Slewing unit: the slewing unit sits at the top of the mast. This is the engine that enables the crane to rotate.
Operating cabin: on most tower cranes the operating cabin sits just above the slewing unit. It contains the operating controls,load-movement indicator system (LMI), scale, anemometer, etc.
Jib: the jib, or operating arm, extends horizontally from the crane. A "luffing" jib is able to move up and down; a fixed jib has
a rolling trolley that runs along the underside to move goods horizontally.Counter jib: holds counterweights, hoist motor, hoist drum and the electronics.
Hoist winch: the hoist winch assembly consists of the hoist winch (motor, gearbox, hoist drum, hoist rope, and brakes), the hoist motor controller, and supporting components, such as the platform. Many tower cranes have transmissions with two or more speeds.
Hook: the hook (or hooks) is used to connect the material to the crane. It is suspended from the hoist rope either at the tip, for luffing jib cranes, or in the hoist rope belly underneath the trolley for hammerhead cranes.
Weights: Large, moveable concrete counterweights are mounted toward the rear of the counterdeck, to compensate for the weight of the goods lifted and keep the center of gravity over the supporting tower.