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. 14, 1999
Filed:
May. 04, 1998
William Douglas Graham, East Moline, IL (US);
Ronald Lee Pratt, Taylor Ridge, IL (US);
Deere & Company, Moline, IL (US);
Abstract
Frame sections on an implement are supported above the ground by lift wheel assemblies having positive mechanical depth stops and series connected lift cylinders. A pressure responsive bypass valve is installed in series with an orifice between the ports of the series connected cylinders. The valve permits the corresponding cylinder to be retracted and positively held against the depth stop and allows bypass flow to the next cylinder in series for continued retraction of the next cylinder until it bottoms against the stop. The orifice protects the bypass valve poppet from damaging high flows and controls the rate of descent of the other frame sections onto the remaining stops. The system permits the cylinders to positively maintain the down-stopped positions of the sections without unwanted looseness typical with slotted or other lost motion types of connections. A restrictor valve may be added to limit the maximum pressure so that all the bypass valves cannot open at the same time.