Tower crane
A fixed-base or rail-mounted lifting machine with a tall vertical mast and horizontal jib, used for building tall structures where the crane stays on site for the duration of construction.
A tower crane is a fixed lifting machine that's erected on a construction site at the start of a project and dismantled at the end. It consists of a vertical mast (the tower) that can be tens to hundreds of metres tall, topped by a horizontal jib that rotates 360 degrees around the mast. A trolley runs along the jib to position the hook over the load.
The two main types are saddle-jib (also called hammerhead, with a fixed horizontal jib and a counter-jib carrying the counterweight) and luffing-jib (where the jib pivots up and down, useful in city-centre sites where over-sailing neighbouring buildings is restricted). Self-erecting tower cranes are a compact category used for low-rise residential and infill projects — they fold for transport and stand themselves up hydraulically without a separate assembly crane.
Tower cranes climb as the building grows. Internal-climbing variants ride up through the building's structural cores; external-climbing variants add tower sections from outside using a climbing frame. Maximum free-standing height (without external support) typically tops out around 80 metres; with building tie-ins, total height can exceed 200 metres.
Capacities range from 1-2 tonnes for small self-erecting models to 32+ tonnes for heavy industrial tower cranes (Liebherr, Potain, Wolffkran, Comansa). On the buyer side, the key specs are maximum jib length, capacity at the jib tip, climbing system type, and mast-section type (which determines what other Kranly listings the same crane is compatible with for jib extensions).