Patents by Inventor John E. Hull, Jr.

John E. Hull, Jr. 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).

  • Mine vehicle safety apparatus
    Patent number: 4340920
    Abstract: A mine safety system for use with a direct current power supply delivering power via a pair of conductors to the direct current load components of mining apparatus which includes a conductive frame electrically isolated from ground and at least one of the conductors. In the safety system, an alternating current generator transmits a predetermined frequency signal over the pair of conductors to the mining apparatus. A filter which passes the predetermined frequency signal is disposed at the mining apparatus in a shunt circuit with the load components, the filter thereby being connected to the generator.
    Type: Grant
    Filed: March 30, 1981
    Date of Patent: July 20, 1982
    Assignee: Peabody Coal Company
    Inventors: Ronald P. Gill, Dempsey G. Tucker, John E. Hull, Jr.