COMPACT FOLDING FRAME FOR A FOLDING FURNITURE SUCH AS A SOFA BED

Abstract

 The invention relates to a folding framework for an item of folding furniture such as a sofa bed, as well as an item of folding furniture comprising this framework. The framework is advantageous in part thanks to the front and rear lever coupling (6, 7), which allow a very compact folding of the framework thanks to their shape and position.

Description

TECHNICAL FIELD

[0001] The invention relates to a folding framework for an item of folding furniture such as a sofa bed, as well as an item of folding furniture comprising this framework.

PRIOR ART

[0002] Frameworks for folding furniture, and in particular sofa beds, are known in the art. Such frameworks can be folded and unfolded.

[0003] WO 2004 086 913 describes such a framework known in the art. The framework according to WO '913 provides two roto-translational couplings, which are connected at a first end to a body support coupling and at a second end are connected to two different base beams.

[0004] The framework according to WO '913 is disadvantageous in that the second ends of the roto-translational couplings are connected vertically spaced on said two base beams. Such vertical spacing requires a framework that requires a substantial amount of (vertical) space for folding and unfolding. In addition, the inventors note that the shape and placement of the roto-translational couplings does not allow a smooth unfolding of the framework. These and further disadvantages of the framework according to WO '913 are illustrated in Example 1 below.

[0005] The present invention has as its object a folding framework which eliminates at least one of the drawbacks associated with the prior art or associated with an alternative embodiment as described, for example, in Example 2.

[0006] In particular, the present invention has a framework as its object that is compact and can be folded and unfolded smoothly.

SUMMARY OF THE INVENTION

[0007] In a first aspect, the invention relates to a folding framework for an item of folding furniture such as a sofa bed, according to claim 1.

[0008] In a second aspect, the invention relates to an item of folding furniture such as a sofa bed, comprising the framework according to the first aspect, according to claim 15.

[0009] Preferred embodiments of the present invention are discussed in claims 2 to 14, as well as throughout the description, examples and figures.

[0010] The present invention is advantageous due to its compact size; provided at least in part by the shape and placement of the front and rear lever coupling. In particular, the present invention is advantageous in that there are no basally projecting elements present in the framework when folded up. As a result, the framework can be placed on a substrate without a substructure. However, if a substructure is mounted on the framework, the free basal space formed allows cleaning such as vacuuming under the framework. In addition, the present invention is also advantageous due to a smoother unfolding of the framework.

[0011] Further advantages, embodiments and preferred embodiments of the invention are discussed below in the detailed description, examples and figures.

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] 

Figures 1 and 2 show a framework according to the prior art - WO 2004 086 913.

Figures 3 and 4 show an alternative embodiment of a framework for a sofa bed.

Figures 5 to 16 show the folding and/or unfolding of a framework for a sofa bed according to a preferred embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0013] The invention relates to a folding framework for an item of folding furniture such as a sofa bed, as well as an item of folding furniture comprising this framework. The invention has been summarised in the section provided for that purpose. In what follows, the invention is described in detail, and preferred embodiments are explained.

[0014] Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meaning as commonly understood by a person skilled in the art to which the invention pertains. For a better understanding of the description of the invention, the following terms are explained explicitly.

[0015] In this document, 'a' and 'the' refer to both the singular and the plural, unless the context presupposes otherwise. For example, 'a segment' means one or more segments.

[0016] When the terms 'approximately', 'about', 'around' or 'substantially' are used in this document with a measurable quantity, a parameter, a duration or moment, and the like, then variations are meant of approx. 20% or less, preferably approx. 10% or less, more preferably approx. 5% or less, even more preferably approx. 1% or less, and even more preferably approx. 0.1% or less than and of the quoted value, insofar as such variations are applicable in the described invention. However, it must be understood that the value of a quantity used where the term 'approximately', 'about' or 'around' is used, is itself specifically disclosed.

[0017] The terms 'comprise', 'comprising', 'consist of', 'consisting of', 'provided with', 'have', 'having', 'include', 'including', 'contain', 'containing' are synonyms and are inclusive or open terms that indicate the presence of what follows, and which do not exclude or prevent the presence of other components, features, elements, members, as known from or disclosed in the prior art.

