Reworking process of starting tube with circular cross section to U-shaped section and apparatus for making the same

摘要

A method of deforming an initial pipe having a circular cross-section into an U-shaped section and a device for carrying out the method wherein the inner surface of one half of the initial pipe rests in a positively engaging manner against the inner surface of the opposite half of the pipe, with the exception of lateral loop-shaped ear portions. The initial pipe is secured in its position by mandrels inserted in the ends of the pipe. Initially, the initial pipe is with its lower half at least over areas thereof supported by an abutment and the top half of the initial pipe is pressed in by a ledge-like top die with a convexly curved front portion located opposite the abutment until the top half of the initial pipe is pressed in until it makes contact with the diametrically oppositely located bottom half of the pipes so as to produce a U-shaped top half. Subsequently, the top die and another bottom die having the external contour of the section are moved toward each other to finish the U-shaped section while the mandrels which remain in the ends of the pipe are moved as required.