Used Self Erect Cranes Canada - Usually the base that is bolted into a huge concrete pad provides the necessary support for a tower crane. The base is connected to a mast or a tower and stabilizes the crane which is attached to the inside of the building's structure. Often, this attachment point is to an elevator shaft or to a concrete lift.
The crane's mast is usually a triangulated lattice structure that measures 10 feet square or 0.9m2. Connected to the very top of the mast is the slewing unit. The slewing unit consists of a gear and a motor which allows the crane to rotate.
Tower cranes are able to have a maximum unsupported height of eighty meters or two hundred sixty five feet. The maximum lifting capacity of a tower crane is sixteen thousand six hundred forty two kilograms or 39,690 lbs. with counter weights of 20 tons. Furthermore, two limit switches are used to be able to make certain that the operator does not overload the crane. There is even another safety feature referred to as a load moment switch to make sure that the operator does not exceed the ton meter load rating. Last of all, the tower crane has a maximum reach of 70 meters or 230 feet.
There is certainly a science involved with erecting a tower crane, specially because of their extreme heights. At first, the stationary structure needs to be transported to the construction site by utilizing a huge tractor-trailer rig setup. Then, a mobile crane is utilized so as to assemble the equipment part of the crane and the jib. These parts are then attached to the mast. The mobile crane next adds counterweights. Crawler cranes and forklifts can be some of the other industrial equipment that is utilized to erect a crane.
Mast extensions are added to the crane as the building is erected. This is how the height of the crane can match the building's height. The crane crew utilizes what is called a climbing frame or a top climber that fits between the slewing unit and the top of the mast. A weight is hung on the jib by the work crew so as to balance the counterweight. When complete, the slewing unit can detach from the top of the mast. In the top climber, hydraulic rams are used to adjust the slewing unit up an extra 6.1m or 20 feet. Next, the operator of the crane utilizes the crane to insert and bolt into place another mast section piece.
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