Patents by Inventor Isamu Ikeda

Isamu Ikeda 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: 3963880
    Abstract: An improved moving coil-type phonograph cartridge producing reliably higher output and being easily manufactured is provided. Moving coils disposed in the center of a gap in magnetic circuit of permanent magnet and pole pieces is supported rotatably about a fulcrum positioned out of coil bobbin and an axial line of the gap so that coil sections on remote side from the fulcrum will transverse magnetic fluxes in the gap with a larger rotation radius and at a higher velocity than those of the other coil sections on fulcrum side. Further, at least a pole piece on the fulcrum side has a cavity surrounding the fulcrum so that the fluxes will be distributed to be circumferentially away from the fulcrum whereby the coil sections on the fulcrum side will be disposed out of the fluxes. Electromotive force eventually produced in the coil sections on the remote side from the fulcrum is larger than that produced in the other sections so that effectively and reliably higher output can be obtained.
    Type: Grant
    Filed: April 9, 1975
    Date of Patent: June 15, 1976
    Assignee: Fidelity-Research Inc.
    Inventor: Isamu Ikeda