Automatic end surface positioning apparatus for use with digitally controlled machine tools

Claim 1

In a digitally controlled machine tool including a bed, a table slidably mounted on said table to support a workpiece, a table driving means to slidably move said table along said bed, and a tool carriage arranged to be moved toward and away from said workpiece, an automatic positioning apparatus for an end surface of said workpiece comprising an automatic end surface measuring device arranged to be engaged by the end surface of said workpiece to generate an output proportional to the displacement of said end surface, means to mount said automatic end surface measuring device on said bed, means to move said measuring device in a direction parallel to the sliding direction of said table, and a control circuit including a comparator circuit to compare said output from said automatic end surface measuring device with a reference voltage to provide a coincidence signal when said output and said reference voltage coincide with each other, and means responsive to said coincidence signal to simultaneously or selectively energize said driving means for said table and said moving means for said automatic end surface measuring device, said control circuit operating to move by a predetermined quantity said automatic end surface measuring device toward said end surface to be worked and to move in synchronism said table and said automatic end surface measuring device in a direction to bring said end surface to be worked to come into contact with a tool carried by said tool carriage so as to work said end surface by said tool and said circuit including means to generate a signal when the output from said automatic end surface measuring device reaches a predetermined value.