Used Self Erect Cranes Fresno - The base of the tower crane is usually bolted to a large concrete pad that provides very crucial support. The base is attached to a mast or a tower and stabilizes the crane which is attached to the inside of the structure of the building. Normally, this attachment point is to a concrete lift or to an elevator shaft.
The crane's mast is normally a triangulated lattice structure which measures 0.9m2 or 10 feet square. Attached to the very top of the mast is the slewing unit. The slewing unit is made of a motor and a gear which enable the crane to rotate.
Tower cranes may have a max unsupported height of 80m or 265 feet, while the tower crane's maximum lifting capacity is 16,642 kg or thirty nine thousand six hundred ninety lbs. with counter weights of 20 tons. In addition, two limit switches are used to be able to ensure the driver does not overload the crane. There is also one more safety feature referred to as a load moment switch to ensure that the driver does not surpass the ton meter load rating. Finally, the maximum reach of a tower crane is seventy meters or 230 feet.
There is definitely a science involved with erecting a tower crane, especially due to their extreme heights. At first, the stationary structure needs to be brought to the construction location by utilizing a large tractor-trailer rig setup. Next, a mobile crane is utilized so as to assemble the machine portion of the crane and the jib. Afterwards, these sections are connected to the mast. Then, the mobile crane adds counterweights. Forklifts and crawler cranes can be a few of the other industrial machines which is commonly utilized to erect a crane.
When the building is erected, mast extensions are added to the crane. This is how the crane's height could match the building's height. The crane crew uses what is referred to as 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 so as to balance the counterweight. When 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 6.1m or 20 feet. Next, the crane driver utilizes the crane to insert and bolt into position another mast section piece.
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