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:
Apr. 01, 2008
Filed:
Sep. 23, 2005
Mark A. Spickard, Rockford, IL (US);
Mark A. Spickard, Rockford, IL (US);
Woodward Governor Company, Rockford, IL (US);
Abstract
A low energy stepper motor driven actuator that eliminates the need for a position sensor is provided. The stepper motor rotates a cam in a control piston valve. The cam rotation increases the gap between the cam and nozzle on one side of the cam and decreases the gap between the cam and nozzle on the other side. The gap differences affect the pressures on the control piston ends, which forces the piston in the direction that will re-equalize the cam-nozzle gaps. As a result, piston moves to a position such that the head or rod of the actuator piston receives high pressure flow, thereby moving the actuator. Movement of the actuator rod provides mechanical feedback to the cam, causing the cam to move back to its mechanical null position.