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:
Dec. 27, 2016
Filed:
Nov. 12, 2013
Kobe Steel, Ltd., Kobe-shi, JP;
Kobelco Cranes Co., Ltd., Shinagawa-ku, JP;
Kobe Steel, Ltd., Kobe-shi, JP;
KOBELCO CRANES CO., LTD., Shinagawa-ku, JP;
Abstract
Provided is a hydraulic drive apparatus for working machine capable of preventing an excessive pressure drop on a meter-in side and moving a load in a lowering direction at a stable speed requiring no counter balance valve, including a hydraulic pump, a first hydraulic actuator lowering a first load, an operating device, a first hydraulic circuit including meter-in and meter-out flow passages, a control valve, a meter-in-flow-rate controller, a meter-out-flow-rate controller making a meter-out flow rate not lower than a meter-in flow rate, a second hydraulic actuator, a second hydraulic circuit between the first hydraulic circuit and a tank and for the second hydraulic actuator, a back pressure valve between the second hydraulic circuit and the tank, a regeneration line leading a part of hydraulic fluid from between the second hydraulic circuit and the back pressure valve to the meter-in flow passage, and a check valve in the regeneration line.