Fluid operating mechanism for a rotary chuck

Abstract

Fluid operating mechanism providing stationary and rotary companion parts of a fluid coupling having in the rotary part a cylinder with a piston defining therein opposite chuck closing and opening cylinder ends, and ports in both coupling parts which, together with two fixed conduits, form fluid passages to the opposite cylinder ends, with each passage having an interposed check valve and an associated plunger, of which the check valve in either passage will open to admit fluid into, but will normally close to block fluid flow from, the associated cylinder end, and the plunger associated with the check valve in either passage will open this valve on being subjected to the pressure of fluid in the other passage. At least the plunger associated with the check valve for the chuck-closing cylinder end is a stepped plunger with opposite larger and smaller faces, of which the larger face is subjected to the pressure of fluid in the chuck-opening cylinder end and the smaller face is subjected to the pressure of fluid in the passage to the chuck-closing cylinder end ahead of the check valve therein, so that this check valve can be opened for blending the fluid in the chuck-closing clyinder end with fluid of a lower control pressure applied to the passage to this cylinder end ahead of the check valve therein on admission to the chuck-opening cylinder end of fluid lower than the control pressure. There is also provided a system of control valves in association with the mechanism for operating the same for high-low operation of an associated chuck requiring the latter to exert a heavy grip on work for an initial part of a machining operation thereon, followed by a lighter grip on the work for the final part of the machining operation.