GB1375046A - - Google Patents

Abstract

1375046 Welding by fusion R NEVILLE 11 May 1972 [11 May 1971 (2)] 14316/71 and 14317/71 Heading B3R A transferred arc non-consumable or consumable electrode arc welding tool comprises an electrode holder 15 fast with the downwardly spring-pressed plunger 14 of a solenoid having a coil 11 disposed in the arc current circuit through the electrode and the workpiece, this arrangement providing for axial vibration of the electrode (e.g. for easy arc striking), contact of the workpiece by the electrode causing solenoid energization and an electrode withdrawal, said withdrawal in turn causing the arc current circuit to be broken and allowing the electrode to be spring returned into contact with the workpiece to renew the cycle. The electrode/ workpiece return speed may be adjusted by adjustment of spring loading and/or electrode holder displacement. Trigger-controlled, shortcircuiting means cuts out the solenoid for non- vibratory use. When using a non-consumable electrode, the tool may be used for heating a workpiece such as to melt soldering or brazing compounds. In Fig. 1, the ends of the coil 11 are respectively connected to a supply cable C and, through a leaf spring 20 and the plunger 14, the electrode. A casing and handle 10 are of insulating material. A downwardly acting spring 24 is pressure adjusted and plunger displacement is determined by screw knobs 21, 23 respectively. A trigger 25 in the released position shown, allows a spring blade contact 26 to short-circuit a solenoid supply cable end 11a to the plunger 14. On pulling up the trigger, the solenoid is rendered operable. The trigger may be arranged to operate in the reverse manner. In Fig. 2, the downwardly acting spring 24a is shown acting on the electrode holder 15 via a metal disc 32. The ends of the coil 11 are respectively connected to the supply cable C, via a ring 26a and the casing 26, and to the electrode holder. An insulated trigger 28 comprises a pivotable conductive bridge 29 through which is positioned a set screw 31 co-operating with a rotatable, slotted, insulating collar 30. When the latter is rotated so that its slot is not aligned with the screw, the trigger may be upwardly moved and correspondingly an end 29a of the bridge 29 may be downwardly moved to limit, in co-operation with the disc 32, electrode holder displacement, the latter being determined by the setting of the screw. When the collar is rotated to align its slot with the set screw, upward trigger movement may extend to a position in which the bridge end 29a contacts the disc 32 and the set screw 31 contacts a sleeve 27 electrically connected to the cable C to shortcircuit the solenoid. In Fig. 3 (not shown), short-circuiting is effected by raising a trigger to connect the supply cable to the plunger, via a conductive casing or, where the casing is non-conductive, a further conductive means.