Patents by Inventor David C Janssen

David C Janssen 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).

  • Self-destruct electrical interlock for cylinder lock and key set
    Patent number: 5186031
    Abstract: A cylindrical lock and key set with an electronic interlock circuit includes a self-destruct circuit portion which is intercepted, engaged and destructed by an intercept member when the cylinder is forcibly, axially removed from the lock sleeve. A second intercept member may engage the circuit and destruct it when the cylinder is forcibly rotated. Either or both of the intercept members may be located on the cylinder.
    Type: Grant
    Filed: August 20, 1991
    Date of Patent: February 16, 1993
    Assignee: Briggs & Stratton Corporation
    Inventors: David C. Janssen, Larry R. Grimmer