[0018] 'Framework' in the context of the present text is to be understood as an assembly of parts that serves as a supporting structure for further elements and/or structures. Such parts can be, for example, couplings, coupling pieces, brackets or frames. Such structures can be a sofa bed. Preferably, a framework is provided internally to such structures. Such a framework can also be provided externally to said structures. Such a framework can be provided both internally and externally to said structures.

[0019] 'Coupling' is to be understood in the context of the present text as an element suitable for entering into a coupling or connection with another coupling, bracket and/or frame, etc. This can be done, for instance, by means of a simple opening in which the coupling and one of the aforementioned elements are anchored, for instance by means of a hook, screw or other coupling piece. 'Beam' should be understood in the context of the current text as a substantially beam-shaped framework element.

[0020] 'Frame' should be understood in the context of the present text as an assembly of parts within the framework. The sub-parts of the assembly are connected in a mutually immovable manner, for example by means of a welded seam.

[0021] 'Pivotable' or 'hingeable' should be understood in the context of the current text as rotatable about a support point. The support point can be a connection point between two couplings or between a coupling and another framework element.

[0022] 'Longitudinal' or 'longitudinal axis' should be understood in the context of the present text as a direction that is horizontal when the framework is placed on a horizontal surface. In essence, said direction is the direction in which the framework, i.e. the various mattress frames, is folded and/or unfolded.

[0023] Quoting numerical intervals by endpoints comprises all integers, fractions and/or real numbers between the endpoints, these endpoints included.

[0024] In a first aspect, the present invention relates to a folding framework suitable for an item of folding furniture such as a sofa bed, the framework comprising:

a substantially rectangular head support mattress frame comprising a mattress mounting surface and a long side;

a substantially rectangular body support mattress frame comprising a mattress mounting surface and a long side, which side is pivotally connected to said long side of the head support mattress frame;

a head support coupling with a first end pivotally connected to the head support mattress frame;

a body support coupling having a first end pivotally connected to the body support mattress frame;

a base beam provided in a longitudinal axis of the framework in unfolded state and connected to a second end of the head support coupling;

a front lever coupling, having a first end pivotally connected to a frontal side of the body support coupling, and having a second end pivotally connected to a frontal end of the base beam; and

a rear lever coupling, having a first end pivotally connected to a second end of the body support coupling, and having a second end of the rear lever coupling pivotally connected to the base beam.

[0025] In a second aspect, the present invention relates to an item of folding furniture such as a sofa bed comprising the framework according to the first aspect;

preferably wherein the item of folding furniture is a sofa bed;

further preferably wherein the sofa bed comprises a seat, back support and mattress.

[0026] A person of ordinary skill in the art will appreciate that the framework according to the first aspect of the present invention is one and the same invention as the item of folding furniture according to the second aspect of the present invention. In what follows, both aspects of the present invention are therefore treated together. Any feature described herein may refer to any aspect, even if the feature is described in conjunction with a particular aspect of the present invention.

[0027] It will be apparent to a person of ordinary skill in the art that any technical element described according to the aspects of the invention can be provided multiple times without going beyond the object of the present invention. In particular, the head support coupling, the body support coupling as well as the lever couplings can be provided in two, three, four, five, six, seven, eight, nine or tenfold. Preferably, the head support coupling, the back support coupling and the body support coupling are provided in duplicate. Preferably, said couplings are provided in duplicate respectively on each (longitudinal) side in a direction perpendicular to the longitudinal direction of a framework.

[0028] A framework for a sofa bed according to the present invention, like a prior art framework, can be unfolded from a folded state to an unfolded state. To this end, a simple embodiment of the framework provides a mattress frame suitable for supporting, mounting and/or fixing a mattress. So that the framework can be folded and unfolded, the mattress frame is divided into several sub-mattress frames, specifically a substantially rectangular head support mattress frame and a substantially rectangular body support mattress frame; which are pivotally connected to each other on a long side.

[0029] Preferably, the substantially rectangular body support mattress frame is divided into an upper body support mattress frame and a leg support mattress frame, both substantially rectangular and pivotally connected to each other with a long side thereof. The body support mattress frame is with further preference provided with a seat mounting surface for mounting a seat, and a back support mounting surface for mounting a back support. Such a configuration is compactly foldable relative to the base beam. The seat and back support mounting surfaces face outward when the framework is folded up. Such a configuration provides a folding sofa bed with a comfortable seating position.

