Threading head for a numerically controlled multiple spindlehead indexing machine tool

摘要

A threading head for use on a numerically controlled multiple spindlehead machine tool includes a frame 12 having a hollow bore spindle 16 journaled therein so that the spindle extends therebeyond. The spindle is helically advanced out from and is retracted into the frame by the combination of a ball nut and a ball screw disposed between the spindle and the frame. The helical movement of the spindle is precisely controlled by a first servo-controlled motor 35 which rotatably drives the ball screw in response to numerical control commands. A cross block cutting tool 60 is slidably mounted on the face of the spindle distal from the frame and is displaced radially across the spindle face by a screw 44 journaled in the spindle perpendicular to the axis of the spindle so as to threadedly engage the cross block cutting tool, the screw being driven by a second servo controlled driver motor 54. Thus, by controlling the excitation of each of the two servo controlled drive motors, the length of the threads chased, the speed at which such threads are chased and the depth of threads cut can be controlled accordingly. IMAGE