| 摘要 |
A screw (1) with a plurality of screwing angle (S(θ1-θ4)) comprises a first section having a first thread (11) with a first screwing angle (θ1), at least one third section having a second thread (12) with a second screwing angle (θ2); and a fifth section having a fifth thread with the first screwing angle wherein the fifth thread is identical to the first thread. The second screwing angle (θ2) is not equal to the first screwing angle. Moreover, screw further comprises a second section connected between the first section and the third section; the second section having a fourth thread with a fourth screwing angle (θ4); a fourth section connected between the third section and the fifth section; and the fourth section having a third thread with a third screwing angle. A thread rolling die for forming the screw is also included. <IMAGE> |
