CHUCK

PROBLEM TO BE SOLVED: To prevent a floating-up of a gripped workpiece, and to prevent a grip from being weakened by centrifugal force accompanying a fast rotation. SOLUTION: A configuration of this chuck includes master jaws 3 each having a gripping claw 4 and fitted into recessed grooves 2 provided on a plurality of radial lines in a front surface of a rotor 1 that rotates together with a spindle A so as to slide within a range between grasping and grasping release, pistons 9 provided so as to slide forward and backward by a fluid pressure applied behind the master jaws inside of the rotating body, an interlocking means provided so as to slide the master jaws in a grasping direction and in a grasping release direction by the sliding of the pistons, weights 28 incorporated behind the respective master jaws of the rotator so as to slide centripetally and circumferentially along the rotor and be given pressing force in the circumferential direction, and levers 35 each provided so that a distance between an intermediate supporting point and one end engaging with each of the weights is larger than a distance between the intermediate supporting point and another end engaging with each of the master jaws. COPYRIGHT: (C)2008,JPO&INPIT