As an indispensable heavy equipment in industrial production, the safety and reliability of bridge cranes are directly related to production efficiency and personnel safety. In order to ensure that bridge cranes are always in good working condition, a set of systematic and comprehensive inspection procedures is particularly important. This procedure not only covers a full range of inspections from appearance structure to electrical system, mechanical system and safety protection devices, but also clarifies key elements such as the purpose, cycle, and personnel qualification requirements of the inspection. Through a strict inspection process, potential safety hazards can be discovered and eliminated in a timely manner, providing a solid guarantee for the stable operation of bridge cranes. This article will elaborate on each link of the inspection procedure for bridge cranes in order to provide a practical operating guide for enterprises and inspectors.
In an industrial production environment, bridge cranes are key material handling equipment, and their safety and reliability have a decisive impact on the efficiency and safety of production operations. In order to ensure that bridge cranes are always in good working condition, it is particularly important to formulate a set of scientific and comprehensive inspection procedures. This general principle aims to stipulate the inspection purpose, importance, cycle, standards and personnel qualification requirements of bridge cranes, so as to provide clear guidance and basis for actual inspection work.
The main purpose of bridge crane inspection is to timely discover and eliminate potential safety hazards, prevent accidents, and protect the lives and property of personnel. Through regular inspections, it can be ensured that all performance indicators of the crane meet the design requirements, thereby ensuring its stability and reliability during operation. In addition, inspection work can also help to timely discover and solve potential equipment failures, effectively extend the service life of the equipment, and improve production efficiency. Therefore, the inspection of bridge cranes is of great significance to ensure the safety and efficiency of industrial production.
The determination of the inspection cycle should take into account a variety of factors, including the frequency of use of the crane, the working environment, and the condition of the equipment. Generally speaking, for high-intensity bridge cranes, a comprehensive inspection should be carried out every six months; for cranes with less frequent use, a comprehensive inspection can be carried out once a year. In addition, for cranes working in special environments, such as high temperature, high humidity, corrosive environments, etc., the inspection frequency should be appropriately increased to ensure the normal operation of the equipment. The inspection standards should strictly follow the relevant national laws and regulations, industry standards and the technical specifications of the manufacturer. For some special types of bridge cranes, special inspection standards may also need to be formulated according to actual conditions.
The personnel who perform the inspection of bridge cranes must have the corresponding professional qualifications and skill levels. First, the inspectors must hold a valid crane inspector certificate to prove that they are qualified and capable of doing this work. Secondly, the inspectors should also have electrical safety knowledge and mechanical maintenance experience, and be familiar with the structural principles, operating procedures and safety requirements of bridge cranes. During the inspection process, the inspectors should be able to accurately judge the status of the equipment, discover potential safety hazards, and put forward effective rectification suggestions.
The appearance integrity inspection is an important part of the crane inspection, focusing on the integrity and good condition of the overall structure of the crane. The inspectors need to carefully check the various components of the crane, including the main beam, end beam, walkway, railing, etc., to see if there are cracks, deformation or severe rust. At the same time, it is also necessary to pay attention to the paint coating of the crane to see if it falls off or wears out. If necessary, the paint should be repainted in time to prevent corrosion.
Structural stability assessment is the key to ensuring the safe operation of the crane. Inspectors need to use professional measuring equipment, such as distance meters and levels, to accurately measure the camber and lateral curvature of the main beam and the parallelism of the trolley track. Changes in these indicators may affect the stability and safety of the crane. Once any deviation beyond the allowable range is found, it must be taken seriously and appropriate measures must be taken in a timely manner to repair or adjust it.
Structural stability evaluation index
| Evaluation indicators | Description | Measurement method | Allowed range/standard |
| Main girder upper arch | The degree of upturning of the middle part of the main beam relative to the two ends | Measuring with a rangefinder or level | According to crane model and design requirements |
| Main girder bypass curvature | Degree of bending of the main beam in the horizontal direction | Measuring with a distance meter | According to crane model and design requirements |
| Trolley track parallelism | Parallelism of the trolley tracks in the horizontal direction | Measurement with a level or laser rangefinder | According to crane model and design requirements |
| Connected Component Integrity | The integrity and reliability of connecting parts such as bolts, nuts, welds, etc. | Visual inspection, using tools if necessary | No looseness, breakage or welding defects |
| Fastener tightening degree | The degree of tightening of fasteners (such as bolts, nuts) | Measurement with a torque wrench | Meet the torque value of the design requirements |
| Paint coating integrity | Paint coating coverage and degree of wear | Visual inspection | No shedding or severe wear |
| Cracks/deformations in structural components | Cracks and deformations of major structural components such as main girders, end girders, walkways, railings, etc. | Visual inspection, using non-destructive testing where necessary | No cracks, no obvious deformation |
Details of inspection of connection parts and fasteners
| Inspection items | Inspection content | Inspection method | Treatment measures |
| Bolts and nuts | Is there any looseness, breakage or corrosion | Visual inspection, using a torque wrench | Tighten or replace damaged parts |
| Weld | Whether there are welding defects such as cracks, slag inclusions, and lack of fusion | Visual inspection, using non-destructive testing where necessary | Repair or replacement of defective welds |
| Riveted parts | Are the rivets loose or falling off | Visual inspection, using percussion tests | Re-rivet or replace loose rivets |
| Connection plates/connectors | Whether there is deformation, cracks or severe rust | Visual inspection | Repair or replace damaged parts |
| Fastener installation location | Whether the fasteners are installed in the correct position and meet the design requirements | Visual inspection against design drawings | Adjust or reinstall misaligned fasteners |
| Fastener materials and quality | Whether the fastener material meets the design requirements and whether the quality is reliable | Check against the list of materials and quality supporting documents | Replace fasteners that do not meet the requirements |
Connection parts and fasteners are the key to the structural strength of the crane. Inspectors need to carefully check these parts, such as bolts, nuts, welds, etc., to see if there are loose, broken or welding defects. For problems found, such as loose or broken parts, they must be repaired or replaced in time. At the same time, it is also necessary to ensure that all fasteners are fastened in place and the weld quality is reliable. For problems found, such as loose fasteners or unreliable weld quality, they must be dealt with in time to ensure the safe operation of the crane.
