure may be located at a level vertically above that of a second position at which the support member is attached to the outer framework structure.

Each support member may form a slope extending between a first plateau at which the first end part rests in the bed state, and a second plateau arranged vertically below the first plateau, at which the first end part rests in the sofa state.

The first position may be located at a rear part of the outer framework structure and the second position may be located at a forward position at a bottom part of the outer framework structure, wherein the support member is inclined upwards from the forward position towards the rear position in use. Further, each support member may comprise a third support part being arranged essentially parallel to a horizontal axis of the outer framework structure in use, wherein the third support part supports the first end part when the transformable framework structure is in the sofa state. The third support part may be arranged vertically below the first support part in use.

A first intermediate part of the interconnected parts at a first end may be pivotably connected to an end of the first end part oppositely arranged to the support member, and at a second end pivotably connected to a first connection member that is rigidly attached to a front part of the outer framework structure.

A second intermediate part of the interconnected parts at a first end may be pivotably connected to the second end of the first intermediate part, and at a second end pivotably connected to a first end of a second end part of the interconnected parts.

The second intermediate part in the sofa state may act as a framework for a sitting surface of the sofa bed. The second end part in the sofa state may act as a framework for a backrest surface of the sofa bed. Using the framework structure as supportive parts both in the sofa state and in the bed state is highly advantageous, since additional support parts are not necessary for these purposes.

The second end part may comprise a pivotably connected leg part having a retracted state in which the leg part is essentially parallel to the extension of the second end part and an extracted state in which the leg part supports the second end part in relation to the floor.

One of said first end part or a top part of the outer framework structure comprises a locking member, said locking member being adapted for engaging with a spring loaded support member provided at the other one of said first end part or top part of the outer framework structure, when the transformable framework structure is in the bed state.

The frame construction may further comprise an extension member at one end pivotably connected to the spring loaded support member, and at the other end pivotably connected to the first end of the second intermediate part. The extension member may comprise a rounded end member extending at least partly around the second end of the first intermediate part in the sofa state. Further, the extension member may comprise an elongated slot arranged to slide along an engagement member connected to the spring loaded support member. The extension member provides an advantageous way of unlocking the first end part and the first intermediate part from each other, thus preventing unintentional folding of these parts.

The outer framework structure may comprise a locking member for preventing a downward folding of the second intermediate part relative to the outer framework structure, when the transformable framework structure is in the sofa state.

According to a second aspect, a sofa bed is provided comprising the frame construction according to the first aspect. The sofa bed may further comprise a mattress pad, of which a major part is comprised within the outer framework structure in the sofa state, and where the remaining part of the mattress pad extends from the outer framework structure and upwards and behind the second intermediate part in use.

BRIEF DESCRIPTION OF THE DRAWINGS

Fig. 1 shows a sofa bed in a sofa state according to an embodiment;

Fig. 2 shows a cross-section of the sofa bed of Fig. 1 in the sofa state;

Fig. 3 shows another cross-section of the sofa bed of Fig. 1 in the sofa state; Figs 4 to 9 respectively show a further cross-section of the sofa bed of Fig. 1 in different transition stages between the sofa state and the bed state;

Figs 10 to 12 respectively show cross sections of a locking mechanism during transition between the bed state and the sofa state;

Fig. 13 is an isometric view of the locking mechanism in the bed state according to Fig. 12;

Fig. 14 shows a view the frame construction of the sofa bed of Fig. 1 ; and Fig. 15 shows a magnified view of the frame construction of the sofa bed of

Fig. 14.

DESCRIPTION OF EMBODIMENTS

An idea of the present invention is to provide a compact sofa bed having a frame construction improving the robustness and comfortability of the sofa bed in its bed state. A further idea of the present invention is to provide a sofa bed having an optimized frame construction allowing for storage of the associated mattress pad in the sofa state.

In an embodiment, according to Fig. 1 a sofa bed 100 is provided. Fig. 1 shows the sofa bed in the sofa state where seat and back cushions are provided over its frame construction 10 (not shown).

Figs 2 to 9 respectively show a cross section of a frame construction 10 of the sofa bed of Fig. 1. The frame construction comprises an outer framework structure 1 1 defining the width of the sofa bed 100. Moreover, the frame construction comprises a transformable framework structure 12 being transformable between a sofa state in which the sofa bed acts as a sofa and a bed state in which the sofa bed acts as a bed. The transformable framework structure 12 comprises a number of interconnected parts 121, 122, 123, 124. The frame construction further comprises at least two support members 13. Each support member 13 is rigidly connected to the outer framework structure 1 1 at a first position 11 11 and at a second position 1 121 on the interior of the outer framework structure 1 1. The at least two support members 13 are arranged to support a first end part 121 of the number of interconnected parts when the transformable framework structure 12 is in the bed state.

