Used Self Erect Cranes Vallejo - The base of the tower crane is typically bolted to a huge concrete pad which provides really necessary 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.
Typically, the mast is a triangulated lattice structure measuring 0.9m2 or 10 feet square. The slewing unit is attached 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 265 feet, while the tower crane's maximum lifting capacity is sixteen thousand six hundred forty two kg or thirty nine thousand six hundred ninety lbs. with counter weights of 20 tons. Moreover, two limit switches are utilized in order to make certain that the driver does not overload the crane. There is even another safety feature called a load moment switch to ensure that the driver does not exceed the ton meter load rating. Finally, the tower crane has a maximum reach of seventy meters or 230 feet.
There is certainly a science involved with erecting a tower crane, particularly due to their extreme heights. First, the stationary structure has to be transported to the construction site by utilizing a huge tractor-trailer rig setup. After that, a mobile crane is utilized in order to assemble the equipment portion of the jib and the crane. Then, these parts are attached to the mast. The mobile crane then adds counterweights. Crawler cranes and forklifts may be some of the other industrial machinery that is utilized to erect a crane.
As the building is erected, mast extensions are added to the crane. This is how the crane's height is able to match the building's height. The crane crew utilizes 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 additional 6.1m or twenty feet. After that, the driver of the crane utilizes the crane to insert and bolt into position another mast part piece.
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