In the inspection of the electrical system, it is a crucial link to test the function and performance of each key electrical component. Contactors, relays, circuit breakers and other components are the core components in the crane control system. The performance of the components is directly related to the operating stability and safety of the entire system.
For devices such as contactors, which are mainly used to connect and disconnect high-current circuits, it is necessary to confirm whether their actions are sensitive and accurate during inspection, that is, when the control signal is input, whether the contactor can quickly and accurately complete the pull-in and release actions; the contact condition of the contacts is also the focus of the inspection, requiring good contact between the contacts, without oxidation, wear and other problems, to maintain the reliability of the circuit connection and disconnection; it is also necessary to check whether the contactor is overheated or burned after long-term operation, which may be caused by excessive current, insufficient contact pressure or poor heat dissipation. If found, it should be handled in time to avoid causing more serious electrical faults.
The safety and stability of the electrical circuit are the basis for ensuring the normal operation of the crane. The inspector needs to check the cables, wires and their connections with the wiring terminals one by one along the direction of the electrical circuit. Focus on whether the insulation performance of cables and wires is good, whether there are aging, cracking, damage and other problems, so as to avoid short circuit faults or leakage accidents; check whether the terminal is firm and reliable, including whether the bolts are tightened, whether the gaskets are complete, whether the wiring is loose, and other details, to ensure that all circuit connections can still maintain good contact under vibration and impact environment; check whether the internal layout of the electrical control cabinet is reasonable, whether the distance between the components meets the requirements of the specification, and whether the markings are clear and eye-catching, so as to facilitate daily maintenance and repair.
For cranes in areas prone to lightning, the effectiveness of their lightning protection and grounding protection measures is crucial. During the inspection, the grounding resistance value must be measured first to ensure that it is within the specified range (such as not more than 4 ohms). The layout of the grounding grid should comply with relevant national standards to ensure that the housing of electrical equipment, metal structures, etc. can be effectively grounded; check whether the installation position of the lightning protection device is reasonable, including the integrity of components such as lightning rods, lightning strips, and down conductors and their connection with the equipment.
As one of the most core and critical working parts of the crane, the operation status of the lifting mechanism is directly related to the safety and efficiency of the entire lifting operation. During the inspection process, the main components of the lifting mechanism need to be carefully inspected and evaluated. This includes the wear and damage of key components such as motors, reducers, drums, and wire ropes. It is also necessary to check the sensitivity and reliability of the brake. The brake is an important part of the lifting mechanism, and its performance directly affects the safety and efficiency of the lifting operation. It is necessary to check whether the brake is sensitive and reliable, and whether the braking force is sufficient to ensure that the movement of the lifting mechanism can be stopped quickly and accurately when needed.
The inspection of the operating mechanism and trolley mechanism is an important part of ensuring the normal operation of the crane. It mainly includes the status evaluation of wheels, tracks, transmission devices and drive motors. The contact between the wheels and the track directly affects the operating stability and safety of the crane. During the inspection, the contact between the wheels and the track needs to be observed to ensure that the wheels can run smoothly on the track and maintain good contact with the track. It is also necessary to check the degree of wear of the wheels and tracks. Excessive wear may affect the contact between the wheel and the track, and thus affect the operation stability and safety of the crane. The transmission device is an important part of the operating mechanism and the trolley mechanism. Its lubrication and noise conditions will affect the service life and performance of the transmission device. During the inspection, it is necessary to check the lubrication of the transmission device to ensure good lubrication; it is also necessary to check the noise of the transmission device to ensure that it runs smoothly and has low noise. The drive motor is the driving source of the operating mechanism and the trolley mechanism. Its temperature rise and vibration conditions will affect the performance and life of the drive motor. During the inspection, it is necessary to check the temperature rise of the drive motor to ensure that its temperature rise is within the normal range; it is also necessary to check the vibration of the drive motor to ensure that it runs smoothly and has low vibration.
