Working principle of tower crane slewing mechanisms

Tower cranes apply tower type slewing mechanisms, which rely on hoisting jibs of tower cranes to guarantee work range of slewing mechanisms. The generation of slewing apply upper and lower slewing supports of tower cranes installed on internal and outer rings, slewing mechanisms of building tower cranes drive pinion, by mesh of pinion and gear wheel of slewing bearings of self-erecting tower cranes, that let upper support work relative to lower support of construction tower cranes. Slewing mechanisms of tower cranes are made up of slewing motor, hydraulic coupler, planetary reducer and pinion. In addition, according to customers’ requirements, slewing mechanisms sometimes have load moment limiter, slewing buffer device, slewing limiter of hammer head tower cranes and other safety devices. To avoid hoisting jibs of tower cranes slide when it is windy, slewing mechanism will be installed stopper. However, under non-work, slewing mechanisms allows hoisting jibs and balanced jibs of tower cranes turn freely with wind.

Light tower cranes and medium tower cranes usually have one set slewing mechanism. Heavy tower cranes have two sets slewing mechanisms. Over heavy tower cranes will have three or four sets slewing mechanisms according to different loading capacities and rotational inertias. Applying stable speed control system and change pole motor makes topkit tower cranes, topless tower cranes and luffing tower cranes start and stop stably. Tower cranes are divided into top-slewing tower cranes and lower-slewing tower cranes.