Collet chuck

Abstract

A collet chuck for holding a tool or workpiece on a spindle of a machine tool. The collet chuck has a hollow collet mount having a rear end to be attached to the spindle. A plurality of radially disposed holes extending from the exterior surface to the interior surface of the collet mount. A cam surface is disposed adjacent the front end on the interior surface. The chuck also has a two-piece, tubular collet with a collet cam adjacent the front end on the exterior surface for interacting with the cam surface of the collet mount. The two-piece collet comprises a collet head with an annular groove adjacent the rear end and a hook portion between the rear end and the groove, and a collet body with a flange portion at its front end. The flange portion of the collet body engages the hook and groove of the collet head. A slot associated with each radially disposed hole is provided in the collet body. The collet body has a draw bar adapter which is threaded to the draw bar mechanism of the spindle in such a way as to limit the stroke length of the collet. A stop member is disposed inside the tubular collet at a clearance from the interior surface of the collet. A pin passes through each radially disposed hole and associated slot and is fixed to the stop. A spring corresponding to each pin is provided for biasing the pin toward the rear of the collet mount. Screws are provided for adjusting the tension of the spring. When the collet is displaced, the collet cam interacts with the cam surface on the collet mount to close the collet, but the displacement of the collet does not affect the axial position of the stop.

Dependencies are inferred from the claim text.