Automatic centering controller for a machine tool

In a combination of a machine tool having a tool spindle rotatably carried therein, and a plurality of servomotors for effecting movement of said tool spindle relative to an article mounted on said machine tool along orthogonal first and second axes, the improvement comprising:

• drive control means connected to said servomotors for selectively controlling operations of said servomotors in accordance with feed pulses and axis designation signals applied thereto;
• and
• an automatic centering controller comprising,
• touch sensing means capable of being received in said tool spindle, with a probe thereof being in concentric relation with the axis of said tool spindle and capable of outputting a touch signal each time said probe in said tool spindle is brought into contact with a reference circumferential surface provided on said article,
• a pulse generator connected to said drive control means for applying thereto said feed pulses so as to drive said servomotors,
• first pulse control means connected to said pulse generator and said drive control means and responsive to said touch signal for applying said axis designation signals to said drive control means and controlling said feed pulses applied to said drive control means so as to effect the relative movement of said tool spindle along each of said first and second axes from one to the other of two points at both of which said probe in said tool spindle touches said reference circumferential surface,
• second pulse control means connected to said pulse generator and said drive control means for applying said axis designation signals to said drive control means and controlling said feed pulses applied to said drive control means so as to effect said relative movement of said tool spindle from said other toward said one of said two points along each of said first and second axes, and
• pulse counting means connected to said first and second pulse control means for counting said feed pulses applied from said first and second pulse control means to said drive control means so as to cause said second pulse control means to stop applying said feed pulses to said drive control means when receiving from said second pulse control means said feed pulses of a number of corresponding to half of said feed pulses applied from said first pulse control means.