| 摘要 |
A spring loaded frame pivotably mounted in the backrest frame is easily unlocked by light pressure applied to a lever disposed at the side of the seat proper whereby the pressure of the seated person's back pressing against the backrest portion urges the pivotable frame to a new position, in which the pressure applied to the dorsal and lumbar regions of his or her back are substantially equal, and in which it is lockable. |
