CHUCK STRUCTURE, FASTENING MEMBER ADAPTOR FOR TIRE ANTI-SKID DEVICE, AND TIRE ANTI-SKID DEVICE

PURPOSE:To provide a chuck structure allowing a fixed body to be gripped positively while withstanding the repeated use of plural times. CONSTITUTION:An elastically deformable inner cylinder 114 is disposed in the recessed part 118 of the outer cylinder 112 of an adaptor 110, and the recessed part 118 is provided with a taper part 118A. The inner cylinder 114 is provided with hard balls 140 embedded in the positions corresponding to the taper part 118A, and the hard balls 140 are partially protruded from the inner wall and outer wall of the inner cylinder 114. A wheel nut 87 is inserted into the inner cylinder 114, and a fastening screw 124 is fastened thereto. When the inner cylinder 114 is moved onto the opening side of the outer cylinder 112, the hard balls 140 are guided by the taper part 118A, so that the inner cylinder is contracted in diameter, and the hard balls 140 bite into the outer peripheral surface of the wheel nut 87. The adaptor 110 is thereby fitted positively to the wheel nut 87. When the fastening screw 124 is loosened, the inner cylinder 114 is enlarged to the original diameter by elasticity, and the hard balls are also spaced from the wheel nut 87.