Method and apparatus for automatically controlling pressure in fluid-actuated systems

Abstract From the Canadian patent

Abstract of the Disclosure, 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 apreferred 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) …