Patents by Inventor William G. Krawczak

William G. Krawczak 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).

  • Piston loudspeaker
    Patent number: 4013846
    Abstract: An electroacoustic loudspeaker having a rigid, light-weight diaphragm and a substantially closed loop magnet support of a magnetically permeable material having a channel-shaped cross-section and supported adjacent and spaced from the diaphragm with the open side of the channel facing the diaphragm. The magnet support carries a pair of magnets magnetized and positioned with opposite poles in spaced facing relation and a voice coil is secured to the diaphragm and lies in the gap between the magnets.
    Type: Grant
    Filed: June 1, 1976
    Date of Patent: March 22, 1977
    Assignee: Minnesota Mining and Manufacturing Company
    Inventors: William G. Krawczak, William M. Mularie