| 摘要 |
<p>The invention provides a method and apparatus for controlling the level of clamping pressure applied by a clamp (14) to a load (16). A pump (20), whose output is controlled by a normally open valve (34), establishes an initial level of clamping pressure. Through the use of a number of controllable fluid discharge means (50, 52, 54), this pressure is automatically increased in increments depending upon the resistance of the load to the clamping pressure exerted. In a preferred embodiment, the controllable fluid discharge means include discharge cylinders (58, 70, 90) that contain predetermined volumes of fluid dischargeable by free-floating pistons (62, 82, 92) residing therein. The outputs of the discharge cylinders are controlled by pressure-responsive valves (72, 92) to produce the desired relationship between clamp pressure and load rigidity.</p> |