[0030] For placing a framework according to the present invention on a substrate, according to a simple embodiment this framework is provided with a base beam provided in a longitudinal axis of the framework in unfolded state. The base beam may or may not be provided in a base frame, further comprising for instance one or more transverse beams, couplings, plates, etc., and/or one or more additional cross beams provided in a longitudinal axis of the framework. The base frame may or may not further include a substructure; preferably a plurality of legs, wheels, etc.

[0031] To support the head support mattress frame, a simple embodiment provides a head support coupling with a first end connected to the head support mattress frame and with a second end connected to the base beam. To support the body support mattress frame, a simple embodiment also further provides a body support coupling with a first end connected to the body support mattress frame. The invention is distinguished by the provision of a front lever coupling and rear lever coupling. A first end of the front lever coupling is pivotally connected to a frontal side of the body support coupling. A second end of the front lever coupling is pivotally connected to a front end of the base beam. A first end of the rear lever coupling is pivotally connected to a second end of the body support coupling, preferably to the frontal side of the second end of the body support coupling. A second end of the rear lever coupling is pivotally connected to the base beam. Such a configuration provides a more compact and smooth folding. The advantages of the front and rear lever coupling are explained in more detail in the examples.

[0032] The compact folding of a framework having a front lever coupling with the first end pivotally connected to the frontal side of the body support coupling and with the second end pivotally connected to the frontal end of the base beams can be explained by the fact that such a framework can be folded and unfolded in relation to a single supporting leg, i.e. the front lever coupling. This is possible because this supporting leg is connected to the frontal side of the body support coupling and to the frontal end of the base beam. The positioning of the rear lever coupling is also relevant for further support of the framework; in particular, the connection of the first end of the rear lever coupling to the second end of the body support coupling.

[0033] The connection point of the second end of the rear lever coupling to the base beam can take various forms. This is mainly determined by the shape and/or design of the rear lever coupling. For example, the rear lever coupling can be foldable, spring-actuated, flexible or fixed. Preferably, the rear lever coupling is fixed. In the case of a fixed rear lever coupling, although this embodiment is not limited thereto, the second end of the rear lever coupling is preferably hingedly connected to the base beam at a connection point on this base beam, said connection point being provided on a substantially perpendicular axis relative to the base beam and substantially through the centre of gravity of the second end of the body support coupling. Such an embodiment provides the most support, and therefore forms the most stable framework.

[0034] Preferably, the front lever coupling is provided with a curvature with respect to a longitudinal axis through the first and second connection point of said coupling. Preferably, the rear lever coupling is provided with a curvature with respect to a longitudinal axis through the first and second connection point of said coupling. Such curvature of the front and rear lever couplings prevents jamming of these couplings during unfolding. In addition, such curved couplings also provide a smoother folding and unfolding of the framework. The advantages of the curved front and rear lever coupling are illustrated in the examples.

[0035] With further preference, the curvature of the front lever coupling is curved in a frontal direction of the framework, when the framework is in the unfolded state. With further preference, the curvature of the rear lever coupling is curved in a frontal direction of the framework, when the framework is in the unfolded state. Such curved coupling provides a smoother folding and unfolding of the framework. The advantages of such frontally curved front and rear lever couplings are explained in the examples.

[0036] According to a preferred embodiment, an interior angle of the curvature of the front lever coupling is between 100° and 150°, preferably between 105° and 145°, more preferably between 105° and 145°, more preferably between 110° and 140°, more preferably between 115° and 135°, more preferably between 120° and 130°, more preferably between 122° and 138°, more preferably between 124° and 136°, most preferably the interior angle of the curvature of the front lever coupling is substantially equal to 125°. The advantages of such interior angle of the curved front lever coupling are illustrated in the examples.

[0037] According to a preferred embodiment, an interior angle of the curvature of the rear lever coupling is between 100° and 150°, preferably between 105° and 145°, more preferably between 105° and 145°, more preferably between 110° and 140°, more preferably between 115° and 135°, more preferably between 120° and 130°, more preferably between 122° and 138°, more preferably between 124° and 136°, most preferably the interior angle of the curvature of the rear lever coupling is substantially equal to 125°. The advantages of such interior angle of the curved rear lever coupling are illustrated in the examples.

