Solution for dynamic connections

Reliable assurance

Since 1900, the HEICO Group from Niederense, Germany has specialized in reliable quality solutions for fastening technology. Worldwide, the family-owned company has fourteen offices and over 450 employees. From Groningen, HEICO Benelux BV focuses mainly on the HEICO-LOCK® Locking System and the HEICO-TEC® Prestressing System. 

Sales Engineer Johan Sikkema: "We work together with technical wholesalers, whom we can supply from stock. Because we work in a niche of bolted connection technology, we also have a lot of contact with end users. We are happy to explain our products to them and help them think about concrete applications. In addition to our products, we also have a service center that customers can use. Here, among other things, we can do bolt calculations and carry out various tests, such as, for example, a Junker test up to as much as M64!"

Increasingly critical bolted joints

"What we see is that lighter and lighter construction is taking place. The edges of possibilities are literally being explored." This trend has implications for bolted connections, according to Sikkema. "Clamping lengths are becoming shorter and shorter and bolted connections are therefore becoming more critical. When the joint is dynamically loaded, this results in the joint loosening independently. The higher the frequency of this loading, the faster the clamping force is lost, with all its consequences. The degree of peak loading is very uncertain and therefore difficult to predict."

To solve this problem, a locking method must be applied. "A common method is to use a locking agent that increases friction, such as self-locking nuts. However, this only delays the loss of clamping force in the joint. In contrast, our system locks on the basis of preload. A HEICO-LOCK® Lock washer consists of two discs, with which you create a wedge in the bolted connection. Because the washers are hardened and have radial teeth on the outside, they fix themselves in the construction on one side and in the nut or bolt on the other side. This creates a dimensionally stable connection. When dynamic loading occurs and the bolt wants to loosen, the angle of the wedge between the washers is always greater than the angle of the pitch of the thread. This prevents the bolt from loosening. This keeps the connection reliable and secured."

Unloading vibration impossible

A concrete example occurred in a car factory where doors and engine covers were pressed from sheet steel. "Due to the vibration of the machines, the hall was vibrating and shaking, causing the joints in the trusses to vibrate loose. When this brought production to a halt, the solution was found in the HEICO-LOCK® Locking System. Our product has also been used in the Dubai Ain, the world's largest Ferris wheel. Here, too, our rings ensure that the connections are reliably secured." Closer to home, HEICO-LOCK® is being used for 5G antenna masts and in a steel structure at Chemiepark Delfzijl, among others.

HEICO-LOCK® may be used in accordance with EN1090. "There is an ETA approval according to the EN15048 standardization of SB bolts. For HV sets according to EN14399, there is a clearance from the DIBt to replace the washers from the set with HEICO-LOCK® HLK washers."