Structural design specification for 63/20t, span 25.5m, double girder overhead travelling crane

As a key component of heavy industrial equipment, the 63/20t double girder overhead travelling crane with a span of 25.5m plays a pivotal role in modern manufacturing and logistics. Its structural design is not only related to the efficiency and safety of lifting operations, but also a measure of the level of manufacturing technology. The purpose of this manual is to elaborate the design concept, structural composition, force analysis and material technology and other core contents of the crane, in order to provide a comprehensive and accurate technical reference for the manufacturing, installation, maintenance and operation personnel. Through in-depth discussion of the design details of the main and auxiliary girders, hoisting and operating mechanisms, as well as the arrangement of safety devices and protective measures, it demonstrates its excellent performance and reliability in complex industrial environments.

Crane Overview

Double girder overhead travelling crane, as a leader in heavy machinery and equipment, plays a vital role in industrial production. Their unique structural design allows for excellent performance when lifting and handling heavy loads. The double girder overhead travelling crane has two parallel and sturdy main girders, which are connected by end girders to form a solid frame structure, ensuring that the crane moves horizontally along the length of the plant on a track. This design not only improves the stability of the crane, but also ensures its safety and efficiency when lifting goods.

Main technical indexes and parameters

The main technical specifications and parameters of this crane include a rated lifting capacity of 63/20t, a span of 25.5m, and a lifting height that can be customized according to the actual needs of users, ensuring the flexibility and adaptability of the crane; The work level is A5, indicating that the crane is suitable for frequent use occasions; The operating speed includes lifting speed, trolley operating speed, and crane operating speed, all of which are designed according to actual needs to ensure the efficient operation of the crane; In addition, relevant parameters of the working environment, such as temperature and humidity, were also considered to ensure that the crane can operate stably and reliably in specific environments.

Application Scenario and Demand Analysis

Double girder overhead cranes play a crucial role in large steel mills, heavy machinery manufacturing plants, harbor terminals and other places where heavy goods need to be lifted frequently. In these environments, the performance stability and safety of the crane is crucial. This crane is designed to meet the needs of efficient, safe and stable work. At the same time, considering that different working environments have their own special characteristics, such as high temperature, humidity, corrosion, etc., this design optimizes the crane in a targeted manner. For example, in the high temperature environment, high temperature resistant materials and design are selected; in the humid environment, the anti-corrosion treatment is strengthened. These optimization measures aim to ensure that the crane can operate stably and reliably under various working environments.

Design Principles and Criteria

Design Principles

In the process of crane design, we always adhere to and practice the core design principle of “safety, reliability, economy and high efficiency”. This principle requires us to scientifically and reasonably optimize the structural layout of the crane during the design process, and adopt advanced design concepts and technical means to ensure that the whole machine can still maintain stable and trouble-free operation in the face of the maximum rated load or even overloading and other extreme working conditions, so as to fully guarantee the safety of the operation process. At the same time, we attach great importance to the maintainability and expandability of the equipment, and by anticipating possible future functional requirements and technology upgrade paths, we pre-design the corresponding interfaces and structures, so as to facilitate convenient and efficient maintenance or functional expansion in the future, thus effectively reducing the maintenance costs and potential investment risks of the users in the process of using the equipment.

Standards and Criteria

In this design program, strictly follow and strictly implement the national and industry standards and specifications on crane design, manufacturing, installation, commissioning, use and maintenance of the whole life cycle. These standards and norms cover, but are not limited to, “Crane Design Code” (GB/T 3811), a national standard, which specifies the basic requirements and parameters of various types of cranes in terms of structural design, strength calculations, material selection, manufacturing process, safety protection devices set up, etc.; as well as the “Crane Safety Regulations” (GB 6067), an important industry regulation, which is designed to ensure that Crane safety regulations (GB 6067), an important industry regulation, which aims to protect the safety and reliability of the use of lifting machinery in the process of crane design, manufacturing, installation, commissioning, use and maintenance of cranes and other aspects of the proposed clear safety requirements and operational standards.

