Patents by Inventor John F. Keidel

John F. Keidel 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: 4264788
    Abstract: This invention relates to damping pads and accoustical horns for use with transducer assemblies. The problems of proximity detection ranges, subfreezing operating temperature ranges, ringing and backwave reflection are addressed. In a preferred embodiment of an ultrasonic level control indicator using a piezoelectric transducer, a resilient, compressible sound absorbing damping material (like polyurethane pads) is compressed against the transducer vibrating member to decrease ringing and backwave effects. An acoustical horn assembly with a tapered opening is positioned adjacent the transducer to improve the signal.
    Type: Grant
    Filed: January 31, 1979
    Date of Patent: April 28, 1981
    Assignee: Princo Instruments, Inc.
    Inventors: John F. Keidel, Larry P. Kahhan