Patents by Inventor Yoshio Dohi

Yoshio Dohi 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: 4583888
    Abstract: A drill made of cemented carbide, is constructed for compensating for the brittleness of cemented carbide to increase its cross-break strength. For this purpose, the ratio of the diameter c of the web portion (1) to the drill diameter d is set in the range of 25% to 35%, and the flute width ratio (b:a) is set in the range of 0.4:1 to 0.8:1. Further, to decrease the cutting resistance on the drill, the radial rake .theta..sub.r angle of the cutting lip 4 measured at positions spaced at least 2/3 of the drill diameter toward the outer peripheral side is set in the range of -5.degree. to positive valves. Furthermore, to promote the chip ejecting function, the relative distance L between the cutting lip 4 and the flute wall 5 opposed thereto, is decreased.
    Type: Grant
    Filed: May 1, 1984
    Date of Patent: April 22, 1986
    Assignee: Sumitomo Electric Industries, Ltd.
    Inventors: Yoshikatsu Mori, Yoshio Dohi, Hideo Fukagawa