Patents by Inventor Masaaki Jindai

Masaaki Jindai 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).

  • Drill bit structure
    Patent number: 4728231
    Abstract: A drill bit structure has a drill bit body 4 and a plate-like hard tip member 9. The cutting end of the drill bit body 4 has a groove 7 extending substantially at right angles to the central drill bit axis, and the hard tip 9 is fitted and fixed in the groove 7. The web thickness is 25-35% of the drill bit diameter and the flute width ratio is 0.4:1 to 0.8:1. The rake angle of each cutting lip 10 measured at positions spaced at least 2/3 of the drill bit diameter radially outward from the drill bit center is in the range of -5.degree. to positive values.
    Type: Grant
    Filed: March 4, 1985
    Date of Patent: March 1, 1988
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Nagatoshi Kunimori, Yoshikatsu Mori, Masaaki Jindai