Patents Assigned to Kozo Yamamoto
  • Head drive for threaded fastener
    Patent number: 5137407
    Abstract: A threaded fastener having a recess or projection in a head for engagement with a jointing equipment is disclosed. The recess or projection is composed of a center portion and radial portions extending radially outward of circumference of the center portion. Each of the radial portions includes a pair of straight line section and a rounded corner to prevent stress concentration for providing substantial strength against press-molding and applied torque.
    Type: Grant
    Filed: November 19, 1990
    Date of Patent: August 11, 1992
    Assignees: OSG Corporation, Kozo Yamamoto
    Inventor: Kozo Yamamoto