Vergnet incorporates RotaBolt tension control
Vergnet is now fitting Rotabolt® tension
control technology on its unique GEV HP wind turbines. The company is using RotaBolt fasteners on the main structural joint where the two halves of the turbine nacelle are joined.
ergnet’s design allows the main turbine to be quickly disassembled into two halves so that the upwind nacelle section, complete with rotors, can be lowered to the ground and easily secured. This can be
either as a protective measure in extreme weather conditions, or for much quicker service and maintenance. Each turbine uses thirty M90 RotaBolts on the main nacelle
structural joint. The fasteners assure the integrity of this critical joint because they achieve and accurately maintain the correct joint tension through the precise measurement technology built into each bolt. Traditional tightening practices using a standard bolt only measure the force that is being applied to tighten the bolt. The clamping
force, or tension across the bolted joint, is completely unmeasured and unknown and yet it is critical to its reliability. In addition to achieving joint integrity, the RotaBolt fasteners can be instantly finger-tip checked to see if any tension has been lost
at all. The RotaCap on the head of each bolt locks-off at the correct design tension and as soon as any tension is lost, it spins freely, making it quick and easy to check. Rotabolt points out that this not only dramatically speeds up the assembly process, but also makes routine maintenance much more cost effective.
Promoting ‘green’ operations The PEMSERTER® Series 3000™ automatic fastener-
installation press system introduces ‘green’ technology by performing without hydraulics to install all types of self-clinching fasteners rapidly, accurately, and permanently in thin-metal sheets.
t the heart of this environmentally friendly press is a custom- built, full servo controlled, electro-mechanical actuator which PennEngineering says delivers measurable efficiencies and economies compared with conventional technologies. The
Series 3000™ press system is additionally sealed and lubricated for life to eliminate environmental issues and minimise maintenance and associated costs. Other key press features highlighted by PennEngineering include the
dual axis actuator which allows for ram speed optimisation, high pressing forces, and dramatically reduced energy usage; a proprietary clutch system provides smooth, energy-efficient transition between servo axes; roller screw technology enables the press to carry larger loads at higher speeds; and regenerative/dynamic braking captures inertial energy and applies it to deceleration for a reduction in external energy requirements. The Series 3000™ press is engineered for user-friendly operation. After
initial PC setup, all run logic is maintained in solid-state servo controller memory. Multiple types of self-clinching fasteners can be installed automatically without any need for tooling changeovers. The Series 3000™ press is designed with a 24 inch/61cm throat depth,
can realise a ram force up to 16,000lbs/71.2kN, and can be operated remotely through networking. The press is CE certified to comply with applicable European standards.
116 Fastener + Fixing Magazine • Issue 68 March 2011