The cable drum (also called rope drum or rope winch) is the central lifting element of a crane. The hoisting rope is wound and unwound on it to raise and lower loads. The drum is driven hydraulically or electrically and has a brake (holding brake + service brake) that safely holds the load in any position.
On tower cranes, there are separate drums for the hoisting mechanism (load lifting), trolley drive (moving the trolley), and if necessary, the luffing mechanism (luffing the boom). Mobile cranes have an additional auxiliary hoisting drum for the auxiliary hook. The rope capacity (rope length × rope diameter) determines the maximum hook height.
Rope drums are calculated according to DIN/ISO 16625: minimum of 3 rope layers on the drum at maximum rope length, grooved (organized rope guidance) or smooth drum (multilayered). Modern winches from Liebherr, Hoist, and Rotzler feature electronic rope tension monitoring that measures the load curve in real-time and warns of overload.