Tensioning of large bolted joints usually requires the use of electric, hydraulic or pneumatic tools, a factor that adds additional costs and delay.
Also, when using a hydraulic cylinder a percentage of the elongation of the bolt is lost in joint settlement meaning only around two thirds of the bolt strength can be utilized.
The HEICO-TEC® Tension Nut has a unique design that eliminates the requirement for such specialist tools and maintains the full capacity of the bolt strength. In fact all that is needed to achieve the required tension is a hand held torque wrench, resulting in savings in both time and money in comparison to such specialised tooling. Also, it is possible to directly replace commercial hex nuts from the same strength class with HEICO-TEC®, a benefit not available when using common tension nuts.
The design consists of the nut body with several thrust bolts with associated pressure pins arranged around the main thread inside the nut body. Tightening of the thrust bolts pushes the pressure pins against the clamped parts while simultaneously elongating the bolt. As the stress on the bolt is purely axial, not torsional, thread friction and deformation is greatly reduced, ensuring that the full load-bearing capacity of the bolt can be utilized.
HEICO demonstrated the large bolt tensioning capabilities of the innovative system at the Offshore Europe Show with National Sales Manager, Paul Windsor, commenting “We really looked forward to demonstrating this unique tensioning system on our own demonstration rig and our technical experts were on hand to discuss specific applications to see how we can help”.