Patents by Inventor Takumi Funahashi

Takumi Funahashi 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).

  • Method for processing vacuum switch and vacuum switch processed by the method
    Patent number: 4736078
    Abstract: A vacuum switch having two main electrodes encased in a vacuum vessel to be operable in opening and closing the main electrodes, is provided with a contact piece made of a copper-chromium alloy secured or formed on at least one of the main electrodes. The operational property of the main electrodes is substantially improved by flowing and interrupting an electric current of a predetermined current density for a number of times through the two main electrodes for improving surface condition of the contact piece by forming a recrystallized layer over the outer surface of the contact piece.
    Type: Grant
    Filed: April 28, 1987
    Date of Patent: April 5, 1988
    Assignee: Kabushiki Kaisha Toshiba
    Inventors: Koichi Yasuoka, Tohru Tamagawa, Eiji Kaneko, Mitsutaka Homma, Satoru Yanabu, Takumi Funahashi
  • DC Circuit breaker
    Patent number: 4458121
    Abstract: A DC circuit breaker of the type using a blown arc-extinguishing gas is disclosed which allows for reliable fast interruption of DC currents through the provision of arc extension current paths. The extension current paths are relatively long and are bent after the incidence of the arc-extinguishing gas on the arc. The arc is formed to extend for a long distance in a loop configuration. An auxiliary electrode short-circuits the extended arc with one auxiliary electrode being provided for each extension current path.
    Type: Grant
    Filed: September 30, 1982
    Date of Patent: July 3, 1984
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Satoru Yanabu, Tohoru Tamagawa, Eiji Kaneko, Takumi Funahashi
  • DC Circuit breaker apparatus
    Patent number: 4442469
    Abstract: A DC circuit breaker apparatus comprises a first interrupter and a second interrupter connected in series. A first capacitor and a discharge gap are respectively connected in parallel with the first and second interrupters. An impedance element is connected between a first junction between the first capacitor and the discharge gap and a second function between the first and second interrupter, and a second capacitor is connected in parallel with the second interrupter.
    Type: Grant
    Filed: August 18, 1982
    Date of Patent: April 10, 1984
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Satoru Yanabu, Tohoru Tamagawa, Takumi Funahashi
  • Vacuum interrupter
    Patent number: 4246458
    Abstract: In a vacuum interrupter of the type comprising a vacuum vessel and a pair of separable main electrodes located in the vacuum vessel, at least one of the main electrodes being provided with a coil electrode for generating an axial magnetic field, the vacuum interrupter further comprises a flat annular intermediate electrode disposed between the main electrodes and provided with an opening at its center through which one of the main electrodes passes.
    Type: Grant
    Filed: April 4, 1978
    Date of Patent: January 20, 1981
    Assignee: Tokyo Shibaura Denki Kabushiki Kaisha
    Inventors: Satoru Yanabu, Tohoru Tamagawa, Shigeo Souma, Takumi Funahashi, Hiroyuki Okumura, Nobuyuki Takahashi