tower crane
Crane used on construction sites with a usually horizontal jib mounted on top of a tower.
operator’s cab 
Cab at the top of the tower from which the operator manipulates the crane.
counterweight 
Blocks of concrete stacked at the base of the tower to stabilize the crane.
hoisting block 
System of pulleys that work with the trolley pulley to improve leverage to lift heavy loads.
jib 
Metal lattice that pivots on the tower and lifts and extends the hoisting system.
trolley 
Vehicle running along and under the jib; the hoisting rope is suspended from it.
counterjib ballast 
Concrete mass attached to the counterjib to balance the weight of the jib and its load.