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. 22, 2010
Filed:
Aug. 30, 2006
Satoru Kaneko, Tsuchiura, JP;
Tomohiko Yasuda, Tsuchiura, JP;
Takashi Yagyu, Tsuchiura, JP;
Yasuo Tanaka, Tsuchiura, JP;
Michio Fushiki, Tsuchiura, JP;
Satoru Kaneko, Tsuchiura, JP;
Tomohiko Yasuda, Tsuchiura, JP;
Takashi Yagyu, Tsuchiura, JP;
Yasuo Tanaka, Tsuchiura, JP;
Michio Fushiki, Tsuchiura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
In a hydraulic drive device for vertical pivoting movement of a load carrying platform, a first directional control valve has only three switchover positions, including a neutral position relating to operation of stopping and holding a load carrying platform, a switching position relating to operation of lifting the load carrying platform, and a switch over position relating to operation of forced lowering of the load carrying platform. A second directional control valve has only three switchover positions, including a neutral position, a switching position, and a switchover position relating to operation of allowing the load carrying platform to fall by its own weight. The device includes a first on-off valve, a second on-off valve, and a third on-off valve that are proportional control solenoid valves for switching an appropriate one of the first and second directional control valves.