Patents by Inventor Henry L. Pfister

Henry L. Pfister 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: 4775865
    Abstract: A system for providing early warning of the approach and egress of emergency vehicles in which the warning system provides a display to indicate the direction from which the emergency vehicle is approaching and in addition provides preemption control of the traffic signals at an intersection. A transmitter mounted on an emergency vehicle transmits a signal whenever it is on an emergency call which is received by infrared (I.R.) receivers positioned at an intersection to respond to the transmitted signals. The received signal is then processed by a master controller which in turn pre-empts operation of traffic signals to control traffic flow at the intersection to which the emergency vehicle is approaching. The master controller also provides an output to display signs facing approaching traffic on each road approaching the intersection which displays messages and symbols indicating the direction of the approaching emergency vehicle.
    Type: Grant
    Filed: July 10, 1987
    Date of Patent: October 4, 1988
    Assignee: E-Lited Limited, A California Limited Partnership
    Inventors: Michael R. Smith, Paul J. Davidson, Henry L. Pfister