As the main equipment for carrying and lifting heavy objects in various places, cranes are widely used, bringing a lot of convenience to everyone in construction. But it needs to be erected before it can be used, so how should the crane be erected reasonably and correctly? Next, I will take you to learn more about it.

1. Set up the mast in the middle of the main beam of the crane, and slightly close to the side of the heavier main beam, so that the lifting equipment will not tilt, and the electric hoist is firmly tied to the main beam and lifted at the same time.

2. When the crane is hoisted, it should keep rising stably, and it should not swing at will. In order to enable people to control it, ropes can be tied to both ends of the equipment.

3. Use the hoist and mast to pass the rope into the hoisting hole to lift.

4. Lift the equipment to an appropriate height, bolt the control room to the connecting frame and the connecting seat, and then weld the connecting seat to the main beam and the cross beam according to the attached drawings.

5. When hoisting the equipment to over the track, pull the rope to twist, and gradually fall down so that the crane wheel groove is aligned with the track.

The erection of a crane is an important task, and the quality of the erection will directly affect the subsequent use of the equipment. Therefore, we should make reasonable assumptions for it in accordance with the above process.

Looseness: The newly processed and assembled parts have deviations in geometric shapes and matching dimensions. In the early stage of use, they are affected by alternating loads such as impact and vibration, as well as heat, deformation and other factors, as well as excessive wear and tear. , It is easy to loosen the originally fastened parts.

Leakage phenomenon: due to the loosening of the machine parts, vibration and the influence of the machine’s heat, there will be leakage in the sealing surface of the machine and the pipe joints; some defects such as casting and processing are difficult to find during assembly and debugging, but due to the operation In the process of vibration and impact, this kind of defect is exposed, which manifests as leakage (seepage) of oil (water). Therefore, leakage is prone to occur during the running-in period.

Fast wear speed: Due to the influence of factors such as the processing, assembly and adjustment of new machine parts, the friction surface is rough, the contact area of the mating surface is small, and the surface pressure is uneven. During the operation of the machine, the concave and convex parts of the surface of the parts fit and rub against each other.The metal scraps that are ground down are used as abrasives and continue to participate in friction, which accelerates the wear of the mating surface of the parts. Therefore, the parts (especially the mating surfaces) are easily worn during the running-in period, and the wear rate is fast. If overloaded, it may cause damage to parts and cause early failure.

Poor lubrication. Due to the small fit clearance of newly assembled parts, and due to assembly and other reasons, it is difficult to ensure the uniformity of the fit clearance. Lubricating oil is not easy to form a uniform oil film on the friction surface to prevent wear. Thereby reducing the lubrication efficiency, causing the early abnormal wear of the machine parts. In severe cases, it will cause scratches or seizures on the friction surface of the precision fit, leading to failures.

Crane trolley  is a widely used lifting equipment. When selecting a vehicle, one must pay attention to the operating environment of the vehicle. The selection of a vehicle must be confirmed according to the detailed working conditions of the workshop.

Improper driving type selection can easily lead to safety accidents.  The primary cause of the accident is the use of ordinary cranes to lift molten metal, which is not allowed.

Therefore, users must be cautious when choosing a trolley, and choose a trolley that is suitable for the production conditions of the workshop. Generally speaking, driving is only suitable for general occasions, and the heavy work level should be light and medium. If lifting molten metal, it is necessary to choose a special metallurgical crane. The working level of crane trolley should be greater than or equal to M6, and the lifting mechanism should have a double braking function. The insulation class of the motor should be h-class, high temperature resistance, and with thermal protection device. The operation method of the whole machine should be operated in the driver’s cab or Remote Control as far as possible to ensure that the operator has a certain safe distance from the metal bag.

The driving trolley environment has a great influence on driving planning. The most suitable trolley for cost planning. If we do not go to the site inspection of the single-beam crane , we will not be able to proceed from the actual situation to solve the customer’s needs.

Overhead crane motors often generate heat, which will shorten their service life. The difference in the thermal expansion coefficient of each part of the motor will lead to the change of the structural stress and the slight change of the internal air gap, and it will also affect the dynamic response of the motor, and it may lose step at high speed. In the case of high operating frequency, the motor simply generates heat. Especially in summer, the temperature difference between the surface and the inside of the motor in use is small, and the heat dissipation is not ideal. The motor heats up for a long time, which simply causes the motor to run at high load.

