Patent GB-1450160-A (GB)
Title: Apparatus for welding tubes
IPC: B23K9/028
Filed: 1973-12-19
Abstract: 1450160 Welding by fusion CLARKE CHAPMAN Ltd 15 Nov 1974 [19 Dec 1973] 58946/73 Heading B3R THE FIG In an orbital welding apparatus, two clamps holding bars, rods, wire, or, as particularly described, tubes end-to-end are relatively transversely adjustable to align the tubes. As shown in the provisional Specification drawing, a support (not shown) carries an orbital welder 12, fixed and adjustable tube clamps 14, 16 and a tube stop 18. The orbital welder 12 comprises two halves 60, 20 secured together by turn-pins 62, the lower half 20 being vertically movable, by a pneumatic cylinder 26, in a frame 10. The device 12 is of the type comprising a non-consumable electrode and is connectible to electrode and filler wire drive motors. The fixed clamp 14 comprises jaws 30, 32 respectively fixed and movable by a pneumatic cylinder 34. The adjustable clamp 16 comprises jaws 40, 42 relatively movable by a pneumatic cylinder 44 and horizontally and vertically movable together by gear mechanisms not shown. The tube stop 18 is movable by a pneumatic cylinder 50. The apparatus is intended for autogenous welding alone, or as particularly described, by autogenous root welding followed by welding with a filler wire. Operation is effected sequentially by control means including switch and timing devices. The welding process includes gas-purging and pre-heating. In operation, (i) the stop 18 is raised, (ii) a first tube is inserted in the fixed clamp 14 into engagement with the stop 18 and clamped, the stop 18 then retracting, (iii) a second tube is inserted in the adjustable clamp 16 into engagement with the first tube and clamped, (iv) the tubes are aligned by suitable horizontal and vertical movement of the clamp 16, (v) the welder lower half 20 is raised, (vi) the welder upper half 60 is secured by the twin pins 62, and (vii) welding is effected. As shown in Fig. 3, fixed and adjustable clamps comprise "V" blocks (34), (162) and plain blocks 36, 64 which are vertically movable, and, by way of cam means, simultaneously clearingly rotated through 90 degrees, by pneumatic actuators (44), 72. A body 160 of the adjustable clamp is vertically movable, in a frame 80, by a motor 90 acting through gearing, a cardan shaft 88 and a screw 82; and the frame 80 is swingable about pivots 92, to give, effectively, horizontal transverse movement to the body 160, by a motor or a handwheel actuated screw. The adjustable clamp body 160 also carries an orbital welder 120 of the gapped ring type including two motors driving a non- consumable electrode and a filler wire feed, slip-ring current and cooling water supplies, and an inert gas supply controlled by a peripheral cam. A pneumatically actuated tube stop 150 is provided with a pneumatically actuated wedge to hold the stop in raised position. In operation: (i) the welder is indexed to present an open gap, (ii) the stop 150 is raised and locked, (iii) a first tube 116 is inserted in the welder against the stop 150 and clamped in the adjustable clamp, the stop 150 then retracting, (iv) a second tube (114) is brought into engagement with the first tube and clamped in the fixed clamp, (v) the tubes are aligned by suitable vertical and transverse adjustment of the body 160, and (vi) welding is effected.