Solid state resistance welder control system

Claim 1

A CONTROL FOR A RESISTANCE WELDER HAVING A PAIR OF IGNITRONS EACH CONDUCTIBLE FOR PASSING SELECTED PORTIONS OF ALTERNATE HALF CYCLES OF AN ALTERNATING CURRENT TO A LOAD FROM AN ALTERNATING CURRENT SUPPLY, COMPRISING; A FIRST NOR UNIT COUNTER MEANS ARRANGED TO COUNT A PREDETERMINED NUMBER OF CYCLES OF THE ALTERNATING CURRENT SUPPLY TO TIME THE DURATION OF AN OPERATION, SAID COUNTER MEANS BEING ARRANGED TO INITIATE EACH COUNT AND PROVIDE AN OUTPUT SIGNAL WHEN THE COUNTER HAS COUNTED A PREDETERMINED NUMBER OF CYCLES AT A PREDETERMINED POINT DURING A HALF CYCLE OF ONE POLARITY ON THE VOLTAGE WAVE OF THE SUPPLY, A SECOND NOR UNIT COUNTER MEANS FOR CONTROLLING THE SEQUENCE OF OPERATIONS TO BE PERFORMED BY THE WELDER, SAID SECOND COUNTER HAVING AN INPUT RESPONSIVE TO THE INPUT SIGNAL OF THE FIRST COUNTER AND ARRANGED TO PROVIDE A RESET SIGNAL TO THE FIRST COUNTER MEANS IN RESPONSE TO THE INPUT, SAID SECOND COUNTER BEING ARRANGED TO PROVIDE AN OUTPUT SIGNAL DURING A HALF CYCLE OF OPPOSSITE POLARITY AND AT A PREDETERMINED POINT DIFFERENT THAN THE HALF CYCLE AND POINT AT WHICH THE FIRST COUNTER MEANS PROVIDES AN OUTPUT SIGNAL, MEANS INCLUDING A PAIR OF NOR UNITS EACH HAVING OUTPUTS AND INPUTS CONNECTED AS A NOR MEMORY, SAID NOR MEMORY HVING AN INPUT RESPONSIVE TO THE OUTPUT SIGNAL OF THE FIRST COUNTER AND PROVIDING AN OUTPUT SIGNAL IN RESPONSE TO THE OUTPUT SIGNAL FROM THE FIRST COUNTER, AN ADDITIONAL NOR UNIT HAVING; AN OUTPUT, AN INPUT RESPONSIVE TO THE OUTPUT OF THE NOR MEMORY, AN INPUT RESPONSIVE TO THE OUTPUT SIGNAL OF THE SECOND COUNTER MEANS, AND A THIRD INPUT, MEANS CONNECTED TO THE THIRD INPUT OF THE ADDITIONAL NOR UNIT PROVIDING AN ALTERNATING SIGNAL WHICH CHANGE ONCE DURING EACH HALF CYCLE OF CURRENT FLOW OF THE SUPPLY AT AN ADJUSTABLE POINT DURING EACH HALF CYCLE, SAID ADDITIONAL NOR UNIT PROVIDING AN OUTPUT RESPONSIVE TO ALL OF THE INPUTS THERETO, AND MEANS RESPONSIVE TO THE OUTPUT OF THE ADDITIONAL NOR UNIT PROVIDING AN ALTERNATING SIGNAL FOR CONTROLLING THE CONDUCTION OF THE IGNITRONS, SAID INPUTS TO THE THIRD NOR AND THE NOR MEMORY BEING ARRANGED SO THE LAST MENTIONED MEANS PROVIDES A SIGNAL WHICH IS INITIATED AT THE PREDETERMINED POINT DURING THE HALF CYCLE WHEREIN THE SECOND COUNTER MEANS HAS AN OUTPUT AND TERMINATES DURING THE HALF CYCLE WHEREIN THE FIRST COUNTER MEANS HAS AN OUTPUT TO ASSURE DELAYED FIRING OF THE IGNITRONS IN A LEAD-TRAIL SEQUENCE.