| 摘要 |
PURPOSE:To contrive to sharply improve the durability and chucking force of the chuck by a structure wherein an engagement structure with surface contact is established between the rear surface of a chucking jaw and a gear in each of the jaws of the chuck, which automatically responds the position of the chucking jaws to work pieces with various chucking sizes. CONSTITUTION:A plurality of the chucking jaws 8 are insertedly fitted so as to be movable in back and forth toward the radial direction of a chuck main body 20. Each of the chucking jaws 8 is provided with a rack 11 engaging with a drive gear 22 on its rear surface. When the movement of the chucking jaws 8 is performed by driving the drive gear 22, the back-and-forth radial movement is made relatively large. The relatively samll movement of the chucking jaws 8 is performed by moving a drive shaft 9 axially. The movement of the drive shaft 9 is performed by moving the drive gear 22 radially with the taper wedge action between a drive jaw 21 and a guide jaw 26. The radial movement of the drive gear 22 causes at the same time the radial movement of the chucking jaws 8 engaging therewith. The movement of the drive shaft 9 is automatically controlled by program control. |
