Chair

Abstract

An object of this invention is to provide a chair comprising a simple and compact rocking mechanism and lock mechanism to lock the rocking movement. The chair comprises a support frame 4 supported by a support rod 12 , a back frame 5 that can make an inclining movement, a seat frame 6 that make a movement in conjunction with the back frame 5 toward a direction along the inclining movement of the back frame 5 , a reactive force mechanism 7 that accumulates a spring force against an interlocking movement, and a lock mechanism 8 that locks the interlocking movement, wherein the reactive force mechanism 7 comprises a spring case 71 and a spring 72 that can make a relative movement in the back and forth direction, and has such an arrangement that the spring case 71 moves in accordance with the interlocking movement while inclining together with the seat frame 6 with a movement of a part of a front end part and a rear end part of the spring case 71 limited by the seat frame 6 during the interlocking movement, and the lock mechanism 8 locks the interlocking movement of the seat frame 6 and the back frame 5 with the support frame 4 by fixing a relative position of the spring case 71 and the seat frame 6.

1 . A chair comprising a support frame supported by a support rod, a back frame that can make an inclining movement relative to the support frame, a seat frame that is related to the support frame and the back frame so as to make a movement in conjunction with the back frame toward a direction along the inclining movement of the back frame, a reactive force mechanism that accumulates a spring force against an interlocking movement of the seat frame and the back frame with the support frame, and a lock mechanism that locks the interlocking movement of the seat frame and the back frame with the support flame, and is characterized by that the reactive force mechanism comprises a spring case arranged inside of the seat frame and a spring related to the spring case and the seat frame, the spring case moves in the back and forth direction relatively to the seat frame in accordance with the interlocking movement while the spring case inclines together with the seat frame with a movement of a part of a front end part and a rear end part of the spring case limited by the seat frame during the interlocking movement, and the lock mechanism locks the interlocking movement of the seat frame and the back frame with the support frame by fixing a relative position in the back and forth direction of the spring case and the seat frame. 
     
     
         2 . The chair described in  claim 1 , wherein
 the front end part and the rear end part of the spring case are restricted from making a movement in a vertical direction relative to the seat frame.   
     
     
         3 . The chair described in  claim 1 , wherein
 the front end part and the rear end part of the spring case are arranged inside of the seat frame and restricted from making a movement in the right and left directions relative to the seat frame.   
     
     
         4 . The chair described in  claim 2 , wherein
 the front end part and the rear end part of the spring case are arranged inside of the seat frame and restricted from making a movement in the right and left directions relative to the seat frame.   
     
     
         5 . The chair described in either of  claim 1 , wherein
 the lock mechanism comprises a stopper member that can make a proceeding and receding movement in a direction orthogonal to a back and forth direction, a reciprocatory moving mechanism that moves the stopper member, and an engaging bore into which the stopper member is inserted, wherein the stopper member and the reciprocatory moving mechanism are arranged in either one of the seat frame and the spring case, and the engaging bore is arranged in the other.   
     
     
         6 . The chair described in either of  claim 2 , wherein
 the lock mechanism comprises a stopper member that can make a proceeding and receding movement in a direction orthogonal to a back and forth direction, a reciprocatory moving mechanism that moves the stopper member, and an engaging bore into which the stopper member is inserted, wherein the stopper member and the reciprocatory moving mechanism are arranged in either one of the seat frame and the spring case, and the engaging bore is arranged in the other.   
     
     
         7 . The chair described in either of  claim 3 , wherein
 the lock mechanism comprises a stopper member that can make a proceeding and receding movement in a direction orthogonal to a back and forth direction, a reciprocatory moving mechanism that moves the stopper member, and an engaging bore into which the stopper member is inserted, wherein the stopper member and the reciprocatory moving mechanism are arranged in either one of the seat frame and the spring case, and the engaging bore is arranged in the other.   
     
     
         8 . The chair described in either of  claim 4 , wherein
 the lock mechanism comprises a stopper member that can make a proceeding and receding movement in a direction orthogonal to a back and forth direction, a reciprocatory moving mechanism that moves the stopper member, and an engaging bore into which the stopper member is inserted, wherein the stopper member and the reciprocatory moving mechanism are arranged in either one of the seat frame and the spring case, and the engaging bore is arranged in the other.   
     
     
         9 . The chair described in  claim 5 , wherein
 each of the spring case, the stopper member and the reciprocatory moving mechanism is housed in the seat frame within its height.   
     
     
         10 . The chair described in  claim 6 , wherein
 each of the spring case, the stopper member and the reciprocatory moving mechanism is housed in the seat frame within its height.   
     
     
         11 . The chair described in  claim 7 , wherein
 each of the spring case, the stopper member and the reciprocatory moving mechanism is housed in the seat frame within its height.   
     
     
         12 . The chair described in  claim 8 , wherein
 each of the spring case, the stopper member and the reciprocatory moving mechanism is housed in the seat frame within its height.   
     
     
         13 . The chair described in  claim 5 , wherein
 a portion where the engaging bore is arranged is in a plate shape, and the stopper member moves within the height of the seat frame.   
     
     
         14 . The chair described in either of  claim 5 , wherein
 the engaging bore is a slit extending in a direction orthogonal to the back and forth direction and a plurality of engaging bores are arranged at predetermined intervals in the back and forth direction, a stopper member is formed in a plate shape and is provided with a projecting part that fits into the engaging bore, and the stopper member makes a proceeding and receding movement with a surface of the stopper member guided by an inner surface of the stopper case where the stopper member is housed.   
     
     
         15 . The chair described in  claim 14 , wherein
 the stopper case is fixed to the seat frame, the engaging bore is arranged in the spring case, an auxiliary engaging bore into which the projecting part of the stopper member can make a proceeding and receding movement tightly is arranged on the seat frame, and the projecting part of the stopper member is inserted into the engaging bore and the auxiliary engaging bore simultaneously at a position where the engaging bore and the auxiliary engaging bore overlap each other.   
     
     
         16 . The chair described in  claim 5 , wherein
 the reciprocatory moving mechanism comprises a stopper case to house the stopper member, an operating lever to operate the stopper member to make the proceeding and receding movement, and a spring member that gives the stopper member a force to make the proceeding and receding movement by making use of the displacement of the operating lever, wherein the spring member is arranged to switch a direction to urge the stopper member at a released position and a locked position.