Abstract: The present invention is directed to a curved pipe manufacturing method comprising the steps of: inserting a curved mandrel into a curved cavity of a fixed die having an entrance opening and an exit opening, the curved mandrel being attached to the distal end of an ejecting rod; forming a curved pipe by pressing a work, with a present rod through the entrance opening of the curved cavity into a curved annular chamber defined by the surfaces of the curved cavity and the mandrel; turning the movable block in one direction so that an ejecting rod attached at its base end with the movable block and concentrically integrated with the mandrel, ejects the mandrel together with the curved pipe from the entrance opening of the fixed die; advancing a movable chuck provided outside the entrance opening for chucking only the curved pipe; turning the movable block to another direction opposite to the one direction so as to return only the mandrel into the curved cavity of the fixed die; and retracting the movable chuck fo

Abstract: A curved pipe manufacturing method comprises the steps of: inserting a curved mandrel into a curved cavity of a fixed die having an entrance opening and an exit opening through the exit opening thereof, said cavity being formed in a circular arc and extending from the entrance opening to the exit opening thereof, said curved mandrel being attached to one side of a movable block; forming a curved pipe by pressing a work, with a presser rod through the entrance opening of the curved cavity into a curved space defined by the surface of the curved cavity and the mandrel; turning the movable block for extracting completely the curved pipe together with the mandrel from the exit opening of the curved cavity; inserting a retaining pin into a groove provided in the movable block for retaining a tip end of the curved pipe; and further turning the movable block so as to turn the mandrel while the curved pipe is restrained by the retaining pin so that the curved pipe is separated from the mandrel.

Abstract: A curved pipe manufacturing method comprising steps of inserting a mandrel attached to one side of a movable block so as to be inserted into and to be pulled out from a curved cavity of a circular arc formed in a fixed die and having an entrance and an exit into the curved cavity through the exit thereof, forming a curved pipe by pressing a work, namely, a straight pipe, with a pressing rod through the entrance of the curved cavity into a curved space defined by the surface of the curved cavity and the mandrel in the shape of a curved pipe to be manufactured, turning the movable block to retract the mandrel slightly relative to a curved portion of the work after pressing the work into the curved space by a predetermined length to mitigate the pressure of contact of the curved portion of the work with the mandrel, restarting pressing the work into the curved space to complete a curved pipe, turning the movable block to pull out the mandrel from the curved pipe formed in the curved space, and further turning th