Patents by Inventor John Robert Thornton

John Robert Thornton 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).

  • Vehicle headlamp control circuits
    Patent number: 4117453
    Abstract: An automatic vehicle headlamp intensity adjustement circuit includes a high sensor. A tuned rectifier circuit for producing a d.c. signal of magnitude dependent on the amplitude of the 50Hz (or other local supply frequency) component of the signal picked up by the sensor. A lamp current modulating circuit is controlled by this d.c. signal through the intermediary of an averaging circuit. The averaging circuit has a relatively long time constant and a timer is connected to reduce this time constant if the d.c. signal continues to fall for more than a predetermined period of time.
    Type: Grant
    Filed: February 4, 1977
    Date of Patent: September 26, 1978
    Assignee: Lucas Industries Limited
    Inventors: Duncan Barry Hodgson, John Robert Thornton, Jonathan Rose