GB395348A - Improvements in or relating to electric arc welding - Google Patents

Abstract

395,348. Uniting by fusion. ARNOLD, C., 11, Southampton Buildings, London.- (Lincoln Electric Co. ; 12818, Coit Road, Cleveland, Ohio, U.S.A.) Oct. 9, 1931, No. 28071. [Class 83 (iv).] In an electric-arc welding-apparatus an inflexible rod electrode, preferably of non- fusible material such as carbon, is continuously rotated about its longitudinal axis so as to prevent unevenness at the tip. The electrode 1 is secured in a holder 4, which is keyed to a sleeve 33, rotated by worm gear 31, 32 and spur gear 28, 27, 24, 23, Fig. 8, from an electricmotor 21. The sleeve carries a stub shaft 38 further supported by a bracket 39, the stub shaft carrying a bevel pinion 40 and a spur pinion 41, which meshes with a pinion 42, Fig. 6, on a shaft provided with a further pinion 44 engaging a rack 45 on the holder. The pinion 40 meshes with a pair of bevel wheels 36, 37 loosely mounted on the sleeve, either of which may be automatically held by adjustable brakes 47, 48, Fig. 5, so as to cause rotation of the pinion 40 and thus feed the electrode axially in one or other direction. The brake shoes are mounted on pairs of arms 49, 50 respectively carrying armatures and electromagnets 52, which are energized by a relay operative when the arc voltage varies to either side of a predetermined value. The arc length is thus maintained constant. A rod 51 is provided to eject the electrode from the holder. The current is led away from the electrode by a contact 8 through which the electrode passes, this contact being in engagement with a helical water-cooled tube 9, connected to a current lead 15. The tube is embedded in refractory material 10 between a shell 7 and a magnetic core 6 connected to but insulated from the casing 19 so as to stabilize the arc. The shaft 29 of the worm 31 is connected by a clutch to a shaft 57, Fig. 7, which through worm gear 58 and spur gear 60, 61 rotates a grooved roll 63 co-operating with an idle roll 68 mounted on a spring- pressed link for feeding a strip of combustible material such as paper or other carbonaceous material to the arc to produce a protective blanket over the pool of molten metal. The electrode is a slack fit in its holder so as to compensate for inaccuracies of the axial alignment thereof. For this purpose the holder may be provided with radial slots 75, Fig. 9, to contain certain balls 76, which are forced into semi-spherical recesses in the electrode by a sliding collar 77. In another form, Fig. 10, the lower end of the holder is formed with a. diametral slot and is cut away on one side and the other portion 78 is provided with a lug pivoted in the slot, the two parts being held closed by a collar 81 which presses chordal pins 81<1> or balls into recesses in the electrode. In a further form, Fig. 12, the holder may be slit at 86 into three parts and provided with slots to receive balls 87 which press into longitudinal grooves in the electrode. The apparatus may be mounted on a shaft 89 provided with a bracket which is oscillatable with the shaft by a screw 90 engaging in a block secured to a bracket 94 fixed to a frame. Vibration of the apparatus due to looseness of the screw adjustment is avoided by a spring 93.