Improvements in and relating to the art of electric arc welding

摘要

409,955. Uniting by fusion. HUME, W. R., and HUME STEEL, Ltd., Kinnear House, King Street, Melbourne, Australia. Aug. 8, 1933, No. 22161. [Class 83 (iv).] In electric arc welding, the electrode is fed by a number of reciprocal driving elements capable of limited forward movement and adapted for alternate operation to feed the electrode when they move forwards, and being disconnected from the electrode in their reverse movement. Electrode wire 6 is fed from a coil by rolls 36, Fig. 3, through a guide 4, Fig. 5, connected at 18 to one terminal of the circuit, the guide having a metal liner 8 surrounded by an insulating liner 9 and also at the nozzle end a pair of terminals 13 to which are secured by flexible tapes a series of radially movable contact pins 11 engaging spring rings 12. Threads 24 are carried on spools 22 in a carrier 3 having guide eyes 26, the carrier being rotated round the electrode. The threads are coated with a fluxing paste or liquid prior to winding on the spools. The coated electrode passes through spring arms 28 on the carrier so as to compress the coating, thus preventing overlapping and obtaining a uniform coating, the coating being baked by evaporation of the moisture due to the heat in the region of the arc. Unravelling is thus prevented and the electrode kept cool. The feed roll shaft 37 is connected by gearing 38 to the shaft of a pulley 32 which drives the carrier through an endless band 31 of rubber, the resilience of which prevents the frictional resistance and inertia of the carrier from affecting the start of the electrode feed. The resilient effect may alternatively be produced by springs in the drive. The feed rolls are continuously driven through change speed gear 42 from a lay shaft 41 rotated alternately by each of a pair of co-operating hydraulic rams 46, 47 moving simultaneously in opposite directions, the rams being raised hydraulically and moved downward to effect the feed by weights 51 through flexible lines, chains or bands 52. Part of the lines is in the form of sprocket chain 56 engaging sprockets 57 connected by free wheels with the shaft 41 so that when either of the rams is moving upwardly it does not affect the downward feed of the electrode. Water is supplied to and exhausted from the ram cylinders through inlet valves 46b, 47b and outlet valves 46c, 47c, automatically operated by the rams, the exhaust passing through a main valve automatically operated by an electromagnet controlled by current fluctuations in the welding circuit as described in Specification 399,846. The inlet valves are operated by tappets 68, 68a, Figs. 10 and 11, on the rams engaging rollers 69a-72a on two pairs of wrist plates 69-72, the plates of each pair being connected together by rods 74. The valves are connected by links 81 to rotatable discs 79, the discs and the plates 69, 71 having projecting pins 82 to engage and operate weighted arms 78. When the ram 47 commences its downward stroke the tappet 68a engages the roller 69a and so rotates the wrist plate 69, which through pin 82 raises the arm 78 over its dead centre position. The arm thus falls over and engages a pin 82 on the disc 79 so as to rotate it and close the valve 47b. At the same time the plate 70 is rotated to bring the roller 70a into alignment with the tappet 68 of the ram 46 so that when the ram 46 reaches its uppermost position it turns back the plates 70, 69 and so re-opens the valve 47b. The valve 46b is similarly actuated. The tappets 68a are spring mounted so as to be rendered inoperative in the upward stroke. The exhaust valves are operated by the tappets 68 through rollers 86a, 87a, Figs. 13 and 14, on a pair of diagonally arranged wrist plates 86, 87, which are connected by rods 95 to discs on a shaft 94. The plate 86 has pins 91 co-operating with a weighted arm 88 and pins on a rotatable disc 89, which is connected by a link 93 with the operating links 92 of both valves 46c and 47c so as to open one and close the other. The arc is surrounded by a hood 101 from which fumes may be withdrawn by a fan 104 through an exhaust 103. The hood has a window 107 and can be moved about a pivot 106 by a handle 109. A pivoted nozzle 97 is used to spray water either on the coated part of the electrode to keep it cool or on the spools so as to keep the threads moistened. Specifications 245,911 and 316,360, [both in Class 83 (iv)], also are referred to.