- The new Locking Assembly series RINGFEDER® RfN 7012.2 is specially designed to fulfil the requirements of constantly increasing bending moments for conveyor pulleys.
- The challenge was to develop a product with the same dimensions as the standard RINGFEDER® RfN 7012 to fit into existing end discs – yield point of end disc has to be checked – so that also material handling equipment at hand can be upgraded. At the same time the Locking Assembly should carry a multiple of the bending moments of the standard RINGFEDER® RfN 7012.
- To comply with these requirements, we have collected the experiences of our customers and our knowledges of supplying to
the market of heavy industry for more than 90 years. The result is the brand new RINGFEDER® RfN 7012.2.
- A special bolt for type RfN 7012.2 has been developed by RINGFEDER for the increased requirements occurring when subject to loading by bending moments.
These special bolts guarantee loadings above strength class 12.9 at simultaneous higher expansion with regard to tensile strength and yield strength.
These bolts were manufactured specially for RINGFEDER with
qualified steel analysis.
Every bolt is labelled with RPT-B and the batch number. This allows every bolt to be traced back to manufacture.
The benefit of this bolt is the considerably increased fracture resistance under additional bending stress.
Explanation to table
A bending moment, created by radial forces, results in an additional load for the Locking Assembly, shaft and hub. This load creates an additional pressure, works in rotation and has to be superpositioned with the pressure resulting from the Locking Assembly. For a viable connection, a minimum surface pressure at the contact areas between Locking Assembly, shaft and hub must be maintained, as soon as shaft and hub have to take up the maximal pressures. Additionally, the listed torque values (T) have been reduced due to the additional bending moments. To achieve lower stresses for the Locking Assemblies the screw tightening torques (TA) have also been reduced.