At present, the common ones are 42 meters, 45 meters, 47 meters, 48 ??meters, 50 meters, 53 meters, 55 meters, 56 meters, 60 meters, 63 meters, 65 meters and 70 meters.

At present, the most commonly used arm length for high-rise buildings in our buildings is 63 meters.

The function of the tip of the tower crane is to bear the upper load from the boom rope and the balance arm rope, and directly pass through the turntable through the structural components of the rotating tower, turntable, bearing, etc. passed to the tower structure.

Tower cranes are divided into two categories: upper slewing tower cranes and lower slewing tower cranes. Among them, the bearing capacity of the former is higher than that of the latter. What we see in many construction sites is the upper rotary type tower crane with upward lifting and joint height. According to whether they can move, they are divided into: walking type and fixed type. The fixed tower crane body is fixed and does not rotate. It is installed on a solid concrete foundation or on a strip-shaped X-shaped concrete foundation. The walking type can be divided into four types: crawler type, vehicle type, tire type and track type. In the construction of houses, fixed ones are generally used. According to its luffing method, it can be divided into two types: horizontal boom trolley luffing and boom luffing; according to its installation form, it can be divided into three types: self-elevating type, overall quick disassembly and assembly type, and assembly type. The most widely used are down-slewing, quick-disassembly, orbital tower cranes and self-elevating tower cranes that can be used in four applications (orbital, fixed, attached and internal climbing).