Patent GB-674052-A (GB)
Title: Pressure welding apparatus
IPC: B23K11/00
Filed: 1948-10-01
Abstract: 674,052. Welding by pressure. BABCOCK & WILCOX CO. Oct. 1, 1948 [Oct. 4, 1947; Oct. 4, 1947; Oct. 7, 1947], Nos. 25640/48, 25641/48 and 25642/48. Class 83 (iv). [Also in Group XXXV] In a welding-machine with a pair of roller electrodes 10, 12 for traversing the work 14, 16 along parallel lines, separate transformers 22, 50 form with each electrode 10, 12 integral units mounted for independent vertical movements with an electrode constituting a terminal of each secondary circuit and means including flexible leads 312 disposed between the electrodes 10, 12 connect the secondaries of the units. A carriage structure comprises portions 32, 33 which include vertical sliding members 30, 58 respectively, to which are attached frames 28, 56 supporting electrode-transformer units in bearings 24, 26 and 52, 54. Attached to the sliding members 30, 58 are pistons 64, 66 respectively, which operate in air cylinders 60, 62 secured to the carriage 32, 33. Control means 68 serve to supply air pressure to cylinders 60, 62 and hence pressure to the electrodes 10, 12 in a sequence synchronized with electric pulses to the electrodes 10, 12. An initial electric pulse with an initial electrode pressure which does not damage the surface plate is employed followed by a cooling period of a few cycles with a final higher electrode pressure and higher current value to complete the weld. The carriages 32, 33 are mounted for traverse across the work 14, 16 in the direction of the welding line, on a bridge 34 by means of a motor 352 and gearing 354-359 engaging a rack 360 on the bridge 34. The carriages 32, 33 with the respective units are movable towards one another between guides 370-373 by manual adjustment of gearing 450,452,454,456,458,460. The bridge 345 mounted on supports mounted on rollers 40, 42, 320, 322 which engage rails 44, 46 and by means of motor 324 and gearing 326-330, 332, 334, 336 engaging racks 338, 340, the bridge 34 traverses the work at right angles to the welding path. The transformers 22, 50 (see Group XXXV) have primaries consisting of a large number of pancake coils of four turns each of square copper tubing through which a flow of coolant is maintained. From a supply pipe 74 attached to a hollow shaft 70 the coolant passes through the primary coils to an outlet formed by a passage in the shaft 70 in the centre of the transformer to fall on to the welding zone. The electric supply to the primary is by way of brushes and slip-rings. The secondary circuit of the transformers consists of a single turn which forms the casing for the primary; one secondary terminal being formed by an electrode and the other being connected by flexible leads 312 to one terminal of the adjacent transformer. The arrangement is such that the transformer primaries are connected in parallel to the same supply and the secondaries are connected in series. The Specification as open to inspection under Sect. 91 comprises also the production of clad plate by welding two superimposed corrosionresistant alloy steel plates to a higher carbon steel base-plate, there being an interposed nickel sheet between the base-plate and the first steel alloy plate, by forming parallel rows of overlapping welds. This subject-matter does not appear in the Specification as accepted.