Maintenance measures after fatigue test of hand chain hoist

Maintenance measures after fatigue test of hand Chain Hoist
In many fields such as industrial production and logistics transportation, hand chain hoists are widely used as light and small lifting equipment due to their small size, simple operation and easy portability. For international customers engaged in wholesale procurement of hand chain hoists, it is crucial to ensure the performance and life of hand chain hoists. After the hand chain hoist undergoes fatigue test, a series of maintenance measures need to be taken to ensure its subsequent safe and efficient operation.

1. Overview of fatigue test of hand chain hoist
Fatigue test is a key link before the hand chain hoist leaves the factory or during regular inspection. By simulating the frequent stretching, compression, twisting and other working conditions in actual use, it is repeatedly loaded and unloaded to detect its performance under long-term alternating stress. For example, within the specified lifting weight range, hundreds or even thousands of lifting operations are performed to observe whether the key components of the hand chain hoist, such as the chain, hook, gear, etc., have fatigue phenomena such as deformation, cracks, and wear, so as to determine whether it meets the design and use requirements.

2. Appearance inspection
(i) Remove surface dirt
After fatigue testing, the surface of the chain hoist is often covered with dust, oil and impurities. These dirt will not only affect the appearance of the equipment, but may also accelerate the wear of the components in subsequent use. Therefore, first use a clean cloth to dip in an appropriate amount of detergent or water, and carefully wipe the body, chain, hook and other parts of the chain hoist to remove surface dirt.
(ii) Check surface damage
Carefully observe the surface of the shell, hook and chain of the chain hoist to check for scratches, collision marks, cracks and other damage. For example, if there are tiny cracks on the surface of the hook, it may gradually expand in subsequent use, affecting its load-bearing capacity, and even causing the hook to break and cause a safety accident. For the surface damage found, the location, size and degree of information should be recorded in detail for further processing.

3. Inspection and maintenance of key components
(i) Maintenance of lifting chain
Check the wear of the chain: Check each link of the chain one by one to see if there is excessive wear. It can be judged by measuring the diameter of the chain ring. If the chain ring diameter wear exceeds a certain proportion of the nominal size, such as 10%, it means that the chain is seriously worn and needs to be replaced.
Check the elongation of the chain: measure the elongation of the chain after the fatigue test. If the elongation of the link pitch exceeds 3% and the elongation of the single link pitch exceeds 5%, the chain may not work properly and needs to be replaced.
Check the lubrication of the chain: observe whether there is enough lubricating oil on the surface of the chain. If the lubricating oil dries up or is contaminated by dirt, the old oil should be removed in time and re-applied with an appropriate amount of special lubricating oil. Lubricating oil can reduce the friction coefficient of the chain during use, reduce wear, and play a certain anti-rust role.
(II) Maintenance of the hook
Check the deformation of the hook: check whether the hook has torsional deformation, hook size deformation and increase. For example, if the dangerous section or neck of the hook undergoes plastic deformation, the load-bearing capacity of the hook will be greatly reduced, posing a safety hazard.
Check the wear of the hook: measure the cross-sectional dimensions of the hook. If the wear exceeds 10% of the nominal size, the hook needs to be replaced. At the same time, check whether there are cracks, burrs and other defects on the surface of the hook. If so, use appropriate tools to repair or replace the hook.
Check the opening of the hook: If the opening of the hook increases by more than 15% compared to the original size, the hook should be scrapped to prevent dangerous situations such as unhooking when lifting heavy objects.

Maintenance of gears and transmission components
Check the wear of the gear: Check whether the tooth surface of the gear has wear, cracks, broken teeth, etc. If the wear of the tooth thickness exceeds 10% of the nominal size, the gear cannot mesh normally and needs to be replaced.
Check the flexibility of the transmission components: Manually turn the transmission components such as gears and bearings to check whether they rotate flexibly and whether there are abnormal conditions such as jamming and looseness. If the rotation is found to be inflexible, it may be caused by poor lubrication, damaged parts or improper installation, which needs to be further investigated and resolved.
Lubricate gears and transmission parts: Apply an appropriate amount of grease to the gears and bearings to ensure smooth operation and reduce wear in subsequent use. It is very important to choose the right grease. According to the use environment and working conditions of the hand chain hoist, grease with appropriate viscosity, anti-wear performance and anti-oxidation performance should be selected.
(IV) Maintenance of the brake
Check the friction pad of the brake: Check the wear of the friction pad. If the wear exceeds 25% of the nominal size, the friction pad needs to be replaced to ensure the braking torque of the brake.
Check the friction surface of the brake: Ensure that the friction surface of the brake is clean, free of oil and impurities. If there is dirt, it should be cleaned in time to prevent brake failure.
Check the brake clearance of the brake: Adjust the brake clearance of the brake so that the brake can brake quickly and accurately when needed, ensuring the safety of the hand chain hoist when lifting heavy objects.

