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.