| 摘要 |
<p>The apparatus comprises a support 10, at least one piston and cylinder assembly 12 having user-operable means for effecting relative reciprocatory movement between the piston and cylinder and means to provide a predetermined maximum fluid pressure to resist the relative movement in at least one direction of reciprocation during the or each cycle of reciprocation. The piston 16 may include a return valve 22 and a seal 20. The user-operable means (Figure 2) may comprise a handle (30) connected to an elongate flexible member 24 which passes around pulleys 26,28. <IMAGE></p> |
