RotaBolt Aid for Divers

One of the major benefits of RotaBolt measurement technology is its ease of use. In maintenance, it only requires a finger and thumb 'instant' check to see if the RotaCap is still locked on the head of the bolt indicating that the correct tension is being maintained across the joint. However matters become slightly more complex if the maintenance check is underwater and you are wearing a diver’s suit complete with neoprene gloves!

RotaBolts have been used on subsea pipelines and platform installations since the mid 80s and it wasn’t long before the difficulty of checking for correct tension with heavy gloves surfaced as an issue. It was still possible to carry out the checks, and they were still much quicker than conventional systems, but it presented a challenge to the technical team at RotaBolt to see if they could overcome the problem and come up with an innovative solution.

The RotaBolt ‘Divers Wheel’ was their answer. The unique tool is a ‘female’ checking device which is manufactured to fit over the different sizes of RotaBolt indicator cap and is made up of 4 essential components - a nose piece containing the form of the indicator cap, a body which is gripped by the operator and a ball bearing/spring assembly which provides the required ratchet operation to indicate when the RotaCap indicator on the head of the fastener is locked meaning the bolt is at the correct design tension level setting.

All ‘Divers Wheels’ are in-house calibrated to a specific resistance force i.e. 30 to 40ozf.in (21 to 28N.cm), before they ratchet. This force was derived from hundreds of physical tests measuring the force applied, on a torque meter, from the ‘finger & thumb’ grip applied by several different personnel.

This ensured that the RotaBolt ‘Divers Wheel’ emulates the physical ‘finger & thumb’ grip operation which is a standard feature/check of a RotaBolt.

As the RotaBolt is tightened the ‘Divers Wheel’ which is now engaged on the RotaCap is lightly rotated. At the point when the RotaCap locks the RotaBolt ‘Divers Wheel’ will ratchet-click on the ball bearing/spring mechanism providing a very simple, accurate and effective physical indication felt by the operator that the bolt design tension setting has been achieved.


17 July 2014

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