The daily use and maintenance of lever chain cranes should focus on the following core issues and solutions, which can be systematically summarized into five dimensions based on mechanical principles and engineering practice:

1、 Common faults and cause analysis

Chain breakage: Chain links are prone to breakage when worn by more than 10% or have cracks, and need to be regularly inspected and replaced; Diagonal pulling and hard pulling (angle>5 °) cause lateral stress concentration, and the direction of operation needs to be adjusted.

Brake failure: Brake wheel wear exceeding 1-2mm or rim thickness wear exceeding 40% needs to be replaced; Hydraulic brake fluid contamination or insufficient oil level can cause lock failure, and it is necessary to check the oil quality and replenish the oil.

Unstable rotation radius: Jamming of the boom telescopic mechanism or oil leakage from the hydraulic cylinder can cause deviation in the rotation radius. It is necessary to inspect the hydraulic system and adjust the boom telescopic limit.

Walking vibration/noise: The accumulation of debris on the guide rail, deformation of the running wheels, or wear of the coupling are the main causes. It is necessary to clean the track, replace the deformed parts, and calibrate the coupling.

2、 Operating standards and safety points

Load management: Overloading is strictly prohibited (rated load must be clearly marked). When lifting multiple machines, load distribution must be coordinated, and the "three-point one arc" principle must be followed to ensure stable center of gravity.

Operation process: Check the status of the chain, brake, and safety device before starting; During operation, avoid sudden stop and start, with a diagonal angle of ≤ 5 °. If the hand cannot move, investigate the cause instead of forcibly increasing the number of personnel.

Environmental adaptation: Anticoagulant hydraulic oil is required for low-temperature environments, and heat dissipation needs to be strengthened for high-temperature environments; In humid/corrosive environments, anti-corrosion coatings should be applied and metal components should be inspected regularly.

3、 Key maintenance measures

Lubrication management: Chain, gear set, and pulley set need to be coated with lithium based grease every 3 months; The hydraulic system needs to be regularly replaced with hydraulic oil that meets the ambient temperature.

Component replacement standard: If the radial wear of the pulley groove reaches 1/4 of the rope diameter, it needs to be replaced; The brake wheel wear exceeds the limit or the hydraulic cylinder output force is insufficient, requiring maintenance or replacement.

Structural inspection: Regularly detect metal structure deformation, cracks, and loose connection bolts; The electrical system needs to be cleaned and the reliability of cable insulation and safety devices checked.

4、 Design Principles and Mechanical Optimization

Leverage balance: Force amplification is achieved through "power arm x power=resistance arm x resistance". For example, a 3:1 power arm can amplify 3 times the force, and the position of the fulcrum and the counterweight design need to be checked.

Benefit of pulley system: n-section load-bearing rope can reduce tension to 1/n of the weight of the object, combined with lever system to form a dual force amplification effect.

Hydraulic system: Based on Pascal's law, pressure is transmitted through hydraulic cylinders to push pistons to achieve arm extension or lifting actions, ensuring sealing and adjusting oil pressure.

5、 Safety devices and emergency response

Safety device: The weight limiter cuts off the power supply when overloaded; Buffer reduces collision impact; The emergency stop switch can quickly cut off the power circuit.

Emergency response: In case of chain jamming or brake failure, immediately press the emergency stop button and evacuate personnel; Regularly organize emergency drills to simulate scenarios such as overloading and chain breakage.

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