By Kari Williamson
The self-lubricating sintered composite material used for the bearings is maintenance-free and features high static and dynamic load-carrying capacity and a low friction coefficient, due to homogeneous solid lubricant -moreinclusions such as graphite and PTFE, within the bronze matrix. The bearings were designed in close cooperation with German tower clock manufacturer Perrot.
The clock tower is 601 m tall -a bout six times the height of Big Ben’s clock tower in London, and each of the four clock faces measure 43 m in diameter.
The hour and minute hands, weighing around 7.5 tonnes each, move only once per minute, leading to huge static and inertia loads for the bearings to carry.
Arranged in quarter segments for easy mounting, each of the 16 bearings required for the four movements carries a self-lubricating contact layer just 1.5 mm thick on a 5 mm backing.
