Patent GB-1501817-A (GB)
Title: Flash welding apparatus
IPC: B23K11/04
Filed: 1976-04-27
Abstract: 1501817 Making metal strip; shearing; welding by pressure ISHIKAWAJIMA-HARIMA JUKOGYO KK and NIPPON KOKAN KK 27 April 1976 [14 Nov 1975] 17055/76 Headings B3A B3R and B3W Apparatus for flash-welding together the ends of two strips S1, S2 comprises strip clamping means 17, 18 mounted on a frame 5 movable forwardly and backwardly of the strip path, and strip clamping means 38, 39 mounted on a frame 24 immovable in the direction of the strip path; welding electrode means 11, 12 and 32, 33 mounted on frames 3 and 26, respectively, both frames being movable forwardly and backwardly of the strip path and releasably engageable with frames 5 and 24, respectively; and a shear unit 65 and a flash trimmer 66 mounted on a carriage 63 on one side of the strip path and movable both in the direction of the strip path and transversely thereto. Fig. 1 shows the machine in elevation, Fig. 2 a section along the line II-II of Fig. 1, Fig. 3 in plan, and Fig. 28A-N the sequence of operations. On carriage 63 are a shear unit 65 with crop discharge device 80, undersurface scribing device (82), Figs. 19-21 (not shown), electrode cleaning device 83, flash trimmer unit 66, and edge preparation device 81. The initial position is shown in Fig. 28A with strip S1 passing through the machine. As the trailing edge of strip S1 passes through the machine, electrode cleaning device 83 is lowered, cleans the electrodes and is retracted while shear unit 65 is moved into the strip path and lowered, Fig. 28B. Strip S1 is stopped and reversed so that its edge engages the stopper in the shear unit, and strip S2 is advanced against the stopper, Fig. 28C, guides 20, 41 align the strips S1 S2, and upper strip clamps 18, 39 and upper electrodes 12, 33 are all lowered to clamp the ends of the strips, Fig. 28D. Then the edges of strips S1, S2 are cut by shear unit 65, Fig. 28E, and the cropper removes the loose ends down shoot 181 into bin 182, Fig. 2. Then shear unit 65 is removed from the strip path, and edge preparation device 81 machines the facing ends of strips S1 and S2 and scribing device (82) scribes their undersurfaces to make projections (180), Fig. 21, for good electrode contact, and upper electrodes 12, 33 raised, Fig. 28F. Then electrode mounting frames 3, 26 are moved towards each other and coupled to clamp mounting frames 5, 24, Fig. 28G. The edge of strip S2 is brought against the edge of strip S1 and upper electrodes 12, 33 are lowered again to again clamp against the ends of strips S1, S2, Fig. 28H. Then current is caused to flow through the electrodes from transformer 43, Fig. 1, the leading edge of strip S2 is brought into light contact with the trailing edge of strip S1 to create the flash action and when the leading and trailing edges are molten, the leading edge is forced against the trailing edge to make the weld between them, Fig. 28I. Then upper electrodes 12, 33 are raised, Fig. 28J, and their frames 3, 26 released from frames 5, 24. Frame 3 is moved reversely to engage electrodes 11, 12 with strip clamps 17, 18, frame 26 is moved forwardly to engage electrodes 32, 33 with strip clamps 38, 39, Fig. 28K, and electrodes 12, 33 again lowered to clamp strips S1, S2 and flash trimmer unit 66 aligned with the weld and moved transversely into the strip path to remove the flash, Fig. 28L. Electrodes 12, 33 and clamps 18, 39 are raised, Fig. 28M, and unit 66 retracted from the strip path, Fig. 28N, the strip line is then reactivated and strip S2 moves on again.