The at least two support members may be arranged at either lateral side of the frame construction, such as to support an end portion at each lateral side of the first end part 121 transformable framework structure 12.

Each support member 13 comprises a first support part 131 being arranged essentially parallel to a horizontal axis, identified by the dotted line A in Fig. 2, of the outer framework structure 11 in use. This means that when the floor on which the sofa bed stands on, i.e. the underlying foundation, is horizontal, the first support part 131 is arranged substantially parallel to the floor. The first support part 131 supports the first end part 121 when the transformable framework structure 12 is in the bed state, as shown in Fig. 9, or during the last moments of transition between the sofa state and the bed state with reference to Fig. 8.

Each support member 13 further comprises a second support part 132 being inclined at an angle in relation to the horizontal axis of the outer framework structure 11 in use, wherein the second part 132 guides the first end part 121 when the transformable framework structure 12 is in transition between the bed state and sofa state and vice versa.

The first end part 121 is slidably guided relative the support member 13 by means of a guide means 134, 121 1. Guiding of the first end part 121 may e.g. be accomplished by a low-friction connection between the first end part 121 and the support member 13, or by allowing a wheel to run along the first end part 121. The guide means 134, 1211 may be formed by a guide rail 134 provided along the extension of the support member 13 and a guide member 1211 of the first end part 121 slidably engaging with the guide rail 134. However, it should be noted that the present invention is not limited to a guide means only being in the form of a guide rail and corresponding guide member. Any arrangement allowing the first end part 121 to be moved, e.g. by sliding/rolling along each of the at least two support members 13 may also be used within the scope of the present invention.

As may be observed in Figs 2 to 9, and 14 to 15, the first position 11 1 1 is located at a level vertically above that of the second position 1121 in use.

Moreover, the first position 1 11 1 may be located at a rear position at a rear part 1 11 of the outer framework structure 11 , whereas the second position 1 121 is located at a forward position at a bottom part 112 of the outer framework structure 11. Each support member 13 is inclined upwards from the forward position 1121 towards the rear position 1111 in use.

Each support member 13 is rigidly attached to the outer framework structure 11, e.g. by soldering or any other suitable attachment solution at the first position 1111 and the second position 1121.

In an embodiment, each support member 13 further comprises a third support part 133 being arranged essentially parallel to a horizontal axis of the outer framework structure 11 in use. An effect of the third support part 133 is to support the first end part 121 when the transformable framework structure 12 is in the sofa state, as shown in Figs 2 to 3, and in the earlier phases of transition between the sofa state and the bed state with reference to Figs 4 to 6.

The third support part 133 is arranged vertically below the first support part 131 in use.

The frame construction further comprises a first intermediate part 122 forming part of the number of interconnected parts. The first intermediate part 122 is at a first end thereof pivotably connected to the end of the first end part 121 being oppositely arranged to each support member 13. The pivot joints may be provided on each side of the parts 122, 121, such that the transversal distance between the joints is as large as possible. The first intermediate part 122 is at a second end pivotably connected to a first connection member 1131 being rigidly attached to a forward part 113 of the outer framework structure 11. Also in this case the pivot joints may be provided on each side of the part 122, such that the transversal distance between the joints is as large as possible.

The frame construction 10 further comprises a second intermediate part 123 forming part of the number of interconnected parts which is at a first end pivotably connected to the second end of the first intermediate part 122. The second intermediate part 123 is at a second end further pivotably connected to a first end of a second end part 124 of the interconnected parts. As previously described, the pivot joints may be provided on each side of the parts 123, 124, such that the transversal distance between the joints is as large as possible.

In the sofa state, the second intermediate part 123 acts as a framework for a sitting surface of the sofa bed as may be observed in Figs 2 and 3.

In the sofa state, the second end part 124 acts as a framework for a backrest surface of the sofa bed as shown in Figs. 2 and 3. The second end part 124 comprises a pivotably connected leg part 1241 having a retracted state in which the leg part is essentially parallel to the extension of the second end part 124 and an extracted state in which the leg part 1241 supports the second end part 124 in relation to the underlying foundation. In the transition between the retracted and extracted state the leg part 1241 may be used as a handle for pulling the second end part 124 and the second intermediate part 123 out from their respective positions in the sofa state.

