Tower crane is the most commonly used lifting equipment on construction sites. It is connected in length (height) section by section, like an iron tower. It is also called a tower crane and is used for lifting construction equipment. Equipment for obtaining construction raw materials such as steel bars, wooden corrugations, and scaffolding pipes. It is an indispensable equipment for construction.
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. The top of the self-elevating tower can be divided into truncated cone column type, forward or backward tilting truncated cone column type, herringbone type and diagonal brace type. All upper slewing tower cranes need to be equipped with a counterweight, whose function is to support the counterweight to form a counterweight moment in the direction opposite to the lifting moment required by the design. In addition to the counterweight, a lifting mechanism is often installed at the tail. The reason why the lifting mechanism is placed at the end of the balance arm together with the balance weight is that it can play a partial counterweight role and increase the distance between the rope drum and the guide wheel at the top of the tower to facilitate the winding of the wire rope and avoid accidents. Rope tangle phenomenon. The amount of balance weight is inversely proportional to the length of the balance arm, and there is a certain proportional relationship between the length of the balance arm and the length of the lifting arm. The balance weight is quite considerable, generally at least 3 to 4t for light tower cranes and nearly 30t for heavy ones.
According to the luffing method, it can be divided into: 1. Pitch luffing type; 2. Car luffing type. According to the operation mode, it can be divided into: 1. Self-elevating type; 2. Non-self-elevating type. According to the rotation method, it can be divided into: 1. Boom type; 2. Lower rotating type. According to the fixing method, it can be divided into: 1. Orbital type; 2. Jellyfish rack type. According to the spire structure, it can be divided into: 1. Flat head type; 2. Pointed head type. According to the operation mode, it can be divided into: 1. Mechanical automatic; 2. Human control.
1. According to whether there is a traveling mechanism or not
It can be divided into mobile tower crane and fixed tower crane. Mobile tower cranes can be divided into four types according to different traveling devices: track type, tire type, automobile type, and crawler type. The orbital tower crane body is fixed on the traveling chassis and can run on a specially designed track. It has good stability, can travel with load, and has high work efficiency, so it is widely used in construction and installation projects. Tire-type, car-type and crawler-type tower cranes do not have track devices and are easy to move, but they cannot travel with load and have poor stability. They are rarely produced now. Fixed tower cranes are divided into two types, the attached self-elevating type and the internal climbing type, depending on the installation location. The attached self-elevating tower crane can rise with the rise of the building. It is suitable for high-rise buildings. The building structure is only It can withstand the horizontal load transmitted by the tower crane and is easy to attach, but takes up a lot of structural steel. The internal climbing tower crane climbs inside the building (elevator shaft, stairwell) with the help of a set of brackets and lifting systems, and the jacking is more cumbersome. , but it occupies less structural steel and does not need to install a foundation. All dead weight and loads are borne by the building.
2. The structural characteristics of the boom
It can be divided into pitching Luffing jib (boom) and trolley luffing jib (flat jib) tower cranes. The pitch luffing jib tower crane relies on the lifting and lowering of the jib without luffing. Its advantages are: it can fully utilize the effective height of the jib and its mechanism is simple. The disadvantage is that the minimum amplitude is limited to about 30 of the maximum amplitude. , cannot be completely close to the tower body, the load rises and falls with the boom during luffing, and cannot luff with load. The trolley luffing jib tower crane achieves luffing by traveling on a trolley installed on the horizontal boom track. Its advantages are: a large luffing range, the load-carrying trolley can approach the tower, and it can luff the amplitude with load. Disadvantages Yes: The stress on the crane arm is complex and the structure requirements are high. The crane arm and trolley must be at the upper part of the building. The installation height of the tower tip must be 15-20 meters higher than the roof of the building.
3. Tower structure rotation mode
It can be divided into lower rotation (tower body rotation) and upper rotation (tower body does not rotate) tower crane. The lower slewing tower crane has the slewing support and the main balance weight mechanism at the lower end. Its advantages are: the tower is subject to less bending moments, low center of gravity, good stability, and easy installation and maintenance. The disadvantage is that it requires more slewing support. High, the installation height is limited.
The upper slewing tower crane has the slewing support, counterweight, and main mechanisms set at the upper end. Its advantage is that since the tower body does not rotate, the lower structure of the tower body can be simplified, and lifting and adding sections are convenient. The disadvantage is: when the building exceeds the height of the tower, the rotation of the tower crane is restricted due to the influence of the balance arm. At the same time, the center of gravity is higher, the wind pressure increases, and the pressure weight increases, which increases the total weight of the whole machine.
