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:
Jun. 28, 2022
Filed:
Nov. 12, 2019
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Yoshiyuki Tsuchie, Matsudo, JP;
Kouichi Shibata, Kasumigaura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
In a work machine including a solenoid valve that generates a pilot pressure to drive a directional control valve with use of the delivery pressure of a pilot pump as a source pressure, a shut-off valve that shuts off a hydraulic operating fluid from the pilot pump to the solenoid valve, a first sensor that senses the amount of operation of an operation lever, and a second sensor that senses a state amount relating to operation of the solenoid valve, whether or not an abnormality of the second sensor exists is determined on the basis of a sensing signal of the second sensor. When it is determined that the second sensor is abnormal, on the basis of a sensing signal of the first sensor, an opening command is made to the shut-off valve if operation of the operation lever is sensed, and a closing command is made to the shut-off valve if the neutral state of the operation lever is sensed.