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. 26, 2020
Filed:
Feb. 21, 2018
Hitachi Construction Machinery Co., Ltd., Taito-ku, Tokyo, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
To prevent increase/decrease in pump flow rate due to load variation with change in the posture of a work attachment and improve the operability in arm pushing operation. A hydraulic excavatorwith a front mechanism including an armdriven by a hydraulic actuatorthrough operation of an operating leverincludes: first and second angle sensorsandwhich detect the posture of the arm; and a controllerwhich, when the posture of the armis at a remoter side from an upperstructurethan a preset position and the position of a bucketis adjusted from a maximum or nearly maximum preset operation amount of the operating leverin arm pushing operation by the operating lever, changes the flow rate characteristic of pressure oil in relation to discharge pressure of a hydraulic pumpfor supplying pressure oil to the hydraulic actuator, to characteristic PTS with a higher flow rate than flow rate characteristic PT at the time of operation with an operation amount other than the above operation amount, to drive the hydraulic pump