Used Self Erect Cranes Los Angeles - The tower crane's base is generally bolted to a huge concrete pad that provides really crucial support. The base is attached to a mast or a tower and stabilizes the crane which is connected 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 usually a triangulated lattice structure which measures 10 feet square or 0.9m2. Attached to the very top of the mast is the slewing unit. The slewing unit is made of a gear and a motor that allows the crane to rotate.
Tower cranes may have a max unsupported height of 80m or two hundred sixty five feet, while the tower crane's maximum lifting capacity is 16,642 kg or 39,690 lbs. with counter weights of 20 tons. Furthermore, two limit switches are utilized to be able to make sure that the operator does not overload the crane. There is also one more safety feature referred to as a load moment switch to ensure that the operator does not surpass the ton meter load rating. Lastly, the tower crane has a maximum reach of 230 feet or 70 meters.
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 location by utilizing a big tractor-trailer rig setup. Next, a mobile crane is utilized in order to assemble the equipment portion of the crane and the jib. After that, these sections are attached to the mast. The mobile crane then adds counterweights. Crawler cranes and forklifts can be some of the other industrial equipment that is typically used to erect a crane.
Mast extensions are added to the crane as the building is erected. This is how the height of the crane is able to 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 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 utilized to adjust the slewing unit up an additional 6.1m or twenty feet. Then, the operator of the crane uses the crane to insert and bolt into position another mast section piece.
Self Erect Cranes PDF