4. Tower crane installation methods are different
They can be divided into quick-installation tower cranes that can be folded for transportation and erected as a whole by themselves, and those that require the help of auxiliary machines for assembly and disassembly. Tower crane. Quick-installation tower cranes that can be erected by themselves are small and medium-sized lower-slewing tower cranes. They are mainly used in low-rise buildings with short construction periods and frequent movements. The main advantages are that they can improve work efficiency, save installation costs, and save time, labor, and materials. , the disadvantage is that the structure is complex and the amount of maintenance is large. Tower cranes that require disassembly and assembly of auxiliary engines are mainly used in mid-to-high-rise buildings and places with large working range and heavy lifting capacity. They are currently the main type of crane on construction sites.
5. According to the structure with or without a spire
It can be divided into flat-head tower crane and pointed-head tower crane. The flat-head tower crane is a new type of tower crane developed in recent years. Its characteristic is that the tower spire and its front and rear tie rods are eliminated from the structure of the original self-elevating tower crane, and the structural strength of the boom and balance arm is enhanced. , the big arm and the balance arm are directly connected. Its advantages are: 1. The whole machine is small in size, easy and safe to install, and reduces transportation and warehousing costs; 2. The lifting arm has good tolerance and uniform stress, which is good for the structure and connecting parts. Less damage; 3. The component design can be standardized, modularized and highly interchangeable, reducing equipment idleness and improving investment efficiency. The disadvantage is that the price of flat-head tower cranes is slightly higher among tower cranes of the same type.
Definition
Tower crane design outsourcing service: refers to corporate customers hiring professional tower crane design service providers to provide corporate customers with a full range of CMD technical services to enhance the company's technical advantages and reduce costs. Behavior of Development Costs.
Classification
Developmental design: Apply mature design experience or feasible new technologies to design new tower cranes, mainly including functional design and mechanism design. Upgradeable design: Update and upgrade the existing tower crane design based on usage experience and technological development to improve performance, reduce manufacturing costs or reduce operating expenses. Generative design: In order to adapt to new needs, some parts of the existing tower crane are modified, added or deleted, thereby developing derivative products that are different from the standard type. Serialized design: Taking one type of tower crane as the mother model, we design a series of products with the same function and similar appearance, but with different power, tonnage and size.
Development process
1. Develop requirements analysis. Based on factors such as function, performance, operating environment, etc., we work with customers to formulate detailed user requirements specifications to determine development goals. 2. Preliminary scheme design. Based on demand analysis, plan formulation is carried out, including function and parameter setting, basic calculations, preliminary three-dimensional rendering, etc., and then preliminary review is conducted with the customer. 3. Detailed plan design. Listen to the preliminary review opinions and implement the plan design. Modify and refine the general drawing of the 3D model, draw 3D drawings of parts, and conduct finite element analysis and dynamic simulation of structural components. Then conduct a second review with the customer. 4. Final plan determination and drawing drawings. Listen to the opinions of the second review and modify the plan design. Draw floor plans (such as parts drawings, component assembly drawings and general assembly drawings, painting drawings, etc.), and produce parts lists and wearing parts lists. 5. Produce all technical documents, including promotional and technical samples, and product instructions.
For small high-rise buildings below 100 meters, use QTZ5008, about 230,000 yuan; for medium-high buildings below 140 meters, use QTZ5013 or QTZ5313, for 270,000 to 320,000; for high-rise buildings below 200 meters, use QTZ6313 or QTZ7030, for 800,000 to 1.2 million yuan Prices above RMB 10,000 are the mid-range prices currently on the market, and may vary greatly depending on the manufacturer and configuration.
Tower crane, referred to as tower crane, also known as tower crane, originated in Western Europe. According to records, the first patent related to tower cranes for construction was issued in 1900.