List of relevant standards and norms

Name of standard/norm	Serial number	Description/Scope of Application
Crane Design Specifications	GB/T 3811	Provides for all types of cranes in the structural design, strength calculation, material selection, manufacturing process, safety protection device settings and other aspects of the basic requirements and parameters
Safety Regulations for Cranes	GB 6067	The design, manufacture, installation, commissioning, use and maintenance of cranes and other aspects of clear safety requirements and operational standards
_	_	Other national and industry standards and norms related to crane design, manufacture, installation, commissioning, use and maintenance
_	_	(Note: Some of the key standards are listed here and the actual project should cover all relevant standards throughout the life cycle.)

Crane Design Related Standards and Codes Sources

Type of source	Descriptive	Typical example
National standard	Issued by the National Standardization Administration Committee, with nationwide uniformity and mandatory nature	GB/T (recommended standard), GB (mandatory standard)
Industry standard	Formulated by the relevant administrative department of the State Council and reported to the administrative department for standardization of the State Council for the record, with uniformity and norms in a particular industry	Such as machinery industry standard JB, construction industry standard JGJ, etc.
International standard	Developed by the International Organization for Standardization or regional standardization organizations with wide international acceptance and applicability	ISO (International Organization for Standardization), IEC (International Electrotechnical Commission)
Local standards	Developed by the competent administrative department for standardization of provinces, autonomous regions and municipalities directly under the Central Government, and uniformly implemented within the administrative region.	e.g. DBXX (XX is the abbreviation and code name of the province)
Enterprise Standard	Developed by the enterprise itself and implemented uniformly within the enterprise, usually used for internal technical management, quality control, etc.	e.g. Q/XXX (enterprise code)

Structural composition and component design

Main beam structure design

The main beam is the core load-bearing component of a crane, and its structural design has a crucial impact on the performance and stability of the entire crane. In order to meet the lifting requirements under various working conditions, the main beam adopts an advanced box structure, which has the advantages of high strength, high stiffness, and good stability. By using finite element analysis method, the main beam structure is repeatedly optimized to ensure that it can maintain sufficient strength and stiffness under maximum load, effectively avoiding deformation and damage. In order to improve the torsional resistance of the main beam, a reasonable reinforcement plate structure is set inside the main beam. These reinforcement plates not only enhance the overall rigidity of the main beam, but also improve its torsional performance. Meanwhile, considering the long-term service life and wear resistance of the crane, high-strength low-alloy steel is selected as the main beam material, which has high strength and toughness, can withstand large loads, and maintain good durability. In order to further improve the comprehensive mechanical properties of the main beam, the main beam will also undergo heat treatment to eliminate internal stress in the material, improve material uniformity and stability.

Design of secondary beams and end beams

The design of the secondary beam and end beam, as important components connecting the main beam and supporting the operation of the crane, is equally crucial. The auxiliary beam adopts a box shaped structure similar to the main beam to ensure a firm and reliable connection with the main beam. The auxiliary beam provides stable support and load-bearing capacity for the entire crane through its connection with the main beam. In order to ensure a firm and reliable connection between the secondary beam and the main beam, a combination of high-strength bolts and welding is used for their connection. The end beam is welded with steel plates and reinforced internally to improve its load-bearing capacity. At the same time, a wheel set is installed on the end beam to ensure smooth operation of the crane on the track. The design of the wheel set is crucial for the smooth and stable operation of the crane.

Design of lifting mechanism

The lifting mechanism is one of the important components of a crane, responsible for achieving vertical lifting and lowering of materials. According to user needs and actual working conditions, the lifting mechanism can be in the form of an electric hoist or winch, and can be customized in design. The lifting mechanism ensures that the lifting speed meets actual needs through reasonable transmission ratio and motor power design. The design of the transmission ratio considers the efficiency and power performance of the mechanism to ensure that the material can maintain stable speed and acceleration during the lifting process. The design of motor power takes into account factors such as material weight, lifting speed, and frictional resistance of the mechanism to ensure that the motor can provide sufficient power to drive the mechanism to operate normally. At the same time, the lifting mechanism is also equipped with braking devices and limit devices to ensure safety and stability during the lifting process. The braking device can quickly and effectively stop the movement of the mechanism when necessary, while the limit device can limit the range of motion of the mechanism, avoiding excessive stretching or contraction that may cause damage or safety accidents.

