Safety features of wire rope electric hoists

Safety features of wire rope electric hoists: the key to ensuring the safety of industrial operations

In modern industrial production, wire rope electric hoists are a common lifting equipment and are widely used in factories, warehouses, construction sites and other places. With its high efficiency and convenience, it provides great convenience for material handling and lifting operations. However, safety is always the primary consideration for using wire rope electric hoists. This article will explore the safety features of wire rope electric hoists in depth, and conduct detailed analysis from multiple aspects such as design and manufacturing, operational safety, maintenance and inspection, and environmental adaptability, aiming to provide users with comprehensive safety guidance to ensure the safety and reliability of industrial operations.

1. Overview of wire rope electric hoists

(I) Definition and basic structure
Wire rope electric hoists are a light and small lifting equipment, mainly composed of motors, transmission mechanisms, drums and wire ropes. It drives the drum to rotate through the motor to wind or release the wire rope, thereby realizing the lifting and moving of heavy objects.
(II) Working principle
The working principle of wire rope electric hoists is relatively simple. When the motor is powered on, the motor shaft drives the gear in the reducer to rotate, and the gear drives the drum to rotate. The wire rope on the drum is wound or released when the drum rotates, and the hook moves up and down with the rise and fall of the wire rope, thereby realizing the lifting of heavy objects.
(III) Application fields
Wire rope electric hoists are widely used in various industrial fields, including but not limited to:
Factory workshops: used for material handling, equipment installation and maintenance on production lines.
Warehouses: used for stacking, loading and unloading of goods.
Construction sites: used for lifting construction materials, installation of construction equipment, etc.
Port terminals: used for loading and unloading of goods.

2. Design and manufacturing safety

(I) Material selection
The material selection of wire rope electric hoists is crucial and directly affects its safety and service life. Its main components such as motors, reducers, drums, wire ropes, etc. must be made of high-quality materials.
Motor: Usually a conical motor is used, which has a large torque and good braking performance. The motor housing should be made of high-strength cast iron or steel to ensure its structural strength and heat dissipation performance.
Reducer: It adopts a three-stage fixed-axis helical gear transmission mechanism. The gears and gear shafts are made of heat-treated alloy steel. The box body and box cover are made of high-quality cast iron, which are tightly assembled and well sealed.
Drum: The drum is one of the important components of the wire rope electric hoist. Its material should have sufficient strength and wear resistance, and is usually made of high-quality steel.
Wire rope: The wire rope is a key component of the wire rope electric hoist. Its quality and performance directly affect the safety of the equipment. The wire rope should be a lifting-type wire rope with high breaking tension and fatigue resistance. Common wire rope structures include 6×36WS, 6×37, etc.
(II) Structural design
The structural design of the wire rope electric hoist should follow the principles of safety, reliability and rationality to ensure the stability and safety of the equipment under various working conditions.
Layout of the motor and drum: The relative position of the motor axis and the drum axis has an important influence on the structural compactness and performance of the equipment. Common layout methods include four types: the motor axis is perpendicular to the drum axis, the motor axis is parallel to the drum axis, the motor is installed inside the drum, and the motor is installed outside the drum. Each layout method has its advantages and disadvantages, and needs to be selected according to specific application scenarios and needs.
Braking system: The wire rope electric hoist is equipped with a reliable braking system to ensure that the heavy object can be stably suspended in the air during the lifting process. The brake usually adopts a conical brake, which is connected to the motor shaft. When the motor stops, the brake automatically locks to prevent the heavy object from sliding down.
Limit device: The limit device is one of the important safety devices of the wire rope electric hoist. It is used to limit the up and down travel of the hook to prevent the wire rope from being over-wound or loose. The upper and lower limiters should be installed at both ends of the drum. When the hook rises or falls to the limit position, the limiter will automatically cut off the power supply and stop the motor from running.
(III) Manufacturing process
The manufacturing process of the wire rope electric hoist directly affects its quality and performance. During the manufacturing process, relevant standards and specifications should be strictly observed to ensure the manufacturing accuracy and assembly quality of each component.
Parts processing: Use advanced processing equipment and technology to ensure the dimensional accuracy and surface quality of parts. For example, high-precision gear processing machines should be used for gear processing to ensure the gear tooth profile accuracy and meshing performance.
Assembly process: Assembly is a key link in the manufacturing process of wire rope electric hoists, and it needs to be operated strictly in accordance with the assembly process requirements. During the assembly process, attention should be paid to the matching accuracy of each component to ensure the smooth operation and reliability of the equipment. For example, when assembling the wire rope, it should be ensured that the wire rope is wound neatly on the drum without crossing or twisting.
Quality inspection: During the manufacturing process, strict quality inspections should be carried out, including raw material inspection, parts inspection, assembly inspection and finished product inspection. Inspection items include dimensional accuracy, appearance quality, performance testing, etc., to ensure that the wire rope electric hoists shipped from the factory meet relevant standards and specifications.

