Patents by Inventor John Roydhouse

John Roydhouse 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).

  • Fracturable-key activated control system
    Patent number: 4871053
    Abstract: A key activated control unit to be activated by a key having a shank portion and a blade portion, the unit is operated by inserting the key and having the blade portion trigger a switch at a predetermined location. The blade portion is not returnable from that predetermined position, and a key destruction blade is provided to destroy the blade portion once at that predetermined position.
    Type: Grant
    Filed: August 7, 1987
    Date of Patent: October 3, 1989
    Inventors: Dara Cosgrave, John Roydhouse