Used Self Erect Cranes Yukon - The tower crane's base is typically bolted to a big concrete pad that provides very crucial support. The base is attached to a tower or a mast and stabilizes the crane which is affixed to the inside of the structure of the building. Usually, this attachment point is to an elevator shaft or to a concrete lift.
The mast of the crane is normally a triangulated lattice structure that measures 10 feet square or 0.9m2. Attached to the very top of the mast is the slewing unit. The slewing unit consists of a gear and a motor that enable the crane to rotate.
Tower cranes may have a max unsupported height of eighty meters or 265 feet, while the minimum lifting capacity of a tower crane is 16,642 kg or 39,690 lbs. with counter weights of 20 tons. Additionally, two limit switches are utilized in order to ensure the operator does not overload the crane. There is also another safety feature referred to as a load moment switch to ensure that the driver does not surpass the ton meter load rating. Lastly, the maximum reach of a tower crane is seventy meters or two hundred thirty feet.
Due to their extreme heights, there is a science involved to erecting a crane. The stationary structure would at first need to be brought to the construction location by using a huge tractor-trailer rig setup. Then, a mobile crane is used in order to assemble the machinery part of the jib and the crane. These parts are then connected to the mast. Then, the mobile crane adds counterweights. Forklifts and crawler cranes may be a few of the other industrial machinery which 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 could match the building's height. The crane crew uses what is known as a climbing frame or a top climber that fits between the top of the mast and the slewing unit. A weight is hung on the jib by the work crew in order to balance the counterweight. Once complete, the slewing unit could detach from the top of the mast. In the top climber, hydraulic rams are used to adjust the slewing unit up an additional 6.1m or twenty feet. After that, the crane operator uses the crane to insert and bolt into place one more mast section piece.
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