Operating mechanism design

The operating mechanism includes the small car operating mechanism and the large car operating mechanism. The small car operating mechanism is responsible for the lateral movement of the crane on the main beam, while the large car operating mechanism is responsible for the longitudinal movement of the crane on the track. By selecting appropriate motors, designing reducers, and arranging wheels, the crane ensures sufficient stability and load-bearing capacity during operation. The selection of motors takes into account the load size and speed requirements of the operating mechanism; The design of the reducer improves the transmission efficiency and reliability of the mechanism through a reasonable gear ratio and structural form; The arrangement of wheels affects the stability of the mechanism and the accuracy of the operating trajectory.

Force Analysis and Calculation

Static force analysis

Static force analysis is to study the mechanical characteristics of the crane when it is subjected to the maximum load, and calculate the stress distribution and deformation through the principle of statics. Using finite element analysis software to refine the modeling of the key components of the crane, such as the main girder, sub girder, end girder and other structures, and set the corresponding material properties, boundary conditions and load conditions. Through simulation, the stress concentration and maximum deformation of each component under maximum static load are predicted to ensure that it meets the requirements of strength and stiffness, and to avoid structural damage due to overloading or irrational design.

Dynamic force analysis

Dynamic force analysis focuses on the impact of dynamic loads on the structure generated during the startup, braking and operation of the crane. Cranes will produce large dynamic load effects due to inertia when starting and braking, while vibration and impact during operation may also lead to an increase in dynamic stresses. Modeling and calculation of cranes through dynamic analysis software should not only consider the structure’s own elastic vibration, but also assess its response characteristics and stability under dynamic loads to prevent the occurrence of structural resonance or instability.

Stress and deformation calculation

Based on the results of static and dynamic force analysis, the stress and deformation are calculated in detail. Through finite element analysis or other numerical simulation methods, the stress distribution cloud diagram and deformation shape diagram of each component when it is subjected to the maximum load, as well as the specific numerical results. These data help the designers to judge whether the crane components meet the design requirements, especially whether they can maintain sufficient safety margin when subjected to the ultimate load to ensure the safe and reliable operation of the crane during the whole service life.

Stability and safety assessment

Stability assessment is an important part of the crane design process, through the stability analysis of the overall structure of the crane to assess its ability to resist overturning and slip when subjected to the maximum load. At the same time, combined with the design of safety devices and protective measures, such as anti-tipping devices, anti-slip devices, overload protection devices, etc., to ensure the safety and reliability of the crane in the operation process. In addition, it is necessary to simulate and analyze the possible extreme conditions or misoperation and propose corresponding improvement measures to minimize the potential safety risks.

Material selection and process requirements

Main material selection

As heavy machinery equipment, the structural stability and load-bearing capacity of cranes are crucial. Therefore, there are strict requirements for the selection of main materials in the manufacturing process. Steel is the main structural material of cranes, and high-strength low-alloy steel is usually selected. This type of steel has high tensile strength and yield point, which can ensure that the crane will not experience structural damage when bearing heavy objects. In addition to steel, castings and forgings are also important materials in the manufacturing of cranes. Castings and forgings are commonly used to manufacture complex shaped parts such as gears, bearing seats, etc. To ensure the quality and performance of these parts, high-quality alloy materials should be selected for castings and forgings. These materials have excellent mechanical properties and durability, which can meet the requirements of cranes in various working conditions. All materials must comply with the requirements of relevant standards and specifications, and their quality must be ensured through strict inspection and testing.

