Sofa bed

Abstract

A sofa bed has a seat portion, a backrest portion and a hinge mechanism including a first section, a second section and a third section sequentially and pivotably connected. The first section is fixed to a side of the seat portion. The second section is fixed to a side of the backrest portion. A protruding portion is provided at a position where the first section is connected with the second section. Each of the armrest frames is formed with a slideway for receiving and guiding the protruding portion. An end of the third section opposite to the second section is pivotally connected to the armrest. The first section and the second section are be lockable to place the main body frame into a sofa configuration. The sofa bed can be easily switched between sofa and bed positions.

I claim: 
     
         1 . A sofa bed, comprising:
 a main body frame comprising a seat portion and a backrest portion movable between a bed configuration and a sofa configuration;   an armrest frame detachably disposed on both sides of the main body frame;   the armrest frame comprising a substantially downwardly-opened U-shaped outer frame and a reinforcing beam detachably connected between two legs of the outer frame, each of the ends of the reinforcing beam having a tongue, and the two tongues configured to be detachably snapped and retained onto the two legs.   
     
     
         2 . The sofa bed according to  claim 1  wherein the outer frame of the armrest frame further comprises a connecting section located at a bottom of the U-shaped outer frame, and the two legs are respectively pivotally connected to a connecting section via a hinge, so that the legs can be folded onto the connecting section. 
     
     
         3 . The sofa bed according to  claim 1  wherein the outer frame of the armrest frame comprises a plurality of sections connected in sequence, an end of one section of any two adjacent sections has an opening, an end of the other section is formed with a joint portion shaped to match the opening, so that the joint portion of the other section can be extended into the opening to connect the two adjacent sections. 
     
     
         4 . The sofa bed according to  claim 1  wherein the leg has a rectangular cross-section, the tongue is L-shaped and adapted to abut against two adjacent side surfaces of the leg. 
     
     
         5 . The sofa bed according to  claim 1  wherein the leg has a rectangular cross-section, the tongue has a U-shaped cross section, and a spacing between the two U-shape legs of the tongue corresponds to a width dimension of a side surface of the leg connected to the armrest frame, so that the tongue can be snapped on the leg. 
     
     
         6 . The sofa bed according to  claim 4  wherein the sofa bed further comprises a bottom supporting structure positioned and supported below the main body frame, and the bottom supporting structure comprises bottom supporting structure longitudinal beams connected between two armrest frame brackets;
 the tongue of each of the armrest frames comprising a first tongue portion facing the other armrest frame and abutting against the leg, and the bottom supporting structure longitudinal beam is configured to be attached to a first tongue portion and thereby connected to the armrest frame. 
 
     
     
         7 . The sofa bed according to  claim 1  wherein a slideway is formed on each of the reinforcing beams, so that a movement of the hinge mechanism is guided by the slideway,
 wherein the sofa bed is configured to lock the backrest portion relative to the seat portion at a predetermined angle when the backrest portion and the seat portion pivot relative to each other about the hinge mechanism, and enable the hinge mechanism to drive the sofa bed main body to move guided by the slideway. 
 
     
     
         8 . The sofa bed according to  claim 7  wherein the hinge mechanism comprises:
 a seat portion connecting rod attached to a transverse side edge of the seat portion and extending along the transverse side edge; 
 a backrest portion connecting rod attached to a transverse side edge of the backrest portion on the same side as the transverse side edge of the seat portion and extending along the transverse side edge of the backrest portion; 
 a pivot connecting the seat portion connecting rod with the backrest portion connecting rod such that the backrest portion and the seat portion can pivot relative to each other. 
 
     
     
         9 . The sofa bed according to  claim 7  wherein the sofa bed main body is configured to release the locking between the seat portion connecting rod and the backrest portion connecting rod when the seat portion is operated to pivot toward the backrest portion in a locked state.