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:
Aug. 09, 2005
Filed:
Oct. 26, 2004
Louis C. Harms, Evanston, IL (US);
Zilek Liberfarb, Morton Grove, IL (US);
Louis C. Harms, Evanston, IL (US);
Zilek Liberfarb, Morton Grove, IL (US);
Parker-Hannifin Corp., Cleveland, OH (US);
Abstract
This invention generally concerns electronically controlled hydraulic valves for use in electro-hydraulically controlled transmissions. The proportional pressure control valveincludes a hollow cagepierced by cage tank ports, cage clutch ports, and cage pump ports. The cage pump portsreceive fluid from a pump. The cage clutch portssupply fluid to a hydraulic actuator. The cage tank portsreturn fluid from the valveto a tank from where fluid circulates back to the pump. Main spoolcontrols fluid flow between cage clutch portsand cage pump portsor cage tank ports. An electro-magnetically operated pilot valve regulates fluid pressure applied to a control pressure surface. A feedback pressure passage, having feedback restriction orifice, restrains the rate fluid flows between the cage clutch portsand the feedback pressure surface