In 1905, a crane with a fixed tower body and a jib appeared. In 1923, a prototype of a modern tower crane was made. In the same year, the first relatively complete modern tower crane appeared. In 1930, Germany had begun mass production of tower cranes and used them in construction. In 1941, the German industrial standard DIN8770 for tower cranes was announced. The standard stipulates that the lifting capacity of the tower crane is expressed as the gravity moment as the product (tm) of the hoisting load (t) and the amplitude (m). my country's tower crane industry started in the 1950s. Compared with the downturn in the tower crane industry in Central and Western European countries due to the weak construction industry, Shanghai Boch Drive System Co., Ltd. my country's tower crane industry is in a period of rapid development. . From the perspective of the technical development of tower cranes, although new products are emerging one after another, and the new products have improved in terms of production efficiency, ease of operation, ease of maintenance and reliable operation, the technology of tower cranes has not fundamentally changed. Research on tower cranes is moving towards combined development. The so-called combined type is to take the tower body structure as the core, decompose the tower body into several parts according to the structural and functional characteristics, and then divide each part into several modules according to the serialization and generalization requirements and the modular system principle. According to the parameter requirements, appropriate modules are selected to form tower cranes with different technical performance characteristics to meet the specific needs of construction. The implementation of combined tower cranes will help speed up the development of tower crane products, save product development costs, and better serve customers. 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 is fixed and does not rotate, and is installed on a solid concrete foundation or on a strip-shaped X-shaped concrete foundation. In the construction of houses, fixed ones are generally used.
1. Before use, you should check that all metal structural parts and appearance are intact, the sound is normal during no-load operation, the braking is reliable in heavy-load testing, all safety limits and protection devices are complete and intact, and the action is sensitive and reliable before operation. 2． When operating each controller, you should operate it step by step, and it is strictly prohibited to operate beyond the gears. When changing the running direction, the operating handle should be returned to zero, and the motor should stop rotating before changing direction. Try to make it smooth. Emergency opening and stopping are strictly prohibited. 3． When the equipment is in operation, if any abnormality is found in the machinery, it should be stopped immediately for inspection, and the operation can only be carried out after the fault is eliminated. 4． It is strictly forbidden to work with a certificate. It is strictly forbidden to work while drunk. It is strictly forbidden to use a travel switch instead of a parking operation. It is strictly forbidden to work in violation of regulations, leave the job without permission or give the machine to others to drive. 5. When loading heavy objects, you should first leave a certain distance from the ground and check that the braking is reliable before proceeding. 6. Adhere to the "ten" and never hang up. After the operation is completed, the power should be turned off and the lock box should be turned off, and the "cross" operation of the machine should be done well. The ten don’ts of lifting are as follows: (1) Don’t hang when hanging at an angle (2) Don’t hang if it is overloaded (3) Don’t hang if the bulk goods are too full or not tied tightly (4) Don’t hang if there are no protective measures on the edge of the hanging objects (5) Do not lift the hoisted object if there is a person standing on it (6) Do not hoist if the command signal is unclear (7) Do not hoist the components buried underground (8) Do not hoist if the safety device fails (9) Cannot see the hoist in dark light Do not lift objects (10), do not lift in strong winds above Level 6
The tower crane model preparation method [1] is extremely diverse. In the past, our country has made unified regulations on this. At present, although this regulation is still implemented, many tower crane manufacturers still have a way of expressing it. There are two main parameters expressed by the tower crane model: one is the rated lifting moment, and the other is the maximum arm length and arm end lifting capacity. Several typical preparation methods are introduced as follows. Three common classification methods are:
1. Numbering method stipulated in the standard
According to ZBJO4008, the model composition of my country's tower cranes is: Class group code form attribute code main parameter code. Category: Q——(starting) Group: T——(Tower) Type: Upper slewing self-elevating type Z——(self-elevating) Fixed type G——(solid) Internal climbing type P——(climbing) Lower slewing self-elevating type Formula S (liter) The main parameter is the nominal lifting moment.
Examples of markings are as follows: Fixed tower crane with a nominal lifting torque of 600kNm: QTG600; Self-elevating tower crane with a nominal lifting torque of 1000kNm: QTZ1000. Some tower cranes still use tm as the crane torque measurement unit, so the above three tower crane models are expressed as QTG60, QTZ100.
2. Enterprise characteristic numbering method
(TowerCrane) TC replaces the group code, omits the formal characteristic code, and uses two maximum amplitudes (m) and maximum lifting weight (kN) The basic parameter code replaces the main parameter code. Marking examples are as follows: Sichuan Construction Machinery C7050, indicating that the maximum arm length of the tower crane is 70m, and the lifting weight at this time is 50kN. Zoomlion TC5613 (QTZ80H) means that the maximum arm length of the tower crane is 56m, and the lifting weight at this time is 13kN. Fushun Yongmao Construction Machinery Co., Ltd. ST70/30 means that the maximum arm length of the tower crane is 70m, and the lifting weight at this time is 30kN. STT293 and STT553 (this series number is quite special), respectively indicating that the maximum working range of the tower crane is 74m and 80m, and the end lifting weight is 2.5t and 3.55t.