As best shown in Figs 8 to 13, one of the first end part 121 or the top part 114 of the outer framework structure 1 1 comprises a locking member 1212 for engaging with a spring loaded support member 1141 provided in the other one of the first end part 121 or the top part 1 14 of the outer framework structure 1 1 , when the transformable framework structure 12 is in the bed state. The spring loaded support member 1 141 may have a chamfered surface 1 141a and a socket 1 141b for receiving the locking member 1212. At the last stages of transition from the sofa state into the bed state, the locking member 1212 comes into contact with the chamfered surface 1141 a of the spring loaded support member 1141. This is realized by the fact that the first intermediate part 122, to which the first end part 121 is pivotably connected, is itself pivotably connected to a first connection member 1131 being rigidly connected to a forward part 1 13 of the outer framework structure 1 1. In this way upon pulling the second end part 124 outwards, the first end part 121 is forced to move rearwards and upwards toward the spring loaded support member 1141.

As shown in Figs. 10 and 11 the locking member 1212 has come into contact with the chamfered surface 1 141a of the spring loaded support member 1 141. Upon the further rotation of the second intermediate part 123, the locking member 1212 of the first end part 121 is forced upwards along the chamfered surface 1 141a of the spring loaded support member 1 141 against the action of a spring urging to pull the spring loaded support member 1 141 rearwards. Thereby the spring loaded support member 1 141 is forced towards engagement with the locking member 1212. Fig. 11 shows the locking member 1212 just as it is at the edge of the socket, whereas Fig. 12 shows the locking member 1212 having snapped in the socket (corresponding to the bed state), whereby the spring loaded support member 1141 now supports the first end part 121 for forces acting on the first end part 121 in a direction downwards.

An opposite movement of the locking member 1212 in relation to the spring loaded support member 1 141 is obtained when the transformable framework structure 12 is folded back from the bed state to the sofa state. Although not shown in the drawings, when pulling up the second end part 124, which is pivotably connected to the second intermediate part 123, which in turn is pivotably connected via the connecting member 1 131 to the first end part 121 , which is pivotably connected to the second intermediate part being pivotably connected to the connecting member 1 131, the second end part 124 will move fold downwards relative the second intermediate part 123. Hence, the hinge-like connection between the second intermediate part 123 and the second end part 124 will move upwards. The motion of the second end part 124 and the second intermediate part 123 will eventually cause the locking member 1212 to force the spring loaded support member 1 141 to the right around its pivot point 1 142 and to such extent that the locking member 1212 eventually is forced out of the socket of the spring loaded support member 1 141. When the locking member 1212 is free from the spring loaded support member the first end part 121 can once again move downwards and forwards into its sofa state position.

In an embodiment, the first support surface 131 , the socket of the spring loaded locking member 1 141 and the connecting member 1 131 are all located in the same horizontal plane, or essentially in the same horizontal plane to assure that when the transformable framework structure is fully extended into the bed state, the transformable framework structure 12 is parallel to the horizontal axis of the frame construction, thereby providing for a flat bed surface.

In an embodiment, as is e.g. shown in Fig. 9, the frame construction 10 further comprises an extension member 1 17 at one end pivotably connected to the spring loaded support member 1 141, and at the other end pivotably connected to the first end of the second intermediate part 213. The extension member 117 comprises a rounded end member 1171 extending at least partly around the first connection member 1 131 at the second end of the first intermediate part 122 in the sofa state. The rounded end member forms a kind of umbrella handle shape of the extension member 1 17. This umbrella handle shaped appearance of the extension member is particularly

advantageous as the extension member 1 17 will not interfere with the connecting member 1 131 to which the first intermediate part 122 and the second intermediate part 123 are connected.

At the end opposite that of the rounded end member the extension member 1 17 comprises an elongated slot 1172 arranged to slide along an engagement member 1142 connected to the spring loaded support member 1 141 during the transition between the sofa state and bed state and vice versa. The engagement member 1142 is rigidly attached to the top part 1 14 of the outer frame construction 1 1. Folding of the sofa bed back to the sofa state will now be further described with reference to Fig. 14. When the sofa bed is transformed from the bed state back to the sofa state, a user will first grip the second end part 124 or its associated leg 1241 and push it inwards towards the framework structure 1 1. Upon this the joint between the second end part 124 and the second intermediate part 123 will move upwards. Hence, the position of the extension member 1 17 is maintained. However, when a folding action is initiated between the second intermediate part 123 and the first intermediate part 122, the extension member 117 will pull the engagement member 1 142 of the spring loaded support member 1 141 such that the socket 1141b of the support member 1 141 is forced to move due to a pivoting movement of the spring loaded support member 1 141. The pulling action is performed until the locking member 1212 is released from the socket 1 141b. Upon this, the first intermediate part 122 is allowed to pivot relative the first end part 121 as is shown in Fig. 7.

