Patent ID: 7328903

Claim:
A chuck comprising: an attachment device adapted to attach the chuck to a motor-driven machine spindle; a collet connected to the attachment device; the collet having clamping jaws defining an insertion opening at an axial end face of the chuck facing away from the attachment device; a sliding sleeve slidably connected to the collet and surrounding the clamping jaws, wherein the sliding sleeve is axially moveable in a first direction into a clamping position for clamping a shaft of a machining tool inserted into the insertion opening and in a second direction from the clamping position into a release position for releasing the shaft; wherein between an inner circumference of the sliding sleeve and an outer circumference of the clamping jaws a mating pressure zone pair is provided that is comprised of a contact path conically tapering in an axial direction and comprised of counter pressure members that engage positively the contact path; wherein the contact path is positioned at a slant angle relative to the axial longitudinal center of the collet, wherein the slant angle is so small that under expected operating forces of the chuck a self-locking action between the contact path and the counter pressure members is maintained at all times; wherein the clamping jaws have an outer circumferential surface that forms the contact path; wherein the sliding sleeve has an inner circumferential wall and the inner circumferential wall has recesses; wherein the counter pressure members are arranged in the recesses of the inner circumferential wall of the sliding sleeve; and wherein the counter pressure members are rolling elements and wherein the recesses have a shape matched to the shape of the counter pressure members.