Compact folding framework for folding furniture such as a sofa bed

Abstract

The invention relates to a folding framework for a piece of folding furniture such as a sofa bed, as well as a piece of folding furniture comprising this framework. The framework included a substantially rectangular head support mattress frame; a substantially rectangular upper body support mattress frame; a substantially rectangular lower body support mattress frame; a first hinge fixedly connected to the head support mattress frame; an elongated base beam provided in a longitudinal axis of the framework in the unfolded state; a head support coupling; a body support coupling; a front lever coupling; a rear lever coupling; a synchronization coupling; a second hinge; a pull lever; a locking coupling; a lever coupling; a foot section; and, a foot synchronization coupling.

1 . Folding framework suitable for folding furniture such as a sofa bed, wherein the framework in unfolded state has a foot end on a frontal side and a head end on a distal side, the framework comprising:
 a substantially rectangular head support mattress frame comprising a mattress mounting surface;   a substantially rectangular upper body support mattress frame hingedly connected to said head support mattress frame;   a substantially rectangular lower body support mattress frame, hingedly connected to the upper body support mattress frame;   a first hinge fixedly connected to the head support mattress frame and hingedly connecting the head support mattress frame to the upper body support mattress frame;   an elongated base beam provided in a longitudinal axis of the framework in the unfolded state, and suitable for anchoring in and/or forming a housing of the piece of folding furniture;   a head support coupling having a first end hingedly connected to the first hinge and having a second end hingedly connected to the head end of the base beam;   a body support coupling having a first end hingedly connected to the upper body support mattress frame;   a front lever coupling having a first end hingedly connected to a second end of the body support coupling, and having a second end hingedly connected to the foot end of the base beam;   a rear lever coupling having a first end hingedly connected to the second end of the body support coupling, and wherein the rear lever coupling has a second end hingedly connected to the foot end of the base beam at a position less frontally located than where the front lever coupling is connected to the base beam;   a synchronization coupling having a first end hingedly connected to the first hinge and a second end hingedly connected between the first and second ends of the head support coupling;   a second hinge, with a first end hingedly attached to the upper body support mattress frame and with a second end hingedly attached to the lower body support mattress frame;   a pull lever, having a first end hingedly connected to the first end of the body support coupling at a point located more extremally at the first end of the body support coupling than where it is hingedly connected to the upper body support mattress frame, and having a second end hingedly connected to the second hinge at a point spaced from the axis connecting the hinged connections of the second hinge to the upper and lower body support mattress frame;   a locking coupling having a first end hingedly connected to the upper body support mattress frame at a point located outside the longitudinal axis of the upper body support mattress frame;   a lever coupling having a first end hingedly connected to a second end of the locking coupling;   a foot section having a first end hingedly connected to the lower body support mattress frame, and wherein the second end of the lever coupling is hingedly connected to the foot section at the first end thereof; and,   a foot synchronization coupling, which at a first end is hingedly connected to the lower body support mattress frame via a first coupling and at a second end is hingedly connected via a second and third coupling at a shared point of the foot synchronization coupling, to the hinged connection between the foot section and the lever coupling, and to the foot section at a point other than the hinged connection between the foot section and the lever coupling, respectively.   
     
     
         2 . The framework according to  claim 1 , wherein the head support coupling when the framework is unfolded is at an angle relative to the base beam, directed towards the head support mattress frame, of at least 75°, and wherein the length of the relevant head support mattress frame has a length of at least 450 mm, wherein the body support coupling when the framework is unfolded is at an angle relative to the base beam, directed away from the head support mattress frame, of at least 35°. 
     
     
         3 . The framework according to  claim 1 , wherein the foot section has a length of at least 300 mm. 
     
     
         4 . The framework according to  claim 1 , wherein the rear lever coupling is at least as long as the front lever coupling. 
     
     
         5 . The framework according to  claim 1 , wherein the rear lever coupling has a longitudinal axis through the first connection point and the second connection point of the rear lever coupling approximately perpendicular to a longitudinal axis through the connection point of the first end of the rear lever coupling and the connection point of the first end of the front lever coupling, when the framework is in the unfolded state, wherein approximately perpendicular concerns an intermediate angle between 70° and 110°. 
     
     
         6 . The framework according to  claim 1 , wherein the second end of the front lever coupling is connected at a distance from the second end of the rear lever coupling, where this distance is approximately equal to the length of the front lever coupling. 
     
     
         7 . The framework according to  claim 1 , further comprising a back support frame, fixedly connected to the foot section at an angle between 60° and 120°, wherein the back support frame in the folded state of the framework defines a smallest angle with respect to the lower body support mattress frame of at least 60°, and in the unfolded state of the framework defines a smallest angle with respect to the lower body support mattress frame of at most 25°. 
     
     
         8 . The framework according to  claim 1 , further comprising a bridging coupling, wherein the second hinge is fixedly coupled to the bridging coupling, wherein said bridging coupling extends between the lower and upper body support mattress frame at the top thereof, wherein the bridging coupling limits the rotation of the lower and upper body support mattress frame from a folded or semi-folded state to an unfolded state to a mutually parallel position in line with each other when the framework is unfolded. 
     
     
         9 . The framework according to  claim 1 , wherein the lever coupling is hingedly connected at the first end to the bridging coupling, wherein the hinged connection between the lever coupling and the bridging coupling is located less extremally with respect to the first end of the lever coupling than the hinged connection between the lever coupling and the locking coupling. 
     
     
         10 . The framework according to  claim 1 , wherein the framework comprises the aforementioned parts on both lateral sides, wherein one or more of the parts on both lateral sides are connected to each other via a transverse coupling. 
     
     
         11 . The framework according to  claim 1 , further comprising one or more transverse couplings, wherein the transverse couplings are connected transversely to the framework to the body support coupling and/or the foot section and connect the lateral sides of the framework. 
     
     
         12 . The framework according to  claim 1 , wherein the foot synchronization coupling is held substantially parallel with the lower body support mattress frame via the first, second and third couplings. 
     
     
         13 . The framework according to  claim 1 , wherein the foot synchronization coupling is positioned in substantially the same transverse plane as the lower body support mattress frame when the framework is in a folded state, the transverse plane being substantially perpendicular to the lateral sides of the framework. 
     
     
         14 . The framework according to  claim 1 , wherein the other point where the third coupling is connected to the foot section is further away from the hinged connection between the foot section and the lower body support mattress frame than the hinged connection between the foot section and the lever coupling. 
     
     
         15 . A piece of folding furniture comprising a seat section and optionally a back portion, wherein the seat section comprises a hollow housing in which the folding framework according to  claim 1  is attached to the base beams on the inside of the hollow housing.