The internal structure of a lever chain hoist (also known as a chain hoist or ring chain hoist) is a precision mechanical system, where various components work together to achieve weight lifting and safety control. The internal structure is systematically analyzed from five aspects: core components, transmission principles, braking systems, safety devices, and material processes

1. Core components and transmission system

Crane Chain: Designed with a circular ring chain, it is made of high-strength alloy steel (such as FEC G80 grade) that has undergone heat treatment and surface hardening treatment to enhance wear resistance. The chain links include inner chain plates, outer chain plates, pin shafts, and rollers, which can withstand tensile, fatigue, and impact loads.

Hand zipper and sprocket: The hand zipper drives the sprocket to rotate by manual pulling, and the sprocket meshes with the lifting chain to transmit power; The sprocket material is alloy steel, which has undergone quenching treatment to ensure hardness and wear resistance.

Gear transmission system: Adopting a multi-stage gear reduction and torque increase design, common structures include symmetrically arranged two-stage spur gears, planetary gears, or worm gears (now mostly replaced by gear type). For example, the HS type chain hoist achieves torque amplification and speed adjustment through components such as a five tooth long shaft, a four tooth short shaft, and disc gears, with a transmission ratio of over 35:1, ensuring labor-saving and efficient manual operation.

2. Braking and safety locking system

Ratchet and pawl mechanism: a core safety component. When the hand zipper stops pulling, the pawl is embedded in the ratchet slot locking system to prevent heavy objects from sliding down; When pulling the zipper in reverse, the pawl and ratchet separate to achieve weight lowering control.

Friction pad brake: Used in conjunction with a ratchet wheel, it generates braking force by compressing the friction pad with spring pressure. Some models use dual braking (main brake+auxiliary brake), with the main brake being an electromagnetic brake that operates when the power is cut off, and the auxiliary brake being a centrifugal brake to ensure that heavy objects descend at a constant speed when the main brake fails.

Overload protection device: Mechanical detection of load torque through spring displacement. When overloaded, the secondary shaft gear separates from the shaft and triggers a micro switch to cut off the circuit; The electric type uses a torque limiter to idle the motor during overload, protecting the transmission system.

3. Hook and connection structure

Hook: The upper hook is used to hang the hoist, and the lower hook is used to connect heavy objects. Both are forged from alloy steel and undergo heat treatment. When overloaded, they slowly open instead of breaking, ensuring safe operation; Some hooks can rotate 360 ° and are equipped with tongue plates to prevent detachment.

Chain collecting device: The chain smoothly meshes with the sprocket through the chain guide device and is stored in the chain collecting box. The dust-proof design extends the life of the chain.

4. Drive and control unit (electric model)

Electric motor: It adopts a conical rotor brake motor or a disc brake motor. When powered on, the magnetic tension overcomes the spring pressure to release the brake, and when powered off, the spring force presses the brake wheel to achieve braking; The motor is equipped with a built-in thermal protection device to prevent overheating and burning out.

Electrical control: including limit switches (to prevent the chain from exceeding its travel), electromagnetic contactors (high frequency use shock resistant), reverse protectors (to prevent power wiring errors), and waterproof button switches to ensure reliable operation.

5. Structural materials and processes

Shell and frame: The aluminum alloy shell is lightweight and has fast heat dissipation. The frame is welded or cast from steel plates, and key parts are reinforced with reinforcing bars to increase rigidity; The box body and the box cover are connected by bolts, and the oil seal is tightened to prevent oil leakage.

Gears and bearings: The gears are made of alloy steel that has undergone carburizing and quenching treatment, resulting in high tooth surface hardness; The bearing is a rolling bearing with good lubrication to reduce wear; The reducer adopts oil bath lubrication, and the gears are installed in a sealed box to prevent dust.

Surface treatment: Components such as chains and hooks are galvanized or coated for rust prevention, while nickel hardened chains are resistant to rainwater and seawater corrosion; The brake friction pads are made of asbestos based or asbestos free materials, balancing friction coefficient and wear resistance.

Maintenance points: Regularly check chain wear (replace if it exceeds 15%), brake performance (spring pressure, friction plate thickness), gear meshing and lubrication status; Load testing and material analysis are conducted by professional institutions every six months to one year to ensure compliance with safety standards; Overloading and diagonal pulling are strictly prohibited during operation. Safety ropes should be added when heavy objects are parked, and heavy objects should be cushioned for maintenance when the chain is stuck to avoid being forcefully pulled.

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