| 摘要 |
A seat comprises a frame 10, a sitting portion 12 yieldably carried on the frame so as to be displaceable downwardly under the weight of a sitter when seated thereon, a backrest 14 which includes at least a lower, lumbar region supporting part 16, and an L- shaped force transference lever 24 which is pivotally supported on a convex cam 22 secured on the frame, and which is pivotally secured at its lower free end to the rearward part of the sitting portion, and at its upper free end to the lower part 16 of the backrest. Force Fw produced by the weight of the sitter acts on portion 12 to produce movement downwards about axis 48 to actuate movement of lever 24 around axis 52 and movement of part 16 towards the sitter's back. Fluid pressure operated and/or controlled actuating devices may be used for moving portion 16 and the seat may incorporate a load sensing device (94, Fig. 9). <IMAGE> |
