Patents by Inventor Ryotomo Shirakawa

Ryotomo 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).

  • Patent number: 5338618
    Abstract: An electric contact material containing Li oxide of 0.01 to 2.0% by weight when represented in terms of the amount of Li, oxide of at least one rare earth element of 0.05 to 0.18% by weight when represented in terms of the amount of the rare earth element, and Ag or Ag alloy as the remaining portion; an electric contact material containing Li oxide of 0.01 to 2.0% by weight when represented in terms of the amount of Li, at least one rare earth element of 0.05 to 0.18% by weight when represented in terms of the amount of the rare earth element, at least one element selected from a group consisting of In, Sn, Zn, Mn, Pd, Sb, Cu, Mg, Pb, Cd, Cr and Bi by an amount of 0.1 to 1.0% by weight (however, in the case of Zn and Mn, the amount is set less than 0.5% by weight), and/or at least one element selected from a group consisting of Fe, Ni and Co by an amount of 0.03 to 0.6% by weight, and Ag as the remaining portion; and an electric contact formed by using the above material.
    Type: Grant
    Filed: September 25, 1992
    Date of Patent: August 16, 1994
    Assignees: The Furukawa Electric Co., Ltd., Mabuchi Motor Kabushiki Kaisha
    Inventors: Satoshi Suzuki, Nobuyuki Shibata, Ryotomo Shirakawa, Akira Matsuda
  • Patent number: 5334294
    Abstract: The present invention relates to a processing method of wire material and a processing device therefor at the times of intending to make the tip of wire materials such as guide wire for catheter thin and flexible by tapering.When the wire material passes through the electrolytic tub, the wire speed is made constant and the current value is controlled, or the current value is made constant and the wire speed is controlled to give the processings such as tapering. For the electrolytic polishing bath, it is desirable to use a mixed bath comprising trivalent alcohol, perchloric acid and monovalent alcohol.The inventive method exerts an effect that the tapering can be given efficiently and yet with high precision compared with the traditional method of mechanical polishing or the method of dipping one by one batchwise into the electrolytic polishing bath.
    Type: Grant
    Filed: September 4, 1992
    Date of Patent: August 2, 1994
    Assignee: The Furokawa Electric Co., Ltd.
    Inventors: Hirohisa Iwai, Kaisuke Shiroyama, Akira Matsuda, Takeo Nakamura, Ryotomo Shirakawa
  • Patent number: 5171643
    Abstract: An electric contact material comprising 0.01 to 2.0 weight % of Li, 0.01 weight % or more to less than 0.2 weight % of at least one rare earth metal and the remainder being Ag. The electric contact material may further comprise 0.1 to 1.0 weight % of at least one element selected from a group consisting of In, Sn, Zn, Mn, Pd, Sb, Cu, Mg, Pb, Cd, Cr and Bi, however, for Zn and Mn, the amount is less than 0.5 % by weight; and/or 0.03 to 0.6 weight % of at least one element selected from a group consisting of Fe, Ni and Co. The electric contact material is excellent in arc resistance, wear resistance and lubricity in a small current region and is suitable as a material for a slide contact and a rotary slide contact.
    Type: Grant
    Filed: July 23, 1990
    Date of Patent: December 15, 1992
    Assignees: The Furukawa Electric Co., Ltd., Mabuchi Motor Kabushiki Kaisha
    Inventors: Satoshi Suzuki, Nobuyuki Shibata, Ryotomo Shirakawa, Akira Matsuda