Chair

Abstract

A chair includes a seat, a backrest and a back frame having a rigid structure and arranged behind the backrest with an interval in between. The backrest is attached to the back frame by a first support device arranged at a height position close to an upper end of the backrest and by a second support device arranged at a position lower than the first support device and higher than a seat surface. The first support device is attached to a part close to a right-left middle part of the upper end part in the backrest. The second support device is attached to a left end part and a right end part of the backrest.

1 . A chair comprising:
 a seat;   a backrest; and   a back frame having a rigid structure and arranged behind the backrest with an interval in between, wherein   the backrest is attached to the back frame by a first support device arranged at a height position close to an upper end of the backrest and by a second support device arranged at a position lower than the first support device and higher than a seat surface,   the first support device is attached to a part close to a right-left middle part of the upper end part in the backrest, and   the second support device is attached to a left end part and a right end part of the backrest.   
     
     
         2 . The chair according to  claim 1 , wherein
 the first support device has such an elastic strength that, when a body pressure of a seat occupant acts on the backrest, permits warp deformation and thereby allows an upper part of the backrest to move and deviate rearward, whereas   the second support device has such a rigidity that, even when a body pressure of a seat occupant acts, bending deformation does not substantially occur or, alternatively, although elastic deformation is caused by the body pressure of the seat occupant, the second support device has the elastic strength with which a magnitude of the elastic deformation of the second support device is lower than that of the first support device.   
     
     
         3 . The chair according to  claim 1 , wherein
 the first support device is in an attitude elongated in up and down directions in side view, whereas the second support device is separated into two right and left parts and then the right and left second support devices are in such an inclined attitude that an interval of the right and left second support devices becomes wider as going to a nearer side in plan view.   
     
     
         4 . The chair according to  claim 1 , wherein
 the back frame includes a pair of right and left vertically elongated members, these right and left vertically elongated members being inclined such that an interval becomes narrow as going upward, and upper ends being connected integrally through a linkage part, and   the first support device is attached to the linkage part of the back frame and the second support device is attached to the right and left vertically elongated members.   
     
     
         5 . The chair according to  claim 1 , wherein
 the backrest includes a main member fabricated from resin and attached to the back frame,   the main member includes a framework having a loop shape and constituting an outer periphery and a body support part located in an inner side thereof, and   the body support part is provided with a large number of slits or holes so as to have such a strength that deformation is easily caused by a body pressure of a seat occupant.   
     
     
         6 . The chair according to  claim 5 , wherein
 a cushion is arranged in a front face of the main member and at least the cushion is covered by a skin material.   
     
     
         7 . The chair according to  claim 5 , wherein
 a lower end of the main member is located close to the seat surface,   a lumbar support member for supporting a lumbar portion of a seat occupant is arranged on the front face or the rear face of the main member and, further,   the main member is attached to the second support device at a position slightly higher than the lumbar support member.   
     
     
         8 . The chair according to  claim 1 , wherein
 when a body pressure of a seat occupant acts, the backrest is inclined rearward.   
     
     
         9 - 17 . (canceled)