Patent GB-1479531-A (GB)
Title: Welding apparatus
IPC: B23K9/038
Filed: 1975-03-25
Abstract: 1479531 Welding; planning H A SCHLATTER AG 25 March 1975 [15 Oct 1974] 12399/75 Headings B3R and B3L Apparatus for welding rail sections 15, 30 together in end to end relationship to form a continuous rail comprises a pair of vertical clamping assemblies for respectively clamping and aligning the respective ones of a pair of rail sections, the assemblies instructing electrodes 63 engageable with adjacent ends of the sections, means to cause current flow between the electrodes and the ends of the section in order to make a weld, a pair of horizontal clamping assemblies for clamping and aligning the respective ends of the sections, the vertical clamping assemblies having a pair of upper levers arms 60, and a pair of lower lever arms 61, the arms being spaced on opposite sides of a rail section and affixed for rotation in a vertical plane at one end thereof and having one of the electrodes connected between the opposite ends thereof, and means for pivotally rotating the respective pairs of lever arms to engage the electrodes with the rail sections to vertically clamp the sections between them. The apparatus consists of a main frame 10 supported by wheels 11 on rails 14 and positioned with respect to a continuous rail section 15 by actuation of a hydraulic cylinder 16 between the frame and a brace 17 on the rail 14. Vertical and horizontal clamping and aligning elements for the continuous rail are secured to the frame 10 and similar elements for the rail section 15, together with a shearing apparatus, are mounted in a carriage 20 suspended for longitudinal movement in the frame by a pair of guide shafts 21, movement being effected by hydraulic cylinders 25, 26. Each end of the apparatus has assemblies 44, 45 for clamping the webs of the rails with high force, each assembly consisting of arms 46, 47 which have clamping pads 48 and are movable about pivots 56, 57 by actuation of hydraulic cylinders 52; the arms are coupled together by levers 49, 50 and links 51. Pairs of upper and lower guide rollers 32, 33 and 34, 35 are disposed at opposite ends of the apparatus. The upper rollers are mounted on brackets 36 pivotably adjustable by threaded assemblies 37, and the lower rollers are mounted on brackets 38 pivotable by hydraulic cylinders 39 to press the rails against the upper rollers. The vertical clamping assembly and electrodes for the continuous rail 15 are mounted on the frame 10 and those for the rail section 30 are mounted on the carriage 20. The assembly for the rail 15 consists of two upper lever arms 60 and two lower lever arms 61, the arms being of flexible spring steel, the arms of each pair being arranged one on each side of the rail. The pairs of arms are mounted at one end on brackets 62 and at the other end are secured to the electrodes 63. Further pairs of arms 64, 65 above and below the lever arms 60, 61 are mounted at one end on brackets 72 and at the other end are coupled together by links 66. Hydraulic cylinders 70, 70A, the cylinders 70A being of smaller diameter than the cylinders 70, extend between the respective arms 64, 65 and the lever arms 66, 61 and the arms 64 of the two assemblies are connected to the respective frame or carriage by cylinders 68. Flash shields 71 and a flash guard 71A are secured to the arms 60, 61 and the frame, respectively. Vertical clamping is effected by first operating the cylinders 70 to move the arms 60 to a set position, the cylinders 39 are operated to raise the rollers 33, 35 to engage the rails with the rollers 32, 34, and the cylinders 70A are then activated to raise the arms 61 and engage the electrodes 63 with the rail. Vertical alignment is effected by operation of the cylinder 68. The ends of the rails 15, 30 are horizontal clamped at the head and base of the rails by assemblies carried by the frame and carriage. Each assembly has upper and lower pairs of lever arms 74, 75, Fig. 4, which are provided with jaws 86 and are movable about pivots 76 by hydraulic cylinders 77, 78 connected to levers 81, in turn, movable about pivots 82 by hydraulic cylinders 83 connected to the frame or carriage. Cylinders 78 are larger than cylinders 77 and are actuated first to set the position of the rail horizontally. Independent operation of the upper or lower cylinders 83 of each assembly permits correction of any twist that may be present in the rails. Shearing of the upset metal after welding is effected by apparatus 90 having guide wheels 91 riding on rails 92, 93 fixed to the carriage 20. The apparatus is movable along the rails 92, 93 by operation of hydraulic cylinders 94 and has upper and lower arms 97, 98 movable about pivots by hydraulic cylinders 100, 101 to engage brass shoes 86 with the rail 30, and horizontally arranged arms 106, 107 movable about pivots by hydraulic cylinders 109, 110 to engage brass shoes 87 with the sides of the vents. Each arm carries a cutter 99, 108, the cutters being shaped to the profile of the rail to remove the upset material when the shearing apparatus is advanced. The shearing apparatus extends between the arms 74, 75 of the horizontal clamping in the carriage 20 and only the vertical clamping is removed by retraction of the electrodes 63. The ends of the rails may be automatically set to the correct position for welding by actuation of the hydraulic cylinders under the control of two sets of sensors (117, 118, 119, Figs. 5 and 6, not shown) which are movable on a lever (115) to an operative position to detect the vertical position of the head of each rail 15, 30 and the horizontal positions of the head and base of each rail. The electrical apparatus consists of two groups of transformers 120 and rectifiers connected by conductor bars 122 to the electrodes 63. During heating, the rail section 30 is moved back and forth to flash the ends of the rails and when heated, the rail section 30 is pressed by operation of the cylinders 25, 26 against the continuous rail section 15. The rectifiers and transformers may be delivered by rectifier group 810, Fig. 8, and the transformers may have separate cores and two secondary windings to permit six phase rectifying of the welding current and the primaries be connected by thyristors in a delta connection. The movement of the carriage 20 is controlled in a function of the welding current as measured by a shunt 817 receiving a signal from a converter 818 which provides a D.C. output to a comparator 819 which compares the signal with a preset signal from an input generator 821, the difference passing to an amplifier 820 and control valve 816 for the cylinders 25, 26. Alternatively, the control signal may be varied by pulses from a signal generator 822.