3. The numbering method of the introduction of Potan technology
The tower cranes produced by my country's Sichuan Construction Machinery and Shenyang Construction Machinery that introduced French POTAN technology continue to use the POTAN numbering method, and the technical characteristics represented by their models as follows. a. The first letter of the tower crane model number is the maximum arm length code. The meaning of the code is: F——50m H——60m K——70m M——80m b. The second character of the tower crane model number is the code for the maximum lifting weight of a single rope. The meaning of the code is: 0——2t 3——3t c. The third character of the tower crane model number is the maximum lifting weight of the double rope at the maximum amplitude, in kN. d． The fourth character in the tower crane model number is the design improvement code. H3/36B and F0/23B are typical products that have introduced POTAN technology in my country. Examples of their models are as follows: H3/36B: H——maximum amplitude 60m, 3——maximum lifting capacity of a single rope 3t, 36——maximum amplitude Maximum lifting capacity (kN) B——Design improved code F0/23B: F——Maximum amplitude 60m, 0——Maximum lifting capacity of a single rope 2t, 23——Maximum lifting capacity at maximum amplitude (kN) B—— The design improvement code K50/50 indicates that the maximum arm length of the tower crane is 70m, the lifting capacity is 50kN, and the maximum lifting capacity of a single rope is 50kN; M125/75 indicates that the maximum arm length of the tower crane is 80m, the lifting capacity is 75kN, and the maximum lifting capacity of a single rope is 50kN. The lifting weight is 125kN.
Tower crane (10 photos)
Regulations on the service life of tower cranes
According to the Ministry of Construction's "Eleventh Five-Year Plan" for the promotion and application of construction projects and restrictions on prohibited use Technology (First Batch) Announcement (No. 659), the service life of construction tower cranes (TOWER CRANE) is stipulated as follows: (1) For the following three types of tower cranes, those that exceed the service life shall be evaluated by a qualified evaluation agency Only after passing the qualification can you continue to use: ⒈ Tower cranes below 630kN.m (excluding 630kN.m) and with a factory age of more than 10 years (excluding 10 years); ⒉ 630~1250kN.m (excluding 1250kN.m), Tower cranes with a factory age of more than 15 years (excluding 15 years); ⒊ Tower cranes with a capacity of more than 1250kN.m and a factory age of more than 20 years (excluding 20 years). (2) If the service life specified in the tower crane instruction manual is less than the above provisions, the service life specified in the instruction manual shall be used. (3) In addition to the complete machine, the scrapping regulations for the main load-bearing structural parts of the tower crane should be implemented in accordance with the provisions of Article 4.7 of the "Safety Regulations for Tower Cranes" (GB5144-2006): "Scrapping and Working Life of Structural Parts".
Tower crane sliding hook reasons
1. Sliding hook reasons
1. The contactor power inlet and outlet wire fixing screws in the tower crane distribution box are loose, and the terminal board is loose The wiring bolt has poor contact and the main contact of the contactor has poor contact. 2. The wiring bolts of the motor rotor and stator coil are ablated and have poor contact. 3. The wear of high and low speed motor brake pads exceeds the specified requirements. 4. The gearbox gear is broken and the fixing gear bolts are loose. 5. The phase loss protector does not work.
2. Preventive measures
1. Drivers should calm down when a slip hook occurs during work, and promptly notify the signal worker to let the ground personnel go away. Carry out operations in accordance with the operating procedures, lifting hooks, turning arms, walking trolleys, etc., and place heavy objects in the no-man's area of ??the site. 2. Carry out safety inspections before, during and after the shift, using visual, auditory and manual inspections. 3. Check and tighten various line connection points from time to time. 4. Regularly check whether the brake pads of each brake are normal, whether the motor terminal bolts are in good contact, and whether the main contacts of the contactor are in normal contact. 5. Maintenance personnel must be serious and responsible for their work, strictly follow the requirements of safe operating procedures, must replace the parts that need to be replaced, and do a good job of inspection and trial operation after work.
Edit the overall installation method of the tower crane in this section
(1) Preparation work
Check whether the roadbed and track laying meet the requirements, bury ground anchors, and erect the tower according to The position of the ground anchor is determined by the rotation and lifting direction, the total height of the tower, etc. Ground anchors are divided into main ground anchors and auxiliary ground anchors. The main ground anchor is the key to erecting the tower. All the load of rotating and lifting the tower is borne by the main ground anchor. When the tower is dismantled, the ground anchor still needs to be used, so it must be carefully buried to ensure that it reaches the required bearing capacity. And do anti-corrosion treatment. The center of the ground anchor wheel must be consistent with the center of the track gauge to ensure that during the lifting process of the tower, it always rotates along the track gauge center plane without causing eccentricity, so that the mast can bear balanced stress. The function of the auxiliary ground anchor is to loosen the wire rope as the tower rotates when the tower is lifted. This ground anchor is used as an anchor point for the insurance wire rope to prevent the tower from falling in the opposite direction during the rotation process.
