| 摘要 |
<p>Jack comprises a cylinder with an inner separator connected to a transmission rod and dividing the cylinder into two chambers. The separator consists of a helically wound elastic band with contiguous turns, fixed sealingly to the inner wall of the cylinder by its outer periphery and to the transmission rod by its central turn, and acting as piston by longitudinal sliding of its free turns one over the other when then rod is displaced and fluid is admitted to one of the chambers under pressure. The separator is fixed at each end by a certain no. of turns becoming engaged in a circular recess in the cylinder walls and in the transmission rod respectively. Pref. the separator is made of metal and coated on one surface with an antifriction metal alloy or plastics material e.g. 'Teflon'.</p> |
