| 摘要 |
<p>SPECIFICATION A back for a chair comprises at least one back supporting frame member, a lower back mounted on the frame member for backward tilting movement about a first horizontal, transverse axis and yieldably restrained against such backward tilting and an upper back mounted on the lower back for tilting movement relative to and independently of the lower back about a second horizontal, transverse axis spaced a substantial distance above the first axis and yieldably restrained against such backward tilting. The axis about which the lower back tilts is located a substantial distance above the seat at a location corresponding to about the middle of the back of an adult human sitting in the chair.</p> |