(2) Overall installation
Install the traveling mechanism, mast and weight according to the procedures required in the instruction manual. The lifting arm is inserted into the bracket shaft of the gantry platform, and the tower body and tower cap are assembled on the wooden stacks according to the dimensions of the tower lying down. The tower body is placed on the wooden stacks, and its axis is roughly parallel to the ground. .
(3) Thread the wire rope
Put the winch wire rope through the cab to the pulley block of the tower cap, and finally fix it on the head of the crane. The entire rope length and the distance between the two pulley blocks should be Calculate OK.
(4) Before erecting the tower
Electrical equipment such as controllers and limit switches should be inspected, and the movable control panel in the control room should be removed and installed on an outdoor bracket. Easy to operate when erecting the tower. Clamp the rail clamp and wedge the anti-skid wedge under the running wheel. To enhance the rigidity of the mast, cross braces can be tied to both sides of the mast. Before starting, the responsibilities of each position should be specified, strict division of labor and command liaison signals should be provided. The inspection of the main ground anchor should be carried out by experienced lifting personnel. When abnormal phenomena such as looseness are found, the vehicle should be stopped immediately and measures should be taken (a weight can be added to the ground anchor). Start the winch so that the tower body is about 200mm away from the wooden stack. Stop the machine immediately and check the stress integrity of each component.
(5) Erect the tower
After inspection and confirm that the situation is normal, continue to operate the winch to make the tower erect stably, and the wire rope at the auxiliary ground anchor will loosen. After the tower stands at 60°, the hoist will gradually slow down as the tower's center of gravity changes. When the tower's center of gravity approaches the installation hinge, the hoist will stop working. Use a mobile crane to tighten the safety wire rope, and the tower will slowly fall to the preset position under its own weight. On the prepared skids. After the tower body is stable, tighten the safety wire rope to make the tower body slightly tilted, then remove the skid layer, then loosen the safety wire rope to stabilize the tower body.
Edit this section of safety and insurance devices
1. Safety requirements for tower crane operations
(1) Tower crane drivers and signal personnel must undergo special training and be certified by relevant The department issues a certificate and pays attention to whether the tower type learned by the driver is consistent with the tower type actually operated. (2) Implement dedicated personnel and aircraft management, captain responsibility system, and strict shift handover system. (3) Newly installed or overhauled tower cranes must be tested and run according to the instructions. (4) The tower crane should maintain a safe distance from overhead transmission lines. (5) The driver's cab should be equipped with suitable fire-extinguishing equipment.
2. Safety device of tower crane
(1) Hook safety device: A safety device that prevents the sling on the hook from automatically slipping off the hook. That is, a compression spring piece is installed at the opening of the hook head to close the opening. This spring piece can only be pressed downward and cannot be turned upward after the sling is placed, which can prevent the sling from automatically falling off. (2) Drum safety device: an effective measure to prevent accidents caused by improper winding of the wire rope beyond the drum. The methods vary. The main method is to weld a steel cage outside the drum to limit the movement of the wire rope only within the range of the drum. (3) Fixed foundation: The trench is dug to a depth of 600mm, concrete is poured on the lime soil, the surface is flat, and there are waterproof and grounding protection measures.
3. Tower crane grounding safety protection
Aluminum conductors and rebar must not be used as grounding bodies or underground grounding wires when installing tower cranes. Bolted wires must have an end. There are three main methods for grounding: 1. The grounding body uses regular grounding piles, or 33*4.5 long 1.5m steel pipes, or 70*70 long 1.5m angle steel. 2. The ground plate is made of steel plate or other extendable metal plate, with an area of ??1 square meter. Buried vertically at a depth of 1.5m from the ground. 3. Copper conductors with a cross-section of not less than 28 mm or steel conductors with a cross-section of not less than 50 mm are buried in the wire trough. The buried length is determined by the grounding resistance. Among the above three methods, the cross-sectional area of ??the copper wires drawn from the grounding body should be no less than 25. If the soil conductivity is poor, sodium chloride (salt) can be buried in the soil. Then fill it with water. For traveling tower cranes, each rail must be grounded, and wires should be connected between the two rails. Electrical connections should also be made between the two rail sections, and the grounding resistance should not be greater than 4.