Self-locking alternative to the hex nut 16 December 2021

The CONU counter nut is a new and innovative patent-pending ‘fastener locking device’. Compared to conventional hex nuts this counter nut offers a wide variety of advantages depending on the application, such as reduced space requirements and flow resistance as well as a lower risk of injury.

Thanks to its self-locking effect, CONU does not require any additional safety and prevents ‘self-loosening’. Due to its unique shape the counter nut fits into the countersink without any protrusion. The result - an almost flat surface.

The key to CONU’s strength and versatility is its design. Due to the angle difference between nut and countersunk, 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 ‘self-loosening’. In addition, the joint can be tightened and locked without needing a spanner to hold the nut. In the Junker test (DIN 65151), the constant pre-load force was confirmed despite strong vibrations.

CONU was developed by Fürstenberg Fittings in Hamburg (patent pending). It is distributed by Reyher, one of the leading trading companies for fasteners and fixing technology in Europe, and the Nord-Lock Group, market leader in the field of securing bolted joints. The counter nut is manufactured by HEWI G. Winker, a well established automotive supplier and manufacturer of lock nuts and formed parts from Spaichingen in Baden-Württemberg.

For the launch phase, CONU will be available in sizes M6 to M16 and in two different versions. This means that the counter nut can be used with grade 8.8 and 10.9 high tensile screws and bolts.

Claire Aldridge Deputy Editor t: +44 (0) 1727 743 889

Having joined the magazine in 2012, Claire developed her knowledge of the industry through the numerous company visits, exhibitions and conferences she attended both in the UK and abroad.

Claire prides herself on keeping readers well informed and up to date with the latest industry news.