Manufacturing process requirements

The manufacturing process requirements include welding process, heat treatment process, mechanical processing process, etc. The welding process needs to ensure reliable weld quality, the heat treatment process needs to improve the comprehensive mechanical properties of the material, and the mechanical processing process needs to ensure the dimensional accuracy and surface quality of each component. Welding, as a key link in the manufacturing process of cranes, directly affects the overall performance and safety of the crane. During the welding process, it is necessary to strictly control the welding parameters, including welding current, voltage, speed, etc., to ensure the quality of the weld seam. Meanwhile, in order to ensure the stability and reliability of the welding process, advanced welding techniques and equipment should also be adopted. Heat treatment process is also an important means to improve the performance of cranes. Heat treatment can eliminate internal stress and impurities in materials, improve their microstructure, and thus enhance their comprehensive mechanical properties. During heat treatment, it is necessary to strictly control parameters such as temperature and time to ensure that the heat treatment effect meets the requirements. In addition to welding and heat treatment, mechanical processing technology is also one of the important factors affecting the performance of cranes. In the process of mechanical processing, it is necessary to strictly control the dimensional accuracy and surface quality of each component to ensure the fitting accuracy and installation accuracy between each component. At the same time, advanced mechanical processing equipment and process technology should be adopted to improve processing efficiency and quality.

Welding and connection process

Welding, as an important link in the manufacturing process of cranes, directly affects the overall performance and safety of the crane in terms of its quality. Strict control of welding parameters and welding quality is required during the welding process to ensure that the strength and toughness of the weld meet the design requirements. Necessary inspections and tests are required for the connecting components to ensure their secure and reliable connection. To achieve this goal, manufacturing companies need to take a series of measures. Firstly, it is necessary to establish strict welding process specifications, clarify welding parameters and operational requirements. This specification should include key parameters such as welding current, voltage, speed, as well as preparation work before welding, quality control during the welding process, and inspection after welding. By standardizing the welding process, the quality of the weld seam can be ensured to be stable and reliable. Secondly, the connection process of the connecting components also needs to be strictly controlled. The connecting components are an important part of the crane, and their connection quality and stability directly affect the overall performance of the crane. Reliable connection methods such as high-strength bolt connections, welding, etc. should be used in the manufacturing process of connecting components. At the same time, necessary inspections and tests must be conducted to ensure that the quality and performance of the connecting components meet the design requirements.

Corrosion prevention and surface treatment

Considering that the crane is exposed to harsh working environments for a long time, it is necessary to carry out anti-corrosion treatment to improve its service life. Anti corrosion treatment includes steps such as sandblasting, rust removal, painting with primer and topcoat. Sandblasting can remove impurities such as dirt and oxide scale from the surface, improving the cleanliness and roughness of the surface; Applying primer can enhance the adhesion and corrosion resistance of the surface; Applying topcoat can further improve the appearance and durability of the surface. At the same time, surface treatment is required for key components to improve their wear resistance and corrosion resistance; Surface treatment techniques such as electroplating or spraying can form a protective film on the surface of key components; Surface modification techniques such as laser quenching or nitriding can improve the hardness and wear resistance of key component surfaces.

Safety devices and protective measures

Limit and anti-collision device

In modern industrial production environments, cranes are important logistics handling equipment, and their safety and reliability are crucial for production efficiency and personnel safety. The limit device is an effective controller to ensure the operating range of the crane, usually installed in key parts such as the drive mechanism, running track, and lifting equipment of the crane. These devices monitor and limit the operating limits of the crane in real time through physical or electronic induction, preventing the crane from deviating from the predetermined track due to operational errors or equipment failures, thereby avoiding safety accidents such as mechanical damage, electrical short circuits, and even personnel injuries caused by collisions with buildings, equipment, or other facilities.

The anti-collision device is an active preventive safety protection system that utilizes advanced technologies such as infrared sensors, laser scanners, and camera monitoring to monitor changes in the surrounding environment of the crane in real time. When it detects that the crane is too close to surrounding personnel, objects, or another crane, it can quickly react, issue alarm signals to remind operators and other relevant personnel, and automatically activate emergency braking programs when necessary, effectively preventing possible collision accidents.

