Automatic control system for machine tools
 An automatic control system for machine tools having rotary tools is disclosed in which the tool drive motor load current, which is proportional to the mechanical load on said drive motor, is maintained at a selectable desired level by controlling the duration and phase of the power supplied to an alternating current feed motor which controls the distance between the rotary tool and the workpiece. A sensed load signal which is greater than the preselected level will cause the feed motor to move the tool away from the workpiece, while a load signal less than that desired will cause the feed motor to move the tool toward the workpiece. 
B
B23Q
inventional
Daniel M. David H.
Rukavina Arnold