Patent GB-647337-A (GB)
Title: Improvements in electric arc welding apparatus
IPC: B23K9/12
Filed: 1948-12-21
Abstract: 647,337. Uniting by fusion. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Dec. 21, 1948, No. 32975. Convention date, Dec. 26, 1947. [Class 83 (iv)] Arc-welding apparatus for feeding stick electrodes 1, 2 in succession comprises a pair of electrode holders 3, each movable in a support 10 from a loading position towards the work with one electrode overlapping the other ready to move into arcing position when the consumed electrode is withdrawn for return to the loading position, where it momentarily remains stationary while a new electrode is loaded by hand. The coated electrodes 1, 2 are each damped in a holder 3 by a screw 5, each holder being carried by levers 7 pivoted on adjustable arms 8 of a carriage 9 having four rollers 25 engaged in slots formed in the frame 10, each carriage being,mounted on opposite sides of the frame. The levers 7 are biassed to swing inwards by a spring 12 but at the loading position they are swung outwards by a cam block 11 and locked there by a pivoted latch 15 carried by an arm 13 slidably mounted on the carriage and spring-loaded upwards against a catch 17. The carriage remains stationary at the loading position sufficiently long for a new electrode to be fitted with its further end sprung outwards to engage a groove on the outside of the holder of the descending carriage. Cables 22 supply welding current to the levers and thence to the holder, these parts being insulated from the frame by forming the arms 8 and 13, the cam block 11 and the attachments for spring 12 of insulating material. The carriages 9 are moved from the loading position to the work by a chain 29 driven by a motor 42 which is either separately mounted or is mounted on the frame and is controlled by the arc voltage or similar means to maintain the arc length constant. Lugs 31 are spaced alternately on opposite sides of the chain at distances corresponding to the consumable length of the electrode and engage abutments 32 on the carriages, the lugs being of triangular shape so that the speed of the carriage remains roughly constant as the chain moves round the lower sprocket. For returning the carriages rapidly to the loading position, where they engage a stop 43 on the cam 11 and remain stationary until engaged by another lug 31, wires 44 attached to the carriages are coiled round drums 45, 46, one journalled on a shaft 33 of the chain drive and the other journalled on the first drum and both connected to a spring 47 which is wound up by the descending carriage to provide power for retracting the other carriage. Towards the end of the downward movement of the carriage, an arm 19 of the latch 15 passes inside a spring-loaded trip 20, forcing it temporarily outwards, but soon after the return movement begins the latch is pulled down by the engagement of the arm with the outer surface of the trip and allows the spring 12 to swing the levers inwards to clear them from the path of the other carriage and to allow the new electrode to spring into welding position. The frame is mounted on a roller 54, which may have a V-shaped periphery engaging the V-groove for the weld and is protected by a shield 56, and on a roller 55 driven from the motor 42. A handle 50, and another handle at the top of the frame, are provided and a telescopic brace 63 permits adjustment of the inclination of the frame. An insulating strip 57 prevents short-circuiting when the consumed electrode is swung inwards.