| 摘要 |
1317500 Welding by fusion COMMISSARIAT A L'ENERGIE ATOMIQUE 18 June 1971 [18 June 1970] 28623/71 Heading B3R In an arc welding machine or station, wherein an electrode 16 is held fixed above a movable workpiece, replacement electrodes are held in vertical cells 24 of a magazine drum 23 which is rotatable step-by-step to bring each cell in turn into line with an opening 25 in a drum support plate 22, said opening being aligned with an electrode holder 14. As shown, in the circumferential TIG welding of a plug 11 to a nuclear fuel rod tube 10, an electrode 16 is clamped by a spring pressed jaw 18 in a vertically movable holder 14. The drum is rotatable step-by-step by a pulse-actuated motor 32 via a crank 30 and a pawl-and-ratchet 29, 28. The electrode changing operational sequence, which may be automatically programmed, comprises (i) removing the workpiece, (ii) lowering the holder 14 by the desired working distance of the electrode tip to the workpiece, (iii) retracting the jaw 18 to allow the electrode to drop out, (iv) replacing the or the next workpiece, (v) advancing the drum 23 one step to allow a replacement electrode to drop from the drum, through the opening 25, into the holder 14 and into contact with the workpiece, (vi) releasing the jaw 18 to clamp the replacement electrode, and (vii) raising the holder back to its original position. The electrode holder may be lowered during welding to adjust for electrode wear. For reloading the drum when the latter is disposed inside a shielding gas (helium or argon) chamber, there is provided, as shown, a loader 34 which, in use, is passed through a sealing lock of the chamber and secured to the top of the drum. The loader includes a disc 36 which is provided with suitable electrode passage holes 37 and is rotatable, electrically or hydraulically between loader open and closed position. One drum provided with a plurality of concentric rings of cells 24 may serve a plurality of welding stations. |
