Synchronous weld timer using semiconductor controlled rectifiers

Claim 1

A CIRCUIT FOR CONTROLLING SUPPLY OF ENERGY TO A LOAD COMPRISING: A SOURCE OF ALTERNATING POTENTIAL; A PAIR OF SEMICONDUCTOR, CONTROLLED RECTIFIERS CONNECTED IN PARALLEL TO SAID SOURCE; A BIASING SOURCE ASSOCIATED WITH EACH OF SAID RECTIFIERS AND CONNECTED TO THE GATE THEREOF FOR APPLYING A POSITIVE POTENTIAL THERETO WHEN THE ANODE THEREOF IS POSITIVE; A CAPACITOR CONNECTED AT ONE SIDE THEREOF IN CIRCUIT WITH ONE OF SAID RECTIFIERS AND CONNECTED AT THE OTHER SIDE TO THE GATE OF THE OTHER RECTIFIER WHEREBY SAID CAPACITOR IS CHARGED WHEN SAID RECTIFIERS ARE CONDUCTIVE; MEANS FOR PLACING THE GATE OF SAID ONE RECITFIER AT THE POTENTIAL OF THE CATHODE THEREOF WHEREUPON SAID ONE RECTIFIER BECOMES NONCONDUCTIVE AT THE BEGINNING OF THE NEXT HALF-CYCLE OF SAID SOURCE, THE CHARGE ON SAID CAPACITOR THEREUPON RENDERING THE OTHER RECTIFIER NONCONDUCTIVE; AND MEANS FOR DRAINING THE CHARGE ON SAID CAPACITOR AT A CONTROLLED RATE SO THAT SAID OTHER RECTIFIER BECOMES CONDUCTIVE A PREDETERMINED TIME AFTER IT IS RENDERED NONCONDUCTIVE.