Patents Assigned to Ludwig Hettich & Company
  • Countersunk head screw
    Patent number: 8231320
    Abstract: The invention relates to a countersunk head screw comprising a cylindrical shaft (2) and an essentially conical countersunk head (4) comprising at least two edges (15) on the lower side. Said countersunk head screw is characterized in that the edges each mark an end of a partial surface (10) located on the lower side, each of the partial surfaces lying on a non-concave separate surface of revolution.
    Type: Grant
    Filed: November 17, 2008
    Date of Patent: July 31, 2012
    Assignee: Ludwig Hettich & Company
    Inventor: Ulrich Hettich
  • Thread-cutting screw
    Patent number: 6623228
    Abstract: A thread cutting screw to be screwed into a predrilled hole in concrete, masonry, or the like is characterized in that the relationship between the load bearing thread surface AOn of the loaded thread flank, which surface is standardized to the load bearing thread length he and cut into the wall of the predrilled hole, and the nominal diameter db of the predrilled hole is as follows AOn=k {square root over (db)} wherein k is a constant of which the value is 1<k≦2.5.
    Type: Grant
    Filed: August 13, 2001
    Date of Patent: September 23, 2003
    Assignee: Ludwig Hettich & Company
    Inventors: Ulrich Hettich, Stefan Hettich