The second intermediate part 123 may comprise a locking member 1231 engageable with a locking member 1 143 arranged in the top part 114 of the outer framework structure 1 1, in the sofa state. This arrangement is provided in order to prevent folding of the second end part 124 relative the second intermediate part 123 during use of the sofa bed in the sofa state. In an embodiment, the locking member 1 143 forms a seat and the locking member 1231 is a member resting on the seat when in the sofa state. The seat may be L-shaped as shown in Fig. 15 and the locking member 1231 may have a corresponding L-shape to allow for resting against the L-shaped seat. This solution also provides for a supporting the second intermediate part 123 when it acts as a sitting surface in the sofa state. Hence, it may be observed that the side of the second intermediate part 123 facing upwards in the sofa state is facing downwards in the bed state.

The described locking member 1231 of the second intermediate part 123 and the locking member 1 143 of the top part 1 14 of the outer framework structure 1 1 may be constructed in several different ways. For instance, if there is a need to hold the mattress (which is stored inside the sofa in the sofa state) in a compressed state a relatively strong locking mechanism may be necessary to prevent that the sofa bed is unintentionally moved from the sofa state to the bed state. For instance one (or several) spring loaded pins may be arranged on the framework structure 11 and cooperating with one or more corresponding cut-outs in the second intermediated part 123. Preferably, such spring loaded pin is arranged to cooperate with a cut-out arranged close to the second end 123b (see Fig. 5) of the second intermediate part 123, i.e. where the second intermediate part 123 is connected to the second end part 124. The cut-out may be shaped with a sloping surface to allow the spring-loaded pin to be forced out from the cut-out when the sofa bed is pulled, using manual force from one person, from the sofa state to the bed state.

In the sofa state the frame construction 10 optimizes the storage space within the outer framework structure 1 1 as may be seen with reference to Figs. 2 and 3. This is enabled by the arrangement of the first end part 121 along the bottom part 1 12 of outer framework structure 1 1, the first intermediate part 122 along the forward part 113 and the second intermediate part 123 along the top part 1 13. This storage space allows for accommodating a major part of mattress pad within the outer framework structure 11 in the sofa state as shown in Fig. 2. In the sofa state the remaining part of the mattress pad extends up and behind the second intermediate part 123. Hence, in the sofa state the sofa bed can accommodate the mattress pad completely.

Figs 14 and 15 respectively show an embodiment wherein each of the first end part 121 , first intermediate part 122, second intermediate part 123 and second end part 124 comprises support ribs R extending over the width of the transformable framework structure 12. Also it may be noted that the leg part 1241 may be provided with at least one flat backrest surface, optionally being provided with at least one opening for facilitating pulling out the leg part 1241 for transitioning the sofa bed from its sofa state to the bed state.

It has been described above that the locking member 1212 is arranged on the transformable frame work structure 12 and that the spring loaded support 1141 is arranged on the outer framework structure 1 1. It should be noted however that the present invention is not limited to such an embodiment. The locking member 1212 may be arranged on the outer framework structure 1 1 and the spring loaded support 1141 may be arranged on the transformable frame work structure 12.

Claims

1. A sofa bed frame construction (10), comprising

an outer framework structure (11) defining the width of the sofa bed (100), a transformable framework structure (12) transformable between a sofa state in which the sofa bed acts as a sofa and a bed state in which the sofa bed acts as a bed, the transformable framework structure (12) comprising a number of interconnected parts (121, 122, 123, 124),

at least one support member (13), each support member (13) being rigidly connected to the outer framework structure (11), wherein the at least one support member (13) is arranged to support a first end part (121) of the number of

interconnected parts (121, 122, 123, 124) when the transformable framework structure (12) is in the bed state whereby said first end part (121) is configured to be guided by said at least one support member (13) from a position along the bottom part (112) of the outer framework structure (11), when the transformable framework structure is in the sofa state, upwards and towards a backrest area of the outer framework structure (11) for reaching said bed state.

