| 摘要 |
<p>A chair whose seat (5) slides in a sinking backward direction accompanying the back tilting of a backrest (7) having an elastically deformable back shell (71) as its main body. A back-supporting rod (6) whose lower end is pivotally supported by a support base part (3) disposed under the seat (5) and which supports the back shell (71) has an upper back frame (61) which supports a section above a lumber support part (71L) out of the back shell (71) wherein the lumber support part (71L) is capable of supporting the waist of a seated person, and a lower back frame (62) which supports a section near the lower end of the back shell (71). The back frames (the upper back frame (61) and the lower back frame (62)) are pivotally attached to each other and the pivotally attaching point (a third spindle (X3)) is arranged behind the lower end of the back shell (71). Thus, with the back tilting of the upper back frame (61) relative to the lower back frame (62) around the pivotally attaching point (the third spindle (X3)), the back shell (71) so generally curve-deforms as to make the lumber support part (71L) relatively projected forward.</p> |
