Under what circumstances will the hand chain hoist be overloaded

Under what circumstances will the hand chain hoist be overloaded
The hand chain hoist is a common manual lifting tool, which is widely used in many fields such as industry, logistics, and construction. However, in actual use, if the operation is improper or some key factors are ignored, the hand chain hoist may be overloaded, which will not only affect the service life of the equipment, but also may cause serious safety accidents. This article will explore in depth the various situations of hand chain hoist overload and provide corresponding preventive measures and solutions.

1. Common situations of hand chain hoist overload

(I) Improper operation
Failure to select the model correctly: When using a hand chain hoist, if the rated load of the selected model is less than the actual weight of the heavy object to be lifted, it is easy to cause overload. For example, if a 5-ton heavy object needs to be lifted, but a hand chain hoist with a rated load of 3 tons is selected, this will obviously cause the hoist to bear a load beyond its design range during operation.
Oblique lifting: When the lifting chain of the hand chain hoist forms a certain angle with the vertical direction for lifting, the chain will bear additional lateral force, which is equivalent to increasing the actual load of the hoist. If the angle is too large, even if the rated load of the hoist is sufficient, the chain or other components may be overloaded due to the oblique pull, resulting in overload.
Asynchronous operation when multiple hoists work together: In some large-scale lifting operations, multiple hand chain hoists may be required to lift a heavy object together. If the operation of each hoist is not synchronized, some hoists may bear too much load, while other hoists are lighter. This uneven force distribution will cause some hoists to work overloaded.

(II) Equipment aging or damage
Chain wear: The chain of the hand chain hoist is a key component that bears the main pulling force. With the increase in usage time and frequent use, the chain will wear. When the wear of the chain exceeds a certain limit, its effective cross-sectional area decreases and its strength decreases. Under the same load, the stress on the chain increases, and it is easy to overload.
Brake failure: The brake is an important safety device of the hand chain hoist, which is used to keep the heavy object stationary during the lifting process. If the brake fails due to wear, oil or other reasons, when the operator releases the zipper, the weight will accelerate due to its own gravity. At this time, the chain and other parts of the hoist need to withstand greater impact force, which may cause overload.
Other parts are aging or damaged: If the hook, gear and other parts are deformed, cracked, excessively worn and other problems occur, the load-bearing capacity and stability of the entire hoist will be reduced, and overload may occur under normal load.
(III) Environmental factors
Temperature and humidity: Hand chain hoists usually work normally within a certain temperature and humidity range. If used in an environment with too high or too low temperature, the strength and toughness of metal parts may change, affecting their load-bearing capacity. For example, in a low temperature environment, steel will become brittle and prone to breakage; in a high temperature environment, metal parts may deform due to thermal expansion, reducing their ability to bear loads. In addition, a high humidity environment may cause rust on parts such as chains, increase friction and wear rate, and thus affect the normal operation and load-bearing performance of the hoist.
Uneven or unstable work site: If the support point of the chain hoist is uneven or unstable, such as when used on soft ground, slopes or vibrating platforms, the hoist may tilt or shake during lifting, causing uneven forces on the chain and other components, increasing the risk of overload.

2. How to avoid overloading of chain hoists

(I) Correct selection and use

Choose the appropriate model according to actual needs: When choosing a chain hoist, you should fully understand the weight, shape, size and working environment of the heavy object being hoisted, and choose a model with a rated load greater than or equal to the weight of the heavy object, and consider a certain safety factor. It is usually recommended to choose a chain hoist that is at least 50% greater than the load-bearing weight of the hoisted object.

Operate in strict accordance with the operating procedures: Operators should undergo professional training and master the correct use and precautions of the chain hoist. During the lifting process, keep the chain vertical to avoid oblique lifting; when multiple hoists work together, ensure that the operation is synchronized and the load is evenly distributed.
Regular inspection and maintenance: Before use, carefully check whether the appearance of the hand chain hoist is damaged, deformed, cracked, etc., whether the chain is intact, twisted or knotted, and whether the brake is sensitive and reliable. Regularly maintain the hand chain hoist, including cleaning, lubricating the chain and transmission parts, replacing severely worn parts, etc., to ensure its good working condition.