[0038] According to a preferred embodiment, the curvature of the front lever coupling is provided perpendicular to the longitudinal axis through the first and second connection point of said coupling at a front curvature distance relative to the second end of said coupling. Preferably, wherein the front curvature distance of the front lever coupling is at least 5% and at most 50% of the length between the first and second ends of the front lever coupling, more preferably at least 10% and at most 45%, more preferably at least 15% and at most 40 %, more preferably at least 20% and at most 38%, more preferably at least 25% and at most 36%, most preferably wherein the front curvature distance of the front lever coupling is substantially equal to 33%.

[0039] According to a preferred embodiment, the curvature of the rear lever coupling is provided perpendicular to the longitudinal axis through the first and second connection point of said coupling at a front curvature distance relative to the second end of said coupling. Preferably, wherein the front curvature distance of the front lever coupling is at least 50% and at most 95% of the length between the first and second ends of the front lever coupling, more preferably at least 55% and at most 85%, more preferably at least 60% and at most 80%, more preferably at least 62% and at most 75%, more preferably at least 64% and at most 70%, most preferably wherein the front curvature distance of the front lever coupling is substantially equal to 66%.

[0040] According to a preferred embodiment, the interior angle of curvature of the front and rear lever coupling is substantially equal. According to a further preferred embodiment, a ratio of the curvature distance of a coupling to the length between the first and second connection point of said coupling is substantially equal for the front lever coupling and the rear lever coupling. Such lever couplings are substantially similar in shape but provided mirrored to each other. This allows a more compact and smoother folding of the framework.

[0041] According to a preferred embodiment, the head support coupling comprises a first and second sub-head support coupling, which are hingedly connected to each other at a connecting end. Preferably, the first sub-head support coupling is hingedly connected with a first end to the head support mattress frame, the second sub-head support coupling being connected with a second end to the base beam, the sub-head support coupling further also being hingedly connected to each other with a connecting end. Such an embodiment increases the degrees of freedom of the head support mattress frame during folding, so that folding takes place more smoothly.

[0042] According to a preferred embodiment, the framework further comprises a synchronisation coupling having a first end hingedly connected between the first and second ends of the body support coupling and having a second end hingedly connected between the first and second ends of the head support coupling.

[0043] Preferably, wherein the first end of the synchronising coupling is hingedly connected to the frontal side of said coupling. Preferably, the second end being connected to the second sub-head support coupling; with further preference connected between the connecting end and the second end of the coupling.

EXAMPLES

[0044] In what follows, the invention is described by way of non-limiting examples illustrating the invention, and which are not intended to and should not be interpreted as limiting the scope of the invention.

Example 1: Prior art embodiment

[0045] The present example relates to an embodiment of a framework for a sofa bed according to WO 2004 086 913. The embodiment is shown in figures 1 and 2.

[0046] The framework shown in figures 1 and 2 provides two roto-translational couplings (x, y), which are connected at a first end (x1, y2) with a body support coupling and at a second end (x2, y2) are connected with two base beams.

[0047] Such positioning of the roto-translational couplings is very disadvantageous since the second ends of said couplings are connected vertically spaced to said base beams. Such vertical spacing results in a framework that requires a substantial amount of (vertical) space to be unfolded and folded. In addition, such framework when folded (Figure 2) requires an open basal space under the lower of said two base beams. As a result, the framework cannot be placed on a substrate without a substructure. However, when a substructure is mounted on the framework, the framework leaves no or at most a very limited free basal space for cleaning such as vacuuming, mopping, etc. of a substrate under the mounted substructure of the framework.

[0048] Finally, the inventors note that the shape of the roto-translational couplings according to the framework of WO '913 does not allow a smooth unfolding. Since the roto-translational couplings are straight, they will frequently jam the pivotal connection points during an unfolding, thereby blocking the folding mechanism. In addition, the inventors note that such stiff unfolding is accompanied by wear of the roto-translational couplings.

[0049] It will be apparent to one of ordinary skill in the art that the framework described according to the present invention is advantageous with respect to the present embodiment of WO '913, at least because of the great compactness as well as the rotational and translational movement brought about by the placement and possibly additionally the shape of the front and rear lever couplings.

Example 2: Alternative embodiment

[0050] The present example relates to an alternative embodiment of a framework for a sofa bed. The embodiment is shown in Figures 3 and 4.

