Tower crane hoisting height regulations have?

Lifting height also called hook height is the vertical distance from the surface of the concrete foundation of the tower crane to hook. On the trolley tower crane, its maximum lifting height is immutable, the pitch luffing tower crane, its amplitude varies with different lifting height, lifting height than the minimum amplitude high top tens m, so the pitch luffing tower crane has an advantage in starting the lift.
Tower crane lifting height includes two parameters, lifting height of one tower installation free height, the second is the maximum lifting height of the tower crane attached when the tower crane when installing free height without attachment, usually tower crane It can reach 40 meters, to meet the needs of high-rise buildings below.
In order to prevent the ultra-high tower crane hook lifting accidents and damage to the equipment, on each tower crane was equipped with a height limiter, when the hook rises to 1-2 meters away from the boom hoist is automatically cut off power to prevent the hook continue to rise.
Lifting speed not only with the lifting mechanism, but also to override hook pulley about 2 to 4 times faster rope rope, single rope twice as fast than the 2 ropes.