Patents by Inventor Jonathan B. Lindquist

Jonathan B. Lindquist 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).

  • Patent number: 5003290
    Abstract: An integrated alarm and access control system includes an access control package, an intrusion detection package and an interface unit. A position sensor determines if a door is open or closed and an electrically activated locking device locks the door in its closed position. A supervisory circuit provides line security. A door position relay and a first timer prevent an alarm signal from the supervisory circuit if the door is open and the egress device is actuated for a time period. A door control relay activates locking devices and a second timer responds to the door control relay, the egress device and the door position relay to give a prealarm signal. Fail-safe and fail-secure circuits are included.
    Type: Grant
    Filed: January 11, 1990
    Date of Patent: March 26, 1991
    Inventors: Jonathan B. Lindquist, Granger W. Smith, IV