L68B3 Mast Section Classification, type and characteristics of tower crane
I. press whether there is a walking mechanism
L68B3 Mast Section：
http://www.towercranesupply.com/product/l68b3-mast-section-for-tower-crane-masts
According to whether there is a walking mechanism, it can be divided into mobile tower crane and fixed 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. 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. The tower cranes of tyre, automobile and crawler type have no track device and are easy to move, but they can't walk with load and have poor stability. The fixed tower crane can be divided into two types according to the different installation positions: the attached self elevating tower crane and the internal climbing tower crane: the attached self elevating tower crane can rise with the rise of the building, which is applicable to the high-rise building. The building structure only bears the horizontal load transmitted by the crane, which is convenient to attach, but uses more structural steel; the internal climbing crane is in the building (elevator shaft, stairwell), Climbing with the help of a set of bracket and lifting system, the jacking is more complicated, but the occupied structure uses less steel, does not need to install the foundation, and all the self weight and load are borne by the building.
II. According to the structural characteristics of the 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. The tower crane of luffing boom relies on the boom to lift and not realize luffing. Its advantage is that it can give full play to the effective height of the boom and the mechanism is simple. Trolley luffing jib tower crane realizes luffing by means of trolley traveling installed on the horizontal jib track. Its advantages are wide range of luffing, load-bearing trolley can approach the tower body, and it can luffing with load. The disadvantages are: the force condition of the jib is complex, the structural requirements are high, and the jib and trolley must be in the upper part of the building, and the installation height of the tower tip is 15 higher than the roof of the building- 20 meters.
III. rotation mode according to 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. The lower slewing tower crane sets the slewing bearing and the main mechanism of the balance weight at the lower end. The advantages of the tower crane are: less bending moment, low center of gravity, good stability, convenient installation and maintenance. The disadvantages of the tower crane are high requirements for the slewing bearing and limited installation height. The upper slewing tower crane sets the slewing bearing, balance weight and main mechanism at the upper end, which has the advantages of simplifying the lower structure of the tower body and convenient jacking. 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.
IV. installation method of crane
L68B3 Mast Section：
http://www.towercranesupply.com/product/l68b3-mast-section-for-tower-crane-masts
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 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. The main advantages are that they can improve work efficiency, save installation cost, save time, labor and materials, and the disadvantages are complex structure and large maintenance volume. The 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. according to the structure of spire or not
According to the structure with or without tip, it can be divided into flat head tower crane and tower 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 cap and its front and rear pull rod parts 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,
Its advantages are:
1. The whole machine is small in size, convenient and safe in installation, reducing the cost of transportation and storage;
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 highly interchangeable, so as to reduce idle equipment and improve investment efficiency. Its disadvantage is that in the same type of tower crane, the price of flat head tower crane is slightly higher.
