GB1428120A - Orbital welding apparatus - Google Patents

Abstract

1428120 Welding by fusion CLARKE CHAPMAN Ltd 22 Nov 1973 [25 Nov 1972] 54590/72 Addition to 1143001 Heading B3R An orbital welder capable of introduction transversely of workpieces, such as bars or tubes, to be welded end-to-end comprises a gapped device 10 adapted to be clamped on to the workpiece and rotatably supporting two gapped drive members 44, 38, the member 44 being connected to a MIG or, as shown, a TIG head 18 and a wire feed device 76, 82, and the member 38 being drivingly connected to said feed device, the arrangement being such that a rotational speed difference between the members 44, 38 results in wire feed. The drive members 38, 44 are respectively driven by variable-speed electric, hydraulic or, as shown, air motors 24, 26 driving via wormdrive-including gearing (not shown) and gears 30, 31 in train with pairs of gap-bridging gears (32, 34, Fig. 5, not shown) meshing teeth 36, 42 on said members. The drive train for the wire drive member 38 includes a clutch (not shown) operable by a handle 28. The motors 24, 26 are controlled by an on-off valve 120, forward/ reverse valves 122, 124, and speed-varying flow regulators 126, 128. The head 18 shown comprises a PTFE block 70 on which is mounted a torch 72, a filler wire spool (not shown) and co-operating wire feed drive and grooved rollers 76, 82. The drive roller 76 is connected via bevel gearing to a gear (54) in train with gap-bridging gears 50 journalled in the member 44 and meshing teeth 39 in the member 38. The torch 72 is transversely cam displaceable as described in Specification 1,428,119. Welding current and inert shielding gas are fed to the head 18 via a cable 64 and a current slip-ring (not shown) and gas-sealing device 16. The latter (Figs. 9, 10, not shown) provides for supply of inert shielding gas to the head via gap-bridging kidney ports and a rotary change-over valve, cam-and-gear-operated in dependence on head rotational position, and provides for supply of inert purging gas to prevent air entry at the gap. As shown, the clamp device 10 comprises three self-centring scroll jaws 60, as described in Specification 1,428,118 and air-operable through a valve controlled by a lever 62. In alternative embodiments (Figs. 6, 7 and Fig. 8, not shown) the clamp device comprises a fixed V-shaped jaw and a co-operating jaw fast with a tangentially disposed rod which is longitudinally movable, to effect clamping, by hand-operated screw-and-nut or by an air cylinder, and is rotatable about 90 degrees, to clear adjacent tubing on introduction and removal of the welder, by hand-operated lever or by rotary or, via rack-and-pinion, reciprocating air cylinder. The clamp 10 may be floor-mounted in which case the members 38, 44 and head 18 are mounted on the device 10 so as to be displaceable transversely thereof.