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:
Oct. 19, 2021
Filed:
May. 18, 2018
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Kiwamu Takahashi, Moriyama, JP;
Seiji Hijikata, Tsukuba, JP;
Masatoshi Hoshino, Tsuchiura, JP;
Yuichi Ogawa, Tsuchiura, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A controller () is provided with an elapse time measuring section (A) that measures an elapse time (tx) elapsed since an initial use of an accumulator () based upon a reset signal from a reset switch (), a number-of-operations measuring section (B) that measures a number of operations of the accumulator (), that is, a number (N) of boom lowering operations after a reset, based upon a detection signal from an accumulator side pressure sensor (), a gas permeation amount estimating section (C) that estimates an estimation gas permeation amount (Qloss) of the accumulator (), a sealed gas pressure estimating section (D) that finds an estimation sealed gas pressure (Pgs) of a gas chamber (B) of the accumulator (), and an accumulator degradation determining section (E) that determines a degradation condition of the accumulator () and outputs the determination result.