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:
Feb. 02, 1993
Filed:
Oct. 02, 1991
Applicant:
Inventors:
Nobuaki Tomita, Shizuoka, JP;
Kunio Suzuki, Shizuoka, JP;
Assignee:
Yamaha Corporation, , JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
B23P / ;
U.S. Cl.
CPC ...
295272 ; 295277 ; 29594 ; 148665 ; 164 46 ;
Abstract
In production of a beryllium type diaphragm used for acoustic appliances such as speakers and microphones, formation of a crude beryllium plate by means of vacuum deposition is followed by hot cross rolling and hot pressing. Vacuum deposition well reduces production of undesirable impurities such as BeO and hot rolling increases density of the beryllium crystal structure obtained by the preceding vacuum deposition, both for betterment in acoustic and mechanical characteristics of the product such as sound pressure and mechanical strength.