Used Self Erect Cranes Mexico - Generally the base which is bolted into a large concrete pad provides the crucial support for a tower crane. The base is connected to a mast or a tower and stabilizes the crane that is affixed to the inside of the building's structure. Usually, this attachment point is to an elevator shaft or to a concrete lift.
Usually, the mast is a triangulated lattice structure measuring 10 feet square or 0.9m2. The slewing unit is connected to the very top of the mast. The slewing unit is made of a gear and a motor which allows the crane to rotate.
Tower cranes may have a max unsupported height of 80m or two hundred sixty five feet, while the minimum lifting capacity of a tower crane is sixteen thousand six hundred forty two kg or thirty nine thousand six hundred ninety lbs. with counter weights of 20 tons. In addition, two limit switches are utilized in order to ensure the driver does not overload the crane. There is even one more safety feature called a load moment switch to ensure that the driver does not exceed the ton meter load rating. Lastly, the tower crane has a maximum reach of 70 meters or two hundred thirty feet.
There is definitely a science involved with erecting a tower crane, especially due to their extreme heights. At first, the stationary structure has to be transported to the construction site by using 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. These parts are then connected to the mast. Then, the mobile crane adds counterweights. Forklifts and crawler cranes may be some of the other industrial machinery which is used to erect a crane.
As the building is erected, mast extensions are added to the crane. This is how the crane's height can match the building's height. The crane crew uses what is called a top climber or a climbing frame that fits between the slewing unit and the top of the mast. A weight is hung on the jib by the work crew in order to balance the counterweight. Once complete, the slewing unit is able to detach from the top of the mast. In the top climber, hydraulic rams are utilized to adjust the slewing unit up an extra twenty feet or 6.1m. After that, the crane driver utilizes the crane to insert and bolt into place one more mast section piece.
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