GB1080431A - Improvements in or relating to methods of forming metal tubing and/or apparatus therefor - Google Patents

Abstract

1,080,431. Making tubes; bending; welding. UPRIGHT SCAFFOLD Ltd. Feb. 5, 1965 [Feb. 6, 1964], No. 5079/65. Headings B3A, B3E and B3R. In an apparatus for making lap welded tubes from metal strip in a continuous operation the metal strip is progressively formed into a slotted tube by a series of rollers (1, 2, 3, 4, 8, 9, not shown), the edges are overlapped by final closing rollers 10 with the edges positioned by guide means and the overlapped portions are resistance welded using internal and external electrodes 65, 68. The inner edge of the tube is positioned by a guide 28 which passes between the two edges and has a shoulder against which the inner edge abuts and the outer edge is positioned by a grooved block mounted on a crossbar carried by arms 37. The internal electrode consists of a roller 65 carried by a tube 53 mounted on a plate 45 which is connected to the transformer 81, and is supplied with water for cooling by the tube 53 and a conduit 61. The external electrode consists of a wheel 68 which is pressed against the tube by a compression spring 79, is connected to the transformer 81 by a cable 83 and is supplied with water for cooling by a conduit 85. After welding the tube passes through rollers 86 to straighten the tube and the tube is then cut into lengths, e.g. by a travelling saw (not shown). The rollers (8), 9, 10 are mounted in bridle members 16 which are pivoted to frames 13, the pass of the rollers being adjusted by a screw on arms 21. The rollers (1, 2, 3, 4) and 86 are driven from an electric motor by a chain drive (not shown).