2. The frame construction according to claim 1, comprising at least two support members (13).

3. The frame construction (10) according to claim 1 or 2, wherein each support member (13) comprises a first support part (131) being essentially horizontal in use, wherein the first support part (131) supports the first end part (121) when the transformable framework structure (12) is in the bed state.

4. The frame construction (10) according to claim 3, wherein each support member (13) comprises a second support part (132) being inclined in relation to the horizontal plane in use, wherein the second part (132) guides the first end part (121) when the transformable framework structure (12) is in transition between the bed state and sofa state and vice versa.

5. The frame construction (10) according to claim 4, wherein the first end part guided relative the support member (13) by means of a guide means (134,

6. The frame construction (10) according to claim 5, wherein the guide means (134, 121 1) is formed by a guide rail (134) provided along the extension of the support member (13) and a guide member (1211), such as a wheel, of the first end part (121) movably engaging with the guide rail (134).

7. The frame construction (10) according to any of the preceding claims, wherein a first position (11 11) at which the support member (13) is attached to the outer framework structure (11) is located at a level vertically above that of a second position (1121) at which the support member (13) is attached to the outer framework structure (11).

8. The frame construction (10) according to any one of the preceding claims, wherein each support member (13) forms a slope extending between a first plateau (131) at which the first end part (121) rests in the bed state, and a second plateau (133) arranged vertically below the first plateau (131), at which the first end part (121) rests in the sofa state.

9. The frame construction (10) according to any of the preceding claims, wherein a first intermediate part (122) of the interconnected parts (121 , 122, 123, 124) at a first end (122a) thereof is pivotably connected to a second end (121b) of the first end part (121), which second end (121b) is opposite to a first end part (121) first end (121a) being connected to the support member (13), and at a second end (122b) is pivotably connected to a first connection member (1131) that is rigidly attached to a front part (113) of the outer framework structure (1 1).

10. The frame construction (10) according to any of the preceding claims, wherein a second intermediate part (123) of the interconnected parts (121, 122, 123, 124) at a first end (123a) thereof is pivotably connected to the second end (122b) of the first intermediate part (122), and at a second end (123b) pivotably connected to a first end (124a) of a second end part (124) of the interconnected parts(121, 122, 123, 124) .

1 1. The frame construction (10) according to claim 10, wherein the second intermediate part (123) in the sofa state acts as a framework for a sitting surface of the sofa bed.

12. The frame construction (10) according to claim 10 or 1 1, wherein the second end part (124) in the sofa state acts as a framework for a backrest surface of the sofa bed.

13. The frame construction (10) according to any one of claims 10 to 12, wherein the second end part (124) comprises a pivotably connected leg part (1241) having a retracted state in which the leg part is essentially parallel to the extension of the second end part (124) and an extracted state in which the leg part (1241) supports the second end part (124) in relation to the floor.

14. The frame construction (10) according to any of the preceding claims, wherein at least one of said first end part (121) and a top part (1141) of the outer framework structure (11) comprises a locking member (1212), said locking member (1212) being adapted for engaging with a spring loaded support member (1141) provided at the other one of said first end part (121) and the top part (1 141) of the outer framework structure (11), when the transformable framework structure (12) is in the bed state.

15. The frame construction (10) according to claim 12, further comprising an extension member (117) at one end pivotably connected to the spring loaded support member (1141), and at the other end pivotably connected to the first end (123a) of the second intermediate part (123).

16. The frame construction (10) according to claim 15, wherein the extension member (117) comprises a rounded end member (1171) extending at least partly around the second end (122b) of the first intermediate part (122) in the sofa state, preferably the rounded end member (1 171) extending around a first connection member (1 131) being a fixed pivot j oint for the first intermediate part (122).

17. The frame construction (10) according to claims 15 or 16, wherein the extension member (117) comprises an elongated slot (1172) arranged to slide along an engagement member (1142) connected to the spring loaded support member (1141).

18. The frame construction (10) according to any one of the preceding claims, wherein the outer framework structure (1 1) comprises a locking member (1 143) for preventing a downward folding of the second intermediate part (123) relative to the outer framework structure (11), when the transformable framework structure (12) is in the sofa state.

19. A sofa bed (100) comprising the frame construction (10) according to any of the claims 1 to 18.

20. The sofa bed (100) according to claim 19, further comprising a mattress pad, of which a major part is comprised within the outer framework structure (11) in the sofa state, and where the remaining part of the mattress pad extends from the outer framework structure (11) and upwards and behind the second end part (124) in use.