GB1367259A - Electric arc welding apparatus - Google Patents

Abstract

1367259 Welding by fusion MARKETING ENG ET DEVELOPPEMENT INDUSTRIEL SA 29 March 1972 [31 March 1971] 14606/72 Heading B3R In an electric arc welding apparatus, a guide member 2, 3 includes an end part 4 which in use is held against the workpiece 20 and has a support 1 slidably mounted therein for movement towards the end part. An electrode carrier 7 is slidably mounted on the support and carries electrode 6 which is guided in insulating means 5, 8, 12 and a switch 17 is secured to the carrier, as shown by means of insulated bar 10, and is movable therewith between switch-actuating first and second stop members 14, 13 carried by the support. Means such as spring 22 urges the carrier 7, relative to the support towards the end part 4 and locking means locks the support relative to guide member 2 against movement towards the end part, said locking means as shown including stop 13 pivoted to support 1 and a screw 15 biased towards the end part by spring 16, the stop 13 having an aperture 21 whose sides frictionally engage a rod 2 of the guide member when the stop is inclined as shown. A circuit (Fig. 2, not shown) supplies welding current to the electrode and includes a time delay device, the circuit being connected to switch 17. In operation, the guide member and electrode carrier are held immobilized by abutment of the end part 4 and electrode 6 against the workpiece and the support is moved by hand or by a machine towards the workpiece until switch 17 abuts against the first stop 14 which switches on the welding current and also moves screw 15 upwardly so that the previously perpendicular stop 13, which allowed relative movement of the rod 2 of the guide member, is inclined as illustrated and prevents further movement of the support due to friction. Electrode 6 is consumed and carrier 7 and bar 10 moves downwardly under the action of spring 22, until switch 17 contacts stop 13, when the welding current after a predetermined time delay is switched off. The welding period may be adjustable by altering the spacing between stops 13, 14, stop 14 being threaded on screw 15. The time delay device may also be adjusted by selecting different values of resistor. A manual switch 18, Fig. 1, may be provided for switching on and off the current at will.