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:
Mar. 31, 1987
Filed:
Sep. 11, 1984
Hitachi, Ltd., Tokyo, JP;
M. H. Center, Ltd., Saitama, JP;
Abstract
A method and apparatus for cold working a metallic blank having a central hole into a substantially annular or cylindrical article such as an internally and or externally toothed gear, with the method including forcibly inserting a hollow metallic blank at a normal temperature into a die cavity formed between a mandrel placed on a fixed base and a die concentrically surrounding the mandrel so that the blank is plastically deformed between the mandrel and the die; forcibly inserting a subsequent hollow metallic blank into the die cavity while the relative position between the mandrel, the die and the first blank being plastically deformed therebetween is kept unchanged; and urging the subsequent blank against the first blank to extrude the first blank forwardly out of the die whereby the first-said blank is formed into a tubular article.