The causes of faults in chain hoists (hand pulled/electric hoists) can be systematically analyzed from five dimensions: mechanical wear, operational errors, inadequate maintenance, environmental impact, and design defects. The specific reasons are as follows:

1、 Mechanical wear and component failure

Chain system:

Fracture/deformation: Overloading, long-term overload, or impact load causing fatigue fracture of the chain link; Chain twisting, knotting, or detachment from the sprocket groove can cause chain jamming; Chain ring diameter wear ≥ 10% needs to be replaced immediately (such as NetEase subscription case).

Corrosion/rusting: Corrosion caused by damp environment or irregular lubrication increases the risk of fracture; High temperature environment causes the failure of lubricating grease and increases friction.

Transmission and braking system:

Gear/sprocket damage: tooth surface wear ≥ 30%, cracks or broken teeth need to be scrapped (such as Baidu Education case); Gear wear, bearing damage, or insufficient lubrication of the reducer can cause vibration, noise, and jamming.

Brake failure: Insufficient braking force caused by worn brake pads, spring fatigue, or oil contamination; Wear and deformation of the ratchet/pawl can cause self-locking failure or sliding chain (as in the case of Sohu).

Hook and connector:

Hook fracture/deformation: replacement is required when wear exceeds 10% or cracks exist; Loose or broken connecting bolts cause structural instability.

2、 Operational errors and illegal use

Overloading operation: Exceeding the rated load can cause chain breakage, gear damage, or motor overload (such as in the case of electric hoists); Diagonal pulling or impact loads can cause chain wear or jamming.

Improper operation:

Chain entanglement, incorrect direction, or multiple people pulling the bracelet at the same time (designed to only support single person operation force); Failure to secure the hand zipper resulted in brake failure, leading to a sliding chain accident.

Failure to check the self-locking status of the braking mechanism after lifting, or failure to secure the bracelet when the heavy object is suspended, poses a safety hazard.

Storage/transportation error: chain deformation caused by collision or compression; Storing in a humid environment accelerates corrosion.

3、 Lack of maintenance and upkeep

Insufficient lubrication: The chain, gears, bearings, and other parts are not regularly coated with specialized lubricating oil, resulting in increased dry friction, wear, or jamming; Friction plate failure due to oil contamination (as in the case of NetEase).

Cleaning negligence: Dust, oil stains, or iron filings on the chain and gears have not been cleaned, resulting in chain jamming and wear; Insufficient oil in the reducer/bearings leads to overheating and noise.

Negligence in inspection: Failure to regularly check the integrity of the chain, gear meshing status, braking system, and housing structure; Failure to replace worn parts (such as hooks and gears) in a timely manner.

4、 Environmental factors have an impact

Damp/corrosive environment: Metal components such as chains and hooks corrode, reducing strength; Moisture in electrical components can cause short circuits or control failures.

High temperature environment: grease failure, motor overheating; High temperature leads to a decrease in material properties (such as aging of plastic parts).

Dust/debris: Dust and iron filings enter the transmission components, exacerbating wear or jamming; Failure to clean up internal debris during outdoor work resulted in blockage.

Vibration and impact: Long term vibration can cause loose connections and structural fatigue; External impact causes deformation of the shell and chain.

5、 Design and manufacturing defects

Material issues: The materials of components such as chains and gears do not meet the standards, and their fatigue strength is insufficient; Casting defects such as pores and cracks can cause early failure.

Processing/assembly errors: Poor gear meshing and misalignment of the axis cause operational lag; Design defects in the braking system, such as insufficient spring pressure, can cause self-locking failure.

Electrical malfunction: The electric hoist motor operates in a single-phase manner, the bearings are damaged, or the controller malfunctions, resulting in unstable speed, chain jamming, or overheating (as in the case of WeChat).

Preventive and solution measures:

Strictly adhere to the rated load and avoid overloading, diagonal pulling, or impact operations; Before operation, check the status of the chain, hook, and brake to ensure that there is no wear, deformation, or foreign objects.

Regularly lubricate key parts (chains, gears, bearings) at least once every quarter; Clean the transmission components to avoid the accumulation of oil and dust.

Store in a dry and ventilated environment, avoiding moisture, high temperatures, or collisions; Secure the chain during transportation to prevent deformation.

Regular professional maintenance and replacement of worn parts (such as chains, gears, and brake pads); Electric hoists require inspection of the motor, controller, and electrical wiring.

Secure the hand zipper after operation to prevent brake failure; When heavy objects are suspended, avoid personnel approaching and ensure a safe distance.

Through system maintenance, standardized operation, and environmental control, the failure rate of chain hoists can be significantly reduced, ensuring operational safety and equipment lifespan.

The main equipment produced by Hebei Makita: stage electric hoist, electric chian hoist, wire rope electric hoist，Hand chain hoist, lever hoist, pneumatic hoist and other lifting equipment