GB245911A - Improvements relating to electric welding apparatus - Google Patents

Abstract

245,911. Hume, W. R. Dec. 15,1924. Heating by electricity.-In electric-arc welding- apparatus, the electrode is fed to the work by fluid-operated means. The work carriage 6, Fig. 1, is moved by a flexible line 5 connected to a piston 9 working in a hydraulic cylinder 11. The electrode 12 is simultaneously fed by means of a second line 13 connected to the carriage. The rate of the electrode feed relatively to the rate of traverse of the work is varied by connecting the two parts of the line 13 to different holes 19 in the pivoted lever 18. The angular direction of the electrode is adjusted by shifting the pin 31 on the guide bars 24 into different holes 32 in the horizontal bar 33. The electrode is guided by the guide-sleeve 37 pivoted to a rocking bar 41 supported by the guide-wheels 42 which run along the joint to be welded and run freely over such obstructions as spot welds owing to the pivoted movement of the rocking bar. The electrode is adjusted laterally by means of a hand-wheel 43 operating a transverse screwthreaded rod attached to the member 38. The work and the pivoted cradle 50 are held balanced by the pressure of the guide-wheels so that, should the guide-wheels accidentally leave the jointing groove, the cradle will rotate laterally and the arc will thus be automatically extinguished. The electrode is moved into its initial position by means of a winch 17 geared to a hand-wheel 49. The supply of fluid to the hydraulic cylinder 11 is controlled by the valve 54, Fig. 3, which is opened initially by a screw 53 operating 'the arm 57. After starting, the supply is controlled by the current in the solenoid 63 which is wound in circuit with the electrode and influences an armature on a sliding rod 62, connected to an adjustable tension spring 67. The opening movement of the valve is limited by the stop 72 engaging the adjustable stop 73 and the normal closing movement is limited by the stop 62 and the co-operating yielding stop 77. If excessive current passes through the electrode the resistance of 'the yielding stop is overcome and the rod 62 continues its movement to operate a release valve 81 thus causing the piston to descend and 'the point of the electrode to recede from the work whilst the work moves back correspondingly under the action of the weight 80, Fig. 1. A secondary pipe 92 leads into the main supply pipe 56 and is fitted with a hand controlled valve 93, for example for advancing the work to the starting position. The arc is struck by the action of the solenoid 104, Fig. 4, which when the current flows owing to the electrode touching the work draws back the sliding core 103 to which the electrode is fastened.