| 摘要 |
FIELD: construction.SUBSTANCE: self-cutting screw comprises a leg, besides the normal turn is formed on the leg and turn forming an inner thread is formed on side of the leg tip, besides the turn forming the inner thread has a larger diameter than the diameter of normal outer turn. The thread pitch defined between the top of turn forming the inner thread and top of normal outer turn, adjacent with top of turn forming the inner thread is greater than the pitch of normal outer thread, and thus the support lateral side at stage of fixing and rotation and rear lateral side of the outer turn have no possibility of entering into contact with the inner turn, and only the top of normal turn is wedged in the support lateral side of inner thread under the action of axial force at stage of fastening and locking.EFFECT: increase of detent force of the screw.2 cl, 6 dwg |