3. Operational safety
(I) Operator qualifications and training
The operator of the wire rope electric hoist should have the corresponding qualifications and professional knowledge to ensure that the equipment can be operated safely and correctly.
Qualification requirements: Operators must undergo professional training and obtain the corresponding operation certificate before they can take up their posts. The training content includes the structural principle, operation method, safety precautions, etc. of the equipment.
Safety training: Regular safety training is conducted for operators to improve their safety awareness and operation skills. The training content may include accident case analysis, emergency response measures, etc., so that operators can master the safe operation procedures of the equipment.
(II) Pre-operation inspection
Before using the wire rope electric hoist each time, the operator should conduct a detailed pre-operation inspection to ensure that the equipment is in good working condition.
Appearance inspection: Check whether the appearance of the equipment is obviously damaged or deformed, such as whether the motor housing, reducer, drum, hook and other parts have cracks, wear and other phenomena.
Wire rope inspection: Check whether the wire rope has broken wires, wear, deformation and other abnormal conditions. According to the provisions of GB/T 5972-2017 "Maintenance, maintenance, inspection and scrapping of crane wire ropes", when the number of broken wires of the wire rope exceeds a certain standard, the wire rope should be replaced immediately.
Hook inspection: Check whether the hook has cracks and deformation, and whether the opening degree of the hook exceeds the specified value. The hook should be equipped with an anti-unhooking device to ensure that the heavy objects will not fall off accidentally during the lifting process.
Electrical system inspection: Check whether the power cord, control buttons, limit switches and other electrical components are normal, and whether there are any damage, aging and other phenomena. Ensure that the insulation performance of the electrical system is good to prevent electric shock accidents.
Braking system inspection: Check whether the brake is sensitive and reliable, and whether the braking effect is good. In the no-load state, start and stop the motor several times to observe the response of the brake.
(III) Precautions in operation
When operating the wire rope electric hoist, you should strictly abide by the operating procedures and pay attention to the following matters:
Overloading is prohibited: The wire rope electric hoist has a clear rated load and it is strictly prohibited to overload it. Overloading will cause equipment overload, causing mechanical failure and safety accidents.
Stable lifting: When lifting heavy objects, ensure that the heavy objects are firmly tied and the hook is aligned with the center of gravity of the heavy objects to avoid tilting and slanting. When lifting, lift slowly, and pause when the heavy object is 10-20cm off the ground, check the stability and braking of the equipment, and continue lifting after confirming that there is no abnormality.
Smooth operation: During the lifting process, the heavy objects should be kept stable to avoid shaking and collision. The operator should control the operating handle evenly to avoid sudden acceleration, deceleration or change of direction.
No personnel are allowed to approach: During the lifting process, personnel are strictly prohibited from staying or passing under the heavy objects. Warning signs should be set up in the lifting area to remind people around to pay attention to safety.
Avoid long-term hovering: Try to avoid heavy objects hovering in the air for a long time to avoid increasing the load and risk of the equipment. If long-term hovering is required, the braking system should be reliable and the equipment status should be checked regularly.
(IV) Load management
Reasonable load management is an important part of ensuring the safe operation of wire rope electric hoists.
Load calculation: Before lifting, the weight of the heavy object should be accurately calculated to ensure that it does not exceed the rated load of the equipment. For heavy objects with irregular shapes or uneven weight distribution, a detailed weight distribution analysis should be carried out to ensure balance and stability during the lifting process.
Load distribution: For heavy objects lifted at multiple points, the load should be reasonably distributed to ensure that the force at each lifting point is uniform and avoid local overload.
Load limiter: Some wire rope electric hoists are equipped with load limiters. When the load exceeds the rated load, the load limiter will automatically cut off the power supply and stop the equipment from running. Operators should regularly check the sensitivity and reliability of the load limiter to ensure its normal operation.
(V) Emergency handling
During the operation, some emergency situations may occur, such as equipment failure, heavy objects out of control, etc. Operators should have emergency handling capabilities and be able to take measures quickly to avoid accidents.
Emergency stop: When encountering an emergency, the emergency stop button should be pressed immediately to cut off the power supply of the equipment and stop the equipment from running.
Accident alarm: After the accident occurs, it should be reported to the relevant departments and personnel in a timely manner and the emergency plan should be activated. At the same time, the accident scene should be protected for subsequent investigation and handling.
Personnel evacuation: If the accident may pose a threat to the surrounding personnel, personnel should be evacuated quickly to ensure personnel safety.

