GB773269A - Circle welding machine - Google Patents

Abstract

773,269. Welding by fusion. UNION CARBIDE & CARBON CORPORATION. July 14, 1955 [Aug. 24, 1954], No. 20432/55. Class 83 (4). In a welding-machine for making circular welds, the torch is secured in a holder universally pivoted to the frame of the machine and driving means impart a circular motion to the upper end portion of the torch. The torch uses a gas-shielded non-consumable electrode. When welding tubes B into holes in a header plate W of a heat-exchanger the frame 10 is secured by pegs P in the tubes B. The torch T is clamped to a block C universally pivoted to the frame 10 and adjustable laterally by rotation of a disc 17. The upper end 32 of the torch passes through an offset aperture in a sleeve E eccentrically disposed in a gear 28 journalled in the frame 10. Rotation of the sleeve E relative to the gear 28 varies the radius of the weld. Manual depression of a knob 64 compresses a spring S and lowers a rack. Actuation of a lever 47 first causes the welding current to be switched on and then releases a pawl so that the rack is driven upwards by the spring S and through gearing rotates the gear 28 and causes the electrode to move in a circular path. The speed of the rack is controlled by a piston 56 secured to the rack and moving in a cylinder H forming part of the frame. Fluid above the piston passes through an aperture in the piston at a rate determined by the setting of a valve V. Fluid flows freely in the other direction when the knob 64 is depressed through passages 57 controlled by a check-valve. The frame 10 is provided with a handle D through which pass the cables and conduits for the torch T.