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:
Aug. 11, 1998
Filed:
Nov. 30, 1995
Eiichi Mukumoto, Takarazuka, JP;
Konan Electric Company Limited, Hyogo, JP;
Abstract
The invention intends to provide a relief valve which can prevent malfunction caused by generation of negative pressure lowering the minimum pressure to be originally maintained by a load circuit. Maloperation of a relief valve 401 is prevented by allowing a check valve 423 for preventing a backflow from a main valve element 410 and pilot valve element 412 side to a load port side 402 to be intervened at a pressure chamber 408 between a load port 406 connected to a load circuit, a main valve element 410, and a pilot valve element 412 and by applying a hydraulic lock when negative pressure lower than the minimum pressure to be originally maintained by a load circuit is generated. And by communicating a downstream chamber 425 downstream of the check valve 423 to a return port 407 with a reset oil passage 429 which is opened and closed by a reset valve 430, the hydraulic lock is designed to be released.