Spring-assisted futon frame

Abstract

A futon frame having a base supporting a back and a seat for adjustment between a flat bed position and a sofa position comprises at least one spring having a first end mounted to the base and a second end mounted to the seat for assisting a user in adjusting the back and seat from the bed position to the sofa position. A detent member attached to the seat engages an abutment surface fixed relative to the base to releasably lock the seat in its bed position counter to the spring force. A user lifts a front end of the seat to disengage the detent member and begin adjustment. The spring acts generally along a direction of travel of the seat during adjustment.

What is claimed is:  
     
         1 . A futon frame comprising: 
 a base including a pair of opposing sides connected by front and rear support rails extending laterally between said pair of opposing sides, each of said pair of opposing sides having an upper guide channel and a lower guide channel formed therein;    a back situated between said pair of opposing sides;    a seat situated between said pair of opposing sides and pivotally connected to said back for folding relative to said back along a laterally extending axis;    a pair of upper follower bearings carried by said back and arranged for travel within said upper guide channels of said pair of opposing sides;    a pair of lower follower bearings carried by at least one of said back and said seat and arranged for travel within said lower guide channels of said pair of opposing sides; and    at least one spring having a first end connected to said base and a second end connected to said seat, wherein said at least one spring provides force for assisting a user in adjusting said back and said seat from a flat bed position to a folded sofa position.    
     
     
         2 . The futon frame according to  claim 1 , wherein said at least one spring acts along a linear direction.  
     
     
         3 . The futon frame according to  claim 1 , wherein said at least one spring is loaded during adjustment of said back and said seat from said sofa position to said bed position.  
     
     
         4 . The futon frame according to  claim 1 , wherein said at least one spring comprises a gas spring having a cylinder and a piston received by said cylinder for axially directed movement relative thereto.  
     
     
         5 . The futon frame according to  claim 4 , wherein said first end of said gas spring is associated with said cylinder and said second end of said gas spring is associated with said piston.  
     
     
         6 . The futon frame according to  claim 4 , wherein said first end of said gas spring is pivotally connected to said base and said second end of said gas spring is pivotally connected to said seat.  
     
     
         7 . The futon frame according to  claim 6 , wherein said first end of said gas spring is mounted to one of said pair of sides of said base by a U-shaped bracket and a pivot pin fixed to said U-shaped bracket.  
     
     
         8 . The futon frame according to  claim 6 , wherein said second end of said gas spring is mounted to said seat by an L-shaped bracket and a pivot pin fixed to said L-shaped bracket.  
     
     
         9 . The futon frame according to  claim 6 , wherein said first end of said gas spring is forward of said second end of said gas spring when said seat and said back are in said sofa position and when said seat and said back are in said bed position.  
     
     
         10 . The futon frame according to  claim 1 , wherein said at least one spring comprises a coil spring.  
     
     
         11 . The futon frame according to  claim 10 , wherein said second end of said coil spring is mounted to said seat by a bracket and a pin fixed to said bracket.  
     
     
         12 . The futon frame according to  claim 10 , wherein said second end of said coil spring is forward of said first end of said coil spring when said seat and said back are in said sofa position and when said seat and said back are in said bed position.  
     
     
         13 . The futon frame according to  claim 1 , further comprising a detent member fixed relative to said seat and an abutment surface fixed relative to said base, wherein said detent member engages said abutment surface to releasably maintain said seat and said back in said bed position.  
     
     
         14 . The futon frame according to  claim 14 , wherein said base includes a cam block fixed to one of said pair of sides and having a ramp surface thereon, said abutment surface is provided on said cam block and extends downwardly from an upper end of said ramp surface, and said detent member follows said ramp surface until said detent member drops into engagement with said abutment surface as said seat and said back are adjusted from said sofa position to said bed position.  
     
     
         15 . The futon frame according to  claim 10 , further comprising a detent member fixed relative to said seat and an abutment surface fixed relative to said base, wherein said detent member engages said abutment surface to releasably maintain said seat and said back in said bed position.  
     
     
         16 . The futon frame according to  claim 15 , wherein said detent member includes a pin, and said second end of said coil spring is received by said pin of said detent member to mount said second end of said coil spring to said seat.  
     
     
         17 . The futon frame according to  claim 1 , wherein said at least one spring comprises a pair of springs mounted one near each of said pair of sides of said base.