Abstract: A memory device connected to a storage battery stores a battery identification code and other data such as present and maximum temperature and voltage, and information concerning the vehicle on which the battery is used. Information transfer between the battery memory device and a charger is done through the battery cables, eliminating the need for special connections. A high power, low energy pulse imposed on the battery leads may be detected at each end of the cables, in spite of the low impedance nature of large lead acid batteries. A method and apparatus for transmitting data on a pair of battery cables includes transmitting each data pulse as a plurality of short duration pulses whereby each short duration pulse is created by momentarily imposing a high power, low energy pulse at one end of the cables. These pulses are detected at the other end of the cables and are applied to a resettable multivibrator having a output pulse width slightly greater than the interval between said short duration pulses.

Abstract: A ground power unit capable of no-break power transfer includes a rectifier for converting power from commercial mains to direct current, a switching circuit, a power transformer, and a pattern generator for controlling the operation of the switching circuit. Voltage and current sensors monitor whether the phase of the ground power unit is leading or lagging the phase of the aircraft power bus at the tinge of power transfer. The frequency and phase of the pattern generator converter is adjusted to bring the two systems into alignment quickly, well before the power transfer operation is completed. The ground power unit limits the power transfer between the two systems to prevent the overloading of either.

Abstract: A low noise, essentially ripple free power supply for supplying power to a telecommunications system includes a gasoline, propane, natural gas or diesel fueled engine driving a rotating field power generator to produce an alternating current output which is then rectified and applied to a special filter circuit to provide an output current having less than 100 mVolts ripple and less than 22 dBrnc noise, which is acceptable to the telecommunications industry. A current sensor connected to the output of said filter circuit monitors the output current to the telecommunications system, and a regulator circuit responds to the voltage and current output of the power supply to control current to the rotating field coils to provide a regulated, substantially constant, output voltage level up to a predetermined maximum current output. A high voltage shutdown circuit shuts down the engine and opens a circuit breaker whenever the voltage output to the telecommunications system exceeds a predetermined level.

Abstract: A method and apparatus for welding a branch tube to a header tube includes a fixture having a pair of clamps for supporting the fixture on the header tube. A welding head on the fixture includes a clamp to hold the branch tube in place relative to the header tube. The welding head also includes a collet extending into contact with the header tube. The header tube, the collet and the welding head form a limited volume chamber that contains shielding gas in the vicinity of the joint between the branch tube and the header tube. The welding head includes a mechanism for rotating a tungsten welding electrode around the intersection of the branch tube and the header tube to form the welded joint.

Abstract: An orbital welding head for joining two tubes positioned end-to-end includes a welding electrode which is rotated around the tubes and a pair of clamps for holding the tubes in the correct position with respect to each other and the welding electrode. The clamps include a fixed member, a rotatable member and a hinge assembly for joining the rotatable member to the fixed member. The rotatable clamp members are moved clear of the tubes when the tubes are either inserted into or removed from the welding head. Fluid channels are formed in both the fixed and rotatable clamp members. The hinge assembly connects the rotatable clamp member with the fixed member. Fluid channels within the hinge assembly allows cooling fluid introduced into the fixed member to be carried through that member into the rotatable member, cooling both. A return fluid channel is also provided by the hinge. The hinge is provided with a passageway for transferring cooling fluid from one rotatable clamp member to another.

Abstract: A safety interlock mechanism requires a trailer tow bar to be raised and placed into the mechanism before an electrical power supply cable can be removed from the mechanism and attached to an aircraft. Similarly, the electrical cable must be disconnected from the aircraft and placed into the interlock mechanism before the tow bar can be removed and placed onto a tractor for movement of the ground power unit. The safety interlock mechanism includes a hinged plate, which, in one position, prevents the removal of the electrical cable connector when the tow bar is not in place, and when in another position, prevents the removal of the tow bar when the electrical cable connector has been removed. Locking tabs engage the electrical connector whenever the tow bar has been removed. A locking pin engages a U-bolt attached to the tow bar whenever the electrical connector has been removed.