4. Maintenance and inspection safety
(I) Daily inspection
Daily inspection is an important measure to ensure the safe operation of the wire rope electric hoist. Operators should check before and after each use.
Appearance inspection: Check whether the appearance of the equipment is damaged, deformed, worn, etc., especially the key parts such as wire rope, hook, drum, etc.
Lubrication inspection: Check the lubrication of the equipment to ensure that each moving part has enough lubricating oil. If the lubricating oil is found to be insufficient or deteriorated, it should be added or replaced in time.
Electrical inspection: Check whether the electrical components such as power cord, control button, limit switch are normal, and whether there are any damage, aging, looseness, etc.
Braking inspection: Check whether the brake is sensitive and reliable, and whether the braking effect is good. In the no-load state, start and stop the motor several times to observe the response of the brake.
(II) Regular maintenance
Wire rope electric hoists need regular maintenance and maintenance to ensure their long-term stable operation.
Maintenance cycle: According to the frequency of use of the equipment and the working environment, a reasonable maintenance cycle should be formulated. It is generally recommended to perform minor maintenance once a month, medium maintenance once a quarter, and major maintenance once a year.
Maintenance content:
Minor maintenance: including cleaning the surface of the equipment, checking and replenishing lubricating oil, checking the wear of the wire rope and hook, etc.
Medium maintenance: In addition to the minor maintenance, it also includes checking the gear wear of the reducer, checking the braking performance of the brake, checking the insulation performance of the electrical system, etc.
Major maintenance: In addition to the medium maintenance, it also includes comprehensive disassembly and inspection of the equipment, replacement of severely worn parts, overall debugging and performance testing of the equipment, etc.
Maintenance records: Establish equipment maintenance record files, and record in detail the time, content, problems found and treatment measures of each maintenance. This helps to understand the operating status of the equipment and provide a reference for subsequent maintenance and repairs.
(III) Replacement of wearing parts
Some parts of the wire rope electric hoist are wearing parts and need to be replaced regularly to ensure the safety and reliability of the equipment.
Wire rope: According to the wear and use time of the wire rope, replace the wire rope regularly. It is generally recommended that the service life of the wire rope is 6 months to 1 year, and the specific replacement cycle can be determined according to the frequency of use of the equipment and the working environment.
Brake friction pad: The brake friction pad will gradually wear during long-term use, affecting the braking effect. When the thickness of the friction pad is worn to 1/3 of the original thickness, it should be replaced immediately.
Lubricating oil: Regularly replace the lubricating oil of the equipment to ensure the quality and performance of the lubricating oil. It is generally recommended to replace the lubricating oil every 3 months. The specific replacement cycle can be determined according to the equipment's instruction manual and actual use.
Electrical components: Electrical components such as contactors and relays may have poor contact and aging during long-term use. Regularly check the working status of electrical components and replace damaged components in time.
(IV) Precautions in maintenance
When performing maintenance work on wire rope electric hoists, pay attention to the following matters:
Cut off the power supply: Before maintenance, the power supply of the equipment must be cut off to ensure that the equipment is in a power-off state to prevent electric shock accidents.
Professional operation: Maintenance work should be performed by professionally trained personnel to ensure the correctness and safety of maintenance operations.
Use qualified accessories: When replacing parts, qualified accessories that meet the requirements of the equipment should be used to ensure the quality and performance of the accessories.
Comply with operating procedures: During maintenance, the operating procedures and maintenance manual requirements of the equipment should be strictly followed to avoid illegal operations.

