| 摘要 |
1,213,203. Welding by fusion. KAKUMARU INDUSTRY CO. Ltd. 5 Feb., 1968 [14 June, 1967; 30 June, 1967], No. 5728/68. Heading B3R. In an underwater arc welding process welding is carried out in a compressed gas e.g. air, atmosphere the gas being passed from a supply source through a passage in an electrode holder and through a passage in a composite welding electrode to debouch at the welding tip thereof. The electrode (Fig. 8) comprises a rod 41 coated with a coating 42 and surrounded by a sheath 45 of an insulating tape e.g. a vinyl tape, which melts but does not burn at the temperature of the arc, the sheath being spaced from the rod by a helical aluminium wire or strip spacer 44 such that an annular gas conduit is defined between the rod and sheath. Plugs 46, 48 of strip aluminium and provided with apertures 47, 49 close the ends of the sheath and an uncoated portion of rod projects from the end of the sheath opposite the welding tip end. The uncoated portion and -the plug 46 enter into the electrode holder (Fig. 9, not shown). The plug 46 fits in a bore in an insulating retaining member (61) detachably secured to the rear portion of a conductive member (52). Mounted in the hollow rear portion of the conductive member (52) is a further conductive member (56) which receives the uncoated portion of the electrode rod and also has a gas passage (57) whereby gas entering the holder through a coupler (60) is passed to the welding rod. The conductive member (52) is a screw fit in a further part (51) to which a welding cable (53) is secured. The holder may be surrounded by phenol resin insulation. In a modification (Figs. 10, 11, not shown), the conductive member (52) comprises two parts pivoted together. For automatic underwater welding the electrode holder is mounted on a support (Fig. 3) which maintains an arc of constant length between the work and the tip of the electrode by varying the angle between the work and electrode as the latter is consumed. The electrode and holder are secured at 11 to a plate 9 pivoted at 10 such that (as shown in solid lines) the electrode is biased away from the work due to pressure of a spring urged roller 16 tending to pivot the plate 9 clockwise. To bring the electrode adjacent the work a lever 19 secured to a shaft 17 to which an arm 18 carrying roller 16 is also secured is manually pulled in a clockwise direction. The roller urges a cam plate 15 slideable in a cylinder 12 to the right against spring pressure until the roller slips round a corner of the cam plate when the cam plate then jumps to the left. The roller then urges the cam plate in an anticlockwise direction (as shown in dotted lines) and the electrode is urged against the work. The support is magnetically held on the work by magnets 21, 21<SP>1</SP> when seam welding or, when fillet welding, by magnet 28 the magnets 21, 21<SP>1</SP> being removed. |
