Arc welding system and process

Claim 2

A pulsed arc automatic Welding system comprising welding torch means, weld power supply means for supplying unidirectional output welding current to the electrode of the welding torch means to establish and sustain a welding arc between the electrode and a workpiece, and weld current control means comprising means for supplying a variable current signal and pulse generating means for supplying selectively spaced current pulses, together with the variable current signal, to the weld power supply means to thereby drive the weld power supply means to supply a variable output welding current having selectively spaced higher unidirectional current levels to the welding arc, wherein the pulse generating means comprises means for generating pulses of electrical current which rise in accordance with the formula A(1-e (t+ to)/RC), and fall in accordance with the formula B+De t/RC whereby the shape of the output current has the same form.

Claim 3

A pulsed arc automatic welding system comprising welding torch means, weld power supply means for supplying unidirectional output welding current to the electrode of the welding torch means to establish and sustain a welding arc between the electrode and a workpiece, weld current control means comprising means for supplying a variable current signal and pulse generating means for supplying selectively spaced current pulses, together with the variable current signal, to the weld power supply means to thereby drive the weld power supply means to supply a variable output welding current having selectively spaced higher unidirectional current levels to the welding arc, and feedback means coupled between the output of the weld power supply means and the weld current control means, whereby a portion of said output welding current is subtracted from the combination of the variable current signal and the spaced current pulses supplied to the weld power supply means to insure that the shape of the output welding current corresponds to the combination of the input variable current signal and the spaced current pulses.

Claim 4

A pulsed arc automatic welding system comprising welding torch means, weld power supply means for supplying unidirectional output welding current to the electrode of the welding torch means to establish and sustain a welding arc between the electrode and a workpiece, weld current control means comprising means for supplying a variable current signal and pulse generating means for supplying selectively spaced current pulses, together with the variable current signal, to the weld power supply means to thereby drive the weld power supply means to supply a variable output welding current having selectively spaced higher unidirectional current levels to the welding arc, and feedback means coupled between the output of the weld power supply means and the weld current control means, whereby a portion of said output welding current is subtracted from the combination of the variable current signal and the spaced current pulses supplied to the weld power supply means to insure that the shape of the output welding current corresponds to the combination of the input variable current signal and the spaced current pulses.

Claim 5

A pulsed arc automatic welding system comprising welding torch means, weld power supply means for supplying unidirectional output welding current to the electrode of the welding torch means to establish and sustain a welding arc between the electrode and a workpiece, weld current control means comprising means for supplying a variable current signal and pulse generating means for supplying selectively spaced current pulses, together with the variable current signal, to the weld power supply means to thereby drive the weld power supply means to supply a variable output welding current having selectively spaced higher unidirectional current levels to the welding arc, valve means adapted to supply inert gas and water to the welding torch means, valve actuating means for actuating the valve means, first motor means for driving the welding torch means around the workpiece, travel control circuit means for energizing the first motor means and controlling the speed at which the motor means drives the welding torch means around the workpiece, second motor means for supplying filler wire to the welding arc, wire feed motor control circuit means for energizing the second motor means and controlling the rate at which the filler wire is supplied to the welding arc, timing control circuit means, the timing control circuit means comprising means for actuating the weld power supply means, means for actuating the travel control circuit means and the wire feed motor control circuit means, means for controlling the magnitude and frequency of the selectively spaced current pulses supplied by the weld current control means, feedback means coupled between the output of the weld power supply means and the weld current control means, and means for controlling the magnitude of the variable current signal, wherein the timing control circuit means comprises first timer circuit means responsive to the output current produCed by the weld power supply means for actuating the travel control circuit means and the wire feed motor control means, means, second timer circuit means for controlling the magnitude and frequency of the selectively spaced current pulses supplied from the weld current control means to the weld power supply means and third timer circuit means for gradually decreasing the magnitude of the current supplied to the weld power supply means from the weld current control means a predetermined time after the actuation of the travel control circuit means and the wire feed motor control means.

Claim 6

A pulsed arc automatic welding system comprising welding torch means, weld power supply means for supplying unidirectional output welding current to the electrode of the welding torch means to establish and sustain a welding arc between the electrode and a workpiece, weld current control means comprising means for supplying a variable current signal and pulse generating means for supplying selectively spaced current pulses, together with the variable current signal, to the weld power supply means to thereby drive the weld power supply means to supply a variable output welding current having selectively spaced higher unidirectional current levels to the welding arc, valve means adapted to supply inert gas and water to the welding torch means, valve actuating means for actuating the valve means, first motor means for driving the welding torch means around the workpiece, travel control circuit means for energizing the first motor means and controlling the speed at which the motor means drives the welding torch means around the workpiece, second motor means for supplying filler wire to the welding arc, wire feed motor control circuit means for energizing the second motor means and controlling the rate at which the filler wire is supplied to the welding arc, timing control circuit means, the timing control circuit means comprising means for actuating the weld power supply means, means for actuating the travel control circuit means and the wire feed motor control circuit means, means for controlling the magnitude and frequency of the selectively spaced current pulses supplied by the weld current control means, feedback means coupled between the output of the weld power supply means and the weld current control means, and means for controlling the magnitude of the variable current signal, wherein the timing control circuit means comprises first timer circuit means responsive to the output current produCed by the weld power supply means for actuating the travel control circuit means and the wire feed motor control means, means, second timer circuit means for controlling the magnitude and frequency of the selectively spaced current pulses supplied from the weld current control means to the weld power supply means and third timer circuit means for gradually decreasing the magnitude of the current supplied to the weld power supply means from the weld current control means a predetermined time after the actuation of the travel control circuit means and the wire feed motor control means.

Claim 7

A system according to claim 3 wherein the weld power supply means comprises a magnetic amplifier weld power supply having a control winding for controlling the magnitude of the variable output welding current.

Claim 8

A system according to claim 4 wherein the weld current control means comprises a current amplifier coupled to the control winding of the magnetic amplifier weld power supply, a common collector amplifier including variable output impedance means coupled to the current amplifier for supplying variable voltage signals to the current amplifier, a pulse generator responsive to the second timer circuit means and further coupled to the current amplifier for supplying selectively spaced voltage pulses to the current amplifier and a slope amplifier responsive to the third timer circuit means and further coupled to the current amplifier for supplying a sloping voltage signal to the current amplifier, the sloping voltage signal having a polarity opposite to the polarity of the signals supplied to the current amplifier by the common collector amplifier and the pulse generator.