System for controlling length of welding arc

Claim 1

IN A WELDING SYSTEM OF THE TYPE IN WHICH A COMSUMABLE WELDING ELECTRODE IS FED THROUGH A WELDING TORCH, AND WHEREIN CURRENT IS APPLIED TO THE ELECTRODE TO PRODUCE AN ARC BETWEEN THE END THEREOF AND A WORK PIECE, THE COMBINATION INCLUDING, FEEDING MEANS FOR POSITIONING THE ELECTRODE, DRIVING MOTOR MEANS FOR OPERATING SAID FEEDING MEANS, CONTROL MEANS FOR CAUSING OPERATION OF SAID DRIVING MEANS IN ACCORDANCE WITH AN ERROR VOLTAGE APPLIED THERETO, MEANS PROVIDING A FIRST REFERENCE VOLTAGE, MEANS RESPONSIVE TO THE ARC VOLTAGE BETWEEN THE WELDING ELECTRODE AND THE WORK PIECE FOR PRODUCING A FIRST ERROR VOLTAGE REPRESENTING THE DIFFERENCE OF SAID ARC VOLTAGE FROM SAID FIRST REFERENCE VOLTAGE, MEANS PROVIDING A SECOND REFERENCE VOLTAGE, MEANS RESPONSIVE TO THE POSITION OF THE END OF THE WELDING ELECTRODE FOR PRODUCING A POSITION VOLTAGE WHICH VARIES WITH SUCH POSITION, MEANS PRODUCING A SECOND ERROR VOLTAGE REPRESENTING THE DIFFERENCE OF SAID POSITIONS VOLTAGE FROM SAID SECOND REFERENCE VOLTAGE, AND SWITCH MEANS FOR INITIALLY APPLYING SAID FIRST ERROR VOLTAGE TO SAID CONTROL MEANS, SAID SWITCH MEANS INCLUDING TIME DELAY MEANS CAUSING OPERATION OF SAID SWITHCH MEANS TO APPLY SAID SECOND ERROR VOLTAGE TO SAID CONTROL MEANS AFTER A PREDETERMINED TIME.