Chair with automatically movable back support

Abstract

A chair with an automatically movable back, having a support, and a seat and a back installed on the support. The chair comprises a base frame coupled to a lower surface of the seat in such a way as to define a space between the base frame and the seat; a horizontal movement frame coupled to an upper surface of the base frame to be moved forwards and rearwards, connected at left and right ends thereof to a back frame which in turn is connected with the back of the chair, and having on a lower surface thereof a follower which receives force required for forward and rearward movement; a vertical movement frame which has an upper surface which is connected to the lower surface of the base frame and a lower surface which is connected to the support, and which is coupled to the support such that the vertical movement frame can slide upwards and downwards with respect to the support; and rotation force generation means installed in the vertical movement frame to transmit rotation force generated by upward and downward movement of the vertical movement frame to the follower such that the horizontal movement frame can be moved forwards and rearwards.

1 . A chair with an automatically movable back, having a support, and a seat and a back installed on the support, the chair comprising:
 a base frame coupled to a lower surface of the seat in such a way as to define a space between the base frame and the seat;   a horizontal movement frame coupled to an upper surface of the base frame to be moved forwards and rearwards, connected at left and right ends thereof to a back frame which in turn is connected with the back of the chair, and having on a lower surface thereof a follower which receives force required for forward and rearward movement;   a vertical movement frame having an upper surface which is connected to a lower surface of the base frame and a lower surface which is connected to the support, and coupled to the support such that the vertical movement frame can slide upwards and downwards with respect to the support; and   rotation force generation means installed in the vertical movement frame to transmit rotation force, generated by upward and downward movement of the vertical movement frame, to the follower such that the horizontal movement frame can be moved forwards and rearwards.   
     
     
         2 . The chair according to  claim 1 , wherein the support has a gas cylinder and a piston, and the vertical movement frame is slidably coupled to the piston. 
     
     
         3 . The chair according to  claim 2 , wherein the vertical movement frame comprises an upper frame and a lower frame which are connected with each other, and at least one elastic member is disposed between the upper frame and the lower frame. 
     
     
         4 . The chair according to  claim 3 , wherein the rotation force generation means comprises: a fixed shaft having a lower end which is coupled to the piston and an upper end which passes through the upper frame and is formed with a meshing portion;
 a meshing body arranged in the upper frame to be meshed with the meshing portion such that the meshing body can be rotated by upward and downward movement of the vertical movement frame; and   an intermediate element connected to the meshing body and the follower to transmit rotation force of the meshing body to the follower.   
     
     
         5 . The chair according to  claim 4 , wherein a guide cylinder is fitted around an outer surface of the lower end of the fixed shaft, the lower frame is fitted around an outer surface of the guide cylinder, and a plurality of balls is accommodated in at least one groove defined in an outer surface of the guide cylinder such that the lower frame can smoothly slide with respect to the guide cylinder. 
     
     
         6 . The chair according to  claim 4 , wherein the meshing portion and the meshing body are meshed and operated in a gear type fashion. 
     
     
         7 . The chair according to  claim 6 , wherein the meshing portion comprises a vertical rack gear, and the meshing body comprises a pinion gear. 
     
     
         8 . The chair according to  claim 4 , wherein the intermediate element is directly or indirectly connected with the meshing body to be rotated around a predetermined point, and is meshed with the follower to transmit rotation force thereto. 
     
     
         9 . The chair according to  claim 8 , wherein the intermediate element is coupled to a rotation support member which is connected to a shaft of the meshing body, has an arc-shaped configuration having gear teeth formed on an outer surface thereof, and is meshed with the follower. 
     
     
         10 . The chair according to  claim 4 , wherein the follower comprises a straight horizontal rack gear. 
     
     
         11 . The chair according to  claim 1 , further comprising: braking means for fixing the horizontal movement frame moved with the back to an optional position. 
     
     
         12 . The chair according to  claim 11 , wherein the braking means comprises:
 a plurality of rods fastened on both ends thereof to be spaced apart from the upper surface of the base frame, extending in forward and rearward directions, and defined on lower surfaces thereof with engagement grooves; and   a tilting frame rotatably connected to rear left and right portions of the horizontal movement frame by a pin shaft, having the shape of a plate, and formed on a front end thereof with engagement pieces to be engaged into the engagement grooves of the rods, so that, when the tilting frame is rotated upwards, the engagement pieces are engaged into the engagement grooves of the rods to secure a position of the horizontal movement frame.   
     
