APPARATUS FOR FORMING PIPE

摘要

The present invention relates to a pipe forming apparatus having an undercut protruding from the outer periphery of the longitudinal end of a pipe. The pipe forming apparatus comprises an inner periphery forming part arranged in the inner space of the pipe, and an outer periphery forming part arranged to cover the external side of the pipe. The outer periphery of the inner periphery forming part corresponds to the shape of the inner periphery of the pipe, the inner periphery of the outer periphery forming part corresponds the shape of the outer periphery of the pipe. The inner periphery of the outer periphery forming part includes a concave undercut forming groove corresponding to the shape of the undercut. The outer periphery forming part includes a correspondence round part in order to forming a round part in an intersection area arranged in a blowout direction among intersection lines formed by arranging the outer periphery of the pipe and the undercut in order not to damage the undercut by the inner periphery of the outer periphery forming part when the pipe is extracted from the inner periphery forming part and outer periphery forming part. The concave undercut forming groove includes a correspondence inclined angle and a correspondence inclined plane so that the undercut has an inclined plane having an obtuse angle on the outer periphery of the pipe in the blowout direction.