Abstract: A method and apparatus for welding tubes to a tube sheet uses a gas tungsten arc welding (GTAW) torch assembly that is small enough to be inserted through small access holes in a box header. The welding torch is carried near the end of a rotating mandrel that is supported for rotation within a stationary tube. A centering mechanism is inserted into the tube to ensure proper radial alignment of the welding torch with respect to the tube. At the other end of the mandrel is a mechanism for rotating the mandrel and for supplying electrical power, shielding gas and cooling water to the torch and wire to the weld. Axial spacing of the welding torch is provided by a tube stop device that temporarily engages the end of the tube in combination with an axial adjustment device.

Abstract: A water cooled orbital welding apparatus permits continuous welding of pipes and tubes in a limited space by including a liquid cooled plate inside a head assembly to remove heat from the gear carrying the welding electrode around the tubes being welded. A plurality of spring loaded ball bearings maintain the rotating gear in tight contact with the cooling plate. By keeping the gear and electrode cool, thermal expansion of the internal components of the welding head is minimized. Since thermal expansion is not a major factor, noncompatible materials in terms of thermal expansion characteristics may be used in the construction of the device. A removable cassette of symmetrical design allows a cassette to be mounted on the head from either the right or from the left, thus allowing the operator to open the clamps on the cassette from either the front side or the back side of the weld head. An offset hinge on the cassette permits the cassette to be removed from the welded tubes in confined space.

Abstract: An auxiliary power supply is connected through a fast acting switch to the output of a regulated, constant current welding power supply. A current sensing circuit monitoring the output current level actuates the fast acting switch whenever the current level falls below a predetermined value to insure that a minimum output current level is maintained. The auxiliary power supply is disconnected after the current level rises to a second, higher current level.

Abstract: A manipulator for positioning a series of workpieces relative to a robot. The manipulator contains at least two separate fixture supports. The fixture supports are alternately transferred between a loading position and an operative position adjacent the robot by a transfer motor. The fixture supports are rotated by a single turning motor which is alternately placed into engagement with each fixture only when that fixture in the operative position.

Abstract: A control circuit for an electric arc welder is responsive to the operation of a torch or gun mounted control switch. A first comparator has one input connected to the gun switch and the other input to a reference voltage source. When the gun switch is closed, the output of the comparator will cause a control relay to be energized. When a welding arc is established, a reed switch closes and provides an input to a second comparator which effectively provides a latch to hold the control relay energized. After a predetermined time delay, typically in the order of 1 second, a timer circuit will provide an output to one input of a third comparator, the other input of which is connected to the gun switch. A subsequent closure of the gun switch will caused the output of the third comparator to change the level of the reference voltage, changing the outputs of the first two comparators, thereby removing the latch and deenergizing the control relay.

Abstract: In a three phase welding power supply, the three phase power is connected to a welding arc by a power control circuit having three conducting paths for straight polarity current and three conducting paths for reverse polarity current. The power control circuit comprises a three phase bridge rectifier circuit having eight bridge arms each including a silicon controlled rectifier with the bridge circuit being connected between the three phase power source and the welding arc which is in turn connected to the three phase power supply neutral. An inductor is connected across the direct current terminals of the bridge circuit so that arc current flows in one direction through the inductor regardless of the polarity of the arc current. The conducting paths are selectively activated at non-zero voltage points to conduct repetitive sequences of independent numbers of straight polarity half cycles of arc current followed by independent numbers of reverse polarity half cycles of arc current to the welding arc.

Abstract: A tungsten electrode (35) is positioned adjacent the root face (15) of a tube (10) with the tube and the electrode being connected to a source of direct current (40) such that the electrode is positive with respect to the tube. The electrode is mounted in an assembly (30), and the assembly is provided with a shielding gas from a source (48). The electrode assembly is mounted for rotation on an orbiting head (60) with the electrode axially spaced from the root face. As the electrode is rotated about the tube, the root face (15) and a portion (20) of the inner surface and a portion (25) of the outer surface are simultaneously cathodically cleaned. Preferably, the electrode (35) cleans the root face from two to four times in preparation for a subsequent welding operation.