5. Environmental adaptability and safety

(I) Usage requirements in different environments
The use requirements and safety measures of wire rope electric hoists are different in different working environments.
High temperature environment: In a high temperature environment, the temperature of the equipment's motor, reducer and other components will rise, affecting their performance and life. Effective heat dissipation measures should be taken, such as adding heat sinks and installing cooling fans. At the same time, high temperature resistant lubricants and seals should be selected to prevent lubricant deterioration and seal aging due to high temperature.
Low temperature environment: In a low temperature environment, the metal parts of the equipment may become fragile, and the viscosity of the lubricant will increase, affecting the start-up and operation of the equipment. Lubricants with good low temperature performance should be selected, and preheated before the equipment is started to ensure that the equipment can operate normally.
Humid environment: In a humid environment, the electrical components of the equipment are easily affected by moisture, resulting in reduced insulation performance and causing electric shock accidents. Moisture-proof measures should be taken, such as setting waterproof sealing strips on the equipment casing and installing desiccant in the electrical control box. At the same time, the insulation performance of the electrical system should be checked regularly to ensure its safety and reliability.
Dust environment: In a dusty environment, dust will enter the equipment and affect its normal operation. Dust prevention measures should be taken, such as installing filtering devices at the air inlet and exhaust port of the equipment, and regularly cleaning the dust on the surface of the equipment. At the same time, equipment with good sealing performance should be selected to prevent dust from entering the equipment.
Inflammable and explosive environment: In a flammable and explosive environment, the electrical and mechanical systems of the equipment may generate sparks, causing fire or explosion accidents. Explosion-proof wire rope electric hoists should be selected and installed and used in strict accordance with explosion-proof requirements. At the same time, the explosion-proof performance of the equipment should be checked regularly to ensure that it meets relevant standards and specifications.
(II) Protective measures
In order to ensure the safe use of wire rope electric hoists in various environments, corresponding protective measures should be taken.
Protective devices: Install necessary protective devices on the equipment, such as guardrails, protective covers, etc., to prevent personnel from accidentally contacting the moving parts of the equipment and avoid mechanical injury accidents.
Electrical protection: Take electrical protection measures, such as installing leakage protectors, grounding protection devices, etc., to prevent electric shock accidents. At the same time, ensure that the wiring of the electrical system is firm and reliable to avoid electrical failures caused by loose wiring.
Environmental monitoring: Install environmental monitoring equipment in the working environment, such as temperature sensors, humidity sensors, dust concentration sensors, etc., to monitor environmental parameters in real time. When environmental parameters exceed the normal working range of the equipment, take corresponding measures in time, such as stopping the equipment and adjusting environmental conditions.
Safety warning signs: Set up obvious safety warning signs on the equipment and work area to remind operators and surrounding personnel to pay attention to safety. Warning signs should include equipment operation precautions, dangerous area prompts, emergency treatment measures, etc.

