| 摘要 |
An exercising device comprises a cylinder 1 having a handle 14 fixed to one end, a piston 7 movable in the cylinder and carried at one end of a piston rod 13 extending through a gas-tight seal in the end wall of the cylinder opposite the handle, and a further handle 20 fixed to the other end of the piston rod, the cylinder containing a pressurised gas and the piston having a narrow bore 7A through which the gas can pass during compression and expansion of the device. Since the effective area of the piston on the side opposite the piston rod is greater than that on the other side, the high pressure gas produces a net resilient force on the piston tending to expand the device. The passage of gas through the bore in the piston provides a damping effect which must be overcome when the device is compressed and which slows the expansion of the device when the handles are released. <IMAGE> |