In order to deal with these problems, it is necessary to check the accuracy of the overhead crane wheels and the meshing scale of the gears. After eliminating the first two reasons, the damaged gear should be replaced, and the surface hardness of the replaced gear should be tested, and the transmission organization should be added through frequency conversion transmission to reduce the impact of starting and braking and prolong the service life. In addition to gear defects, the wheelset also has flange wear, bearing damage, and shaft damage. For flange damage, check whether the single-beam overhead crane trolley has rail gnawing. Bearing damage is generally due to bearing selection or bearing quality problems. Shaft damage is related to shaft heat treatment and device accuracy.
When the “jogging” action is frequent, the motor of the bridge crane is often in the process of starting, braking, forward and reverse. The load is very irregular, sometimes light and sometimes heavy, and often accepts larger overloads and mechanical shocks, and is in intermittent periodic work mode. In the starting process of the bridge crane, most of the losses are consumed in the resistors, and a small part of the losses are caused by the series resistance of the rotor. However, because of the large starting current, the power loss during the starting process is still much higher than the power loss at the rated speed. In addition, the temperature rise of the motor will increase with the increase of the number of starts due to the influence of the decrease of the heat dissipation coefficient during the starting process.

Generally speaking, the motor heating of the bridge crane is closely related to the operating frequency. After working for a period of time, the cooling time of the motor should be given. In addition, the overcurrent protection system installed in the electrical cabinet also restricts the heating of the motor.

Cranes are operating at high loads every day. Therefore, if you do not pay attention to daily operations, certain cracks will occur, which is very detrimental to users. How to avoid cracks in the crane?
1. Consider the operating environment of the crane
The operating environment has a great influence on the crane, and it is often affected by many factors such as wind and sun. In bad weather conditions, cranes are often built outdoors. They will not only suffer from heavy rain and assault from the sun, but also strong winds. If the crane persists in operation, it needs to operate against wind. The load will be further increased. If the gravity exceeds the carrying capacity of the crane itself, even if the crane’s mechanical equipment is relatively solid, it will inevitably shake. When it shakes, the fuselage will show cracks. How to check whether there are cracks in ordinary bridge cranes?
Once the crane shows cracks, it will have a greater impact on the use of the crane in the future. Therefore, the crane manufacturer claims that in order to avoid the appearance of cracks in the fuselage, try to avoid the crane operating under strong wind conditions. Many users do not care about the impact of the operating environment on the crane. They believe that even if the crane is operating in a harsh environment, it will not have a big impact. In fact, this idea is very wrong.

2. Reinforce the crane

If the crane is not reinforced during the program production process, it will also cause the crane to show simple cracks. Therefore, the customer should consider the reinforcement plan for the crane when purchasing the crane. In addition, the crane installation method should be very precise. Due to improper installation methods, the crane will be corroded during operation. The crane manufacturer pointed out that the installation must be carried out under the guidance of a technician. Cranes often have cracks during operation, and you must pay attention to ordinary maintenance to ensure that the crane can be used for a long time. Hope the above content can bring you some help.

The service life of the bridge crane is related to the customer and the degree of overweight, and the two are different. About 5 years, 10 years or so, it can be used after major and minor repairs, but the obsolescence period is related to the lifting level of your bridge crane. For example, the obsolete life of 50t is different from that of 8t, and annual inspection is required. The key to the life span of any bridge crane is how long to choose. overhead cranes that have exceeded their service life have entered the phase of obsolescence. There are strict regulations on the invalidation of bridge cranes in various places. As the time for invalidation has arrived, the invalidation statement and disposal must be suspended. Those who do not suspend invalidation will be rewarded and punished.

Long-term use of bridge cranes will reduce their service life. If it is a bridge crane of average quality, its life span will exceed 5 years. Each component will gradually age and be damaged. But if it is a high-quality bridge crane, some are 18 years old. Although it has a service life, it can generally be regenerated. Perhaps in that sentence, any bridge crane has a service life, the key is to choose how long.
Therefore, we not only need to maintain the bridge crane at any time during the operation, but also stop the invalidation after the bridge crane reaches the service life to avoid being punished or causing unnecessary incidents. At the same time, we must pay attention to selecting high-quality products to extend the service life of the bridge crane.

