Used Self Erect Cranes Alberta - The base of the tower crane is generally bolted to a large concrete pad which provides really necessary support. The base is connected to a tower or a mast and stabilizes the crane which is affixed to the inside of the building's structure. Often, this attachment point is to an elevator shaft or to a concrete lift.
The crane's mast is usually a triangulated lattice structure which measures 10 feet square or 0.9m2. Connected to the very top of the mast is the slewing unit. The slewing unit is made of a motor and a gear that enable the crane to rotate.
Tower cranes may have a max unsupported height of eighty meters or 265 feet, while the tower crane's maximum lifting capacity is 16,642 kg or 39,690 pounds with counter weights of twenty tons. Additionally, two limit switches are utilized in order to ensure the driver does not overload the crane. There is also one more safety feature known as a load moment switch to ensure that the operator does not exceed the ton meter load rating. Lastly, the maximum reach of a tower crane is 70 meters or 230 feet.
There is definitely a science involved with erecting a tower crane, particularly due to their extreme heights. At first, the stationary structure has to be transported to the construction site by using a big tractor-trailer rig setup. Next, a mobile crane is used so as to assemble the machine portion of the crane and the jib. Afterwards, these parts are connected to the mast. After that, the mobile crane adds counterweights. Crawler cranes and forklifts can be some of the other industrial equipment that is typically utilized to erect a crane.
Mast extensions are added to the crane when the building is erected. This is how the height of the crane can 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 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 is able to detach from the top of the mast. In the top climber, hydraulic rams are used to adjust the slewing unit up an additional twenty feet or 6.1m. After that, the crane operator uses the crane to insert and bolt into place one more mast part piece.
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