Patents by Inventor Earl L. Dombroski

Earl L. Dombroski 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: 4807295
    Abstract: A loudspeaker design that eliminates the close tolerance magnetic gap used in conventional loudspeakers and in which motion of the diaphragm is produced by the attraction and repulsion of the magnetic poles of a solenoid and a permanent magnet. In the preferred embodiment, the permanent magnet is affixed to the frame, and the solenoid fits loosely about it, the two being coaxial. Elimination of the magnetic gap relaxes the dimensional tolerances of the loudspeaker as well as the possibility that heating will cause the coil to expand to the point of interfering with the pole pieces. Also, the design of the present invention results in the driving portion of the magnetic field being spread over a relatively larger volume of space, and this reduces the production of motion-induced voltages in the windings of the drive coil and improves linearity.
    Type: Grant
    Filed: August 18, 1987
    Date of Patent: February 21, 1989
    Assignee: Dumbroski and Hanson Industrial Designs, Inc.
    Inventor: Earl L. Dombroski