| 摘要 |
PURPOSE:To control feeding of a welding wire automatically, and adequately in an automatic arc welder by providing a detecting circuit for short circuiting between the wire and objects to be welded during inching and a wire retracting circuit which pulls back the wire. CONSTITUTION:When a welding wire 2 is fed by inching and contacts with objects 1a, 1b to be welded, a closed circuit including a welding control circuit 10 and a detecting circuit 9 for short circuiting of the wire is formed. The short circuiting of the wire 2 and the objects 1a, 1b is detected with the circuit 9, by which the feeding of the wire 2 is stopped. At the same time, a wire inching circuit 8 goes off and a signal is transmitted from the circuit 9 to a wire retracting circuit 7, a control circuit 5 for feed speed of the wire, and a wire feed motor 4, so that the wire 2 is retracted automatically to the projecting length which is made adequate at the start of welding, thus even when the wire 2 contacts with the objects to be welded during inching, the wire is prevented from deforming at the tip or from slipping between feed rollers. |
