Patent GB-596959-A (GB)
Title: Improvements relating to multi-electrode welding
IPC: B23K9/18
Filed: 1945-08-07
Abstract: 596,959. Uniting by fusion. LINDE AIR PRODUCTS CO. Aug. 7, 1945, No. 20238. Convention date, Oct. 20, 1944. [Class 83 (iv)] [Also in Group XXXV] In a welding-apparatus two electrodes are arranged in series with respect to the work and are fed by a common driving motor through a differential electrode feed mechanism, so that the rate of feed of each electrode can be controlled independently to maintain a substan. tially equal voltage between the electrodes and the work, The electrode feed and differential control mechanisms are carried on a bracket 10; Fig, 2; and comprise a common driving motor 12 which rotates the electrode feed mechanism through worm gears 20, 22, Fig. 3, and an epicyclic gear system comprising a sun gear 28 rotating planet pinions 30 which are also engaged in the teeth of an internal ring gear 32. The planet pinions are fixed to a plate 36 by studs 34 rigidly retained by set screws 38, so that as the motor rotates pinion 28 they revolve around it and cause plate 36 to rotate. The mechanism is contained in a housing 52 which serves as a bearing for the shafts carrying plate 36 and has a mounting for a bevel gear 42 and its shaft 46. The shaft 46 is driven by a reversible motor 48, Fig. 2, in response to variations in the welding voltages of the arcs and the bevel gear 42 imparts motion to further bevel gears 40, which are secured to the ring gears 32, rotating them and transmitting opposite directional motion in the respective sets of the planet gears to effect a slowing down of the electrode feed on one side and a speeding up on the other whilst motor 48 is rotating. The motor is controlled by a differential relay DR, Fig. 1, connected by conductors 114 and 116 to the work and electrodes respectively and a voltage control unit B connected to the relay by conductors 118 is connected by conductors 120 to motor 12 so that the latter may be controlled to vary the electrode feed in response to fluctuation in welding voltage, and so maintain such voltage substantially uniform. The normal welding current is drawn from a transformer 112 through leads 110 connecting the electrodes in series with the work which comprises a web V for welding to a plate W. Each electrode is surrounded during welding by a blanket of fusible granulated welding material. The shafts 44 are rotated by plate 36 and have worms 64 loosely keyed thereon so that the electrode and feed mechanism can be moved along the supporting arms 56 said movement being limited by slots 58. The arms 56 comprise channel members on which are disposed further short channel members 60, carrying the electrodes and feed assembly, which may be secured at any point by a set screw and wing nut 62. The worm 64 is arranged between a yoke on a back plate secured to channels 60 to move along shaft 44, and it rotates a shaft 82 to which is secured a knurled feed wheel 68 gripping the electrode 14 against a spring-pressed roller 90. The roller and other parts connected with feeding the electrode are mounted on an arcuate plate 104 which has angular movement about the axis of shaft 82 and may be secured in any position by a bolt and nut 106. The electrode is guided into contact with the feed wheel by a lug 96 and is fed by the wheel through electrode holders 100 and a tubular extension 102 to the zone L of welding operations. As it passes through the tube 102 it makes sliding contact with copper jaws which are connected to conductors 110 for supplying welding current. Either the work or the electrode welding apparatus may be movable with respect to the other as desired. Specification 433,723 is referred to.