Welding gun

Claim 1

A portable welding gun for use in making internal orbital welds at the junction of a tube and tube sheet comprising a portable body provided with a handle having separate means for the transfer of electrical energy and inert gas to the body, said body having an axial bore, a rotary motion transmission means fitted in the bore, a conductive rotor assembly fitted in the bore and coupled to the transmission means, the rotor assembly being formed with an axial passageway, rotary fluid coupling means supported by said body and flow connecting the gas transfer means with said axial passageway, rotary electric coupling means supported by said body and electrically connecting the electrical transfer means with said rotor assembly, an electrode holder secured to the rotor assembly, means for stabilizing the rotation of said holder, an electrically conductive tube extending through the holder, said tube having one end thereof communicating with the axial passageway and the other end formed with a plurality of circumferentially spaced radially projecting discharge portions, an electrode carrying end-piece detachably connected to said other end, and including a conduit penetrating the distal end face thereof and extending through a portion of the end-piece in a direction parallel to the axis of rotation thereof and eccentric thereto, said conduit being adapted to supportingly engage an end portion of the electrode wherein said electrode is adjustable relative to said axis of rotation to position the electrode tip at a given radius from the axis for welding along an orbital path of corresponding radius, and means for positively positioning said electrode holder with respect to the intended welding path.