Chair

Abstract

A chair, on a chair seat or a chair frame, includes guide rails which are fixed to the chair seat in a forward and backward direction, and movers which are coupled to the guide rails and are moved in a forward and backward direction of the chair. The chair with a backrest which is movable in a forward and backward direction of the chair comprises a brake device which fixes the movements of the movers, and the brake device comprises brake pieces which receive the operation of a brake lever, and then are compressed to a fixed region of the chair and fix the movers.

1 . A chair, on a chair seat or a chair frame, comprising guide rails which are fixed to the chair seat in a forward and backward direction, and movers which are coupled to the guide rails and are moved in a forward and backward direction of the chair,
 wherein the chair with a backrest which is movable in a forward and backward direction of the chair comprises a brake device which fixes the movements of the movers, and the brake device comprises brake pieces which receive the operation of a brake lever, and then are compressed to a fixed region of the chair and fix the movers.   
     
     
         2 . The chair according to  claim 1 , wherein the brake device comprises an interlocker which interlocks left and right brake units with each other by means of either operation of the left or right brake device. 
     
     
         3 . The chair according to  claim 1 , wherein a structure supporting a backrest comprises a lower structure having left and right ends which are extended downward, and the lower structure is coupled to through holes of a mover, which are bored in an upward and downward direction, so as to adjust the height of the backrest. 
     
     
         4 . The chair according to  claim 1 , wherein the chair comprises tensioned elastic members which are configured so that both ends of the tensioned elastic members are coupled to fixers and the front of the movers of the backrest. 
     
     
         5 . The chair according to  claim 1 , wherein the chair further comprises an immobile backrest behind the movable backrest, separately from the movable backrest. 
     
     
         6 . The chair according to  claim 1 , wherein the chair comprises a lower chair seat cover. 
     
     
         7 . The chair according to  claim 1 , wherein brake pieces are compressed to auxiliary rails after receiving the operation of a brake lever, thereby fixing the movement of the backrest. 
     
     
         8 . The chair according to  claim 1 , wherein the brake pieces are compressed to a fixed region by means of a connecting rod interlocking the operations of the left and right brake pieces with each other after receiving the operation of the brake lever, thereby fixing the movement of the backrest. 
     
     
         9 . The chair according to  claim 1 , wherein the brake pieces are compressed to the fixed region through an up-and-down movement of the brake pieces by means of a cam formed on the connecting rod which interlocks the operations of the left and right brake pieces with each other after receiving the operation of the brake lever, thereby fixing the movement of the backrest. 
     
     
         10 . The chair according to  claim 1 , wherein an upper structure and the lower structure of the backrest is rotatably coupled to a connecting rod, and the angle of the backrest may be adjusted through the operations of stoppers. 
     
     
         11 . The chair according to  claim 1 , wherein the backrest has a height adjustment system which adjusts the height of a backrest upward and downward, and is protruded more below than the bottom of the backrest so that a user sitting in the chair may grab knobs protruded backward from brake operating pieces even in a sitting state. 
     
     
         12 . The chair according to  claim 10 , wherein a part of a structure of the system for adjusting the height of the backrest is fixed to the backrest, and extended lower parts of the structure are formed in a parallel manner and have a protruded fixing lug between the extended lower parts; the brake operating pieces are inserted along the structure on both sides of the fixing lug, and a spring is inserted between the fixing lug and the brake operating pieces; and both outside ends of the each brake operating piece are formed so as to be interlocked with unevennesses formed in the backrest structure. 
     
     
         13 . The chair according to  claim 1 , wherein, the chair comprises a chair seat supporting member of which the one end is fixed to the bottom of the chair seat and the other end is rotatably coupled to a horizontal structural element formed in an upper end of a chair structure in a horizontal direction; and, when a user tilts the chair seat by rotating the chair seat forward or backward, elastic elements which respond to the each tilting and have elasticity different from each other. 
     
     
         14 . The chair according to  claim 13 , wherein the one elastic element comprises a compression spring; an upper end unit and a lower end plate which respectively fixes the top and the bottom of the compression spring; a spring pressure adjuster which supports the lower end plate and is coupled to a rotation supporter; linear expansion suppressing connectors which not only connect the upper end unit and the lower end plate but also pass through the rotation supporter, and have lower ends fastened by means of separation preventing means; a compression spring guide unit which is fixed to the chair seat and coupled to a protrusion of the upper end unit; and the rotation supporter which is rotatably coupled to rotating couplers mounted on the chair structure. 
     
     
         15 . The chair according to  claim 14 , wherein the pressure of the compression spring is adjusted in such a way that the pressure adjuster which supports the lower end plate and is coupled to the rotation supporter by means of screws is moved upward and downward, and thus, elasticity of the compression spring is controlled. 
     
     
         16 . The chair according to  claim 13 , wherein the other elastic element comprises a tension spring; an upper end unit and a lower end unit which respectively fix the top and the bottom of the tension spring; a tension adjuster which maintains the length of the spring between the upper end unit and the lower end unit; a tension spring unit which is rotatably connected to the upper end unit through a rotation shaft pin and fixed to the chair seat; the rotation supporter which is rotatably coupled to the rotating couplers mounted on the chair structure; and an upward movement suppressing element which is coupled to the tension adjuster through screws and is configured below the rotation supporter. 
     
     
         17 . The chair according to  claim 16 , wherein the pressure of the tension spring is adjusted in such a way that the tension adjuster coupled to the upward movement suppressing element, which is larger than a hole in the rotation supporter, through screws is moved upward and downward below the hole bored in the rotation supporter so that the lower end unit which supports the upper end unit and is coupled to the tension adjuster through screws may pass through the rotation supporter, and thus, elasticity of the tension spring is controlled, 
     
     
         18 . The chair according to  claim 1 , wherein the chair comprises a brake mechanism comprising: the chair seat supporting member of which the one end is fixed to the bottom of the chair seat and the other end is rotatably coupled to the horizontal structural element formed in the chair structure in a horizontal direction; and a circular brake frame which is formed on the chair structure so as to be concentric around the rotation shaft of the chair seat, and the brake mechanism is mounted on the chair seat and causes the brake frame to be operated, so as to fix the rotation of the chair seat. 
     
     
         19 . The chair according to  claim 18 , wherein the brake mechanism comprises a brake case which is fixed to the chair seat or the cover, that is, a fixed region; brake pieces which are coupled to the brake case; and a cam which enables the brake pieces to be pressed to the brake frame after receiving the operation of the brake stick.