| 摘要 |
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 followswherein k is a constant of which the value is 1<k<=2.5. |
