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:
Nov. 19, 2013
Filed:
Mar. 15, 2010
Naoki Hagiwara, Tsuchiura, JP;
Tsuyoshi Nakamura, Tsuchiura, JP;
Kensuke Sato, Tsuchiura, JP;
Yasuo Okano, Tsuchiura, JP;
Kouji Ishikawa, Tsuchiura, JP;
Masanori Ezawa, Tsuchiura, JP;
Naoki Hagiwara, Tsuchiura, JP;
Tsuyoshi Nakamura, Tsuchiura, JP;
Kensuke Sato, Tsuchiura, JP;
Yasuo Okano, Tsuchiura, JP;
Kouji Ishikawa, Tsuchiura, JP;
Masanori Ezawa, Tsuchiura, JP;
Hitachi Construction Machinery Co., Ltd., Tokyo, JP;
Abstract
A hydraulic drive system for a working machine provides improved safety during forced regeneration. Upon input of a forced regeneration command signal from a forced regeneration switch, a controller detects non-operated states of all hydraulic actuators such as an arm cylinder arranged on a hydraulic excavator based on a lock detection signal from a gate lock detection switch, and also an attitude of a front working mechanism. The attitude is proper from the standpoint of safety. The detection is based on an arm angle signal from an arm angle sensor, a bucket angle signal from a bucket angle sensor and a boom pressure signal from a boom pressure sensor. Taking the detection of the non-operated states and proper attitude as conditions, the controller outputs control signals to a boosting proportional solenoid valve and flow-rate controlling, proportional solenoid valve to make a forced regenerator conduct forced regeneration.