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. 31, 1993
Filed:
Sep. 25, 1992
Dieter Gawlick, Ludwigshafen, DE;
Deere & Company, Moline, IL (US);
Abstract
A two-stage brake control valve has a larger first stage and a smaller second stage. First stage operates to fill a brake. Then, after a transition phase only the second stage is used to supply the working pressure. A check valve is between the first stage pressure chamber a sump. The check valve opens if the pressure in the first stage pressure chamber exceeds a predetermined value. To minimize the operating force of the valve and to avoid a sudden change of the valve working pressure during the changing phase, the closing force of the check valve is controlled as a function of the valve working pressure. The valve working pressure acts on a valve spool which influences the closing force of the check valve in the way that the closing force decreases with increasing working pressure.