Patents by Inventor Manabu Hanzawa

Manabu Hanzawa 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: 4645893
    Abstract: In the manufacture of spiral-welded steel pipe, material strip or plate is fed in its longitudinal direction and continuously formed into spiral pipe form. One side-edge of the strip and the other side-edge of the strip that has already been spirally formed are welded together by the electric-resistance method where they meet. The edges of the strip and formed pipe are held together simultaneously with or immediately after the electric-resistance welding from both inside and outside the pipe using a pair of pressure rolls. The bead formed as a result of the electric-resistance welding is reformed simultaneously with or immediately after the holding by the pressure rolls is accomplished. Then, the electric-resistance welded side-ends are welded again by the arc method.
    Type: Grant
    Filed: September 30, 1985
    Date of Patent: February 24, 1987
    Assignee: Nippon Steel Corporation
    Inventors: Yasumi Shimazaki, Yoshito Tsuyama, Hiroyo Haga, Manabu Hanzawa