GB1179778A - Improvements relating to Welding Apparatus for Making Welds Along Closed Circular Paths - Google Patents

Abstract

1,179,778. Welding by fusion. ASSOCIATED ELECTRICAL INDUSTRIES Ltd. 11 July, 1968 [13 July, 1967], No. 32337/67. Heading B3R. Apparatus for welding along closed circular paths comprises a rotatable work-table and a cam member co-operable with electrical circuitry for causing the end of the weld bead to overlap by a predetermined amount the bead previously deposited. Single-turn or concentric multi-turn welds may be made. In making a single-turn weld (Fig. 1, not shown), in which the end of the bead overlaps the start by an amount (T 1 ), the operation proceeds as follows: a pneumatic piston-and-cylinder arrangement moves an actuator 7 on to a rotatable worktable 1 carrying flux-coated work and the actuator 7, which may have a magnetic base, rotates with the table as the weld is formed. After one complete revolution the actuator 7 opens contacts of a switch LS3 carried by the head 5 of the piston 4 and the actuator is withdrawn from the table 1 as the piston 4 retracts thereby operating an overlap timer (T 1 ), (Fig. 5, not shown), which causes rotation of the table 1 to cease when the predetermined overlap (T 1 ) has been formed. In making a multiturn weld (Fig. 2, not shown), the weld bead is deposited continuously, the weld head being moved laterally at the completion of each revolution, except the last, of the table 1 and the end of the last concentric turn is overlapped with its start, the operation proceeding as follows: the actuator 7 is moved on to the table 1, and after one revolution it opens the contacts of switch LS3 but since the weld control circuit has been set to perform a continuous weld the actuator 7 remains on the table and the weld head is caused to move laterally by an amount determined by a timer (T 2 ) after which a further revolution of the table proceeds. This sequence is repeated automatically after each revolution of the table until the final turn of the weld is in progress, during which a switch is manually operated so that the apparatus completes the weld as if it were making a single-turn weld. The welding operation may be interrupted at any time and the table can be rotated in either direction to allow the weld to be inspected or repaired, after which the apparatus, when restarted with the table in the correct position, continues from where it left off.