The operating room of the double-beam bridge crane is divided, closed and insulated. The platform entrance of the double-beam bridge crane control room is divided into three types: side surface, end surface and top surface. H is the increased height of the cart buffer. Double girder bridge cranes are divided into indoor and outdoor two types. The technical requirements such as the highest and lowest temperature of the working environment and the type of power supply should be indicated when ordering. An overload limiter, a large-screen display and various protection devices have been added to further increase the safety during use.

Design advantages

1. The double-beam bridge crane pioneered the honeycomb beam design, which has the characteristics of light weight, large load, and strong wind resistance.
2. The unique steel pin connection is not only firm and reliable, but also has a short assembly time.
3. The flexible rod support legs can be disassembled into a single piece for site steering, which is convenient for transportation.
4. The smallest installed capacity solves the difficulty of using electricity for field construction.

Some workshops did not consider the space of the double girder crane in the design. Therefore, after the double girder crane is installed, the hoisting height cannot satisfy the hoisting requirements. So how to choose a double girder crane in this situation?
Double beam crane is a kind of special equipment. Pay attention to some matters when using it to avoid unnecessary damage. The operator of the double-beam crane in the workshop conducts a brief check on the equipment every day, including whether the bolts are loose and whether there is oil leakage. When the double girder crane in the workshop cannot be used normally, it should be shut down immediately for maintenance, and diseased operations are prohibited.

Generally, the electric hoist of a double-beam crane is suspended under the main beam with a height distance of 1.5 meters. If the European-style double beam low headroom crane is used, the lifting height can be increased by 1 m.
Crane repairs should be carried out by crane manufacturers with double beam repair qualifications. It is forbidden for non-repair personnel to repair the double beam crane equipment in the workshop under any potentially dangerous conditions. The repaired double girder crane should be tested before use, and it can be put into normal use only after it is qualified. The double-girder crane that fails the test shall be repaired and re-accepted after inspection. Cranes that have not been inspected shall not be put into operation.
The low headroom European-style double beam crane is light in weight, small in structure, and low in energy consumption, which can effectively increase the use of space. There are trolleys and lifting organizations on the bridge, the trolleys can run back and forth, and the trolleys can move in a three-dimensional space. The design concept of the European-style double girder crane has the characteristics of small size, light weight and low wheel pressure.

Cranes in operation should be checked and accepted regularly. If the wire rope is aging, damaged, the hook insurance is damaged, and the equipment performance is unstable and punctual, it should be repaired and replaced in time. Equipment that does not meet the operating requirements shall be returned. When two double-beam cranes are used to lift objects together, the extra load of the cranes should be reasonably distributed, unified command, and the lifting should be carried out smoothly and gradually. It is forbidden to overload double beam cranes.

Compared with traditional cranes, the limit distance of the hook wall is small and the headroom is low. The European-style double-beam crane can work closer to the front and increase the height higher, which actually adds useful working space in the existing workshop. Because the crane has the characteristics of light weight and low wheel pressure, the space of the new plant can be designed to be smaller and more complete.

During the normal hoisting process of the double-beam crane in the workshop, no more than one person is allowed to command, but the urgent parking signal of anyone should be stopped immediately. , When stopping the operation, do not lift the object into the air. During the operation, when someone is within the range of a moving or falling object, a warning signal should be sent. Do not pierce heavy objects with your head. The elevator must not be too high above the ground.

Therefore, when the height of the workshop is not enough, the European-style double-beam crane can be considered.

In transportation machinery, the steel structure of semi-trailer and full-trailer is the same. The method approximates the crane design. Because of the road conditions in our country. The dynamic load factor used in the design is generally 1.8-2.5.

The fatigue coefficient is generally 1.2-1.4. The trailer travels on the dirt road at a speed of 40 km/h. The dynamic load factor can reach: 3-4. Therefore, different steel structures should pay attention to their characteristics: In the calculation of the trailer:

1. Large dynamic load;

The stress concentration of steel structural members is very significant.

3. Obvious low-cycle fatigue.

Calculation method of trailer steel structure:

1. The static stress value multiplied by the dynamic load factor is less than the allowable stress value.

2. The ratio of the material’s yield strength value to the static stress value is greater than the allowable safety factor value.