     
         13 . The chair according to  claim 12 , wherein the tilting frame has front brackets on front left and right portions thereof adjacent to the engagement pieces, which are defined with slots, an adjustment lever is rotatably coupled through the horizontal movement frame in such a way as to pass through the slots of the front brackets, and a cam is eccentrically fastened to the adjustment lever, such that, as the adjustment lever is rotated, the cam pushes the tilting frame upwards to secure the horizontal movement frame to an optional position. 
     
     
         14 . A chair with an automatically movable back, having a support, and a seat and a back installed on the support, the chair comprising:
 a base frame coupled to a lower surface of the seat in such a way as to define a space between the base frame and the seat, and having hollow pillars which project from a lower surface of the base frame;   a horizontal movement frame coupled to an upper surface of the base frame to be moved forwards and rearwards, connected at left and right ends thereof to a back frame which in turn is connected with the back of the chair, and having on a lower surface thereof a follower which receives force required for forward and rearward movement;   a connection housing coupled to the support, open at an upper end thereof to define a space therein, and having slide pillars into which the hollow pillars of the base frame are respectively inserted;   elastic members disposed between the hollow pillars and the slide pillars to allow the base frame to be moved upwards and downwards with respect to the connection housing; and   rotation force generation means formed in the connection housing to transmit rotation force generated by upward and downward movement of the base frame to the follower such that the horizontal movement frame can be moved forwards and rearwards.   
     
     
         15 . The chair according to  claim 14 , wherein the rotation force generation means comprises:
 a meshing portion fixedly installed in the connection housing and formed on an outer surface thereof with a vertically extending rack gear;   a meshing body installed on support brackets which are connected to the base frame between the hollow pillars and project vertically downwards, and meshed with the meshing portion to be rotated; and   an intermediate element connected with the meshing body and the follower and rotated to linearly move the horizontal movement frame.   
     
     
         16 . The chair according to  claim 14 , wherein one side end of the base frame is bent to face downwards, engagement grooves are defined in an edge of the bent side end of the base frame to create prominences and depressions, a tilting frame is placed on the horizontal movement frame in such a way as to cover the horizontal movement frame and is projectedly formed with an engagement piece on one side end thereof corresponding to the engagement grooves, and an adjustment lever is rotatably installed through side walls of the horizontal movement frame and the tilting frame and has an eccentric cam fixed thereto, such that, as the adjustment lever is rotated, the cam pushes the tilting frame upwards to engage the engagement piece into one of the engagement grooves to thereby limit movement of the horizontal movement frame. 
     
     
         17 . The chair according to  claim 14 , wherein the connection housing is connected with the support through a connection bracket which is coupled to the support such that the connection housing is rotatably connected to the connection bracket, and an angle adjustment elastic member, which is coupled to the connection bracket, and the connection housing are linked with each other so that the connection housing can be inclined rearwards within a predetermined range. 
     
     
         18 . The chair according to  claim 1 , wherein the back of the chair is rotatably coupled to left and right portions of the back frame by way of connection shafts, an angle adjustment lever, which is defined with a plurality of fixing grooves, is axially movably coupled to an end of the connection shaft, which projects out of one side of the back frame, such that fixing pins, which are formed on the back frame, can be selectively locked into the respective fixing grooves to adjust an inclination angle of the back, and an elastic member is connected to a rear lower end of the back such that the elastic member is coupled to a rear portion of the back frame. 
     
     
         19 . The chair according to  claim 18 , wherein one end of the elastic member is coupled to a guide ring which is moved along a guide rod fixedly installed on the back of the chair, and another end is connected to an adjustment rod which is threadedly coupled to a control rod so that the adjustment rod can be changed in its position, the control rod being detachably attached in an opening groove defined in the rear portion of the back frame. 
     
     
         20 . The chair according to  claim 19 , wherein the opening groove is open toward an upper surface of the back frame, such that, by pushing the control rod fitted into the opening groove and removing the control rod from the opening groove, the back can be rotated forwards around the connection shafts in such a way as to be folded.