Method of controlling synchronized movement of backing shoe in automatic one-side welding

摘要

A method of controlling the synchronized movement of a backing shoe in an automatic one-side welding of the type in which a light-transmittable backing material is placed in close contact with the back surface of the welding joint and a backing shoe adapted to be moved along with the movement of a welding apparatus is pressed through the backing material against the back surface of the welding joint just below a welding electrode whereby effecting the welding. The method employs photoelectric detectors which are embedded in the surface of the backing shoe contacting the backing material at four positions, i.e., right-front, right-back, left-front and left-back positions just below the electrode with respect to the direction of welding and the detectors are arranged at predetermined distances from each other, whereby the light emitted from the back surface of the welding joint and transmitted through the backing material is received by the detectors each of which generates an electric signal corresponding to the received light magnitude and the speed of travel as well as the lateral position of the backing shoe are controlled in such a manner that the below-electrode-point is maintained at a predetermined position among the light receiving positions on the backing shoe.