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:
Apr. 26, 2022
Filed:
Mar. 22, 2019
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A work vehicle provided with a loading hydraulic circuit (A), including at least a main hydraulic pump (), a lift arm cylinder () and a control valve (), an auxiliary hydraulic pump (), a negative parking brake device (PB), and a parking brake releasing hydraulic circuit (B), in which the vehicle includes: a loading operation hydraulic circuit (B) located upstream of the parking brake releasing hydraulic circuit; an emergency flow path () for supplying the pressure oil discharged from the auxiliary hydraulic pump to the parking brake device through the loading operation hydraulic circuit in an emergency; and a valve unit () located in the emergency flow path. If the pressure of the parking brake releasing hydraulic circuit is lower than the brake release pressure to release the braking state of the parking brake device, the valve unit is switched to the communicating position.