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:
Jul. 20, 1999
Filed:
Mar. 03, 1997
Yasunori Tokunou, Ehime-ken, JP;
Kouichi Inoue, Oozu, JP;
Toshikazu Shogase, Oozu, JP;
Makoto Sunouchi, Oozu, JP;
Takeshi Yoshikawa, Oozu, JP;
Matsushita Electric Industrial Co., Ltd., Osaka, JP;
Abstract
A manufacturing method is provided for forming a hollow cylinder with a bottom which may be employed in rotary head drums of magnetic recording and reproduction systems such as video tape recorders and digital audio tape recorders. The manufacturing method includes pressing a single circular plate to form the hollow cylinder, thrusting an end of a side wall of the hollow cylinder in a direction substantially parallel to the side wall in a press die so as to adjust the thickness of the side wall to be uniform, and machining an outer surface of the side wall of the hollow cylinder so as to have a given surface roughness and a given roundness.