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. 05, 1988
Filed:
Apr. 28, 1987
Koichi Yasuoka, Yokohama, JP;
Tohru Tamagawa, Chigasaki, JP;
Eiji Kaneko, Yokohama, JP;
Mitsutaka Homma, Inagi, JP;
Satoru Yanabu, Machida, JP;
Takumi Funahashi, Yokohama, JP;
Kabushiki Kaisha Toshiba, Kanagawa, JP;
Abstract
A vacuum switch having two main electrodes encased in a vacuum vessel to be operable in opening and closing the main electrodes, is provided with a contact piece made of a copper-chromium alloy secured or formed on at least one of the main electrodes. The operational property of the main electrodes is substantially improved by flowing and interrupting an electric current of a predetermined current density for a number of times through the two main electrodes for improving surface condition of the contact piece by forming a recrystallized layer over the outer surface of the contact piece.