Patent GB-569456-A (GB)
Title: Improvements in electric welding apparatus
IPC: B23K9/18
Filed: 1943-12-13
Abstract: 569,456. Uniting by fusion. LINDE AIR PRODUCTS CO. Dec. 13, 1943, No. 20804. Convention date, Dec. 18, 1942. [Class 83 (iv)] An electric welding apparatus, particularly for plug or rivet welding, comprises a hopper for containing welding material and means for discharging it into a device for retaining it in position on the work, and a welding rod feedmechanism carried by the hopper to feed the rod into the material and towards the work. A hopper P for the powdered granular fusible mineral welding material M, which may be of the kind described in Specification 433,723, is mounted on three detachable legs S, which are connected thereto by bolts 23 and consist of two-part rods 20, 21, surrounded by insulating sleeves 28 and having buttons 25 secured in their lower ends. Two of the legs are further provided with removable foot-plates 26. To the legs is secured by an apertured ear 31 engaging one leg and by apertured arms 32 engaging the other legs an annular bracket 30 for supporting a ring 34 for retaining the welding material over the work. In the bottom of the hopper is welded a conduit 37 formed with a spout 39 and provided with a rubber or other flexible valve 40 carried between members 43, 44 on a rod 41 passing through an aperture in a bracket 13 and provided with a stop 45. Passing through a flexible friction washer 17 in another aperture in the base of the hopper is an insulating member 47 which is adjustably mounted in a split clamp 16 welded in a semicircular recess 15 in a segment 14 welded to the hopper. Mounted in a bushing 72 in the upper end of the member 47 is a hollow insulating plunger 60 which is provided at its reduced end 62 with a metal washer 66 and is screwed into a nut 50 connected to a feed member comprising a sleeve 48 with apertured ends 49, 51 and containing a block 52 with a vertical bore intersected by rearwardly converging rectangular passages 54, 55 for containing balls 58, aligning blocks 57 and springs 56. The electrode is gripped and fed by the balls when the plunger 60 is moved forward and is released when the plunger is retracted. The travel of the plunger is adjustable according to the amount of metal to be deposited in any one operation by providing thereon a collar 105 containing a clamping screw 107 which is accessible when the collar is brought opposite an aperture 108 in the member 47 provided with a hinged cover 109. To vary the travel, the screw 107 is slackened and the plunger drawn back, a longitudinal groove in the plunger. being provided with a graduated linear scale 64. On the upper end of the plunger 60 is secured by a split clamp 81 a two-part casing 76, 77 having a pair of lateral handles 79 and also a housing for a voltmeter V for indicating the voltage and thus the distance the end of the electrode is from the work, so that the electrode may be fed forward to keep the voltage and thus this distance constant. One terminal of the voltmeter is connected by a conductor 85 to the terminal 68 connected by a conductor 63 passing along a groove in the plunger to the metal washer 66, and the other terminal is connected to the work. The welding current is conducted to the welding rod by a bus-bar assembly provided with a terminal block 97 and secured by a split clamp 94 to an insulating bushing 90 in the lower end of the member 47. The bus-bar B carries a guard plate G and has a split clamp 96 for securing the contact nozzle, the lower end of which has longitudinal slots to form flexible fingers which are surrounded by a clamp 101 to control the pressure on the electrode to keep it stationary during retraction of the plunger 60. The handle 79 is provided with a handoperated remote-control switch for starting and stopping the welding operation, the end of the electrode being pointed or a pad of combustible material such as steel wool being placed between the end of the electrode and the work. The hopper is provided with handles for moving the apparatus from one location to another. When welding an anglebar 116 to the upper side of a plate 115, one of the support legs S is removed from the hopper and the bracket 30 is replaced by an open-sided bracket 30<1> containing an open part ring 34<1>, the vertical leg of the angle-bar 116 completing the enclosure for the welding material.