Tower Cranes
Tower cranes are a form of balance crane. Mounted to the ground or on the structure being built, the tower crane gives the best options of height and load lifting capacity. They are used in the construction of sky scrapers.
The vertical part of the crane is often fitted to the structure being built, lifted to the next level as the building grows. This saves space and provides stability. Mounted to the turntable are the jib or boom and counter jib, where slewing machinery and bearing are located. The counter jib carries counter weight, a trolley is used on the jib to carry the load.
On the mechanical deck on the counter jib, the hoist motor and transmissions are located. The trolley motor is located on the jib. There’s a cabin mounted at the top of the tower where the crane operator controls the crane. The lifting hook is moved by using electric motors to move wire rope cables through sheaves.
To hook and unhook loads, the crane operator works with a signaller (rigger or swamper). They mostly use radios and always use hand signals. Directing the schedule of lifts, and responsible for the safety of the rigging and loads is the rigger.