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:
Feb. 11, 2025
Filed:
Jun. 18, 2020
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
HITACHI CONSTRUCTION MACHINERY CO., LTD., Tokyo, JP;
Abstract
A hydraulic actuator includes a control valve unit that controls a flow of a hydraulic fluid supplied from a hydraulic pump to a plurality of hydraulic actuators, a plurality of control lever devices that output a pilot pressure actuating the control valve unit, with use of a discharged pressure from a pilot pump as a source pressure, a solenoid valve unit including a plurality of solenoid pressure reducing valves connected between the plurality of control lever devices and the control valve unit, and a controller configured to calculate velocity limits for the plurality of hydraulic actuators on the basis of signals from a plurality of posture sensors and control openings of the solenoid pressure reducing valves, in which the controller is configured to control the openings of the solenoid pressure reducing valves for arm crowding and arm dumping to be larger than an opening based on the velocity limits while a boom raising operation signal is being output from the control lever devices.