Abstract: A chuck, each of the clamping jaws of which is adapted to be driven by a wedge bar that can be displaced in the chuck body beyond the clamping stroke to such an extent that the clamping jaws can be removed radially. A locking mechanism in the form of a rotatably held adjusting pin is provided for each clamping jaw. Each wedge bar, on that side that faces the adjusting pin, is provided with a slot-like recess for receiving the adjusting pin in an operating range of the chuck. The slot-like recess extends in the longitudinal direction of the wedge bar. In the operating position of the chuck, the adjusting pin is adapted to be inserted into the slot-like recess in an automatic manner.

Abstract: An automatic indexing chuck comprises a dividing pivot separately and in succession, operated by a dividing shaft and a locking sleeve. The dividing shaft is slideably and sealingly accommodated in a cavity of the locking sleeve which has retention planes for the dividing pivot and is in turn sealingly accommodated in a mandrel body cavity defining two adjacent chambers; the dividing shaft and the locking sleeve defining independent pistons operated by a single hydraulic circuit with reversible inlet and outlet ports, the pistons moving in opposite directions to perform consecutively unlocking, rotation and locking of the dividing pivot.