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:
Jun. 18, 1991
Filed:
Oct. 30, 1989
Douglas M Gage, Dubuque, IA (US);
Deere & Company, Moline, IL (US);
Abstract
The invention is directed to a hydraulic control mechanism for a work vehicle. The work vehicle is provided with a work implement that is operated by a hydraulic actuator. The positioning of the work actuator is controlled by a pilot control system that supplies a pilot control signal to the end caps of a main hydraulic control valve. The mechanism comprises two pressure sensing valves which control the flow of hydraulic fluid from a fixed displacement pump to move the hydraulic actuator, and the flow of hydraulic fluid from a variable displacement pump to hold the hydraulic actuator. The first pressure sensing valve is used to direct fluid from the variable displacement pump to the hydraulic actuator; whereas the second pressure sensing valve is used to decouple one of the end caps of the main hydraulic control valve from the pilot sensing line so that the main hydraulic control valve is shifted to neutral, and blocking the flow of hydraulic fluid from the fixed displacement pump to the hydraulic control actuator.