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:
Nov. 02, 1999
Filed:
Jan. 09, 1998
Thomas S Carroll, Peoria, IL (US);
Chien Chang Lee, Peoria, IL (US);
David M Milam, Metamora, IL (US);
Caterpillar Inc., Peoria, IL (US);
Abstract
A servo control valve includes a valve body that defines a high pressure passage, a low pressure passage and a flow passage. A valve member has a first pressure surface in opposition to a control pressure surface. The valve member is positioned in the valve body and moveable between a first position in which the high pressure passage is open to the flow passage, and a second position in which the low pressure passage is open to the flow passage. A pilot member is positioned in the valve body and is moveable between an up position in which the control pressure surface is exposed to pressure in the high pressure passage, and a down position in which the control pressure surface is exposed to pressure in the low pressure passage. A spring is operably positioned to bias a valve member toward one of its first position and its second position.