The maintenance and repair of chain hoist should follow the principles of systematization, standardization, and safety priority, covering four core links: daily inspection, regular maintenance, fault diagnosis and repair, and safety device verification. Starting from professional processes and combining with the requirements of special scenarios such as tunnel construction, the following provides a complete operation guide:

1. Daily check before operation (daily/before each use)

Key component status verification

Chain system: Check the chain links for cracks, deformation, corrosion, or excessive wear (diameter wear ≤ 10%, pitch elongation ≤ 3%); Double chain design requires confirmation of consistent chain length to avoid uneven force distribution; Apply rust proof grease on the surface of the chain to prevent chain jamming or rusting.

Hook and brake: The hook needs to be equipped with a locking device, without cracks or deformation (breaking force ≥ 5 times the rated load); The friction surface of the brake is clean and free of oil stains, the engagement between the pawl and ratchet is reliable, and the sliding amount is ≤ 5mm (better than the national standard of 15mm); The friction disc brake needs to pass a static load test (maintain 1.25 times the rated load for 10 minutes without slipping).

Gear and bearing: The gear mesh is unobstructed, the bearing operates flexibly, and the sealed bearing needs to be dust-proof (regular cleaning of dust accumulation in dusty environments); Check the condition of lubricating grease in high temperature environment to avoid dry friction.

Environmental adaptability confirmation

Damp/Corrosive Environment: Choose stainless steel chains or nickel plated hardened treatment, regularly apply rust proof grease; Waterproof type (IP65) requires checking the integrity of the sealing ring.

High temperature/explosion-proof environment: High temperature resistant lubricating grease (such as lithium based grease) needs to be replaced regularly; Explosion proof models (Ex standard) require confirmation of explosion-proof markings to avoid electrical sparks.

2. Regular maintenance (monthly/quarterly/annual)

routine maintenance

Clean the surface dirt of the gourd after use, apply rust proof grease, and store it in a dry and ventilated place; Lubricate the chain every half month with rust proof grease to avoid chain jamming; Replace the brake friction plate in a timely manner when the wear exceeds the limit (thickness ≤ 50% of the original thickness).

regular maintenance

Monthly inspection: No load action inspection (all mechanisms operate flexibly and without jamming); The response time of the braking system is ≤ 0.3 seconds, and the sliding amount is ≤ 5mm.

Quarterly inspection: Static load test (maintain 1.25 times rated load for 10 minutes); Dynamic load test (run at 1.1 times the rated load for 3 times); Measurement of chain wear (diameter wear ≤ 10%, pitch elongation ≤ 3%).

Annual inspection: comprehensive disassembly inspection, cleaning of gears and bearings, and replacement of lubricating grease; The welding points must comply with the "Code for Acceptance of Welding of Pressure Pipelines" to ensure no stress and a smooth groove; Intelligent models need to verify the accuracy of sensors and controllers (such as weight and speed monitoring errors ≤ 5%).

3. Fault diagnosis and repair

Common faults and their solutions

Chain stuck/broken: Clean the accumulated dust on the chain and apply rust proof grease; Broken chains need to be replaced with chains of the same specification to avoid mixing different batches of chains.

Brake failure: Check whether the pawl spring is malfunctioning and whether the friction plate is worn beyond the limit; Replace the friction plate or adjust the pawl pressure; The brake seal is aging and needs to be replaced.

Excessive hand pulling force: Check if the gear meshing is smooth and if the bearings are short of oil; Adjust the gear clearance or add lubricating grease; The bracelet wheel needs to be replaced due to wear and tear.

Special scenario fault handling

Narrow tunnel area: Compact hand-operated hoists need to be checked for volume compatibility to avoid restricted operation; Lubricating grease should be replenished in a timely manner when it dries up in high temperature environments.

Explosion proof environment: Explosion proof models need to be checked for loose electrical connections to avoid sparks; During fault handling, the main isolation switch should be disconnected to ensure safety.

4. Safety devices and emergency response

Safety device configuration

Integrated overload protection (automatic shutdown when the load exceeds 10%), height limit infrared sensing, emergency switch and isolation switch, in compliance with CE/CMA certification; The intelligent model is equipped with high-precision sensors and handheld controllers to achieve real-time monitoring of weight and speed, as well as uniform descent control.

Emergency response measures

Stop immediately when the brake fails and take emergency braking measures (such as backup brakes or manual intervention); When decoupling or falling occurs, evacuate personnel quickly and activate emergency plans; Regularly drill emergency operation procedures to enhance personnel's emergency response capabilities.

5. Long term storage and scrapping standards

Long term storage: Apply rust proof grease and place in a dry and ventilated place; The chain needs to be suspended for storage to avoid deformation caused by compression; Conduct no-load operation checks every six months to ensure the flexibility of the mechanism.

Scrap criteria: Chain breakage, hook deformation exceeding 10%, brake failure to self lock, shell crack exceeding 20% length; When the intelligent model sensor fails or the controller cannot be repaired, it needs to be scrapped as a whole.

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