Lau & Asso.
Looseness resisting screw and stud hole
A looseness resisting screw formed with an external thread includes a first thread area having a substantially uniform outer diameter and a second thread area extended from the first thread area toward a leading end of the screw. The second thread area has a plurality of fractional lead parts each of which has an outer thread diameter increasing along a helical direction of the fractional lead part from a start point to an end point, and the outer thread diameter is substantially equal to a thread root diameter at the start point, while the outer thread diameter is equal to a thread top diameter at the end point. The fractional lead part has a thread sectional area increasing along the helical direction from the start point to the end point, and the thread top diameter of the fractional lead part is slightly larger at the end point than the substantially uniform outer diameter of the first thread area so that the second thread area provides a tapping thread section.
Kabushiki Kaisha Suzuki Rashi Seisakusho
F F F
F16B F16B F16B
inventional inventional inventional
Yasuo
Suzuki