GB301044A - - Google Patents

Abstract

301,044. British Thomson-Houston Co., Ltd., (Assignees of Steenstrup, C.). Nov. 23, 1927, [Convention date]. Heating by electricity.- A wire fed mechanism for automatic or semi-automatic arc welding machines comprises feed rolls rotatable on axes tilted slightly in opposite directions from parallelism with the line of the wire feed and rotated about that line, one or other of the rolls being brought into engagement with the wire according to the direction feed. In an automatic arc welding machine two pairs of feed rolls 1, 2 are provided, one roll of each pair being mounted in a frame 5 and the other rolls in a frame 6 pivoted thereto at 10. The frame 5 is keyed to hollow shafts 14, 15 through which the wire passes, the shaft 14 of which is rotated by a constant speed motor 7 through a coupling 22 and worm gear 24, 25, a shield 26 preventing oil &c. from reaching the casing 20. The casing has a covered opening through which access to the rolls is obtained. The pairs of rolls are arranged with their axis inclined to the line of wire feed and crossed relatively to each other so as to feed the wire in opposite directions when the shaft 14 is rotated. Each roll is carried by a bushing 11 angularly adjustable by worm gear 13 to vary the feed. The upper end of the frame 6 has a lug 27 fitting over a crank 29 pin-connected to links 31 joined to the pins 32 of a cross head 33 which is carried by a rotatable hollow rod 34. The rod 34 is connected through a bearing 36 to a cross-head 35 connected to a frame 37 which is pivoted at 38 to the cover 18. The frame is controlled by solenoids 8, 9 responsive to a characteristic of the arc that varies with the arc length as described in Specification 232,995, so as to operate the rod 34 and thus bring the desired pair of rolls into operation. Other means may be used to bring either pairs of rolls into operation. Specification 301,043, also is referred to.