Overload protection device

Overload protection device is a core component of the crane safety management system, which functions to monitor and accurately control the load status of the crane in real time, ensuring that its designed bearing capacity is not exceeded at any time. This device mainly uses high-precision weight sensors for real-time monitoring, which can accurately sense the weight changes of the goods on the lifting equipment and transmit the data to the intelligent control system for processing. Once the control system determines that the load has exceeded the set rated lifting capacity, the overload protection device will immediately activate and take a series of preset safety measures to avoid overload accidents. Common operations include automatically cutting off the power supply or issuing audible and visual alarm signals to alert operators to promptly reduce the load to a safe range.

Electrical safety devices

Electrical safety devices play a crucial role in the overall safety protection system of cranes. In order to prevent safety accidents caused by electrical faults such as leakage and short circuits, leakage protectors are widely installed in the electrical system of cranes. Once a leakage occurs, the leakage protector can quickly detect abnormal current and take measures to cut off the power supply, thereby avoiding the risk of electric shock and fire hazards caused by current leakage. Short circuit protection device is designed for possible short circuit faults in electrical circuits. When overload or short circuit occurs in the circuit, the device can quickly respond and cut off the power supply of the faulty circuit, protecting equipment such as cables and motors from damage. The grounding protection device is set up to ensure the safe grounding state of the crane casing and the metal components connected to it. By reliably connecting the metal parts of the equipment to the grounding grid, in the event of insulation damage or equipment leakage, the grounding protection device can effectively guide the current to flow into the ground, avoiding electric shock injuries to operators.

Maintenance and repair safety measures

In order to ensure the stable and efficient operation of the crane during long-term use, a comprehensive maintenance and overhaul plan must be developed and implemented. When carrying out maintenance and repair tasks, all personnel involved must strictly comply with relevant safety production regulations and operating procedures, always putting safety first. Before maintenance and overhaul, a comprehensive safety assessment and risk analysis of the work environment must be conducted to ensure that the safety conditions of the work area are fully confirmed and addressed. For high-risk activities such as entering confined spaces, using hazardous chemicals, or conducting high-altitude operations, it is necessary to apply for approval and prepare corresponding safety protection measures in advance in accordance with relevant regulations. The waste and pollutants generated during maintenance and repair should be properly disposed of in accordance with national laws and regulations to prevent environmental pollution and ecological damage. At the same time, detailed records and analysis summaries of each maintenance and overhaul are made to form standardized record files, which helps to timely discover hidden dangers and problems in the equipment and take targeted measures to solve them.

Installation and Debugging

Preparation before installation

Before starting the installation of the crane, comprehensive and meticulous preparation work must be carried out to ensure the smooth progress of the installation work and the safe and reliable operation of the final equipment. Firstly, thoroughly clean the installation site, remove any debris or obstacles that may affect the installation work, and ensure that the work area is clean and spacious; Carefully inspect the equipment components, confirm their integrity, and verify whether their quality meets the design requirements, including but not limited to the functionality and durability of major components such as structural parts, electrical components, hydraulic systems, etc; Based on the actual situation, develop detailed installation plans and schedules, clarify various installation steps, personnel arrangements, and safety measures. In addition, it is crucial to provide professional training and safety education to the personnel involved in the installation, so that they can have a deep understanding of the installation process, operating standards, and potential safety risks of the crane, and improve their operational skills and safety awareness.

Installation steps and requirements

The installation steps of a crane cover multiple key links, including foundation construction, equipment installation, commissioning, and acceptance. Basic construction is the cornerstone of ensuring the stability of the crane, and precise construction is required according to design requirements to ensure a flat and solid foundation. During the equipment installation phase, it is necessary to strictly follow the installation plan and schedule to ensure the correct installation position and reliable fixation of the equipment. The debugging phase is the process of verifying the various functions of the crane, including testing of the electrical system, hydraulic system, control system, and other aspects to ensure the normal operation of the equipment. Acceptance is a comprehensive inspection of installation quality, which requires operation in accordance with relevant standards and specifications to ensure that the equipment meets the requirements for use.

