Abstract: An improved filler wire feed controller for a welding system is described in which the filler wire can be supplied to the vicinity of an arc between an electrode and a workpiece in a four-portion cycle. The cycle can include a feed portion, during which the wire is supplied to the weld pool at a rate at which it is consumed and deposited on the workpiece; a retract portion, during which the wire is rapidly withdrawn from the workpiece; a pause portion, during which the wire is stationary with respect to the arc; and an advance portion, during which the wire is advanced rapidly into the arc. This four-portion cycle provides increased flexibility of control of supply of wire to the weld pool, which can be employed to avoid balling of the end of the wire. The wire feed supply may be synchronized to variations in the current of the arc and also to movement of the wire guide/electrode asembly with respect to the workpiece.

Abstract: A system and method for detecting the position of the welding torch with respect to the workpiece by varying the electrical power to the arc, measuring the effect of such variation on the arc current and/or arc voltage and processing the detected effect to produce welding torch position related information. Also, a welding system and method which comprises utilizing this detection system and method to control the position of the welding torch means with respect to the workpiece.

Abstract: The adapter is arranged to be mounted to the horseshoe travelling carriage for a weld head in a pipe welding system to support the torch or weld head at an acute angle to the plane of rotation of the travelling carriage and thus to a plane normal to a pipe axis. This positioning of the weld head or torch facilitates socket welding; that is, welding about the intersection point of larger and small diameter pipes. The adapter comprises a mounting plate and a movable plate supported at an angle to the mounting plate by appropriate guide rods. Left and right racks adjacent to the guide rods and secured to the movable plate are driven by a single pinion bridging the racks and mounted between fixtures secured to the mounting plate. The movable plate is constrained from movement in a plane parallel to itself by the guide rods. A motor operates the pinion so that the weld head can be moved closer to and further from the socket area to be welded as appears necessary to effect a high quality weld.

Abstract: A pipe clamping structure is arranged to clamp an in-place pipe to be welded. A welding mechanism in turn is coupled to the pipe clamping structure for rigid guided movement in directions parallel to itself towards and away from the clamping structure in an axial direction along the pipe. The welding mechanism in turn supports a horseshoe-shaped weld head support rotor which receives the pipe in the horseshoe opening and is arranged to rotate about the pipe axis. A torch head is carried on the horseshoe rotor so that a 360.degree. weld can be achieved and simultaneously, the welding mechanism can be oscillated back and forth by the rigid guidance and alignment coupling with the clamp structure. In addition, the torch head is held on a link plate to the rotor, the link plate being swingable to vary the arc gap and thus provide appropriate voltage control.

Abstract: A compact welding wire feed device is provided capable of being mounted directly on a welding head carriage. The device comprises a ball bearing having an inside race with tangential entrance and exit guides to the race adjacent to opposite axial ends of the bearing. A hub member has an outside diameter less than the inside diameter of the race so that the hub member can be coaxially received in the race and a welding wire passed through the entrance guide and wrapped around the hub and out the exit guide. By now side-loading or expanding the hub against the inside of the race and driving the hub rotationally, the welding wire is continuously fed out the exit guide. The coaxial relationship of the hub and race provides for a very compact structure thereby permitting mounting of the wire feed directly on a welding head carriage adjacent to a weld head or even permitting the feed wire itself to be used as an electrode in a MIG welding system.

Abstract: Power delivered to the welding arc from a constant current rapid response power supply is controllable to maximize arc stability particularly in out-of-position welding operations. A first control modulates the output current from the power supply between a high value close to the maximum output value and a minimum value just sufficient to maintain the welding arc. The modulation is effected at a given frequency appropriately adjusted in accordance with the electrode material and diameter to maintain optimum spray metal transfer in the welding arc. A further control is effected by pulse width modulating the output from the power supply in accord with a set-in current programmed signal which is compared with a current feedback signal or, alternatively, a set in voltage programmed signal which is compared with a voltage feedback signal. This latter control provides for operation of the power supply in a constant current control mode or alternatively, a constant voltage control mode.

Abstract: An electric arc welding system includes programming circuits for controlling the position of a welding torch on a carriage wherein the carriage is caused to move along in the direction of a weld path on a member to be welded. The programming circuits cause the torch to move back and forth across the weld path as the carriage moves parallel to the weld path, the excursion time of the torch and dwell time of the torch on either side of the path at the limits of its excursion constituting the selected position program. The torch thus follows a repetitive generally truncated sawtooth pattern. The welding current to the torch is connected into the programming circuits to be responsive to a selected program so that the level of current provided during the dwell times is different from the level of current provided during the excursion times.