Patent ID: 7214060

Claim:
A handpiece comprising: a hollow shaft, which is rotatable around a longitudinal axis and mounted by bearings in a fixed tubular sheath, a clamp mounted in a front end of the hollow shaft and having a central channel intended to receive a shank of a removable tool, the clamp having axial arms arranged around the longitudinal axis, each of which are provided with a gripping jaw in the central channel, and each arm being attached to an annular section of the clamp, said annular section located at the front end of the hollow shaft, and said arm extending axially towards the rear from said annular section, a tightening mechanism supported by the hollow shaft and arranged to exert a centripetal force on a supporting surface of each arm of the clamp to grip the tool shank between the gripping jaws of the clamp, and a release mechanism supported at least partially by the fixed sheath and arranged to act on the tightening mechanism at least so as to loosen the clamp, wherein each arm of the clamp comprises a lever, a first end of which is attached to the annular section by a joint and said supporting surface of which is axially spaced from the joint, the gripping jaw being located axially closer to the joint than to the supporting surface.