Patents by Inventor William Charles Wheatley

William Charles Wheatley 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).

  • Intrinsically safe telephone systems
    Patent number: 4064366
    Abstract: An intrinsically safe telephone system for use in mines or similar hazardous areas including a battery charging circuit arranged to supply charging current of a predetermined low value to the battery of an operational unit located in the hazardous area during on-hook periods. A circuit is provided for modulating the charging current below the predetermined value to generate both the incoming and outgoing call signals during signaling periods.
    Type: Grant
    Filed: January 15, 1976
    Date of Patent: December 20, 1977
    Assignee: Winster Engineering Group Limited
    Inventors: William Wheatley, Robert Roy Goff, William Charles Wheatley