6. Case analysis
(I) Case 1: Overload accident of wire rope electric hoist in a factory
When a factory used a wire rope electric hoist to lift heavy objects, the rated load of the equipment was exceeded due to negligence of the operator. During the lifting process, the wire rope suddenly broke and the heavy object fell, causing serious equipment damage and casualties.
Cause analysis of the accident
The operator had not received professional training and lacked safety awareness, resulting in overload operation.
The wire rope was not carefully inspected before operation, and the wear and wire breakage of the wire rope were not discovered in time.
The equipment lacked an effective load limiter and could not automatically cut off the power supply when overloaded.
Preventive measures
Strengthen safety training for operators to improve their safety awareness and operating skills.
Strictly abide by operating procedures and prohibit overload operation.
Regularly check the wear of the wire rope and replace damaged wire ropes in time.
Install a load limiter and regularly check its sensitivity and reliability.
(II) Case 2: Fire caused by electrical failure of a wire rope electric hoist in a warehouse
When a warehouse was using a wire rope electric hoist, the aging of the electrical circuit caused a short circuit, which caused a fire and caused huge property losses.
Cause analysis of the accident
The electrical circuits in the warehouse had not been inspected and maintained for a long time, resulting in aging and damage of the circuits.
The electrical system of the equipment lacked effective overload protection and short-circuit protection measures.
The warehouse was not equipped with sufficient fire-fighting facilities and failed to extinguish the fire in time.
Preventive measures
Regularly inspect and maintain the electrical circuits and replace aging and damaged circuits in time.
Install overload protectors and short-circuit protectors in the electrical system of the equipment to ensure the safety and reliability of the electrical system.
Equip the warehouse with sufficient fire-fighting facilities, and conduct regular inspections and maintenance to ensure that they can be used normally.
Strengthen fire safety training for operators to improve their fire prevention awareness and emergency response capabilities.

7. Future development trends and safety prospects
(I) Intelligence and automation
With the continuous advancement of science and technology, wire rope electric hoists are developing in the direction of intelligence and automation. Future wire rope electric hoists will have more intelligent functions, such as automatic load detection, automatic speed regulation, fault diagnosis and early warning, etc. These intelligent functions will greatly improve the safety and reliability of the equipment and reduce the risks caused by human operating errors.
(II) New materials and new processes
The application of new materials and new processes will also bring new opportunities for improving the safety performance of wire rope electric hoists. For example, high-strength and lightweight materials will make the equipment more durable, while reducing the weight of the equipment and improving its operating efficiency. Advanced manufacturing processes will improve the manufacturing accuracy and assembly quality of parts and components to ensure the stability and safety of the equipment.
(III) Continuous improvement of safety standards and specifications
With the development of industrial production and the improvement of safety requirements, the safety standards and specifications of wire rope electric hoists will continue to improve. Future safety standards will be more stringent and detailed, covering all aspects of equipment design, manufacturing, installation, use, maintenance, etc. This will prompt enterprises to pay more attention to the safety performance of equipment and strengthen safety management, thereby effectively reducing the occurrence of safety accidents.
(IV) Construction of safety culture
The construction of safety culture is also of great significance to improving the safety of wire rope electric hoists. Enterprises should strengthen safety education and training for employees, cultivate employees' safety awareness and sense of responsibility, and form a good safety culture atmosphere. Through the construction of safety culture, employees will consciously abide by safety operating procedures, actively participate in safety management, and jointly create a safe production environment.

8. Conclusion
As an important lifting equipment, wire rope electric hoists play an indispensable role in industrial production. However, their safety performance is directly related to the life safety of personnel and the property safety of enterprises. This article discusses the safety characteristics of wire rope electric hoists from multiple aspects such as design and manufacturing, operational safety, maintenance and inspection, and environmental adaptability, and analyzes the causes of accidents and preventive measures based on actual cases. By strengthening the safety management of wire rope electric hoists and taking effective safety measures, safety risks can be minimized to ensure the safety and reliability of industrial operations. In the future development, with the application of intelligence, new materials, new processes, and the continuous improvement of safety standards and safety culture, the safety performance of wire rope electric hoists will be further improved. We have reason to believe that with the joint efforts of the whole society, wire rope electric hoists will bring safer and more efficient services to industrial production and make greater contributions to promoting economic development.