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High-accuracy in bolt tension from Danish wind turbine sector to be shown at Agritechnica by Moller International

Correct bolt tension is hard to achieve but essential to safety and product reliability in farm equipment


Odense, Denmark, 7th November, 2019 - A specialist in identifying engineering solutions suitable for farm equipment, Moller International will show the Bolt-Check, a system that is capable of measuring bolt tension with high accuracy. Using the Bolt-Check system during manufacturing assembly could have significant safety and product reliability benefits for the farm equipment manufacturer.


Vibrations on farm equipment similar to wind turbine

Bolt-check is especially suitable for farm equipment since the vibrations resulting from heavy work in the field is similar to that of a wind turbine. Bolt fatigue and loosening through vibrations can be prevented by achieving and maintaining a correct bolt tension in the bolt joint, a process that begins in the factory at the assembly point.

Safety increased and downtime reduced

Maintaining the right tension of bolt joints on farm equipment increases safety whilst minimising the risk of failure and downtime of equipment, which can be especially costly during harvest time. Installation and service costs can be also reduced, a benefit to the machinery manufacturer because product reliability and thereby company quality image is enhanced.

Danish engineers analyse clamping force

The Bolt-check system was originally developed in Denmark by R&D A/S to ensure a more reliable and, above all, safe operation of wind turbines.

“We noticed our engineers were called to fix jobs where the fault was a bolt that had worked its way lose. We started analysing and found out the root cause of the problem was not the bolts themselves as they were of the highest quality. It was the wrong clamping force that was the culprit. So we decided to find a solution for that and this is how Bolt-check was developed,” says Søren Schmidt Kellenberger, Business Unit Director – Tools & Structures, R&D A/S.

“The correct tension for a particular set of bolt joints is already known to engineers as we can calculate what the optimal tension shoud be. What is difficult however is to actually measure if that tension has been achieved. To be exact it is the friction between the nut and bolt, which is hard to measure. The error tolerance can be as much 30 percent using standard methods, “ adds . Kellenberger.

High accuracy achieved through ultrasonic sensors

The Bolt-Check system can measure the right tension to within 5 percent accuracy which is a real improvement to alternative solutions in this price bracket. The Bolt-Check is priced competitively so that it fits volume production when farm equipment makers employ larger bolts M16 and above, explains Kellenberger.

Highly accurate ultrasonic sensors and software analysis are used to measure the length of the bolt which lengthens according to how much clamping force is applied. This way of measuring makes the Bolt-Check system a direct measurement method and very precise, whereas using the standard torque method does not render the same accuracy.

Bolt-Check can be used when installing new bolts and when evaluating existing bolts as part of the determining the lifespan of farm equipment. Furthermore, as a part of the process, a unique Bolt-Tag is added to each bolt. The tag gives farm machinery manufacturers full traceability of all bolts. Location of each bolt as well as schedule service and maintenance are made easy.

Achieving a consistent clamp force in the bolted joint during assembly is essential for bolted joint integrity. The tool is suitable for most bolt types and requires no special pre-treatment of the bolts.

The advantages of using Bolt-Check include:

  • Full traceability (eliminate process risk)
  • Posssible to track data and hosting of data which enables business intelligence
  • A cost-effective solution
  • Reduce number of service inspections (no re-tightening)
  • Minimise the risk of failure
  • Improve utilisation of bolts
  • Maximise the operation time of the wind turbine

Bolt-Check is shown at the Moller International stand which is located in Hall 17, Stand D33 at Agritechnica.