Abstract: An automatic battery charging apparatus is provided with a regulated battery charger (15) and a control circuit (20) for monitoring the actual voltage across the battery terminals to control the operation of contactor (25). The control circuit includes means (50) for sensing the average battery voltage at regular intervals and means (55, 60) for comparing successive average battery voltage readings. Whenever the present average voltage reading differs from the previous average battery voltage reading by less than a predetermined amount, a signal (63) is applied to a circuit (65), and whenever a predetermined number of consecutive voltage readings have been detected, a logic circuit (70) causes the contactor (25) to terminate the charging operation.

Abstract: A solid state control circuit is connected to the output of an engine or motor driven alternator to provide a direct current output primarily for welding purposes. The control circuit includes gate controlled thyristors (SCRs) which are gated on at precise times within each cycle in order to provide an output having desired characteristics, such as constant current or constant voltage. Synchronizing windings associated with the alternator provide signals used to control the time of gating for the SCRs. Circuit means are included to insure that the control signals will be unaffected by any disturbances generated within the synchronizing signals due to the operation of the SCRs, and one such means includes an amplifier having a feedback circuit providing a hysteresis greater than any voltage change in the synchronizing signal caused by the operation of the SCRs.

Abstract: A water cooled welding gun (10) includes an elongated current carrying inner tube (40) having a central opening (42) through which a consumable electrode and shielding gas may pass. The inner tube is provided with cooling passageways (50). A gas shielding nozzle (35) is connected to a gun tube cover (55) and is in thermal contact with the inner tube (40) through two layers of thermally conductive but electrically insulative materials (100, 105). The first layer (100) is preferably a rigid ceramic material, such as Al.sub.2 O.sub.3, and the second layer (105) is preferably a thermally conducting but electrically insulating material, such as epoxy, which is pliable when initially applied. The second material (105) fills the gaps between the outer surface of the first material and the inside surface of the gun tube cover (55) to provide a direct thermal path for the heat transfer from the nozzle (35) through the cover tube (30) into the cooled inner tube (40) while maintaining electrical isolation therefrom.

Abstract: A square wave welding power supply system includes two constant current power sources. The first power source 10 is preferably an SCR controlled power supply having an output connected in an arc circuit 15 through an inverter circuit including SCR-1 through SCR-4 which controls the polarity and duration of the welding current applied to the arc circuit. The second power supply 20 is preferably a reactor power supply for supplying additional welding current during one polarity of the square wave. A shorting means (SCR-5) is connected across the output of the second power supply to maintain current flow therefrom during those intervals when the output of power supply 20 is not connected to the arc circuit. A gating circuit 30 controls the SCRs (SCR-1 through SCR-5) and commutation circuits (C-1 through C-5) connected across each SCR. A diode D1, or SCR, is connected in series with the second power supply output to prevent short circuiting of the arc by SCR-5.

Abstract: An electrical power supply for providing an electrical power signal of substantially constant voltage when the current level of the power signal is less than a predetermined value and for reducing the voltage of the power signal below said predetermined level when the power signal current level exceeds the predetermined value includes a ferroresonant transformer. A saturable reactor provides a current responsive impedance connected to the primary of the ferroresonant transformer for reducing the voltage supplied to the primary winding. The maximum current level in the secondary circuit of the ferroresonant transformer is adjusted by adjusting the effective impedance of the saturable reactor. A rectifier may be connected in the secondary circuit of the ferroresonant transformer to provide direct current electrical power signal.

Abstract: A square wave welder includes two regulated constant current power supplies which are alternately connected to a welding electrode. The on time and current of each power supply are independently adjustable. Switching is accomplished by means of gate controlled thyristors, and each power supply is either connected to the electrode or its output is short circuited in order to maintain the current flow at a substantially constant level to improve current regulation.

Abstract: A torch handle for use with a nozzle which includes a fume extracting orifice to remove fumes generated by welding or cutting includes a conduit within the handle for carrying the fumes to a vacuum pump and means for cooling the handle. In one embodiment, cooling is provided by mixing large quantitites of ambient air with the fumes in the vicinity of the nozzle. In another embodiment of the invention, ambient air is drawn into the handle and over the fume conduit and thereafter mixed with the fumes in the pipe leading to the vacuum pump. In a third embodiment, compressed air is directed into the handle from an internal source and passed over the fume carrying conduit within the handle. In a fourth embodiment, cooling water is passed over the surface of the fume extracting conduit within the handle.