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:
Sep. 07, 1976
Filed:
Jul. 09, 1975
Michel Ratajski, Bienne, CH;
OMEGA Louis Brandt & Frere S.A., Bienne, CH;
Abstract
An apparatus for testing the gas impermeability of watch cases or other small articles comprises two enclosures. A bellows forms part of a hermetic separation between the enclosures, the bellows serving to move the movable plate of a variable condenser. The condenser is connected in an oscillator circuit to vary the oscillator frequency in accordance with the differential pressures between the two enclosures. The oscillator output frequency is compared with the output frequency of a stable frequency generator to provide a measurement indication. A watch case is placed within one enclosure and both enclosures brought to equal pressures after which the measurement of gas impermeability may begin.