4. Performance testing and debugging
(I) No-load performance test
Perform a no-load operation test, operate the hand chain hoist to perform multiple up and down actions, and check whether it runs smoothly and smoothly, and whether there are abnormal noises, jams, etc.
Check the braking performance of the hand chain hoist. In the unloaded state, pull the lifting chain to make the heavy object (which can simulate an object of a certain weight) a certain height off the ground, then release the hand chain to observe whether the brake can reliably brake the heavy object in the air to ensure normal braking performance.
(II) Heavy-load performance test
According to the rated lifting weight of the hand chain hoist, gradually load the heavy object and conduct a heavy-load performance test. During the loading process, observe the stress of the chain, hook, gear and other components of the hand chain hoist, and check whether there are abnormal phenomena such as deformation and slip chain.
Check whether the performance indicators of the hand chain hoist, such as the lifting speed and lifting weight limiter, meet the requirements. For example, when the lifting weight limiter reaches the rated lifting weight, it should be able to send an alarm signal in time and cut off the lifting power to ensure safe operation.
(III) Debugging and repair
Based on the results of the performance test, debug and repair the problems found. For example, if the chain of the chain hoist is found to jump during the lifting process, it may be caused by the wear of the sprocket or the improper tightness of the chain. The sprocket needs to be repaired or replaced, and the tightness of the chain needs to be adjusted.

5. Anti-corrosion and anti-rust treatment
(I) Clean the surface of the equipment
Clean the residual dirt and moisture on the surface of the chain hoist again to ensure that the surface is dry and clean, and prepare for the subsequent anti-corrosion treatment.
(II) Apply anti-corrosion coating
Evenly apply a layer of anti-corrosion coating to the metal parts of the chain hoist, such as the chain, hook, body, etc. The anti-corrosion coating can isolate the metal surface from the contact with moisture, oxygen and other corrosive media in the air, and effectively prevent metal rust. Common anti-corrosion coating materials include anti-rust paint, oil film, etc.
(III) Reasonable selection of storage environment
Store the chain hoist in a dry, ventilated and clean warehouse or shelf to avoid exposure to moisture, high temperature, corrosive gas or liquid environment. At the same time, when storing, some desiccant should be hung or placed on the hook, chain and other parts of the hand chain hoist to further reduce the humidity of the storage environment and extend the service life of the equipment.

6. Regular maintenance and records
(I) Formulate a maintenance plan
Develop a reasonable regular maintenance plan based on the frequency of use and working environment of the hand chain hoist. Generally speaking, at least one appearance inspection and cleaning maintenance is carried out every month, a detailed inspection and maintenance of key components is carried out every quarter, and a comprehensive performance test and debugging is carried out every year. For hand chain hoists with high frequency of use or harsh working environment, the maintenance cycle should be appropriately shortened.
(II) Keep good maintenance records
Establish a maintenance file for the hand chain hoist, and record in detail the content, time, problems found and treatment measures of each maintenance. Through maintenance records, we can fully understand the maintenance history of the hand chain hoist, facilitate the analysis of the operating status and wear patterns of the equipment, and provide a basis for formulating scientific and reasonable maintenance strategies.

7. Summary
As an important lifting equipment, the performance and component status of the hand chain hoist may change after fatigue testing. Through the above comprehensive and detailed maintenance measures, including appearance inspection, key component maintenance, performance testing and debugging, anti-corrosion and anti-rust treatment, and regular maintenance and record keeping, the good performance of the hand chain hoist can be effectively restored and maintained, its service life can be extended, and the safety and reliability of the equipment in subsequent use can be ensured. For international wholesale buyers, these maintenance measures not only help to improve the quality and reputation of the hand chain hoist, but also reduce the maintenance cost and replacement frequency of the equipment, thereby gaining an advantage in the fierce market competition.