Chuck device

A chuck device to be attached to a driving device having a driving shaft rotatable on an axis, the chuck device comprising:

• a generally cylindrical chuck main body arranged on the axis and having a shaft hole at a front end side thereof, the shaft hole allowing insertion of a base shaft of a rotating jig;
• a plurality of chuck pawls which communicate with the shaft hole at the front end side in the chuck main body, which, at a rear end side, are inserted into a slanting hole opened in a side of the chuck main body, and which are arranged movably relative to the chuck main body;
• a nut ring which moves the plurality of chuck pawls in synchronization with each other in a slanting direction in the slanting hole by screwing with the chuck main body and the chuck pawls;
• a plurality of rolling bodies which roll while being sandwiched between the nut ring and the chuck main body;
• a retainer which holds the plurality of rolling bodies so as to be rolled while being aligned, the retainer being rotatable relative to the chuck main body and the nut ring;
• a first rotation restriction body configured to rotate together with the nut ring and to switch between a rotation restricted state in which rotation of the retainer in a loosening direction is restricted and a restriction released state in which a restriction of the rotation of the retainer in the loosening direction is released;
• and
• a second rotation restriction body which restricts the rotation of the retainer in the loosening direction relative to the chuck main body,
• wherein the plurality of rolling bodies, the retainer, and the second rotation restriction body configure a bearing mechanism between the nut ring and the chuck main body, the bearing mechanism having rotation in a loosening direction being restricted, and
• the retainer, the rolling bodies, and the first rotation restriction body in the rotation restricted state configure a lock mechanism using the rolling bodies sandwiched between the nut ring and the chuck main body as rotation loads;
• wherein the retainer is formed to have a ring-shape and have an inner circumferential ratchet gear provided on a circumference thereof,
• the chuck device further comprising a rotation-fixing means which rotation-fixes the second rotation restriction body to the chuck main body,
• wherein the second rotation restriction body includes an engaging pawl which engages with the inner circumferential ratchet gear of the retainer.