Patents by Inventor William G. Ferguson

William G. Ferguson 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).

  • Latent image ink
    Patent number: 5443629
    Abstract: A latent image ink particularly for use in printing forms such as games or coloring books. An offset lithographic press is used for imprinting a substantially invisible image on a sheet of standard paper. The latent ink used to form the latent image is a mixture of potassium ferrocyanide or other suitable color foxing iron complexing compounds, white ink and varnish. A developing solution such as ferric chloride or ammonium sulfate is subsequently added to the paper to render the image visible.
    Type: Grant
    Filed: May 27, 1994
    Date of Patent: August 22, 1995
    Assignee: Alex Wilson Coldstream, Ltd.
    Inventors: Jacqueline M. Saville, William G. A. Ferguson
  • Oscillatory circuit utilizing PTC resistor
    Patent number: 4320309
    Abstract: A control circuit for producing a repetitive closed-circuit, open-circuit condition between an electrical power source, such as a battery, and an electrical load comprises a positive temperature coefficient resistor in series with a relay coil. The PTC resistor is caused to alternate between a low resistance state and a high resistance state which permits energization and de-energization of the relay coil.
    Type: Grant
    Filed: December 31, 1979
    Date of Patent: March 16, 1982
    Assignee: GTE Products Corporation
    Inventors: Charles R. Griffiths, William G. Ferguson