New tension nut from Heico eliminates need for specialist tooling

Heico Fasteners, manufacturers of the HEICO-LOCK® anti-vibration wedge lock washers, will be launching their new HEICO-TEC tension nut at the upcoming Engineering Design Show (EDS) that promises to eliminate the need for specialist tooling for large bolted joints.

The HEICO-TEC tension nut is unique in the fact that the pre-tension force of the large main thread is distributed to many smaller pressure bolts. Because these pressure bolts are smaller a conventional torque wrench is all that is needed to achieve the correct pretension force, eliminating the need for complex, bulky or heavy tools and makes securing large bolted joints more convenient and easy.

Working with large bolted joints usually means an engineer having to arrange specialist electric, hydraulic or pneumatic bolt tensioning services. HEICO-TEC does away with these time consuming and potentially expensive options and indeed is so fast that HEICO-TEC nuts are often tightened in the same time it takes to set up such tooling.

With HEICO-TEC the nut body is screwed onto the main thread just like a conventional nut – but it is not tightened. Several pressure bolts with associated pressure pins 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 bolts elongate. The pre-tension force created in this way is purely axial and therefore free from harmful torsion or bending. The HEICO-TEC nut also includes an incorporated hardened washer that protects the tensioned parts from high pressure loads caused by the pressure pins.

Also HEICO-TEC tension nuts comply with ISO 898-2 requirements, meaning engineers can directly use any conventional nut from the same strength class.

Paul Windsor, National Sales Manager for Heico Fasteners UK, said of the launch “We are really looking forward to launching HEICO-TEC at EDS this year. We believe this product offers real benefits to engineers both in terms of bolt security and cost. The fact that a conventional torque wrench is all that is needed to tighten our nut makes working with large bolted joints much easier, faster and reliable”. “We have used our knowledge and expertise in producing our HEICO-LOCK® washers and one piece WEDGE LOCK NUT to design HEICO-TEC and I’m sure visitors to the show will appreciate the benefits this unique product has to offer”.