Patent ID: 7373796
Filing Date: 2008-05-20
Classification: B21H,Y10T

Abstract:
1. An automatic releasing-type rolling head for forming a tapered thread on a pipe, comprising: a cylindrical housing with a front closure and a rear closure; a plurality of shaft bearing plates that are configured to be slidably supported in a plurality of guide grooves radially provided on inner surfaces of the front and the rear closures of the housing, said shaft bearing plates being provided on their outer surfaces in the radial directions with a plurality of oblique surfaces; a plurality of thread rolling rollers configured so as to be rotatably supported by the shaft bearing plates through a plurality of roller shafts; a cam ring configured to rotate in the housing and having a plurality of cam oblique surfaces configured so as to be opposed to the oblique surfaces of the shaft bearing plates; a lever that is configured to abut, at its oblique surface, against a cam member, the lever being configured for preventing a movement of the cam member in association with the cam ring; and an abutment member configured so as to be pressed and moved by a thread-rolled pipe, wherein the rolling load that acts on the rolling rollers during a thread-rolling operation is configured so as to be reduced due to contact friction when transferring the rolling load to the cam oblique surface of the cam member and to the oblique surface of the lever; wherein when the to-be-rolled pipe is configured to be thread-rolled to a predetermined length, the oblique surface of the lever is configured to be gradually moved away from the cam member moving in association with the cam ring, in association with the movement of the abutment member; wherein the cam ring is configured to rotate due to the rolling load so that the shaft bearing plates and the thread rolling rollers are configured to move in a radial direction and an outward direction and are configured for releasing from the to-be-rolled pipe.