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. 25, 1989
Filed:
Oct. 27, 1987
Applicant:
Inventors:
Assignees:
Furukawa Aluminum Co., Ltd., Tokyo, JP;
Kawasaki Steel Corp., Hyogo, JP;
C. Itoh & Co., Ltd., Osaka, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B21D / ;
U.S. Cl.
CPC ...
72 47 ; 72359 ; 72379 ; 360135 ;
Abstract
A method of manufacturing a substrate for a memory disk characterized in that a blank material comprising a non-magnetic metal substrate covered with a non-magnetic metal as an underlayer is subjected to a coining operation by two dies having flat compressing surfaces within an apparatus including a mandrel and a die ring arranged to limit the spreading extent of the material whereby a surface having ultra-preciseness is obtained.