When designing and using a lever chain crane, it is necessary to comprehensively consider the five core dimensions of mechanical performance, safety standards, operational adaptability, maintenance costs, and compliance. Specifically, the following 20 key elements need to be focused on:

1、 Mechanical Properties and Structural Design

Leverage balance verification

Strictly follow the lever balance principle of "power arm x power=resistance arm x resistance" to ensure a reasonable ratio between the length of the power arm and the resistance arm (such as amplifying the force by three times when 3:1), and avoid load imbalance caused by insufficient torque.

The position of the fulcrum needs to be optimized through finite element analysis to ensure uniform stress distribution and avoid local stress concentration causing structural fracture.

Design of pulley system and chain

The number of pulley groups needs to match the load requirements. For example, if n sections of load-bearing ropes can reduce the tension to 1/n of the weight, the wear limit of the rope groove needs to be checked (if the radial wear reaches 1/4 of the rope diameter, the pulley needs to be replaced).

The chain should be made of high-strength alloy steel with a tensile strength of ≥ 800MPa. Regular lubrication (such as lithium based grease) should be applied between the chain links to prevent jamming or breakage.

Rotation radius and stability

The rotation radius is defined as the horizontal distance from the center of the hook to the center of rotation, which needs to be dynamically adjusted through the arm length, elevation angle, and counterweight system to ensure a balance between the operating range and stability.

The weight and position of the counterweight need to be verified through the torque balance formula (G_counterweight × L_counterweight=G_load × L_load) to avoid the risk of overturning (such as when the counterweight is 4 meters away from the fulcrum and the weight is 3 tons, the maximum lifting amplitude of 10 meters needs to verify the total torque safety threshold).

2、 Safety devices and compliance with standards

Braking and self-locking system

The normally closed brake needs to automatically lock when the power is cut off to ensure that the heavy object is stationary; The brake wheel/friction pad needs to be inspected regularly, and if the wear exceeds 1-2mm or the rim thickness wears over 40%, it needs to be replaced.

Ratchets, worm gears and other gear sets need to have self-locking function to prevent accidental sliding of heavy objects; The clutch needs to control power transmission accurately to avoid slipping or jamming.

Safety monitoring device

Overload limiter and torque limiter need to monitor the load in real time, and block the output and alarm when exceeding the rated value; The wind speed sensor needs to trigger shutdown protection in strong wind environments.

The limit switch needs to be sensitive. If the end limit switch is activated, the main contactor should be released immediately to avoid mechanism overshoot.

Compliance Standards and Certification

Must comply with international/domestic standards (such as ISO 4306, GB/T 3811), pass CE, UL and other certifications to ensure compliance in design, manufacturing, and testing processes.

3、 Operational adaptability and environmental factors

Load capacity and job scope

The rated load should be clearly marked to avoid overloading; The lifting height and rotation angle need to match the operational requirements, such as reducing the rotation radius in narrow spaces.

When lifting multiple machines, it is necessary to coordinate the rotation radius and load distribution to avoid overloading or imbalance; The three-point arc principle requires ensuring that the equipment lifting point, base center, and foundation center are located on the same arc.

environmental adaptability

Need to adapt to different temperature and humidity environments, such as using anticoagulant models for hydraulic oil in low-temperature environments; The dustproof and waterproof levels should match the working environment (such as IP54 or above).

The ground support system (such as support legs, support wheels, tracks) needs to distribute the load to the ground, expand the effective support area, and improve stability.

4、 Maintenance and cost-effectiveness

Maintain convenience

The structure needs to be designed modularly, for example, the arm length of a crawler crane can be extended to 52 meters (such as the QUY50 model), and multiple standard arms are connected by pin shafts for easy maintenance and replacement.

Key components such as gears and bearings should be easy to disassemble and inspect; Lubrication points need to be centrally arranged for regular grease filling.

Cost benefit analysis

The initial procurement cost needs to be balanced with long-term usage costs (such as maintenance and energy consumption); Compared to electric/hydraulic systems, lever chain cranes have a simpler structure and lower maintenance costs.

The ease of operation needs to be considered, driven by manpower or simple power, with low operational barriers and low training costs, suitable for operators with various skill levels.

5、 Special scenarios and extended functions

Special homework requirements

Special scenario requirements such as explosion-proof and anti-corrosion need to be considered. For environments such as chemical and offshore platforms, explosion-proof motors and anti-corrosion coatings should be selected.

Extended functions such as remote control operation and data monitoring (such as load, angle, temperature) need to be implemented through IoT technology to enhance the level of intelligence.

Ergonomic Design

The operation handle and control panel must comply with ergonomics to reduce operational fatigue; The field of view should be broad to ensure that the operator can clearly observe the load status.

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