Safe bolting

Monitoring the tension in critical bolted joints on, for example, slewing rings helps guarantee the joint's integrity, which improves reliability and safety.

Tower crane manufacturer Terex Comedil fits Rotabolts during production to continually measure tension across bolted joints. Rotabolts are standard fit on all HD23 22.6 and 26.6 crane towers.

“Fitting Rotabolts to our tower cranes and the undercarriages on our HD23 has given us a reliability that we couldn't achieve with tensioning tools and applied torque”, explains Pierluigi Tomasi, head of Terex Comedil technical department.

Rotabolts operate using “internal air-gap technology.” A built-in tactile indicator with a “rotacap” on the head of the bolt requires only a finger check by the operator. Installing and tightening the Rotabolt to its preset tension locks the rotacap, which becomes finger-loose as soon as any tension is lost, providing a simple and instant safety indicator.