Patent GB-1428119-A (GB)
Title: Orbital welding apparatus
IPC: B23K9/028
Filed: 1972-11-25
Abstract: 1428119 Welding by fusion CLARK CHAPMAN Ltd 22 Nov 1973 [25 Nov 1972] 54589/72 Heading B3R [Also in Division F2] In a MIG or, as shown, TIG (with or without filler wire feed) orbital welder, means are provided for automatic radial adjustment of a rotary torch 18 on completion of the or each weld run for overlap or for effecting superimposd runs.  In Figs. 2, 3, a TIG torch 18 and filler wire feed rollers 28, 32 are mounted in a housing 36 pivotable at 59 on a rotary mounting 14. The latter also carries a filler wire spool. The housing 36 has an extension 56 which is urged against a stop 61 by a spring 58. The stop 61 is adjustably mounted in a dovetail groove 62 of a slide 64 which is one-way clutchable at 76 to an arm 80 and one-way brakable at 70, said one-way clutch and brake incorporating sprag or toothed ratchets. The arm 80 is outwardly biased by a spring (not shown) and carries a roller 82 cooperable with a fixed, radially adjustable, cam 84. In operation, when the roller 82 is pushed radially inwards by engagement with the cam 84, the slide 64 and stop 61 are given a clockwise rotational increment via the clutch 76, and detained by the brake 70, thereby allowing the spring 58 to give the housing an anti-clockwise rotational increment to outwardly move the torch and feed rollers by an amount dictated by the setting of the cam 84. After the roller 82 passes over the cam 84 it is outwardly spring- returned, but the stop 61 is detained by the brake 70. With continued rotation of the mounting 14 the torch can move through positions of maximum and minimum distances from the workpiece axis back to its starting position. In modifications, the cam 84 may be so profiled that outward torch movement, on each revolution of the mounting 14, is effected in more than one stage, at a non-uniform rate, or with a pause or pauses during each increment of movement. In Fig. 5, the above arm 80 is one-way clutchable to a gear-wheel 112 co-operable with a further gear-wheel 110 and a rack 130. The wheels 112, 110 are journalled on the above mounting 14 and are discontinuously toothed as shown. This gearing arrangement is such that continued uni-directional rotation of the wheel 112 results in oscillation of the wheel 110 and reciprocation of the rack 130. The wheel 110 is fast with an arm (104) rotatably carrying the torch 18, a chain drive 136 connecting the torch to the mounting 14 such that on swinging of the arm and the torch, the angular orientation of the latter is preserved. In this arrangement, the torch is incrementally outwardly moved on outward return of the roller following cooperation with the cam 84, the gear-wheels 112, 110 and rack 130, and hence the torch, moving a small amount at each revolution of the torch in readiness for the next run. After the weld is completed, the torch can be reset to its starting position by manual oscillation of the arm 80 such that the torch is initially moved further outwards (if such movement is still available) and then moved back inwards. Filler wire feed rollers may be provided mounted to move with the torch, or mounted directly on the mounting 14 in which case a wire guide (e.g. a flexible member of helically coiled wire) may be provided. Such guide member may terminate in a guide tube which may be mounted for movement with the torch. In modifications, the torch may be arranged to move with the wheel 112 or to be moved, arcuately or rectilinearly, by or with the rack 130. The Specification refers to Specifications 1,143,001, 1,385,588, 1,428,120 and 1,428,118.