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. 01, 2011
Filed:
Apr. 04, 2007
Shigeru Yamamoto, Hirakata, JP;
Tomohiro Nakagawa, Hirakata, JP;
Satoru Shintani, Hirakata, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
A tankand a main hydraulic pumpare connected to head side actuator chambersand rod side actuator chambersof hydraulic actuatorsvia conduits. A direction control valveand a quick drop valveare connected to the conduits. A hydraulic circuit is provided with an electromagnetic switch valve, which switches the quick drop valvefrom a non-quick drop positionto a quick drop position. When switching the direction control valvefrom a neutral positionto a lowering operation position, if the manipulation speed of a manipulation leverexceeds a criteria speed, an excitation signal is output from a control deviceto an electromagnetic switch valveto quickly drop a blade, and the quick drop valveis switched from the non-quick drop positionto the quick drop position