Traveling welding apparatus

Claim 1

Apparatus for performing a welding operation to join together the contiguous ends of two axially aligned hollow cylindrical work elements, such as large pipes and the like, in a girth weld lying substantially in a plane more or less perpendicular to the axes of said work elements, comprising, in combination: a. an endless guide track firmly secured to and surrounding one of said work elements near and parallel to the weld plane, b. a self-driven carriage mountable and demountable on said track, adapted to frictionally engage the parallel side edges of said track in driving relationship and to move around said track in a path parallel to and radially outside the weld, c. a mounting sub-frame secured to said carriage in a position generally parallel to the weld plane, said sub-frame supporting a supply of consumable electrode wire, a wire feeding means, and a separate support for a welding head, said welding head support being movably attached to said sub-frame in an orientation generally parallel with said sub-frame and weld plane and being adapted to hold said head generally in the weld plane, d. a welding head secured to said support, e. means operable between said sub-frame and said welding head support, comprising both an alignment adjusting mechanism and a selectively operable power driven cyclical reciprocating means for causing the welding head to follow a sinusoidal path which repeatedly traverses the welding plane, and f. flexible guide means for directing the wire from the wire feeding means into said welding head regardless of the position of the welding head with respect to the weld plane.