The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Apr. 24, 1990
Filed:
Jun. 09, 1989
Hirosato Takeuchi, Tokyo, JP;
Yutaka Tanaka, Tokyo, JP;
Osahiko Miyazaki, Tokyo, JP;
Noboru Saito, Tokyo, JP;
Haruo Kubo, Tokyo, JP;
Naoyuki Kotake, Tokyo, JP;
Makoto Nagumo, Tokyo, JP;
Nitto Kohki Co., Ltd., Tokyo, JP;
Abstract
A forging method comprises the following four steps: a first step of disposing a columnar material into a first die and extruding one end portion of the material with a first punch in a direction opposite to the advancing direction of the first punch, a second step of deepending a first blind hole in a second stepped die with a cavity having large and small internal diameter portions, and extruding the other end portion of the material into the inside of the small internal diameter portion of the cavity with a second punch which has been previously extended thereinto, a third step of fitting the first and second blind holes to third punches while exposing the small outer diameter portion from a third die and pressurizing, by means of a sleeve, only an end face portion of the small outer diameter portion formed with the second blind hole to expand the small outer diameter portion of the material toward an outer periphery, and a fourth step of punching out a blind portion of the material.