Meet Any Construction Challenge With Tower Crane Components
Tower crane components are fixtures at any major construction site. Used to lift steel, concrete, large tools and other building materials, the tower crane components are similar to that of a balance crane. A balance crane contains a horizontal beam (the lever) pivoted about a point called the fulcrum. The principle of the lever allows a heavy load attached to the shorter end of the beam to be lifted by a smaller force applied in the opposite direction to the longer end of the beam. Fixed to the ground (and sometimes attached to the sides of structures as well), components are combined in such a way as to give the best combination of height and lifting capacity and are used in the construction of tall buildings.
The tower crane allows for the ratio of the load's weight to the applied force is equal to the ratio of the lengths of the longer arm and the shorter arm, and is called the mechanical advantage. The components include, among others: the jib (also known as the boom), the counter-jib, a turntable, slewing bearings, slewing machinery, a trolley and a hoist motor, most of which is also found on a jib crane.
The jib and counter-jib are mounted to the turntable, where the slewing bearing and slewing machinery are located. The counter-jib carries a counterweight, usually of concrete blocks, while the jib suspends the load from the trolley. The Hoist motor and transmissions are located on the mechanical deck on the counter-jib, while the trolley motor is located on the jib. The crane operator either sits in a cabin at the top of the tower or controls the crane by radio remote control from the ground. The knuckle boom attachment has also become very popular with tower crane operators, due to the increase it brings in load control. Also see knuckle boom cranes.
An innovative take on the tower crane has been developed and is for sale through the Danish manufacturer, seller, installer, and servicer of wind turbines, Vestas. The company, which operates manufacturing plants in Denmark, Germany, India, Italy, Britain, Spain, Sweden, Norway, Australia, China, and the United States, has developed its Vestas Tower Crane™ (VTC) to meet the demands for replacing main components in 3,0 MW turbines. The VTC is clamped directly to the tower. The crane is the only one on the market that can operate on tapered towers — where the diameter of the tower narrows from bottom to top — and that is flexible enough to lift all types of main components for replacement, including hubs, gearboxes, generators and blades. The VTC weights 50 tonnes and can lift 30 tonnes.
Anders Vedel, senior vice president of technology R&D at Vestas was quoted in Cranes Today magazine, as saying that the tower crane components of the VTC have been designed to attach directly to the mast and climb the tower to carry out maintenance work on essential components, including the hub, gearbox, generator and blades. As it moves up the mast, it is capable of carrying loads weighing up to 30t. It offers a number of operational benefits over traditional methods of maintenance and repair carried out with mobile or crawler cranes