Debugging and Testing

Debugging and testing are important steps to ensure the normal operation of the crane. During the debugging process, technicians need to conduct comprehensive and detailed testing and verification of various functions of the crane. This includes but is not limited to functional testing of key components such as electrical systems, hydraulic systems, and control systems to ensure they meet design requirements and usage needs. A comprehensive assessment of the safety of the crane is also required. This involves testing and validation of structural stability, load-bearing capacity, protective performance, and other aspects to ensure that the crane can maintain good safety performance during long-term use and avoid potential safety hazards.

Acceptance criteria and procedures

Acceptance standards and procedures are important links in ensuring the quality of cranes. During the acceptance process, a comprehensive inspection and evaluation of the crane must be conducted in accordance with relevant standards and specifications. Including but not limited to appearance quality, structural integrity, functional performance, safety performance, and other aspects. Inspect the appearance quality to confirm that there are no damages or deformations on the surface of the equipment; Conduct structural integrity testing to confirm that the structural components of the equipment are intact and securely connected; Test the functional performance to confirm that all functions of the device are operating normally; Evaluate the safety performance and confirm that there will be no safety hazards during the use of the equipment. It is also necessary to test and record the operation of the crane. By conducting actual operational testing, observe the operating status and performance of the equipment to confirm whether it meets the usage requirements. At the same time, establish a comprehensive acceptance record and reporting system, detailing the acceptance process and results, providing reference for subsequent use and maintenance.

Maintenance and upkeep

Daily maintenance and inspection

Daily maintenance and inspection are key links to ensure the long-term stable operation of the crane. Firstly, regularly clean the various components of the crane, removing dust, dirt, and debris to maintain a good working environment. Secondly, according to the requirements of the equipment, regularly lubricate the crane to reduce wear and extend its service life. In addition, it is necessary to regularly inspect and tighten the fasteners of the crane to prevent accidents caused by looseness. At the same time, it is necessary to inspect and record the operation of the equipment, promptly identify and solve problems.

Fault diagnosis and troubleshooting

When the crane malfunctions, it is necessary to promptly diagnose and troubleshoot the problem. Firstly, by checking the operation and fault symptoms of the equipment, analyze the causes and mechanisms of the faults. Secondly, based on the fault analysis results, develop corresponding maintenance plans and measures. During the maintenance process, it is necessary to supervise and inspect the maintenance process to ensure that the maintenance quality meets the requirements of relevant standards and specifications. Finally, inspect and record the repair results to ensure that the malfunction is completely resolved.

Suggestions for major repairs and renovations

As the usage time of the crane increases, its performance may gradually decline. Therefore, it is necessary to regularly carry out major repairs and renovations on the crane. The major overhaul mainly includes a comprehensive inspection and evaluation of the structure and function of the equipment, identifying and resolving existing problems. Renovation mainly involves upgrading and optimizing equipment based on actual needs and technological advancements. During the overhaul and renovation process, it is necessary to supervise and inspect the renovation process to ensure that the renovation quality meets the requirements of relevant standards and specifications. At the same time, it is necessary to inspect and record the results of the renovation to ensure that the expected goals are achieved.

Maintenance plan and records

To ensure the long-term stable operation of the crane, a detailed maintenance plan and records need to be developed. The maintenance plan should include elements such as maintenance cycle, maintenance content, and maintenance personnel. The maintenance cycle should be set according to the actual usage of the equipment and the manufacturer’s recommendations. The maintenance content should cover all components and systems of the equipment, and the maintenance personnel should have professional knowledge and skills. At the same time, a maintenance record management system should be established to provide detailed records of the time, content, personnel, and other information of each maintenance. By managing maintenance plans and records, it is possible to ensure timely and effective execution of crane maintenance work. In addition, it can provide strong reference for the maintenance and management of equipment.