Control system for punch presses and similar machines

Claim 1

AN ELECTRIC CONTROL SYSTEM FOR A POWER-DRIVEN MACHINE OPERATIVE TO START A CYCLE OF OPERATION UPON ENERGIZATION OF AN ELECTRORESPONSIVE DEVICE AND TO STOP THE CYCLE OF OPERATION UPON DEENERGIZATION OF THE ELECTRORESPONSIVE DEVICE, SAID SYSTEM COMPRISING: (A) A PLURALITY OF ELECTROMAGNETIC RELAYS EACH HAVING A PLURALITY OF CONTACTS INCLUDING A PAIR OF NORMALLY CLOSED CONTACTS AND A PAIR OF NORMALLY OPEN CONTACTS AND AN OPERATING WINDING AND EACH BEING OPERABLE TO PICK-UP FOR OPENING THE NORMALLY CLOSED CONTACTS AND CLOSING THE NORMALLY OPEN CONTACTS UPON ENERGIZATION OF ITS ASSOCIATED OPERATING WINDING AND TO DROP-OUT UPON DEENERGIZATION OF ITS ASSOCIATED OPERATING WINDING. (B) A SWITCH HAVING A PLURALITY OF CONTACTS AND MANUALLY MOVABLE FROM A RELEASED TO AN OPERATED POSITION, AND (C) MEANS CONNECTING SAID DEVICE AND SWITCH CONTACTS AND SAID OPERATING WINDINGS IN A SWITCHING NETWORK, (D) SAID NETWORK INCLUDNG: (1) MEANS FOR ENERGIZING SAID OPERATING WINDINGS IN A PREDETERMINED SEQUENCE, (2) A MAIN ENERGIZING CIRCUIT INCLUDING AT LEAST ONE CONTACT OF EACH RELAY AND OPERATIVE UPON MOVEMENT OF SAID SWITCH TO ITS OPERATED POSITION AND PROVIDED ALL OF SAID RELAYS HAVE PREVIOUSLY PICKED UP AS A RESULT OF SAID SEQUENTIAL ENERGIZATION OF THEIR RESPECTIVE OPERATING WINDINGS TO EFFECT ENERGIZATION OF SAID DEVICE, (3) HOLDING CIRCUIT MEANS ARRANGED TO BE COMPLETED UPON ENERGIZATION OF SAID DEVICE FOR MAINTAINING SAID DEVIVE ENERGIZED AFTER MOVEMENT OF SAID SWITCH TO ITS RELEASED POSITION, (4) MEANS FOR EFFECTING DEENERGIZATION OF SAID RELAY WINDINGS AND SAID DEVICE, AND (5) CIRCUIT MEANS INTERCONNECTING A PAIR OF NORMALLY CLOSED CONTACTS OF EACH RELAY IN SAID NETWORK IN A MANNER TO PREVENT RECOMPLETION OF SAID MAIN ENERGIZING CIRCUITS BY MOVEMENT OF SAID SWITCH TO ITS OPERATED POSTION IF ALL OF SAID RELAYS DROP OUT DURING OR IMMEDIATELY AFTER A PREVIOUS PERIOD OF ENERGIZATION OF SAID DEVICE.