[0051] The embodiment comprises a head support mattress frame (1) pivotally connected to a body support mattress frame (2). The framework further comprises a head support coupling (3) with a first end pivotally connected to the head support mattress frame, as well as a body support coupling (z) with a first end pivotally connected to the body support mattress frame. Finally, the framework also comprises a base beam (5) provided in a longitudinal axis of the framework in unfolded state and connected to a second end of the head support coupling.

[0052] The framework according to the present embodiment differs from the present invention in that the body support coupling is connected to a base beam only by one pivot or rotation point (z4). In order for such framework to perform in a controlled manner the rotational as well as translational movement associated with the unfolding of the framework, numerous spring elements and hydraulic couplings must be connected to the head support and body support coupling at an angle to the base beam. Such spring elements and hydraulic couplings are disadvantageous to the present invention as they require substantial vertical spacing of multiple base beams. As a result, no compact framework can be constructed. In addition, the spring elements are disadvantageous in that they raise the dorsal end of the framework during unfolding. To prevent this, a counterweight should be provided at the dorsal end of the framework, further increasing the weight as well as the volume of the framework.

[0053] In addition, such framework when folded up (Figure 4) requires an open basal space under the lower base beam. As a result, such framework cannot be placed on a substrate without a substructure. In addition, such a framework, when mounted with a substructure, leaves no or at most a very limited free basal space between the lower of said two base beams and the substrate on which it is placed. Such free basal space is, for example, useful for cleaning such as mopping or vacuuming said substrate.
It will be apparent to one of ordinary skill in the art that the framework described according to the present invention is advantageous with respect to the present embodiment, at least because of the greater compactness as well as the rotational and translational movement brought about by the placement and possibly additionally the shape of the front and rear lever couplings.

Example 3: Preferred embodiment

[0054] The present example relates to a preferred embodiment of the framework for a sofa bed according to the invention. The embodiment is shown in Figures 5 to 16.

[0055] The present framework shown in Figures 5 to 16 comprises a substantially rectangular head support mattress frame (1) having a mattress mounting surface and a long side, as well as a substantially rectangular body support mattress frame (2) comprising a mattress mounting surface and a long side, which side is pivotally connected to said long side of the head support mattress frame. The frame further comprising a head support coupling (3) having a first end pivotally connected to the head support mattress frame, and a body support coupling (4) with a first end pivotally connected to the body support mattress frame. Finally, the framework also comprises a base beam (5) provided in a longitudinal axis of the framework in unfolded state and connected to a second end of the head support coupling.

[0056] The present framework is characterised by a front (6) and rear lever coupling (7). A first end of this front lever coupling is pivotally connected to a frontal side of the body support coupling, while a second end of the front lever coupling is pivotally connected to a frontal end of the base beam. A first end of the rear lever coupling is pivotally connected to a second end of the body support coupling, while a second end of the rear lever coupling is pivotally connected to the base beam. The connection of the front and rear lever coupling with the body support coupling on the one hand and the base beam on the other hand, ensures that the resulting folding framework has a very compact size, and can also be placed on a substrate without a substructure. In addition, the placement as well as the shape of the aforementioned couplings also ensures a smoother folding and unfolding of the framework. These as well as other advantages are further explained below with reference to the figures.

[0057] Figures 5 and 6 show a side view of the framework in a fully unfolded state. The front and rear lever couplings according to the embodiment have a curvature in a frontal direction of the framework when the framework is in the unfolded state, i.e. the direction in which the body support mattress frame is unfolded. In particular, the interior angle of both couplings is substantially equal to 125°. When the framework is folded up from the fully unfolded state, the inventors note that such couplings, i.e. connected to a frontal side of the body support coupling and connected to a frontal side of the second end of the body support coupling, cause the body support coupling to be rotated longitudinally. This longitudinal rotation lifts the body support mattress frame, causing it to pivotally fold closed relative to the head support mattress frame; thus initiating the folding up of the framework.
In particular, the curvatures of the front and rear lever coupling are provided perpendicular to the longitudinal axis between the first and second connection point of said coupling at a front curvature distance relative to the second end of said coupling. According to the present embodiment, the curvature distance is respectively substantially equal to 33% and 66% of the length between the first and second ends of the front and rear lever coupling. Thus, according to the present embodiment, the curvature of the front and rear lever couplings is substantially equal to each other. In addition, a ratio of the curvature distance of a coupling to the length between the first and second connection point of said coupling is also substantially equal for both the front and rear lever coupling. In other words, the two couplings mentioned are similar in shape but mirrored to each other. The inventors note that a curvature provided in the couplings prevents blocking of these couplings during the folding up of the framework. After all, straight couplings, when moved abruptly, can block the present roto-translational mechanism by clamping the pivotally connected end of said couplings. Curved couplings prevent such clamping due to a non-linear force distribution. Further, the inventors also note that the curvature distances as described above aid the longitudinal rotation of the body support coupling; i.e. by providing a curvature closer to the body support coupling for the rear lever coupling and further from the body support coupling for the front lever coupling, the connection point of the front lever coupling will initially cause a rotation, while the connection point of the rear lever coupling will initially cause a downward translation of the body support coupling - thus resulting in a longitudinal rotation of the body support coupling and thus the folding up of the framework.

