L68B1 Mast Section Introduction to five classification methods and knowledge of tower crane
Knowledge of tower crane: the introduction of five classification methods and knowledge of tower crane is based on whether there is walking mechanism, lifting arm, rotation mode of tower body structure, installation mode of crane and structure with or without tower tip. The following contents are sorted out by Linqing tower crane construction machinery factory and provided for your reference.
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I. whether there is a walking mechanism
According to whether there is walking mechanism, it can be divided into mobile tower crane and fixed tower crane.
According to the different traveling devices, the mobile tower crane can be divided into four types: track type, tyre type, automobile type and crawler type.
< 1 > the tower body of the rail tower crane is fixed on the walking underframe, which can run on the special track, has good stability, can walk with load, and has high working efficiency, so it is widely used in the construction and installation engineering.
< 2 > the tower cranes of tyre, automobile and crawler type have no track device and are easy to move, but they can not walk with load and have poor stability. At present, they are rarely produced.
According to the different installation position, the fixed tower crane can be divided into two types: attached self lifting type and internal climbing type,
< 1 > the attached self elevating tower crane can rise with the rise of the building, which is suitable for high-rise buildings. The building structure only bears the horizontal load transmitted by the crane, which is convenient to attach, but takes up more structural steel;
< 2 > the internal climbing crane climbs inside the building (elevator shaft, stairwell) with the help of a set of bracket and lifting system. The jacking is more complicated, but the occupied structure uses less steel, so there is no need to install the foundation. All the self weight and load are borne by the building.
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II. Boom
According to the structural characteristics of the boom, it can be divided into pitch luffing boom (boom) and trolley luffing boom (flat arm) tower crane.
< 1 > luffing boom tower crane does not realize luffing by lifting boom,
Advantages: it can give full play to the effective height of the boom, and the mechanism is simple,
Disadvantages: the minimum amplitude is limited to about 30% of the maximum amplitude, and it cannot be completely close to the tower body. During luffing, the load will rise and fall along with the boom, and the luffing with load is not allowed.
< 2 > trolley luffing jib tower crane realizes luffing by trolley traveling installed on the horizontal boom track,
Advantages: large range of luffing, the load car can approach the tower body, with load luffing,
Disadvantages: the load-bearing condition of the boom is complex, and the structural requirements are high. The boom and trolley must be on the upper part of the building. The installation height of the tower tip is 15-20 meters higher than the roof of the building.
III. rotation mode of tower body structure
According to the rotation mode of the tower body structure, it can be divided into the lower rotation (tower body rotation) and the upper rotation (tower body does not rotation) tower crane.
< 1 > the lower slewing tower crane sets the slewing bearing, main mechanism of balance weight, etc. at the lower end,
Advantages: less bending moment, low center of gravity, good stability, convenient installation and maintenance,
Disadvantages: high requirements for slewing bearing and limited installation height.
< 2 > the upper slewing tower crane sets the slewing bearing, balance weight and main mechanism at the upper end,
Advantages: because the tower body does not rotate, the lower structure of the tower body can be simplified, and the jacking and joint adding are convenient.
Disadvantages: when the building exceeds the height of the tower body, due to the influence of the balance arm, the rotation of the crane is limited. At the same time, the center of gravity is high, the wind pressure increases, and the pressure weight increases, so that the total weight of the whole machine increases.
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IV. crane installation mode
According to the different installation methods of crane, it can be divided into two types: the fast installation tower crane which can carry out folding transportation, self integral erection and the tower crane which needs to be assembled and disassembled with the aid of auxiliary machine.
The < 1 > self erecting fast loading tower cranes are all small and medium-sized down rotating tower cranes, which are mainly used in low-rise buildings with short construction period and frequent moving requirements,
Advantages: it can improve work efficiency, save installation cost, save time, labor and material,
Disadvantages: complex structure, large amount of maintenance.
< 2 > tower crane, which needs to be disassembled by auxiliary machine, is mainly used in middle and high-rise buildings and places with large working range and lifting capacity. It is the main type of crane on the construction site at present.
V. structure of spire
According to the structure with or without tip, it can be divided into flat head tower crane and pointed head tower crane.
Flat head tower crane is a new type of tower crane developed in recent years, which is characterized by the cancellation of the tower tip and its front and rear pull rods in the structure of the original self elevating tower crane, the enhancement of the structural strength of the boom and the balance arm, and the boom and the balance arm are directly connected,
Advantages: 1. Small size, convenient and safe installation, low transportation and storage costs;
2. The boom has good resistance, uniform force, and little damage to the structure and connecting parts;
3. The design of components can be standardized, modularized and interchangeable, reduce idle equipment and improve investment efficiency,
Disadvantages: in the same type of tower crane, the price of flat head tower crane is slightly higher.
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