GB1493155A - Welding guns - Google Patents

Abstract

1493155 Welding by fusion ZSCHOKKE WARTMANN AG 29 Aug 1975 [19 Sept 1974] 35797/75 Heading B3R [Also in Division H5] In a MIG or MAG arc plug welding gun comprising a contact tube 23 carried within a workpiece-engaging body 29, an arc struck between a consumable electrode wire issuing from the contact tube and the workpiece is rotated with respect to the body by a ring of electromagnets disposed about the arc or, as shown, by orbital movement of the contact tube so as to produce a generally cylindrical plug weld. The body carries a ceramic ring 34 which, by engaging the workpiece, serves to retain the molten pool and close a shielding gas chamber 33. An electro- or permanent magnet 31 is provided to retain the body against the workpiece. As shown, the contact tube 23 is carried by a shank 20 which is supported by a ball and socket joint 30 and orbitally translated, for arc rotation, by an eccentric 32. The shank 20 is current conducting and carries a welding current terminal 21 and an anti-friction plastics electrode wire feed liner 24. Shielding gas, e.g. argon or CO 2 , is introduced into the body 29 at 25. Cooling water or gas is directed through an inlet 26, body cavities 27 and thence through passages (not shown), the terminal 21 and a shank cavity 28. Alternatively, the shielding gas may be so directed so as to serve as the coolant. The gun carries a control switch (11, Fig. 1, not shown) and is cable connected to an apparatus providing a constant voltage welding current source, a weld timing control, an electrode wire supply reel and feed device, shielding gas supply and control, and coolant supply. In alternative embodiments, instead of orbitally translating the contact tube, the arc may be rotated by an alternating magnetic field provided by one or several electromagnets surrounding the chamber 33, and the ceramic ring may (Fig. 3, not shown) include a porous or perforated disc to retain the molten pool. Solid or cored consumable electrode wire may be used.