Used Self Erect Cranes Concord - Generally the base which is bolted into a huge concrete pad provides the necessary support for a tower crane. The base is attached to a tower or a mast and stabilizes the crane that is connected to the inside of the structure of the building. Usually, this attachment point is to a concrete lift or to an elevator shaft.
The mast of the crane is usually a triangulated lattice structure that measures 0.9m2 or 10 feet square. Connected to the very top of the mast is the slewing unit. The slewing unit is made of a gear and a motor that enable the crane to rotate.
Tower cranes are able to have a maximum unsupported height of eighty meters or two hundred sixty five feet. The tower crane's maximum lifting capacity is 16,642 kg or 39,690 lbs. with counter weights of twenty tons. In addition, two limit switches are used to be able to make certain that the driver does not overload the crane. There is even another safety feature called a load moment switch to make certain that the operator does not surpass the ton meter load rating. Finally, the maximum reach of a tower crane is 230 feet or seventy meters.
There is definitely a science involved with erecting a tower crane, specially due to their extreme heights. First, the stationary structure has to be brought to the construction site by utilizing a large tractor-trailer rig setup. After that, a mobile crane is utilized so as to assemble the equipment portion of the jib and the crane. After that, these parts are attached to the mast. Then, the mobile crane 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 is able to match the building's height. The crane crew utilizes what is referred to as a climbing frame or a top climber which fits between the top of the mast and the slewing unit. A weight is hung on the jib by the work crew so as to balance the counterweight. Once complete, the slewing unit could detach from the top of the mast. In the top climber, hydraulic rams are utilized to adjust the slewing unit up an extra 6.1m or 20 feet. After that, the driver of the crane uses the crane to insert and bolt into position another mast part piece.
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