[0058] Figures 7 to 14 show side views of the framework during folding or unfolding. As discussed above, the mirrored curvature of the front and rear lever coupling causes the connection point of the front lever coupling to initially rotate substantially, while the connection point of the rear lever coupling will initially cause substantially downward translation. As the framework is folded up further, this function alternates, i.e. the connection point of the front lever coupling will mainly provide a downward translation, while the connection point of the rear lever coupling will mainly provide rotation of the body support coupling. This alternating function ensures that: during the first half of the folding up of the framework (Figures 7 to 10), the body support coupling is mainly raised, i.e. positioned vertically with respect to a substrate; while during the second half of the folding up of the framework (Figures 11 to 14), the body support coupling is rotated mainly downward toward the plane in which the base beam is provided. Furthermore, the inventors also note that such folding up is aided by a synchronisation coupling (8). The inventors note that this synchronization coupling will after all ensure that the head support coupling will move synchronously with the body support coupling. This will allow the framework to be folded up more smoothly. Further, the inventors also note that a head support coupling comprising a first (31) and second sub-head support coupling (32), which are hingedly connected to each other at a connecting end, also further improves the smooth folding up of the framework. After all, the second sub-head support coupling will ensure that the freedom of movement of the head support coupling increases, so that it will not get stuck during folding up. In particular, the first sub-head support coupling is hingedly connected with a first end to the head support mattress frame, while the second sub-head support coupling is connected with a second end to the base beam. The sub-head support couplings are furthermore also hingedly connected to each other with a connecting end. According to the present embodiment, the second sub-head support coupling is substantially longer than the first sub-head support coupling. Further, the second end of the synchronisation coupling is connected to the second (longer) sub-head support coupling. Such configuration provides improved support of the head support-mattress frame. In addition, such configuration also provides for a more compact folding up of the framework, in that the second sub-head support coupling is provided substantially in the same plane as the base beam of the framework.

[0059] Figures 15 and 16 show a side view of the framework in a fully folded up state. The body support coupling is herein substantially provided in the same plane as the base beam of the framework. As a result, the framework does not have any basally projecting elements, so that the framework can also be placed on a substrate without the installation of an additional substructure. Such folding up is possible in that the front lever coupling is connected to a front end of the base beam and the rear lever coupling is connected to the second end of the body support coupling. Thus, this front lever coupling can provide the required roto-translational movement associated with the folding up of the framework. In addition, the long sides of the curved front and rear lever couplings are provided substantially in the extension of the body support coupling when the framework is in the folded up state. Such configuration increases the compactness of the framework and prevents the basal protrusion of these couplings.

[0060] The head support mattress frame and the body support mattress frame are provided with a mounting surface for a mattress. As illustrated in Figures 5 and 6, the mounting surfaces for the mattress face upwards when the framework is unfolded. The body support mattress frame also comprises an upper body support mattress frame (21) and a leg support mattress frame (22), both substantially rectangular and pivotally connected to each other with one long side. The body support mattress frame is further also provided with a seat mounting surface (23) for mounting a seat, and a back support mounting surface (24) for mounting a back support. Such a configuration is compactly foldable relative to the base beam. As illustrated in Figures 15 and 16, the seat and back support mounting surfaces face outwards when the framework is folded up. Such a configuration provides a folding sofa bed with a comfortable seating position.

