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:
Mar. 22, 2022
Filed:
Mar. 24, 2017
Hitachi Construction Machinery Tierra Co., Ltd., Koka, JP;
Kazushige Mori, Moriyama, JP;
Hajime Yoshida, Omihachiman, JP;
Yoshifumi Takebayashi, Koka, JP;
Natsuki Nakamura, Koka, JP;
Daisuke Oka, Yasu, JP;
Abstract
A hydraulic drive system for a hydraulic excavator that enables leveling work and a jack-up operation by a blade in a float state, that can prevent a body from falling even when an operator has falsely operated the hydraulic excavator during the jack-up operation by the blade, and that yet can perform favorable leveling work with the blade turned into the float state is provided. A float switch, a float valve, and a controllerare provided, the float valveis changed over to a float position VI upon operating the float switchwhen the blade is not in a jack-up state, the float valveis changed over from the float position VI to a normal position V when the float valveis in a state of being at the float position VI and an operation lever devicehas been operated, and the float valveis kept at the normal position V when the float valveis at the normal position V and the float switchhas been operated in the jack-up state.