Patents by Inventor Frank D. Lewis, Sr.

Frank D. Lewis, Sr. has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Pilot operated stepping valve
    Patent number: 4145956
    Abstract: A pilot operated stepping valve where an electrical pulse motor drives a pilot valve spool which controls the flow of hydraulic fluid driving a main valve spool which actuates a hydraulic motor or actuator. The main valve spool follows the pilot spool and is hence sensitive to the pulses received by the pulse motor.
    Type: Grant
    Filed: April 25, 1977
    Date of Patent: March 27, 1979
    Assignee: The United States of America as represented by the Secretary of the Air Force
    Inventors: Edwin W. Rumrill, Jr., Frank D. Lewis, Sr.