| 摘要 |
A machine tool having a rotatable machine tool spindle for performing drilling and tapping operations. The spindle has limited axial movement relative to the spindle carrier. Fluid pressure means may be operated to displace the spindle in opposite directions from a predetermined position in the spindle carrier and to apply a force yieldably opposing return of the spindle to the predetermined position. The position of the spindle in its carrier is sensed by control means and the spindle carrier is translatable toward or away from the workpiece in response to the direction of displacement of the spindle from its predetermined position. The spindle is displaced forwardly to effect translation of the spindle carrier and spindle to engage a tool with a workpiece and the return of the spindle to the predetermined position upon the engagement of the tool with the workpiece is utilized to initiate control means for automatically controlling the depth of drilling or tapping as measured from the surface of the workpiece and the return of the spindle to an automatic repeat position or to a home position. The spindle is allowed to float while a tapping tool is in engagement with the workpiece and the feed and return of the spindle carrier is controlled during this period by sensing the position of the spindle in the carrier. During drilling the spindle is locked against axial movement relative to the carrier while the tool is in engagement with the workpiece. The locking means is engageable over the range of axial movement of the spindle relative to the carrier to locate the spindle in a predetermined position relative to the carrier.
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