Patent GB-536064-A (GB)
Title: Improvements in and relating to welding machines
IPC: B23K11/04
Filed: 1939-10-30
Abstract: 536064. Welding rails pipes, rods &c. BRITISH THOMSON-HOUSTON CO., Ltd. Oct. 30, 1939, No. 28990. Convention date, Oct. 29, 1938. [Class 83 (iv)] Welded joints.-In an apparatus for butt welding pipes, rods or irregular sections, particularly for resistance flash welding rail joints in situ, having a number of pairs of adjustable contact carrying clamping jaws supported on a frame and moved longitudinally with respect to each other, the apparatus is positioned so that the ends of the articles extend beyond the contacts a predetermined distance and means are provided for tilting one of the articles relatively to the other so that irregular contraction after cooling due to the variable thickness of the sections will result in a straight joint. The apparatus for welding rails 21, 21a may consist of two pairs 'of clamps 15, 16 carrying guides 38, 39 adjustable on the flange 37 of an I-beam 10 supported in a frame 9 provided with a bail' 13 by which it may be transported by a crane. The stationary clamp 15 consists of a fixed jaw 18 and a movable jaw 17. To the fixed jaw its secured a block 18a carrying an insulated guide 40 engaging the lower flange 41 of the beam 10 and also a removable contact 56a connected' thereto by tongue and groove preferably of dovetail form. The movable jaw 17 carries a removable contact 36 and is moved into operative position by an hydraulically operated piston 22 against the action of a spring 53. The jaws ,are surrounded by a wedging ring 47 which engages a slot 55 in the beam, is secured to the jaw 18 and has part of its periphery 52 formed convex to engage a counterweighted wedge 50 so that the jaw may pivot about the part 52 during adjustment. The jaw 17 is released by an hydraulically operated piston 25, the rod 26 of which is provided with a nut 44 secured to a bracket 45 on the block 18a. The longitudinally movable clamp 16 is similarly constructed and operated, but the block 20a carrying its contact 36a has an extension 42 provided with screws 63 on which are mounted blocks 62 engaging slots 61 in a lever 27 pivoted at 59 and rocked by an hydraulic piston 28 in cylinder 29. The cylinder is pivotally mounted on a support 64 carried by the flange 37. All the cylinders are controlled by motors 34a, 35a and pumps 34, 35 through hand-operated valves. In order to tilt the rail 21a rounded blocks 75, Fig. 4, serving as fulcrums for the contact block 20a and wedges 74 are provided on the flange 41. The wedges 74 co-operate with wedges 77 on shims 76 which are welded to a plate 78 and are adjusted by a screw 79 loosely mounted in the plate 78. In another form the contacts 36a, Fig. 11, are provided with inclined ribs 36b engaging grooves 36c in the contact blocks so as to set the rail 21 at an inclination. Splattering of metal on the flange 41 is prevented by a removable guard 105 having a handled cover 106. Burr is removed, after welding, from the top and bottom surfaces of the joint by V-notched removable cutters 83, 84 secured to the contact blocks 19a, 20a, and connected together by bolts 85 and wedges 86, the cutters being pushed forward by the piston 28 after the clamp 16 has been released from the rail 21a after welding. The apparatus is centred over the joint prior to welding, by a stop 109 welded to the flange 41. An insulating block 110 is placed between the stop 109 and the end of block 18a, and a second stop 111 on the flange 41 is separated from the clamp 15 by insulator 112. In another form a perforated bracket on the frame may engage a drift pin clamped to the rail. Specification 424,816 is referred to. The Specification as open to inspection under Sect. 91 describes another form of apparatus having two pairs of clamping arms 127, 128 pivoted on shafts 119 and operated by hydraulic pistons 120 in cylinders carried by a horizontal frame 115, supported on the vertical frame 116 which may be transported by a crane. The arms 128 may be moved along the shafts 119 and along guides 135 to give the welding pressure by an hydraulic piston 131 acting through a lever 133. The frame 115 is provided with a laterally adjustable cross bar 138 carrying clamps 140 to engage a rail on the other side of the track to prevent tipping of the apparatus. One end of the machine has a wheel 137 so that it may move along the rail. The plates 136 are provided with ears 136a so as to centre the machine laterally. In a further modification. Fig. 17 (Cancelled) the apparatus is transported along the rack on wheels 155 each set of which has an hydraulic lifting cylinder 156 so that the wheels may be elevated about pivots 157 to lower the clamps for engagement with the rails. This subject-matter does not appear in the Specification as accepted.