Patent GB-1366338-A (GB)
Title: Apparatus for automatically welding pipe joints in steel pipe piles
IPC: B23K9/028
Filed: 1971-12-29
Abstract: 1366338 Welding by fusion SUMITOMO METAL INDUSTRIES Ltd and SUMIKIN PIPING & CONSTRUCTION CO Ltd 29 Dec 1971 [29 Dec 1970 27 May 1971 1 June 1971 29 July 1971] 60566/71 Heading B3R In a process of providing foundation piles wherein, due to desired pile length exceeding pile driver length capacity, sections of steel pipe are serially welded together one on top of another as pile driving proceeds, circumferential welds between the pipe sections 20, 20<SP>1</SP> are effected automatically by a consumable electrode arc welding machine 1 adapted to travel on a track 2 which comprises two or more sections, is adapted to surround the upper pipe section 20, and is axially locatable on said pipe section with respect to the joint, prior to welding being effected, by magnetically held positioners 18 having projections enageable with the joint weld preparation groove and faces engageable by the lower edge of the track. In Fig. 3, the welding machine 1 comprises a frame 6 supporting a wire storage reel (7), a control board 8, and, via height adjustment means (12), a wire feed device 13 in turn supporting, via adjustment means 15, a wire contact tube 14. At its upper end the frame 6 has driving and free V-grooved support rollers 10, 11 engageable with a rail 3 integral with or secured to the body of the track 2. The roller 10 is driven by a motor 9. At its lower end, the frame has support rollers 6 engageable with the lower periphery of the track body. The track 2 comprises two halves hinged at (4) and secured together by toggles (5). The track may be lined with elastic means to increase adhesion between the track and the pipe section 20. In the apparatus of Figs. 4-6 (not shown) for welding of pipe sections of inclined piles, preferably the rail 3 has edge angles chosen to prevent derailment of the rollers 10, 11, and the frame 6 adjustably supports rollers (21) engageable with the underside of the rail 3. The driving roller 10 may have friction linings and may have fast therewith a pinion (26) meshing with a rack (27) fast with the rail 3. For steep inclinations the roller/rail arrangement at the upper end may also be provided at the lower end of the track. For steel pipe sections over 800 mm. outside diameter, the track preferably comprises more than two sections. In the four section track of Fig. 7, section location is by tenons and mortices 38, 34. The sections are held together between 2 4 , 2 1 ; 2 1 , 2 2  and 2 2  2 3  by plain toggles 36 and between 2 3 , 2 4  by an adjustable spring toggle (Fig. 9, not shown) the latter accommodating pipe size variation. The section 2 3 , 2 4  are bridged by an auxiliary rail 51 and an auxiliary contact surface (52) for the roller 16. Track support magnets 50 extend through the track sections to their inner surfaces. To form a multi-layer bead, the welding machine may carry two or more electrodes disposed along the seam (Fig. 10, not shown). A weak current is fed to the first electrode, a stronger current to the second electrode, and if a third electrode is provided this is fed with current equal to or greater than that fed to the second electrode. The distance between the first and second electrodes (e.g. 50-100 mm.) is chosen so that when the second bead layer is laid, the first bead layer back surface and front surface are respectively solidified and still unsolidified. The welding machine may be run two or three laps of the pipe sections, current being increased each lap.