The braking system is a key part to ensure that the crane can stop quickly and smoothly in an emergency. During the inspection, it is necessary to test the brake torque, response time, braking distance and other indicators of the brake, so as to comprehensively evaluate whether the performance of the braking system meets the design requirements.
The overload protection device is a core component in the crane safety management system, and its effectiveness is directly related to the safety and reliability of the entire machine operation. During the inspection process, the hardware configuration of the overload protection device, including sensors, controllers, and possible display alarm devices, should be checked in detail to confirm that it is correctly selected and in stable working condition. Next, various load conditions in actual working conditions should be simulated in accordance with relevant national standards and equipment technical specifications, gradually increasing from the minimum load to the rated load, and repeatedly testing the trigger point of the overload protection device in the process to ensure that it can accurately trigger the warning signal or take protective actions within the preset multiple load intervals to prevent problems such as overloading of the sling or cargo, overloading operation, etc.
In addition to accuracy, the reliability of the overload protection device is also crucial. During the inspection, it is necessary to repeatedly perform loading-unloading cycle tests to confirm that the device can still maintain the original performance indicators after long-term operation and will not have problems such as fatigue failure. At the same time, for overload protection systems that use electronic control or intelligent sensing technology, it is also necessary to verify the effectiveness of their data acquisition, processing and feedback mechanisms to ensure that the system can continuously and stably perform overload protection tasks under complex and changing working conditions.
The limit device is an important part of the operation of the crane. It is used to limit the operating range of the crane and the trolley on the track to prevent collision accidents caused by operating errors or equipment failures. The buffer device is used to absorb the impact energy of the collision during the operation of the crane, reduce equipment damage and extend the service life. During the inspection process, it is necessary to check whether the installation position of these devices is accurate one by one to ensure that they can effectively limit the operating range of the crane and play a buffering role. At the same time, it is also necessary to check whether the action sensitivity of these devices meets the requirements to ensure that they can start in time and absorb the impact energy when they are hit. In addition, it is necessary to check whether the buffering effect of the buffer device meets the requirements, which can be checked through simulated collision tests.
For large bridge cranes, anti-tipping devices and windproof devices are important guarantees to ensure their stable operation. During the inspection process, it is necessary to evaluate whether the structural strength of these devices meets the design requirements, which can be evaluated by force analysis, calculation and test verification of the devices. It is also necessary to check whether the installation position of these devices is accurate and whether the connection method is reliable and firm to ensure that the crane can remain stable under extreme weather conditions. In addition, it is also necessary to check whether the control systems of these devices are normal and reliable and can effectively monitor and control the crane.
During the inspection process, it is crucial to ensure that all key data are recorded in detail and accurately. These key data include but are not limited to detailed results of appearance inspection, such as paint condition, structural wear, etc.; structural measurement data, such as the size and deformation of key components; electrical test data, covering the effectiveness of control systems and protective devices; mechanical performance test data, such as the running stability and load-bearing capacity of the crane; and the verification results of safety protection devices to ensure that they can operate reliably at critical moments.
All these data should be recorded by dedicated inspectors in accordance with strict inspection procedures and methods, and the records should be accurate, clear, and easy to analyze later. This not only helps to improve the efficiency and accuracy of inspection work, but also provides strong data support for equipment maintenance and troubleshooting.
As the final result of the inspection work, the inspection report carries rich information and analysis results. Its preparation process should strictly follow the principles of standardization and simplicity. In addition to clearly marking the inspection date, basic information of the inspector, and detailed information of the inspected equipment, the report should also list in detail the specific items of this inspection and the corresponding inspection data. For the problems and abnormal conditions found, an in-depth analysis should be conducted to provide a detailed description of the problem, cause analysis, and targeted rectification suggestions.
When writing the rectification suggestions section, it is necessary to propose specific and feasible repair measures, improvement plans, and preventive measures for the problems and defects pointed out in the report to ensure that the crane can resume normal operation and continue to maintain good working performance. In addition, the report should also emphasize the timely response and processing process of the equipment management department after receiving the report to ensure that the inspection results and rectification suggestions can be quickly and effectively transformed into practical actions, thereby ensuring the safe and reliable operation of the crane.
For the problems and defects found during the inspection process, in-depth analysis and discussion are required. This includes clarifying the causes of the problems, analyzing the serious consequences that these problems may bring, and exploring how to avoid the same problems from happening again. On this basis, specific rectification suggestions are put forward. These suggestions should include repair measures, improvement plans, and preventive measures. Repair measures refer to specific measures such as repair and replacement of parts for problems that have already occurred; improvement plans are to prevent the same problems from happening again and improve the design, manufacturing or use process of the equipment; preventive measures are to take a series of measures to prevent problems from happening during the operation of the equipment.
While making rectification suggestions, the inspection results and rectification suggestions need to be fed back to the equipment management department in a timely manner. This can help the equipment management department arrange repair and maintenance work in a timely manner to ensure the normal operation of the equipment.
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