GB566908A - Improvements in or relating to electric welding apparatus - Google Patents

Abstract

566,908. Uniting by fusion. UNDER WATER WELDERS & REPAIRERS, Ltd., HUNTING, P. L., and HAMBLIN, H. W. July 14, 1943, No. 11485. [Class 83 (iv)] An arc - welding apparatus comprises a carriage movable over the work and having an electrode holder and means associated with the carriage for bringing the electrode into contact with the. work, retracting it to strike the arc and thereafter feeding it forward by an amount commensurate with the movement of the carriage along the seam. The apparatus may be provided with an electrode as described in Specification 559,033 and may operate under water or other liquid. The carriage 11 which is provided with a feeler 12 engaging the seam 115 in the angle between the overlapped plates 13, 14 to be welded and has rollers 15, 16 for supporting it on the work in an inclined position, is provided with insulated handles 57, 58, and with a slide 22 which carries the electrode 24. The lateral inclination of the carriage is adjustable by mounting the roller 16 on an arm 18 adjustable about its pivot 19. The electrode, which is secured at one end to the cable 26, passes at its other end through insulated grooved feed rollers 28, 29 which are driven by bevel gear 35, 36 from a shaft 37 connected by a universal joint 41 with a shaft 42 driven by but slidable on a shaft 43 carrying a friction disc 49 engaging the side of the traversing roller 15. The shaft 37 carries a cam 39 engaging between arms 40 on the carriage so that it may move the shaft laterally to oscillate the swinging feed roller carrier 32 about its pivot pins 33, 34 across the seam during the welding operation. The shaft 43 is carried by a slide 46 adjustable by a screw 47 for varying the friction gear ratio and the roller 15 is held against the disc 49 by having its spindle screwed at 75 and secured by a lock-nut 76. The shaft 43 may be squared at 51 to receive a friction disc 50 which engages a friction disc 52 rotatable relatively to the shaft 43 and secured to one end of a spring 56 which is secured at the other end to the slide 46. The disc 52 also has a pair of pegs 54 between which passes a stop member 55 carried by the slide 46. When the carriage is pushed forward the spindle 43 is rotated to bring the electrode into contact with the work and at the same time the disc 52 is rotated by the disc 50 until one of the pegs engages the stop member 55. The spring is thus stressed and on release of the carriage, the spring reverses the same and thus causes the arc two be struck. The carriage is then pushed forward to effect the weld. The carriage may be driven by a motor instead of by hand, in which case the spring-operated mechanism is replaced by a lost-motion device in the drive so that the arc may be struck by the operator advancing the carriage a short distance and then retracting it. In another form for effecting the welds step-by-step, a spring-returned serrated eccentric foot lever 61 is pivoted at 63 to the carriage 11 so that on pressing the lever the carriage is moved along the seam and the electrode 24 at the same time brought into contact with the work. On releasing the lever, the spring 65 moves it about its pivot and lifts the end of the carriage to strike the arc, backward motion of the carriage being prevented by a pawl 67 engaging a ratchet wheel 66 on the axis of the roller 15. When the electrode first comes in contact with the work, the current passes in series through the electrode and a solenoid 161, so that the core 166 is raised against the action of a spring 71. The core carries a pair of pawls 72 controlled by a spring 73 so that when the arc lengthens, the core is pushed down by the spring 71, the pawls engage the electrode to feed it forward a short distance until the core engages a stop when the arc breaks. Welding is continued at the next spot by again pressing the lever 61. Water-tight joints are provided at the place of entry of the cables and at the ends of the solenoid.