Patents by Inventor Embry Mayes Kendrick, Jr.

Embry Mayes Kendrick, 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).

  • Alarm system with supervisory system to detect severing or bridging of detection switches
    Patent number: 3997890
    Abstract: A tamper proof detector circuit for use in an alarm system and an integral switch for use therein. The integral switch is comprised of a housing which encloses an alarm condition sensing switching means connected to a diode. The integral switches are connected in a bridge and an AC voltage is applied thereto. A DC voltage drop detecting means is connected to the output of the bridge for detecting a drop in voltage which will occur if an intruder either open circuits or short circuits one of the integral switches. An overvoltage detecting means is provided for detecting a voltage source which an intruder might insert in the circuit to conceal the removal of an integral switch.
    Type: Grant
    Filed: June 11, 1974
    Date of Patent: December 14, 1976
    Inventor: Embry Mayes Kendrick, Jr.