Patents by Inventor Hisao Otsuga

Hisao Otsuga 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).

  • Boring device for opening passages to branch portions of a lined main pipe line
    Patent number: 4882470
    Abstract: A boring device for a lining material in a branched portion of a lined pipe such as a gas-conduit or a city water pipe line to which the lining material has been applied, which device includes a tension coil spring 1, a compression coil spring 2 being connected to the tip of the tension coil spring and having a spring constant smaller than that of the tension coil spring, a head element 5 in the form of a circular truncated cone being connected to the tip of the compression coil spring 2 and having an electric heat-generating device 3 coated with a thermoplastic resin and a single or plural transmission wires 9 being connected to the heat-generating device 3 and being passed in a loosened state through the tension coil spring 1 and the compression coil spring 2, the transmission wires 9 being fixed within the tension coil spring 1 at plural points, and a device N provided in rear of the tension coil spring for rotatably extending the device.
    Type: Grant
    Filed: April 19, 1988
    Date of Patent: November 21, 1989
    Assignees: Tokyo Gas Kabushiki Kaisha, Ashimori Kogyo Kabushiki Kaisha
    Inventors: Katsuaki Zenbayashi, Hisao Otsuga, Akio Morinaga, Osamu Toyoshima, Shinji Shimokawa