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:
Jun. 26, 1984
Filed:
May. 03, 1982
Lael B Taplin, Union Lake, MI (US);
Vickers, Incorporated, Troy, MI (US);
Abstract
An electro-hydraulic servo valve system comprising a two-stage spool type servo valve including a first stage comprising an electrical force motor and a second stage including a spool for controlling flow to an actuator. The force motor is operable upon receipt of a command electrical signal to move the spool. A first feedback is operable to cause the force motor to stop the movement of the spool. A second feedback is also operable to stop the movement of the spool at a predetermined position. The second feedback has a greater gain than said first feedback so that it normally dominates in the system. The second feedback comprises a pair of identical electrical sensors connected in parallel, and operable by movement of the spool. A comparator circuit compares the electrical signals from the sensors and is operable when the signals deviate from one another by a predetermined amount to disable the second feedback so that the first feedback will function permitting the electro-hydraulic servo valve system to operate without the second feedback.