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. 08, 1998
Filed:
Nov. 13, 1996
Goro Daimon, Hitachi, JP;
Yasuhide Takeda, Hitachi, JP;
Tadahiko Nogami, Mito, JP;
Hideo Kawamoto, Hitachi, JP;
Hiroshi Maeda, Hitachi, JP;
Kouichi Sadou, Hitachi, JP;
Hiroyoshi Sadamura, Jyuou-machi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
For the purpose of providing a gas circuit breaker with a structure of hydraulic pressure operation system capable of detecting the occurrence of an incomplete closed state of the valves therein to prevent their erroneous motion during the subsequent motion, and a liquid-pressure driving system to be used therefor, a check valve is arranged so as to suppress the flow into the space on the side of the downstream of a closed-circuit operation spool valve, wherein the space on the side of the downstream of the closed-circuit operation spool valve is connected through a second diaphragm to a low-pressure oil tank and the operation time or operation number of a liquid-pressure pump is measured.