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. 28, 1999
Filed:
Aug. 26, 1998
Seiichi Fuchita, Katano, JP;
Tomio Teranaka, Yawata, JP;
Fujitoshi Takamura, Hirakata, JP;
Harushige Nishida, Hirakata, JP;
Kiyokazu Nakabo, Kyoto, JP;
Komatsu Ltd., Tokyo, JP;
Abstract
A control circuit for a piece of heavy machinery reduces a speed of one actuator, having a lower load, when that actuator and another actuator, having a higher load, are operated simultaneously. The control circuit includes a first control valve for supplying a first actuator with pressurized oil, discharged from a hydraulic pump; a second control valve for supplying a second actuator with pressurized oil, discharged from the hydraulic pump; operating units for actuating the first control valve and the second control valve; and a mode selector for providing a command to the second control valve in order to increase a speed of the first actuator compared with that of the second actuator when the first and second actuators are operated simultaneously. A variable adjustor can be provided to control the open area of a valve for enabling the stroke of the spool of the second control valve to regulated. The control circuit can include a sensor for detecting pilot pressure applied to the first control valve; a sensor for detecting pilot pressure applied to either end of the second control valve; a solenoid valve for passing pilot pressure to pilot ports at both ends of the second control valve; and a controller for actuating said solenoid valve responsive to signals from the two sensors.