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:
Oct. 08, 1996
Filed:
Sep. 26, 1995
Steven C Bray, Washington, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A two stage electrohydraulic pressure control valve includes a pilot stage for providing regulated pressure at lower flows to a larger main stage that handles the higher control flows to and from a pressure applied clutch or pressure released brake. The regulated pressure from the pilot stage acts on an end of the main stage for controlling the position of the main stage. An energy storage device in the form of either an accumulator or a load piston device is connected to the end of the main stage to permit instantaneous independent movement of the main stage relative to the pilot stage. The energy storage device quickly provides for or accepts displaced fluid from the main stage much faster than the limited flow capacity and response time of the pilot stage. This permits the main stage to quickly adjust to flow changes to the clutch or brake with minimal change in pressure until the pilot stage can respond.