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:
May. 20, 2014
Filed:
Mar. 29, 2011
Katsumi Tamura, Omitama, JP;
Toshikazu Minoshima, Kasumigaura, JP;
Michio Fushiki, Tsuchiura, JP;
Takao Kurosawa, Ushiku, JP;
Katsumi Tamura, Omitama, JP;
Toshikazu Minoshima, Kasumigaura, JP;
Michio Fushiki, Tsuchiura, JP;
Takao Kurosawa, Ushiku, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A control valve device comprises two direction control valves. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. The direction control valve includes an expansion side variable throttle portion and a contraction side variable throttle portion. When a hoist cylinder is telescopically operated to raise or lower a vessel, as the hoist cylinder approaches a stop position, a controller determines that the hoist cylinder gets close to the stop position. Based upon this determination, the controller variably adjusts a flow passage area of the direction control valve using the variable throttle portions or variably adjusts a flow passage area of the direction control valve using the variable throttle portions in such a manner as to slow down or speed up the telescopic speed of the hoist cylinder corresponding to the weight in the side of vessel.