(II) Strengthen equipment management
Establish equipment files: Number each hand chain hoist, establish detailed equipment files, record its specifications, models, rated lifting capacity, manufacturer, production date, purchase time, maintenance records and other information, so as to facilitate management and tracking of equipment use.
Regular inspection and scrapping: In accordance with relevant regulations and standards, regularly inspect and test the hand chain hoist, such as conducting a comprehensive inspection and performance test once a year. Hand chain hoists that have been used for too long, are severely aged, or cannot meet safety requirements after multiple repairs should be scrapped in time to avoid safety accidents such as overload caused by aging equipment.
(III) Improve the working environment
Ensure that the work site is flat and stable: Before using the hand chain hoist, check and organize the work site to ensure that the support points are flat, solid, stable, and able to bear the total weight of the hoist and the heavy object. Avoid using it on uneven or soft ground to reduce the possibility of the hoist shaking or tilting during lifting.
Control the ambient temperature and humidity: Try to avoid using the hand chain hoist in an environment with extreme temperature and high humidity. If it cannot be avoided, appropriate protective measures should be taken, such as preheating the hoist before using it in a low temperature environment, and cleaning and drying the equipment in time after using it in a high humidity environment, so as to reduce the impact of environmental factors on the performance of the hand chain hoist.

3. Hazards of overloading the hand chain hoist
Equipment damage: Overloading will cause the key components of the hand chain hoist, such as the chain, gears, and hooks, to bear excessive stress, accelerate their wear and fatigue, and cause problems such as component deformation and fracture, shorten the service life of the equipment, and increase maintenance costs and equipment downtime.
Increased safety hazards: Overload operation can easily lead to safety accidents, such as heavy objects falling, hoists tipping over, etc., which pose a serious threat to the life safety of operators and surrounding personnel, and may also cause losses to equipment, factory buildings and other properties.
Reduced work efficiency: Frequent equipment failures or the need to shut down for maintenance will affect the normal progress of lifting work, reduce work efficiency, and delay production progress.

4. Case analysis
Case 1: Overload accident of hand chain hoist in a factory
During the equipment lifting operation, a factory selected a hand chain hoist with a rated load of 2 tons to lift equipment weighing 3 tons due to negligence of the operator. During the lifting process, the chain of the hoist suddenly broke and the equipment fell. Fortunately, the on-site personnel evacuated in time and no casualties were caused, but the equipment was seriously damaged, causing great economic losses to the factory. The main cause of the accident was that the model of the hand chain hoist was not correctly selected, resulting in overload use, and the chain could not withstand excessive tension and broke.
Case 2: Overload caused by oblique lifting of hand chain hoist
During a warehouse cargo handling, the operator used a hand chain hoist to lift the cargo at an oblique angle for convenience, and the angle was large. As a result, during the lifting process, the chain twisted and deformed due to the additional lateral force, which eventually led to chain breakage and cargo damage. In this case, oblique lifting was the main cause of the overload of the hand chain hoist. The operator violated the correct operating procedures and did not keep the chain vertically lifted.

5. Summary
Hand chain hoists may be overloaded in many cases, including improper operation, equipment aging and damage, and environmental factors. In order to avoid the serious consequences of overload use, we must start from the correct selection and use, strengthen equipment management, and improve the working environment, and take effective preventive measures and management methods. At the same time, through the analysis of actual cases, we have a deeper understanding of the hazards and importance of overload operation. Only in this way can we ensure the safe and efficient use of hand chain hoists, extend their service life, ensure the safety of personnel and equipment, and provide reliable lifting and transportation guarantees for our production and life.