JPS57124569A - Welding method for reinforcing steel bar cage - Google Patents

Abstract

PURPOSE:To weld longitudianl bars and spiral bars without degrading their strength by subjecting the points of intersection of the longitudinal bars and spiral bars of a reinforcing steel bar cage to instantaneous arc spot welding by the short time electricity conduction while both are in contact. CONSTITUTION:A circularly disposed longitudinal bar A group is supported with guides, etc., and is moved at a constant speed upward perpendicularly to the plane of the figure by the gripping at the leading ends by means of clamps and the movement of a carriage while sliding on the outside circumference of a support disc 18. A spiral bar B is wound on the outside circumference of the bar A group by the rotation of a reel 19, etc., and a sliding plate 23 of an electrode 22 presses and slides the outside circumference of the bar B. When the reel 19, etc. rotate and the bar B arrives at the position just before the contact with the bar A, the terminal 34 corresponding to this longitudinal bar operates a switch and at the moment when the bar B contacts the bar A, conduction of electricity is generated for a short time by a power feeder 31. Since the conduction of electricity is in a short time, the point of intersection sparksand is welded 32 without having any time for the bar B and the bar A for burning. Thereby, the deformation of the reinforcing steel bars in the weld zone is virtually eliminated and the degradation in strength is obviated.