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. 01, 1999
Filed:
Dec. 22, 1997
Chandrasekar Ramamoorthy, Downers Grove, IL (US);
Steven P Seaney, Glen Ellyn, IL (US);
Randall A Harlow, Brimfield, IL (US);
John R Connolly, Channahon, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
The present quick drop valve control provides both quick drop and float functions by moving a quick drop valve to a position interconnecting the drop and lift sides of a pair of lift cylinders when a directional control valve reaches a predefined position. The quick drop function valve is established by simultaneously energizing a first solenoid valve to communicate a shift end of the quick drop valve with a resolved pressure port of a resolver connected to the drop and lift sides and a first solenoid of a second solenoid valve to communicate a spring end of the quick drop valve with the drop sides so that the quick drop valve moves to the interconnecting position combining fluid expelled from the lift sides with fluid going to the drop side from a pump. The float function is established by simultaneously energizing the first solenoid valve to communicate the shift end of the quick drop valve with the resolved pressure port and a second solenoid of the second solenoid valve to communicate the spring end of the quick drop valve with the tank so that the quick drop valve moves to the interconnecting position effectively intercommunicating the pump, the tank and the lift sides and the drop sides of the lift cylinders.