Patents by Inventor Richard O. Lightfoot

Richard O. Lightfoot 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).

  • Apparatus for visually indicating when a pool filter is dirty
    Patent number: 3939796
    Abstract: Apparatus for indicating when a swimming pool filter needs to be cleaned, which comprises a flexible diaphragm covering an opening in the conduit on the inlet side of a pool filter and a housing covering the diaphragm with a movable piston member inside the housing and engaging the surface of the diaphragm. Spring means urges the piston against the diaphragm to counteract pressure of water in the conduit against the diaphragm. A movable flag is operated by the piston means to indicate through a window in the housing when the piston has moved a predetermined distance.
    Type: Grant
    Filed: September 27, 1974
    Date of Patent: February 24, 1976
    Assignee: Muskin Corporation
    Inventors: Clarence G. Smith, Richard O. Lightfoot