Patent ID: 6119501
Filing Date: 2000-09-19
Classification: B21D

Abstract:
A method of deforming an initial pipe having a circular cross-section into a U-shaped section, wherein an inner surface of a first pipe half of the initial pipe rests against an inner surface of a second half of the initial pipe with the exception of lateral loop-shaped ear portions where the inner surfaces of the first and second pipe halves do not contact each other, the method comprising securing the initial pipe by mandrels inserted into ends of the pipe, supporting at least areas of the second half of the pipe by an abutment and pressing the first half of the initial pipe by a ledge-like top die having a convexly curved front portion located opposite the abutment until the first half of the initial pipe is pressed in and makes contact with the inner surface of the second half of the pipe so as to produce a U-shaped first half, subsequently moving the top die and a bottom die having external contours of the section toward each other until the U-shaped section is finished, while simultaneously moving as required the mandrels which remain in the ends of the pipe.