[0061] Finally, the framework according to the embodiment is provided with an upper leg support-retaining coupling (9) with a first end connected to the body support coupling and with a second end connected to the leg support mattress frame. Such a configuration provides a more stable and rigid framework.

[0062] When unfolding from the folded state, the same reasoning can be applied mutatis mutandis as discussed above for folding.

Claims

1. A folding framework suitable for an item of folding furniture such as a sofa bed, the framework comprising:

- a substantially rectangular head support mattress frame (1) comprising a mattress mounting surface and a long side;

- a substantially rectangular body support mattress frame (2) comprising a mattress mounting surface and a long side pivotally connected to said long side of the head support mattress frame;

- a head support coupling (3) having a first end pivotally connected to the head support mattress frame;

- a body support coupling (4) having a first end pivotally connected to the body support mattress frame; and

- a base beam (5) provided in a longitudinal axis of the framework when unfolded and connected to a second end of the head support coupling;

characterised in that the framework further comprises a front lever coupling (6) and rear lever coupling (7);

wherein a first end of the front lever coupling is pivotally connected to a frontal side of the body support coupling, a second end of the front lever coupling being pivotally connected to a frontal end of the base beam;

wherein a first end of the rear lever coupling is pivotally connected to a second end of the body support coupling, a second end of the rear lever coupling being pivotally connected to the base beam.

2. The framework according to preceding claim 1, wherein the first end of the rear lever coupling (7) is pivotally connected to the frontal side of the second end of the body support coupling (4).

3. The framework according to any of the previous claims 1 or 2, wherein said front lever coupling (6) is provided with a curvature with respect to a longitudinal axis through the first and second connection point of said coupling.

4. The frame according to preceding claim 3, wherein the curvature of the front lever coupling (6) is curved in a frontal direction of the framework when the framework is in the unfolded state.

5. The framework according to any of the previous claims 3 or 4, wherein an interior angle of the curvature of the front lever coupling (6) is between 100° and 150°, preferably substantially equal to 125°.

6. The framework according to any of the preceding claims 3 to 5, wherein the curvature of the front lever coupling (6) is provided perpendicular to the longitudinal axis through the first and second connection point of said coupling at a front curvature distance relative to the second end of said coupling, wherein the front curvature distance is at least 5% and at most 50% of the length between the first and second ends of the front lever coupling.

7. The framework according to any of the preceding claims 1 to 6, wherein said rear lever coupling (7) is provided with a curvature with respect to a longitudinal axis through the first and second connection point of said coupling.

8. The framework according to preceding claim 7, wherein the curvature of the rear lever coupling (7) is curved in a frontal direction of the framework when the framework is in the unfolded state.

9. The framework according to any of the preceding claims 7 or 8, wherein an interior angle of the curvature of the rear lever coupling (7) is between 100° and 150°, preferably substantially equal to 125°.

10. The framework according to any of the preceding claims 7 to 9, wherein the curvature of the rear lever coupling (7) is provided perpendicular to the longitudinal axis through the first and second connection point of said coupling at a front curvature distance relative to the second end of said coupling, wherein the front curvature distance is at least 50% and at most 95% of the length between the first and second ends of the front lever coupling.

11. The framework according to any of the preceding claims 3 to 6 and any of the preceding claims 7 to 10.

12. The framework according to preceding claims 6 and 10, wherein the interior angle of curvature of the front (6) and rear lever coupling (7) is substantially equal, wherein a ratio of the distance of curvature of a coupling to the length between the first and second connection point of said coupling is substantially the same for the front and rear lever coupling.

13. The framework according to any of the preceding claims 1 to 12, wherein the head support coupling (3) comprises a first (31) and second sub-head support coupling (32), which are hingedly connected to each other at a connecting end.

14. The framework according to any of the preceding claims 1 to 13, further comprising a synchronisation coupling (8) having a first end hingedly connected between the first and second ends of the body support coupling (4) and having a second end hingedly connected between the first and second ends of the head support coupling (3), the first end of the synchronisation coupling preferably hingedly connected to the frontal side of said coupling.

15. An item of folding furniture such as a sofa bed comprising the framework according to any of claims 1 to 14, preferably wherein the item of folding furniture is a sofa bed, with further preference wherein the sofa bed comprises a seat, back support and mattress.

Drawing