| 摘要 |
A flexible plate element of S cross-section is mounted at the lower and upper parts to the lower and upper ends of a backrest frame (6). A V-hinge (15), translatable back and forth, is interposed between the rear surface (7c) of the plate element and the neck region of the backrest frame. A whip-like element (8) tiltable with respect to a horizontal swivel axis (9) is located between the rear surface of the plate element and the lumbar vertebra region of the backrest frame. |
