Tool-holder mandrel for fitting to a rotating machine

A tool-holder mandrel for fitting to a rotating machine, comprising:

• a body comprising a rear portion designed to be attached to a drive shaft of the rotating machine and a front portion in which housings are arranged converging toward the front;
• jaws mounted so as to slide each in a housing of the body and having an inner thread;
• a ring for moving the jaws, mounted so as to pivot relative to the body, having a peripheral thread interacting with the inner thread of the jaws so that the rotation of the ring closes or opens the jaws;
• which mandrel has an axis, the jaws extending along an axis that is inclined relative to the axis of the mandrel, at an angle of between 15° and 30°, and the mandrel further comprising:
• an insert supported by the ring for moving the jaws and immobilized in rotation on this ring,
• a sleeve forming a portion of the outer surface of the mandrel and designed to be actuated manually by a user, the sleeve being mounted so as to pivot relative to the body and having an inner portion which interacts with the insert in order to rotate it relative to the body, and
• a radial locking mechanism supported by the insert and able to move between an unlocked position in which the ring is capable of being rotated relative to the body and a locked position in which the locking mechanism interacts with the body so as to prevent a rotation of the ring in the direction for opening the jaws, the locking mechanism being designed to be actuated by the sleeve.