Patent GB-357852-A (GB)
Title: Improvements in electric welding machines
IPC: B23K11/31
Filed: 1930-11-19
Abstract: 357,852. Welding. SCIAKY, D., 155, Avenue de Wagram, Paris. Nov. 19, 1930, No. 34834. Convention date, Nov. 22, 1929 [Class 83 (iv).] In an electric welding machine, the movable electrode 1 is actuated by two levers hinged to. gether at 5, one, 4, of which brings the electrode into contact with the work, the other 6 being thereafter automatically locked to the first so that the two levers move as one to apply the welding pressure at a greatly increased leverage. There may also be a single manual control which simultaneously adjusts the welding pressure, the current strength, and the time of current flow. By providing roller-fitted electrodes the machine may be used for continuous welding. The lever 4 is pivoted at one end to the movable electrode 1 and at its other end there is pivoted a toothed part 11 having a projection 13 pulled by a spring 12 against the lever 4 so that initially its teeth 11a are clear of the end 6b of the lever 6. The lever 6 is pivoted at its other end 6a to a slide 7 held down by the tension of a spring 8, adjustable at 9, and the lever is held against a fixed stop 18 by a spring 17. The toothed part 11 is connected with a parallel moving operating pedal 2 which first moves the electrode into contact with the work through the lever 4 pivoting about the point 5 whilst the lever 6 remains stationary. The increased resistance encountered thereafter causes the weakest spring 12 to yield and the teeth 11a to contact with the end of the lever 6. The two levers are then locked together and pivot about the slide 7 which lifts against the spring 8 by an amount which determines the welding pressure. This pressure is independent of wear of the electrodes &c., being dependent only on the stroke of the end 6b of the lever 6 which may be limited by an adjustable stop 16 or by the adjustment above referred to. The pedal and electrode are returned by springs 19, 20. The operating pedal 2 may, instead of moving in a slide, be carried by a pair of hinged parallel levers. When the machine is to be operated from a sitting position the parallel moving pedal is replaced by a pair of pedals arranged in the manner of cycle cranks on the adjustable bracket which carries the seat. The single adjustment comprises a lever 47, Fig. 6, carrying an insulated copper cursor 50 and pivoted at 48 to a fixed insulating plate 49 carrying contact studs A<1> .. D<1> taken to primary tappings of the transformer. The lever is pivoted at 45 to a laterally movable plate 42 having a slot 43 engaging a fixed pin 44. The plate has graduated steps A .. D and A<1> .. D<1>, which need not necessarily be in ascending order of magnitude. The former steps control the stroke of the end 6b of the lever 6 and so the welding pressure. The latter steps control the height h of the head 52 of an automatic switch 51 described in Specification 220,628, [Class 38 (ii), Electric currents, Converting &c.], which determines the time of flow of the current and which may be arranged in the machine frame above the transformer. The stepped plate may be replaced by a cam or set of cams, a cylinder provided with grooves or projections, or a cylinder or disc carrying stops for the part 11, contact studs, and a cursor actuating the automatic switch which may be of the maximum current relay type. The various positions of the lever may each be inscribed with the kinds of welding which may be carried out, or these may be grouped in a table.