Patent GB-1299866-A (GB)
Title: Method of making welded electrical contacts to electrical conductors and contacts made by the method
Inventor: NULTY JAMES THOMAS
IPC: H01R43/02
Filed: 1969-02-26
Abstract: 1299866 Welding by fusion; making terminals BRITISH INSULATED CALLENDER'S CABLES Ltd 18 March 1970 [26 Feb 1969] 10186/69 Headings B3A and B3R [Also in Division H2] A composite electrical conductor 2 comprising a plurality of longitudinally extending, high conductivity metal or alloy, elements is provided with a connection terminal (as in Figs. 1, 2) or is connected to a further, solid or composite, conductor (as in Fig. 4) by MIG welding deposition, the conductor 2 being so shaped that every element of the conductor forms part of the wall of a transverse cavity and the MIG torch wire-feed outlet being so moved relatively to the conductor that the arc moves both rotationally and axially with respect to the cavity to deposit metal on the cavity wall and, preferably, fill the cavity. The latter may be of uniform or variable, circular or non- circular, e.g. polygonal. cross-section. The invention is particularly applicable to laminated conductors comprising thin strips of copper or, particularly, aluminium, in which latter case aluminium is used as the deposited metal. In Figs. 1, 2, one end of a cavity 1 at right angles to the conductor laminµ is closed by a metal plate 3 clamped to the conductor, and during welding a recess in the plate is filled to form a downwardly projecting boss 5. A similar, upwardly projecting, boss may be formed by a tubular mold 6. The deposition 8 is subsequently drilled through at (7) and machine bossfaced at (9) for bolting thereto of another conductor or terminal lug. Inert gas, preferably that used with the MIG torch, e.g. argon, may be injected, initially, through a central aperture in the plate 3. In Fig. 4, a cavity 11 is formed between the ends of two conductors 2, 10, the cavity axis being transverse or, as shown parallel to the laminae. In the latter case, narrow gaps 12 constitute parts of the cavity between the conductors and are provided so that metal is deposited over the ends of all of the laminµ. Gap closure plates 13 may be recessed as at 14 to form overlapping ribs (15). Again, one end of the cavity is closed by a metal plate which may have a gas inlet aperture. The conductor(s) and/or closure plates may be pre-heated and, possibly, water cooled. A number of conductors may be stacked with their cavities aligned and the welding begun at a point intermediate the axial length of the cavity of one conductor and continued to an intermediate point of the cavity of a further conductor, the filling of said cavities may then be completed by re-stacking with further conductors and starting again on a cavity partly filled. Subsequently the deposition may be severed between adjacent conductors, removable (divided) or expendable annular spacers preferably being inserted between said conductors to allow cutting tool (e.g. saw blade) access. The MIG torch wire-feed outlet or the workpiece may be rotated and moved axially. The means providing the rotation and axial movement are preferably coupled for the relation of the rotation and axial movement speeds to be predetermined by a programme. The latter may be co-ordinated with a programme controlling welding parameters such as wire feed speed and welding current. The wire-feed outlet may be inclined to and rotated about the torch axis, or may be straight in which case the torch is moved helically. In Fig. 6 (not shown), the work piece is rotated and the torch is raised slowly by a handle electrically or mechanically connected to a workpiece table drive motor. In Fig. 7, a body 23 is secured to the gas nozzle 24 of a conventional MIG torch. A rotor 25 ball-bearing journalled in the body 23 carries an inclined-end wire-feed outlet 26 and is rotated via a pulley 27. The body 23 supports a gas housing 30 fed at 31 and a gas nozzle 32 or 33. Welding current remains connected to the conventional torch contact tube 34 but, to avoid internal arcing, is also connected to the body 23 by leads 35. The wire itself does not rotate.