PURPOSE: To detect exactly a rocking reversed position of a groove weld line, and to raise accuracy of automatic welding, by basing on an electric welding current detecting system, and complementing its base by a position detecting function of a profile detector.
CONSTITUTION: A current comparing circuit 14 compares a detecting value of a current detector 12 for detecting a welding current, with a value obtained by adding a threshold level to a welding current reference value set in advance, and generates an output when the detecting value of the current detector 12 is larger. A reversed position comparing circuit 15 compares a detecting value of a profile detector 13 for detecting a moving extent to the left and right directions against the reference line of the groove of a welding torch 1, with stored information of a storing circuit 25-1 for storing a welding torch reversed position of the same direction side immediately before said time, as a moving extent to the left and right directions against the reference line of the groove, and generates an output when the detecting value of the profile detector 13 is larger. A rocking controlling circuit 16 provides an output for reversing the rocking direction, to the rocking shaft of the welding torch 1 by an output of one of the comparing circuits 14, 15, and corrects automatically the rocking width of the welding torch 1.
MIYAGI YOSHIKAZU
UEDA TSUTOMU
KODAMA MOTOJI
NAKAMURA MASATOSHI
AKITANI SHIORI
SUMIKIN WELDING ELECTRODE CO
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