CPC F16B 25/0047 (2013.01) [F16B 25/0021 (2013.01); F16B 25/0073 (2013.01)] | 15 Claims |
1. A thread-forming or self-tapping screw, comprising: a shank provided with a thread with at least one asymmetric thread turn with a plurality of windings, wherein
(i) the thread has an external diameter (DA), a core diameter (DK) and a thread pitch (P),
(ii) the thread turn has thread flanks with a flank angle phi,
(iii) the thread flanks have a load-bearing flank and a counter-flank which abut one another at a thread bottom and at a thread tip, wherein the load-bearing flank and the counter-flank form a transition region at the thread bottom with a longitudinal extension of at least 0.01 times and at most 0.2 times the pitch P, and
(iv) a flank angle phiL of the load-bearing flank is smaller than a flank angle phiG of the counter-flank,
wherein a ratio Q1=DA/P of the external diameter (DA) in relation to the thread pitch (P) is from 3.0 to 3.6, and a ratio Q2=DK/P of the core diameter (DK) in relation to the thread pitch (P) is from 2.0 to 2.5.
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