GB533830A - Improvements in and relating to electric welding machines - Google Patents

Abstract

533,830. Welding transformer tanks &c. BRITISH THOMSON-HOUSTON CO.; Ltd. Dec. 1, 1939, No. 31269. Convention date, Dec. 1, 1938. [Classes 83 (ii) and 83 (iv)] In a resistance line welding machine co-operating roller electrodes are mounted so as to be bodily turned in the same direction through the same angle about their point of engagement with the work. A bushing pocket 10 may thus be secured by a single continuous weld round an opening in a transformer tank 11. The electrode 12 which is rotated by a motor 67 through a belt 66, bevel gear 62, 61, shaft 18, worm gear 19, 20 and spur gear 21 ... 23 is mounted together with the gear 20, 21 ... 23 in a support 16 secured to a hollow shaft 17 connected with the shaft 18 and carried by a slide 74 which is moved vertically by a fluid pressure cylinder 83 through a tank 85. The lower electrode 13 is mounted on an axle 24 carried by a turn table 26 supported for rotation about a bearing 27 in an arm 28 vertically adjustable by a screw 87. In order to effect simultaneous angular movement of the electrodes about their point of contact with the work, the shaft 17 is connected by worm gear 33, 34 through extensible couplings 39, 40 with universal joints and coupling 43 to a shaft 44 which is connected by bevel gear 35 ... 38 to a shaft 32 connected by worm gear 31, 30 to the turn table 26. The shaft 44 is driven by spur gear 45, 46 and belt 50 from a motor 51. The control circuit of the motor 51 contains a switch 54 and a holding circuit is provided containing a switch 55 which is opened by a cam 56 on a shaft 57 rotated by the shaft 44 through worm gear 58, 59 so that the motor 51 is cut off when a pre-determined angular displacement of the electrodes has been effected. Coasting of the motor 51 may be prevented by an electric brake 60. The electrode 12 is electrically connected to the terminal 69 of the transformer secondary through a conducting ring 73 connected by lugs and flexible straps to the connecter 70 and pressed by springs 76 against rings 75 engaging the support 16. The electrode 13 is connected to the other terminal by a flexible connecter 78, spring-pressed conductor ring 79 and contact rings 80. The electrode 12 is cooled by liquid supplied to a conduit 91 encircling the ring 73 and discharging into a depression 92 from which liquid passes into depression 94 which communicates with a conduit 96 through which liquid is applied to the edge of the electrode and also with a passage 98 in the axle connected to passages 99 from which liquid spills over the electrode. The electrode 13 and adjacent parts are immersed in cooling liquid to a depression 100 sufficient to supply liquid,to the passage 102 in the axle 24. The work, which may be rotated or traversed by the electrodes in welding the sides of 'the pocket, may engage a pivoted support 104 adjustable by a screw. The electrodes may be turned through any desired angle to form arcuate welds or a circular weld.