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:
May. 28, 2019
Filed:
Oct. 02, 2014
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Seiji Hijikata, Tsukuba, JP;
Kouji Ishikawa, Kasumigaura, JP;
Takatoshi Ooki, Kasumigaura, JP;
Shinya Imura, Toride, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
When hydraulic fluid discharged from a hydraulic actuator is to be recovered for driving a different hydraulic actuator, the recovery frequency is increased to achieve further energy saving. To this end, a pressure increasing circuitis provided in which a communication pressure increasing valveis disposed in a communication passagethat connects a bottom side lineof and a rod side linea boom cylinder. A recovery control valveis controlled such that, when a first operation unitis operated in a boom lowering direction (own weight falling direction of the boom) and a second operation unitis operated simultaneously, only if the pressure at the bottom side of the boom cylinderis higher than the pressure at the arm cylinder side that is a recovery destination of hydraulic fluid, the recovery control valveis opened to recover the flow rate discharged from the bottom side of the boom cylinderto the arm cylinder side.