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. 15, 2009
Filed:
Nov. 21, 2006
William C. Shelbourn, Bismarck, ND (US);
Kyle D. Kaldor, Bismarck, ND (US);
William C. Shelbourn, Bismarck, ND (US);
Kyle D. Kaldor, Bismarck, ND (US);
Clark Equipment Company, West Fargo, ND (US);
Abstract
A valve arrangement includes a spool movable in first and second strokes. A first biasing member has a first spring constant and a first preload, and a second biasing member has a second spring constant lower than the first spring constant and a second preload higher than the first preload. The first biasing member and not the second biasing member biases the spool toward the center position through the entire first stroke and is deflected during movement of the spool from a center position to an intermediate position within the second stroke. The first and second biasing members are deflected during movement of the spool from the intermediate position to an end of the second stroke.