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:
Aug. 31, 1993
Filed:
Mar. 13, 1992
Kenneth D Garnjost, Buffalo, NY (US);
Moog Inc., East Aurora, NY (US);
Abstract
An improved two-stage servovalve (70) has a pilot-stage and an output-stage. A torque motor (16) produces pivotal movement of a flapper (18) in response to a supplied electrical current. The pilot-stage produces a flow which is used to selectively displace a second-stage spool (61) relative to a body bore. The servovalve has a hydromechanical pressure feedback loop closed about the load and second-stage spool. The pressure feedback loop is intertwined with an electrical spool position feedback loop closed about the spool and driver. The command to the pressure loop is a function of the error of the spool position loop. The gain of the spool position loop dominates that of the pressure loop. The valve has pressure-flow characteristics approximating those of a 'flow-control' servovalve but affords access to an electrical signal substantially proportional to the load pressure differential.