A fastening system without additional locking nuts & washers - Due to self-locking mechanism
The key to CONU’s strength and versatility is its design: Due to the angle difference between nut and countersunk hole, plus due to the added serrations on the conical surface, the self-locking mechanism starts and then gets stronger the further the nut is pulled into the countersunk hole. This prevents the joints from ‘self-loosening’. In addition, the counter nut can be tightened and locked without needing a spanner to hold the nut.
Junker tests prove constant preload
Various vibration tests, including the Junker test (the most demanding vibration test for bolted joints standardised according to DIN 65151), have confirmed that the preload remains almost constant despite strong vibrations and that the loss of preload due to ‘settlements’ is very low, at approx. 15 %.
The tests were carried out in the laboratories of REYHER, NORD-LOCK, HEWI and IMA Dresden.
The CONU nut has also demonstrated that an adequate securing effect can still achieved, even when lower preload (such as 6 kN or 2 kN) are applied.