Thread cutting apparatus and method of operating same

摘要

A cutting tool is mounted on a tool slide which is movable along a workpiece to cut a thread therein or thereon. The tool is shiftable toward and away from the workpiece by a piston and cylinder arrangement having a fixed stroke length. Adjustment of the starting and therefore the ending point of the stroke is accomplished by a differentially threaded assembly which is rotated by a drive motor. Rotation of the threaded assembly produces pulses which are counted and compared with a stored count to start and stop the drive motor. Cycles of operation are also counted and compared with fixed counts, the extent of adjustment in each cycle being related to the number of cycles.