| 摘要 |
PURPOSE:To moderate impact of a piston by additionally forming ports between an exhaust port and the end wall of a cylinder and providing the added ports with respective cut-off valves which are closed by resilient members acting against pressure of fluid contained in the cylinder. CONSTITUTION:Additionally to a fluid discharge port 4, ports 10H, 10M and 10L are formed in a cylinder 2, ranging from the fluid discharge port 4 and the end wall 8 thereof. Cut-off valves 11H, 1M and 11L which are pushed by springs 14H, 14M and 14L are disposed in the additional ports 10H, 10M and 10L, respectively. Pressure of fluid contained in the cylinder may be thereby restricted from excessive in crease so that impact of the piston 1 can be moderated smoothly. |
