GB743806A - Improvements in or relating to arc welding - Google Patents

Abstract

743,806. Welding by fusion. PRECISION EQUIPMENT, Inc. July 9, 1953, No. 19075/53. Class 83 (4). An alternating current arc-welding devico comprises an electrode 17, Fig. 4, connected to a plunger 18 slidable in a sleeve 19 forming the core of a solenoid 23, energized by the arc current, slidably mounted in an insulated casing 10 and biased by a spring 25 abutting against a metal nose piece or a shield 12 which forms the second electrode and is adapted to be placed in contact with the workpiece to be welded, tho solenoid and the electrode 17 being moved forwardly in the casing by a handle or trigger 46 whereby the electrode 17 engages the workpiece thereby causing flow of current through the solenoid which retracts the electrode and thus establishes an arc. The plunger has an adjust-. able abutment shoulder 33 for a spring 34 which biases the electrode 17, which is preferably of carbon, towards the open end of the shield 12. The electrodes are connected in series with the solenoid and are supplied with current at 55 volts, 40-60 cycles per second, from a transformer 50. The arc consumes about 12 amperes. In operation the shield 12 is placed against the work to be welded, which may be a copper to iron connection, and the trigger 46 is pressed clockwise. Through a pin and slot connection 54, 55 the solenoid assembly and electrode 17 are moved to the right against spring 25 so that the electrode 17 touches the work. Current then flows through the solenoid which retracts the electrode causing it to strike the arc. The length of the arc is a function of the arc current. Due to the reactance of the transformer and solenoid, the arc current and voltage lag behind the transformer secondary voltage and this contributes to the stability of the arc. A shoulder 47 attached to the plunger limits the forward movement of the electrode 17. Detachable tips may be used with the shield 12 and the latter may have its open end cut away, Figs. 7, 8 (not shown), to give access to the electrode. For welding together wires 64, 68, Fig. 6, particularly for electronic components, a flexible wire 65 with an alligator clip 67 may be used to connect the shield 12 with one of the wires. The wire 64 may be insulated and the insulation will be burned off during the welding. In another embodiment, Fig. 5, the shield 60 is connected to the body 10 by a flexible tube 59 and the electrode 17 to the plunger 18 by a flexible wire 61 which is insulated from the tube. In this embodiment the solenoid assembly is moved forwardly by a pin 39 passing through a slot in the casing 10. For mass-production welding the device may be fastened to a fixed support and the movement of the solenoid may then be effected by a foot lever. Instead of moving the solenoid relative to the casing they may be fixed together and the shield 12 may be spring biased and movable relative to the casing. The pin 39 may engage a notch in the casing 10 so as to hold the electrode 17 in its advanced position. The welding operation is then initiated by moving the work into contact with the nose and the electrode. Alternatively the supply voltage may be controlled. German Specification 662,973 is referred to.