Bolt tensioners avoid incorrect tightening

Although bolted assemblies are widely used throughout industry, incorrect assembly is said by Pilgrim to account for around 45 per cent of all fatigue failures. Common problems include the application of insufficient preload, and either over or under-tightening of component parts, together with misalignment in some cases. All can contribute to significantly reduced service life in a joint, and each has the potential to cause inconvenience at best, and sometimes far worse. Damian Lewis, General Manager at Pilgrim, part of the SKF Group explains: "Conventional methods for tightening bolts use torque, applied either by hand or torque tools. But these methods can damage threads and flange faces, leading to re-machining and added downtime. The bolts may also become loose over time and need re-tightening. An alternative is heat induction, but this requires specialist contractors and additional cost."

Pilgrim says that HYDROCAM overcomes these problems by axially stretching the bolts and studs, using a pre-determined residual load to create a high integrity fixing which can be mounted and dismounted quickly and safely without damage. The company can supply HYDROCAM as a single tool, or it can be incorporated into a multi-tensioner for homogenous tightening. In most applications it is intended to be reused with multiple fittings, but can also be permanently incorporated into the nut assembly. Each unit is manufactured by Pilgrim, (a fully owned SKF company), and is supplied ready for use with the tensioner unit, power pack and all relevant fittings. To provide flexibility the power pack can be hydraulically, electrically or hand operated.

Go to www.skf.co.uk for more information about the HYDROCAM bolt tensioner.