| 摘要 |
<p>A pair of hydraulic or pneumatic cylinders are operated in a cycle of four phases from a common control. In the first phase fluid, is admitted to a port and flows through piston controlled ball valves to reach a first cylinder. At the same time the second cylinder is maintained under pressure by a non-return valve. In the second phase, the fluid is admitted to the other port and acts on a piston to open the non-return valve and release the fluid from the second cylinder which pushes the ball to one side and flows out through the port. The third and fourth phases pressurise the second cylinder and releases pressure from the first cylinder.</p> |
