Variable feed device and control therefor

Claim 1

IN AN ELECTRIC ARC WELDING APPARATUS IN WHICH A WIRE IS FED THROUGH A TORCH, GAS IS FED THROUGH SAID TORCH TO ENVELOP, SAID WIRE, A DIRECT CURRENT VOLTAGE SOURCE WHICH DROPS UNDER HIGH CURRENT LOAD AND INCREASES UNDER LOW CURRENT LOAD PROVIDES THE POWER FOR THE ARC, AND AN ALTERNATING CURRENT VOLTAGE SOURCE PROVIDES THE POWER FOR CONTROLS, THE COMBINATION THEREWITH OF A SWITCH ON SAID TORCH; A SOLENOID VALVE FOR CONTROLLING SAID GAS; A FIRST CONDUIT MEANS RESPONSIVE TO SAID SWITCH FOR ENERGIZING SAID SOLENOID VALVE; FEED MEANS FOR FEEDING SAID WIRE, SAID FEED MEANS INCLUDING AN ELECTRIC MOTOR HAVING AN ARMATURE IN PARALLEL WITH SAID ARC AND A FIELD COIL; A RECTIFIER CONNECTED TO SAID ALTERNATING VOLTAGE SOURCE, SAID RECTIFIER BEING ARRANGED TO ENERGIZED SAID FIELD COIL; A SECOND CIRCUIT MEANS RESPONSIVE TO SAID FIRST CIRCUIT MEANS FOR SELECTIVELY ENERGIZING SAID ARMATURE, THE VOLTAGE ACROSS SAID SECOND CIRCUIT MEANS BEING DIRECTLY PROPORTIONALLY TO THE DIRECT CURRENT VOLTAGE SOURCE.