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. 27, 1994
Filed:
Oct. 18, 1993
Robert E Shelhart, Brentwood, TN (US);
Carl J Klug, Brooklyn Park, MN (US);
Wickes Manufacturing Company, Charlotte, NC (US);
Abstract
A vehicle convertible top is moved by hydraulic cylinders between extreme raised and lowered positions. The cylinder ends are connected to ports in a reversible hydraulic pump in one end of an elongated housing, which has a reservoir in the other end, separated by a pump cap. The pump cap houses two fluid circuits connecting the pump to the ends of the cylinders. Each circuit has an end of cycle hydraulic locking device comprising a normally-closed valve and a valve actuator. The circuit valves are alternately opened by pump pressure to pressurize one end of the cylinders to alternately raise and lower the top. The opened valve closes when the pump ceases operation, preventing fluid backflow through the one circuit to the pump. This hydraulically locks the top in extreme raised and lowered positions to facilitate top latching and tonneau installation. A groove in the valve seat forms a leakage path which bypasses the closed valve to slowly reduce hydraulic pressure in the actuator at a predetermined rate until pressure is relieved after a predetermined period of time sufficient to accomplish top latching or tonneau installation. A manually-operated pump bypass in the pump cap vents both circuits to the reservoir to enable manual top operation when the pump is inoperative. The pump cap includes makeup valving for accommodating the displacement differential in the cylinder.