| 摘要 |
The chuck is for use with turning machines, and includes a chuck body and radially displaceable jaws each movable by a key bar which is guided in the chuck body tangential to the axis of turning, with each key bar having a splined strip meshing with teeth on the associated jaw and being displaceable to an extent such that, for removing the associated jaw, the splined strip attains a position in which it is disengaged from the teeth of the associated jaw. The actuating mechanism comprises a control member, in the form of a cylindrical sleeve, concentrically guided in the chuck body and axially displaceable in the latter through a key bar operating range and into end positions beyond the operating range. The control member may be formed with wedge surfaces extending obliquely to the direction of displacement of the key bars and each key bar is formed with a corresponding mating surface. Thereby, responsive to axial displacement of the control member in the chuck body, the key bars are displaced to displace the chuck jaws radially of the chuck body. Alternatively, the control member rotatably carries antifriction bearings engageable with both the wedge surfaces of the control member and surfaces of a slot in the chuck body. In a third embodiment of the invention, gears are rotatably mounted in respective recesses of the chuck body and each gear has teeth meshing with teeth on the control member and teeth meshing with teeth on the associated key bar. The control member is displaceable by a fluid pressure operated linear actuator mounted on the machine spindle and controlled by a solenoid valve. The piston of the actuator carries a cam engageable with a limit switch at the end of the operating stroke of the control member, and the limit switch may be bypassed by a manually operable switch to move the control member into one of its end positions. Alternatively, the linear actuator may be incorporated directly in the chuck body. |
