There is a wide variety of bolt-locking devices available on the market, but not all of them meet the basic requirement of reliably preventing bolted joints from self-loosening.
Conversely, to provide maximum bolt security even under extremes of vibration or dynamic loads, the HEICO-LOCK range of wedge-locking washers use preload force, instead of friction.
The system uses wedge-shaped cams on the inside of the washers and radial teeth on the outside that work together to maintain the bolts preload. When a bolt is tightened, the external radial teeth embed themselves in an interlocking fashion with the respective mating surface. The wedge angle of the internal cams is greater than the pitch of the bolt thread and, with movement only possible across these internal cams, any loosening causes an expansion in the thickness of the HEICO-LOCK washers, leading to an increase in the clamping force.
One-piece design
HEICO’s innovative approach to product development has seen the introduction of further fastening systems incorporating the wedge-locking technology, including combining the washers with a flanged nut to create a one-piece design that removes the need for separate fasteners.
This methodology has seen HEICO recently launch the HEICO-LOCK Combi-Washers, for highly loaded bolted connections, and the HEICO-LOCK HLK Washers for steel construction. The Combi-Washers incorporate an inner plastic locking ring that ensures the permanent securing and correct positioning of the washers on the bolt, enabling quick and easy assembly, especially in difficult situations, and also reduces the chances of dropped objects.
The HEICO-LOCK HLK Washers deliver anti-vibration security for HV sets, according to DIN EN 14399-4 and DIN EN 14399-8. Due to the increased head radius of HV bolts, the HLK washers are chamfered on the internal diameter to ensure optimal surface contact while tightening. The HLK washers can be used to replace washers according to DIN EN 14399-6 and are approved by the German Institute for Structural Engineering (DIBt).
The HEICO-LOCK range of products are available in steel and stainless steel and can also be produced from other special materials, such as 254 SMO and INCONEL/Alloy 718, both of which are resistant in highly corrosive environments, including seawater and acids.
Paul Windsor, national sales manager for HEICO Fasteners UK, comments: “Our products are ideally suited to the subsea and offshore industries, and provide real-world solutions to safety critical issues.”
