Abstract: A quick release mig gun tip comprises a contact tip having an exterior frusto-conical surface and external threads, and a gas diffuser having an internal frusto-conical surface and internal threads. The threads are preferably stub acme threads. The contact tip is assembled to the gas diffuser by engaging their threads until the frusto-conical surfaces mate. Large currents can be conducted through the frusto-conical surfaces and the threads without causing excessive resistance heating. The contact tip threads are designed so that assembly and release of the contact tip requires only one turn relative to the gas diffuser.

Abstract: A quick release mig gun tip comprises a contact tip having an exterior frusto-conical surface and external threads, and a gas diffuser having an internal frusto-conical surface and internal threads. The threads are preferably stub acme threads. The contact tip is assembled to the gas diffuser by engaging their threads until the frusto-conical surfaces mate. Large currents can be conducted through the frusto-conical surfaces and the threads without causing excessive resistance heating. The contact tip threads are designed so that assembly and release of the contact tip requires only one turn relative to the gas diffuser.

Abstract: A battery box for an engine driven welding machine slides in an opening in the welding machine base between closed and open positions. When the battery box is in the closed position, a battery secured to a battery box is concealed inside the base. When the battery box is in the open position, the battery is exposed for servicing. Panels assembled to the base define an opening in the base. The panels cooperate with the base floor to form slots in which the battery box slides. The panels and base floor provide a cantilever support for the battery box when it is in the open position. A finger hole in the battery box is surrounded on one side by a small housing that keeps foreign material out of the machine base when the battery box is in the closed position.

Abstract: A weld current switch includes a channel-shaped core, a shunt, and a magnetic reed switch. The magnetic reed switch and shunt are placed across the core poles. An electrical conductor carrying high current passes through the core. Upon deenergization of the electrical current, a residual magnetism remains in the core. The residual magnetism is normally high enough to prevent the magnetic reed switch from opening. However, the shunt directs sufficient magnetic flux from the switch such that the switch senses a much lower level of magnetic flux than if the shunt were not present. As a result, the switch opens, even with the high residual flux in the core. The increased reliability of the switch upon decreasing current at electrical conductor deenergization enables the weld current switch to use a higher sensitivity switch than was formerly possible.

Abstract: A welding gun having a switch comprising two spaced apart coaxial conducting springs which act as switch contacts for completing a circuit to initiate a welding process. A coaxial flexible wall in the handle of the welding gun surrounds the two springs such that, when a welding machine operator depresses the flexible wall, the two springs make electrical contact to complete the circuit. When the flexible wall is released, the springs return to their original positions, thereby interrupting the electrical circuit.

Abstract: An electric welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply (SMPS) as control element, the switching mode power supply preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed to a microprocessor via an entry keyboard, and in the microprocessor they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modulator of the switching mode power supply.

Abstract: An electronic welding apparatus which, for controlling at least one welding parameter, such as welding voltage or welding current, comprises a switching mode power supply as a control element and preferably being regulated on the primary. The actual values of voltage and current are taken from the output of the switching mode power supply and fed to an analog control circuit. The set values of voltage and current are fed via an entry keyboard to a microprocessor where they are stored in a memory and passed on in analogous form to the analog control circuit which carries out a comparison of set value and actual value and, in dependence thereon, produces an error signal that is fed to a pulse width modultor which is connected to the driver stages of the power supply's switching stages which are designed as a boost regulator or a buck regulator, and thus a pulse width modulation of the current pulses of the switching stages is effected in dependence on the difference between actual and nominal values.

Abstract: A fail-safe voltage reducing circuit for an arc welder. The welding transformer has two primary windings connected in parallel across a power source. After an arc is struck, if the arc is then broken for a predetermined time period, the circuit automatically disconnects one of the primary windings from the power source, thereby reducing the voltage across the welder's output terminals to a safe standby voltage lower than the full open circuit voltage. If the voltage has not been reduced after a second predetermined time period, the fail-safe feature of the circuit automatically disconnects both primary windings from the power source, thereby completely removing all power from the welder.

Abstract: An alternating current constant potential power source suitable for use in a submerged arc welding process. An inductor (Z1) of large value is placed in the D.C. output of thyristor bridge (SCR1 to SCR4) fed from a transformer (T1). The four thyristors (SCR1 to SCR4) and the inductor (Z1) are controlled in such a manner as to provide essentially square wave currents. The square wave is adjustable in amplitude with very rapid zero crossing. The thyristor bridge (SCR1 to SCR4) is controlled in a firing sequence so as to prevent free wheeling of the square wave inductor (Z1) at polarity reversals of the voltage supply. The inductor (Z1) is capable of storing vast amounts of energy, and the thyristor firings are timed to deliver this energy into the arc. Two regulating sub-systems respectively responsive to arc voltage and arc current operate together to control the output.

Abstract: The position of the main rheostat on an arc welding machine determines the pre-set welding current. An operator, working at a location remote from the welding machine, carries a pen-type adjustable rheostat which carries calibrations indicative of various percentages of the pre-set welding current. There are no extra electrical connections, such as wires, between the remote rheostat and the welding machine. If the operator wishes to change the magnitude of the welding current, he need not return to the main rheostat at the welding machine, but instead merely sets the remote rheostat for the percentage of pre-set current desired, and inserts the remote rheostat between the electrode holder and the workpiece. The minimum resistance of the remote rheostat is sufficiently high to prevent an arc from being struck. A current transformer in the welding machine senses the output (calibrating) current flowing through the welding cable.

Abstract: A constant potential single phase A.C. power welding source is connected to a thyristor network and an energy storing inductor to create a square wave welding current that is adjustable in height, and is further adjustable to allow either half-cycle to be wider than the other, the sum of two adjacent half-cycles always equaling 360.degree.. The welding current is forced to reverse rapidly by a substantial voltage to insure conduction when the welding load is an arc to an aluminum work piece, and the aluminum tends to rectify. The heights of the positive and negative half-cycles are simultaneously adjustable in response to manual control and feedback signals.