Patents by Inventor Hidetoshi Shirakawa

Hidetoshi Shirakawa 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).

  • Publication number: 20190257426
    Abstract: A gasket includes a reinforcing body made of a resin film, a one-side gasket body on one surface of the reinforcing body, and another-side gasket body on another surface of the reinforcing body. The reinforcing body has, between both gasket bodies, a three-dimensional shape in which the resin film is bent. The one-side gasket body includes an inversely-tapered engaging convex portion protruding toward the other-side gasket body, the reinforcing body includes a deformation portion as the three-dimensional shape deforming along a shape of the engaging convex portion, and the other-side gasket body includes an inversely-tapered engaging concave portion embedding therein the engaging convex portion and the deformation portion. At least one of the one-side gasket body and the other-side gasket body includes a flat surface-shaped seal surface, and the reinforcing body has a convex shape as the three-dimensional shape protruding toward the flat surface-shaped seal surface.
    Type: Application
    Filed: September 21, 2017
    Publication date: August 22, 2019
    Applicant: NOK CORPORATION
    Inventors: Sohei SHIRAKAWA, Hajime YUI, Takayuki HORIMOTO, Hidetoshi SASO
  • Patent number: 6771792
    Abstract: An elongated oval track-shaped loudspeaker has a diaphragm of a track-shape having major and minor axes, and a pole piece of an elongated oval shape and disposed to conform its major axis to that of the diaphragm, whereby a sufficient space is secured for a width size of a diaphragm-supporting damper at its portions on both sides along the major axis of the diaphragm, a magnet around the pole piece is enlarged, and the pole piece is dimensioned in its sectional area to correspond to the magnet to cause no magnetic saturation.
    Type: Grant
    Filed: December 17, 1999
    Date of Patent: August 3, 2004
    Assignee: Foster Electric Co., Ltd.
    Inventor: Hidetoshi Shirakawa
  • Patent number: 5740265
    Abstract: A loudspeaker unit includes a magnetic system of dual magnetic gaps formed with a permanent magnet disk carrying on both sides top and bottom plates and a cylindrical yoke surrounding the plates to form therebetween upper and lower magnetic gaps, and a vibratory system formed with a cylindrical voice coil bobbin carrying upper and lower voice coils for use in the dual magnetic gaps as disposed in half off-set state with respect to the gaps and a diaphragm coupled to upper end of the bobbin, the bobbin being supported by upper and lower dampers with respect to the magnetic system for vibration in axial directions of the magnetic system, allowing the bobbin to be supported at fulcrums positioned above and below voice-coil driving points.
    Type: Grant
    Filed: December 23, 1996
    Date of Patent: April 14, 1998
    Assignee: Foster Electric Co. Ltd.
    Inventor: Hidetoshi Shirakawa
  • Patent number: 5511131
    Abstract: A loudspeaker has two magnets disposed directly with respect to voice coils for generating a repulsion magnetic field at the voice coils, without interposition of yoke but with mutually repulsing magnetic polarities of the magnets, and a diaphragm directly coupled at inner peripheral edge substantially to the center of outer periphery of the voice coils. Driving force is transmitted highly efficiently from the voice coils to the diaphragm, and the loudspeaker can be sufficiently minimized in the thickness and weight.
    Type: Grant
    Filed: July 20, 1994
    Date of Patent: April 23, 1996
    Assignee: Foster Electric Co., Ltd.
    Inventors: Rintaro Kohara, Takeshi Yoshimura, Hidetoshi Shirakawa
  • Patent number: 5371806
    Abstract: A loudspeaker has two magnets disposed directly with respect to voice coils for generating a repulsion magnetic field at the voice coils, without interposition of yoke but with mutually repulsing magnetic polarities of the magnets, and a diaphragm directly coupled at inner peripheral edge substantially to the center of outer periphery of the voice coils. Driving force is transmitted highly efficiently from the voice coils to the diaphragm, and the loudspeaker can be sufficiently minimized in the thickness and weight.
    Type: Grant
    Filed: May 28, 1993
    Date of Patent: December 6, 1994
    Assignee: Foster Electric Co., Ltd.
    Inventors: Rintaro Kohara, Takeshi Yoshimura, Hidetoshi Shirakawa