Patents by Inventor Hishayoshi Toyoshima

Hishayoshi Toyoshima 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 of producing a channeled plastic pipe with closed channel ends
    Patent number: 4474726
    Abstract: A method of producing plastic pipe having air channels axially extending through the wall thereof, with at least one of the respective ends of the air channels being closed by an annular slotted channel-closure filled with a caulking material in its annular slot. The channel-closure is force-fitted on the pipe end, so that the caulking material is pressed into the air channels.
    Type: Grant
    Filed: March 1, 1982
    Date of Patent: October 2, 1984
    Assignee: Kubota Tekko Kabushiki Kaisha
    Inventors: Ryozo Ohta, Takehiro Itoh, Hishayoshi Toyoshima, Jun Yoshikawa