Patents by Inventor L. Paul Hartwick

L. Paul Hartwick 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: 4881024
    Abstract: The voltage comparison circuit uses digital gates formed into at least two pairs of flip flops, one digital gate having a volt reference supply to and acting to disconnect a load from a source when the voltage of the source declines below a predetermined threshold. In another aspect the circuit provides further digital gates which operate upon transistor and cycle a load for connection to a source on a duty cycle of 100 to 150 seconds on and off so that the load is provided with an intermitten secondary energy source which provides limited drain on the permanent source, which if it be a battery or a storage battery insures that the battery is not drained on a continuous basis even though the load may so demand. The circuit also monitors the voltage threshold of the primary source so that should it fall below that threshold the load is disconnected.
    Type: Grant
    Filed: December 9, 1988
    Date of Patent: November 14, 1989
    Assignee: Trek-Tron Coolers Inc.
    Inventor: L. Paul Hartwick