TENSION NUT | thefastenerfactory

HEICO-TEC TENSION NUT

SIMPLE · FAST · RELIABLE

For a secure joint with a HEICO-TEC® Tension Nut, no electric, hydraulic, or pneumatic tools are needed. All you need is a torque wrench.

The HEICO-TEC® Tension Nut is unique in the fact that the pretension force of the large main thread is distributed to many smaller pressure bolts. Because the pressure bolts are smaller, a conventional torque wrench can be used to achieve the correct pretension force.

This eliminates the need for complex, bulky, or heavy tools and makes securing large bolted joints more convenient and easy.

TENSION NUTS ACCORDING TO ISO 898-2

HEICO-TEC® Tension Nuts in strength class 8 and 10 meet all the requirements of ISO 898-2 which enables you to easily replace any hex nut from the same strength class while also offering all the advantages of a hand-tightened nut.

Our standard program of HEICO-TEC® Tension Nuts offers you the following advantages:

Fast delivery: On stock and therefore directly available
Compatible with DIN EN ISO 898-2: Direct replacement of hex nuts from the same strength class possible
Extended service through consultation as well as installation aids for technical documentation (e.g. assembly template)

DESIGN AND FUNCTION

1. The nut body (1) is screwed onto the main thread just like a conventional

nut – but is not tightened.
2. Several pressure bolts (2a) with associated pressure pins (2b) are arranged around the main thread inside the nut body. When the pressure bolts are tightened, they push the pressure pins against the part to be tensioned and at the same time the bolt elongates.
The pretension force created in this way is purely axial and therefore free from harmful torsion or bending.
3. The hardened incorporated thrust washer (3) protects the tensioned parts
from high pressure loads caused by the pressure pins.

ADVANTAGES OF HEICO-TEC TENSION NUT

SIMPLE

A hand-held torque wrench is all you need for tightening and loosening. No special tools are required. This makes maintenance far easier.

FAST

A hand-held torque wrench is all you need for tightening and loosening. No special tools are required. This makes maintenance far easier.

RELIABLE

The pressure pins act like springs and increase the flexibility of the bolted joint. This compensates for
settlement of the joint, thus preserving preload.

SAFE

With the inherent mechanical elasticity of the HEICO-TEC® design, the bolted joint performs as
if it has a greater clamping length, making it highly resistant to loosening forces.

DURABLE

The greater elasticity reduces the bolted joint’s dynamic stress, thus increasing its service life.

PRECISE

Controlled friction characteristics ensure the highest tightening and repeat accuracy – guaranteed and
confirmed by DNV GL.

REUSABLE

As the HEICO-TEC® assembly is not damaged during. Tightening and loosening, the HEICO-TEC® Tension Nuts are reusable.

ECONOMICAL

Our efficient and high volume manufacturing process means that we can transfer the cost benefits directly to our customers.

Disassembly

Preparation

The bolt thread and the contact surface have to be clean and free from burrs. Place the washer on the mating surface and center it. Now hand-tighten the tension nut. Then turn the tension nut back approx. 1/4 turn so that there is a small gap between the tension nut
and the washer.

Assembly

Materials and Dimensions | Metric Sizes

Strength Class 8

• Tightening torque per pressure bolt: tightening torque and preload are proportional, i.e. half the tightening torque results in half the preload.

• Approx. 2/3 of the breaking load of a bolt of strength class 8.8 (tested according to ISO 898-2 up to M120)

• FVmax is the maximum bolt load (FS) that the tension nut can withstand (i.e. preload + additional bolt load). This force value must not be exceeded.

• In the event that larger forces have to be generated or endured, the use of HEICO-TEC® strength class 10 is recommended.

Both series (8 and 10) of HEICO-TEC® Tension Nuts are marked with the strength class according to ISO 898-2.
Other strength classes, sizes, pitches or thread forms are available on request.

All HEICO TEC® Tension Nuts can optionally be ordered with a zinc flake coating for better protection against corrosion.
Other coatings or stainless steel finishes are available upon request.

Strength Class 10

• Tightening torque per pressure bolt. Tightening torque and preload are proportional, i.e. half the tightening torque results in half the preload.

• Approx. 3/4 of the breaking load of a bolt of strength class 10.9 (tested according to ISO 898-2 up to M90).
• FVmax is the maximum bolt load (FS) that the Tension Nut can withstand (i.e. preload + additional bolt load). This force value must not be exceeded.

In case that larger forces have to be generated or endured or larger thread dimensions are required, the use of special Tension Nuts is recommended.

Both series (8 and 10) of HEICO-TEC® Tension Nuts are marked with the strength class according to ISO 898-2.
Other strength classes, sizes, pitches or thread forms are available on request.

Grade BH