HEICO Fastening Systems

HEICO-LOCK® Wedge Lock Washers

Self-loosening of critical bolted joints can result in extremely negative situations: machine damage, loss of revenue, work stoppages and even harm to personnel.  HEICO-LOCK^® wedge locking systems prevent bolt loosening through tension principles and not with commonly used friction-based locking methods or chemical adhesives.  

This is a two-part lock washer consisting of identical pairs with radial teeth/serrated edges on the outside and wedged surfaces on the insides.  When the bolt is tightened, the external radial teeth of the HEICO-LOCK^® wedge lock washers imprint into the mating surfaces while simultaneously engaging the interlocking internal wedges. 

If the bolted joint is subject to dynamic stresses (vibration, dynamic loads), movement is only possible between the wedge lock washer’s internal wedge-shaped surfaces, which creates a slight increase in the clamping forces. Since the wedge angle is greater than the angle of the bolt’s pitch thread, self-loosening potential is eliminated.

Characteristics:

• Certified and proven (DIN 25201-4, DIN 65151, NASM 1312-7)
• Performance ensured whether lubrication is/is not used
• Can be reused
• Easy to install; comes as a pre-assembled pair
• Suitable for up to 12.9 strength class and grade 8 bolts and their respective nuts
• Available in zinc-flake coated carbon steel, stainless steel, SMO 254 and Inconel 718, in both narrow and enlarged OD’s
• Heavily stocked in Hickory, NC in standard sizes up to 3” and M76
• Custom sizes and coatings available

Large bolted joints are found throughout the Iron, Steel and supporting industries, from large diameter tie rods, press columns, foundation bolts, cranes, material handling attachments, pumps and compressors.  Correctly tightening bolts greater than one inch in diameter becomes a challenge that often requires large, cumbersome and expensive hydraulic or pneumatic torque or tensioning tools.

Since the advent of the mechanical tensioner, many applications and processes have benefited for both the field operator and the OEM design engineer.  The HEICO Group’s design engineering team has taken this technology and incorporated multiple improvements.  The HEICO-TEC® family of tensioning products provides the market with a fast, safe, precise and reusable method to tighten the largest of bolted joints. 

The HEICO-TEC® Tensioning System’s performance has been independently verified by DNV-GL to meet global standards of tightening accuracy, reuse and strength class proof loads.  The HEICO-TEC® is designed to be compatible with heavy hex nuts and bolts used in existing applications as a one-for-one replacement.

The HEICO-TEC® design prevents damage to the primary bolt threads since only tension is exerted on the bolt.  The two part pressure bolt/pin is designed to prevent harmful torsion stresses, bending and other damage that could severely impact field performance and reuse.  Additionally, friction conditions are secured and stable since HEICO-TEC® lubrication is enclosed and protected within the pressure bolt bore, preventing exposure to the outside environment.   All HEICO-TEC® tensioners leave our factory pre-lubricated ready to install on the application with no additional preparation required.

Although power tools can be used to tighten the HEICO-TEC® tensioner, accurate tensioning can be achieved by a common torque wrench and appropriate sized socket- two items that are generally on hand in even the most remote field site.  This is a huge benefit when clearance issues arise that would prevent easy access by a power tool.  With a torque wrench, an operator can easily access tight spaces in order to tighten or loosen the HEICO-TEC® tensioner.

The standard HEICO-TEC Tension Nut is heavily stocked in Hickory, NC in both inch and metric sizes, in strength grades B, C, DH and class 8 and 10.  Additionally, HEICO-TEC® Tension Nuts are available in both uncoated and zinc-flake coated material.  Custom HEICO-TEC® tensioners can be designed specific to an application’s unique requirements, such as unique sizes, materials, strength and non-standard thread types/pitches.