FOCUS on HEICO: Securing of bolted joints under high vibration

HEICO-LOCK® wedge lock washers are pitched as the reliable solution to the problem of securing bolted joints in high vibration assemblies against self-loosening by rotation.

Since 1900, HEICO has been providing high-class fastening solutions. Starting with the production and distribution of upholstery and decorative nails, mainly for the furniture industry, the range of products has increased steadily over the subsequent years. In the early 1990s HEICO began manufacturing design specific cold formed parts and mouldings, mainly for the automotive sector. After passing on the management of the family-held company to the fourth generation, the product portfolio was extended significantly by the introduction of the HEICO-LOCK® wedge lock washers range. Today the company has over 400 employees across two production plants in Germany and eleven worldwide sales and distribution sites.

There are 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. The renowned German Institute for Standardisation (DIN) has subsequently verified a number of devices as not applicable in preventing high strength bolts from self-loosening.

In response to these changes a number of surveys were undertaken by independent research institutes to test the ‘bolt locking’ effectiveness of the HEICOLOCK ® wedge lock washers. The locking performance of fasteners under vibration, specifically locking devices, can be evaluated on a vibration test rig according to DIN 65151 known as the ‘JUNKER’ test after its inventor, Gerhard H. Junker. The results of these independent tests showed that the HEICO-LOCK® wedge lock washers met the E DIN 25201 requirements of maintaining a residual preload > 80% after an alternating transverse load, representing the effects of vibration, of over 2,000 load cycles. These results underline the anti-vibration effectiveness of the product.

HEICO has always aspired to innovation and advancement, the cornerstones that more than 100 years of the company’s history are based upon. In accordance with this philosophy the R&D-department works continuously in their in-house laboratory to improve and develop established bolt locking solutions. Only a few years after the launch of the HEICO-LOCK® wedge lock washers, this development culminated in the launch of four new products: The HEICOLOCK® ring lock washers, the HEICOLOCK® wedge lock nuts and the HEICO-LOCK® HLK-washers for steel construction; all followed more recently by the launch of the innovative HEICOLOCK® combi-washers. In 2016, HEICO founded a new division for pretensioning systems and introduced the HEICO-TEC® tension nut for large bolted joints. The company’s innovation driven philosophy has seen HEICO become a major player in the bolt fastening market and the company continues its drive to provide customers with the most reliable bolt security solutions to what are often safety critical problems.


Heico 1

This proven locking system is for the most demanding of bolted joint applications. The self loosening of bolted joints is one of the most commonly occurring failure modes in the operation of machines and systems. HEICOLOCK® wedge lock washers prevent loosening of the bolted joint by providing a safe and reliable bolt securing system – even for extremes of vibration or dynamic loads. They are available in steel or stainless steel with narrow or wide bearing surfaces from M3 – M76 and ¼” – 3”.


Heico 2

An innovative system with added security, HEICO-LOCK® ring lock washers provide high-quality, user-friendly bolt securing for the most demanding of applications and are ideal for repeated use. The ring locking system guarantees that the two wedge lock washers are always fastened in the correct position with the wedge shaped cams on the inside and the radial teeth on the outside.

This means that the bolt locking system is always easy, safe and quick to install, even for non-specialist users. Ring lock washers are available in steel or stainless steel with narrow or wide bearing surfaces from M4 – M24.


Heico 3

Based on the philosophy of ‘combined, efficient, safe’, HEICO-LOCK® wedge lock nut is a reusable one piece design that delivers high quality, user friendly bolt security without the need for separate fasteners. The captive and rotary combination of the nut and the original HEICO-LOCK® wedge lock washers makes securing your bolted joints more efficient, effective and easier even under the most extreme vibrations and dynamic loads. It’s available from M6 – M27 in strength class 10 and with fine thread: M20x1.5 and M22x1.5.


Heico 4

Pitched as flexible, fast and innovative, HEICO-LOCK® combi-washers are efficient combined securing systems for highly loaded bolted connections. They enable quick and easy assembly, especially in difficult installation situations. Combine the simple-to-use HEICO-LOCK® combi-washers with all commercially available bolts provided by your suppliers, quickly and easily. Combi-washers are available from M8 to M16 and can be supplied completely pre-assembled on request.


Heico 5

The HEICO-LOCK® HLK-washers deliver high quality anti-vibration security for HV sets according to DIN EN 14399-4 and DIN EN 14399-8. Even under extremes of vibration or severe dynamic loads in steel construction the HEICO-LOCK® HLK-washers, which are approved by the German Institute for Structural Engineering (DIBt), provide maximum reliability. Due to the increased under head radius of HV bolts, the HEICO-LOCK® HLKwashers are chamfered on the internal diameter to ensure optimal surface contact while tightening. They are available for HV sets from M12 up to M36.

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