Patents Assigned to Interior Fasteners, Inc.
  • Patent number: 4027573
    Abstract: A screw fastener formed with improved thread construction adapted to provide a staged or graduated entry into a workpiece. The fastener comprises a shank section formed with an integral driving head at one end and a tapered or conical point section at the other end, and a raised helical thread extending from near the tip of the conical point substantially throughout the length of the point and shank sections. The diameter of the thread increases gradually from the point tip along the length of the conical surface and then decreases in diameter - or increases at a lesser degree - as it approaches the cylindrical shank section.The fastener may also comprise a second raised helical thread, parallel to and lying within the first thread and extending from near the junction of the conical point section and the cylindrical shank section substantially throughout the length of the shank.
    Type: Grant
    Filed: June 20, 1975
    Date of Patent: June 7, 1977
    Assignee: Interior Fasteners, Inc.
    Inventor: Richard C. Laverty