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. 03, 2019
Filed:
Sep. 04, 2015
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Ryohei Yamashita, Tsuchiura, JP;
Shinya Imura, Toride, JP;
Kouji Ishikawa, Kasumigaura, JP;
Hidekazu Moriki, Mito, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
Provided is a hydraulic control system for a construction machine, including: a control valve () for controlling supply and discharge of hydraulic fluid to and from an arm cylinder (); an operation lever () for controlling the position of a spool of the control valve (); a meter-out flow passage () for passing therethrough hydraulic fluid discharged from the arm cylinder; a variable restrictor () provided in the meter-out flow passage; pressure sensors () for detecting a magnitude of a negative load applied by an external force to the arm cylinder in a same direction as an actuation direction of the arm cylinder; and a controller () for reducing an opening area of the variable restrictor () according to an increase in the magnitude of the negative load calculated with a detection value from the pressure sensors ().