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. 20, 1994
Filed:
Dec. 09, 1993
William K Holmes, San Diego, CA (US);
United States Elevator Corp., Spring Valley, CA (US);
Abstract
A control valve assembly for an hydraulically operated elevator includes separate control valve units for controlling upwards and downwards movements of the elevator. The up valve unit is connected to a pump output and controls connection of the pump output to the elevator cylinder via a check valve. The up valve unit includes an orifice for connecting the pump output to a reservoir, and a valve member for varying the size of the orifice to control the amount of fluid passed to the reservoir, and thus the amount of fluid supplied to the elevator cylinder. The down valve unit has an inlet for connection to the elevator cylinder, a variable orifice connected to a reservoir, and a valve member for controllably varying the size of the orifice to control the rate of descent of the elevator.