Low-headroom chain-type electric hoists are increasingly being used in a wide range of everyday applications today. But do you know the history of chain-type electric hoists and what they originally looked like? In the 1950s, Japan developed the chain-type electric hoist and, building on its rapidly growing economy, put it to efficient use in lifting and material-handling operations, achieving significant progress. Since then, in response to the diverse needs of different markets, continuous efforts have been made to develop and innovate a variety of styles and functions of chain-type electric hoists, expanding their scope of application ever further.

Product Structure and Characteristics of Low-Headroom Electric Chain Hoists

1. Housing: The aluminum alloy housing is robust and lightweight, featuring specially engineered heat sinks for excellent thermal dissipation, eliminating concerns about downtime due to overheating. It can be used in a wide range of environments, offering exceptional adaptability.

2. Side-mounted magnetic brake: Thanks to the addition of a new magnetic generator, magnetic force and braking can be activated simultaneously when the power is cut, ensuring safer and more reliable braking, especially for heavy loads.

3. Limit Switches: All suspended limit switch devices automatically stop operation to prevent overtravel of the chain, thereby ensuring reliability.

4. Chain: All chains are made from imported alloy steel and undergo heat treatment to ensure reliable performance under a wide range of harsh operating conditions. They exhibit excellent resistance to corrosion from seawater, chemicals, rainwater, and other corrosive environments.

5. Hooks: Hot-forged, high-strength, and highly resistant to breakage. The lower hook can rotate 360 degrees, and its attachment ensures reliable operation.

6. Support: The heavy-duty support, composed of two steel plates, is exceptionally robust.

7. Transformers: voltage conversion devices such as 24V, 36V, and 48V. During operation, in the event of an electrical leakage, precautions should be taken to prevent accidents, and the equipment can be used as safely as possible in rainy conditions.

8. Electromagnetic contactors: Suitable for high-frequency operation and withstand high duty cycles.

9. Reverse Protection Device: A special electrical device that prevents the control circuit from operating if the power supply wiring is incorrect.

10. Push-button switch: Uses a waterproof push-button switch that is lightweight and durable.

Overall Structure of a Low-Headroom Electric Chain Hoist

The chain-drive hoist consists of a high-performance steel plate frame that supports the winch assembly. On the right side of the hoist is the hoist motor, while on the left are the braking device and gear mechanism. For ease of repair and maintenance, the power supply and inspection hatch are designed as plug-in units. The main frame is primarily constructed from a single-piece, non-welded steel plate, characterized by its light weight, simple appearance, high production efficiency, and convenient maintenance.

(1) Round-link chain

Due to the chain’s specific operating conditions and characteristics—high-speed engagement with sprockets and frequent operation under dynamic loading—tensile strength, fatigue strength, toughness, and wear resistance are of paramount importance. Therefore, the materials used for chains must exhibit both quench-hardened (surface-hardened) properties and adequate toughness, while also being developed into alloy steels that offer good formability, weldability, and resource efficiency. In addition, to ensure the chain’s balanced mass and reliable performance over time, all ring-type electric hoists undergo tensile tests at 1.5 to 2 times their rated capacity before leaving the factory, thereby guaranteeing safe operation for users.

(2) Brakes

To accommodate high-speed, frequent operation, the high-speed chain electric hoist is equipped with a dual-braking system consisting of an automatically adjustable primary brake and an auxiliary brake built into the motor. The primary brake engages automatically when power is cut, providing immediate braking; it is also self-adjusting. In other words, as the brake wheel wears and the air gap between the electromagnet and the armature increases, the adjustment lever will automatically compensate to maintain proper clearance. If the clearance becomes excessive, the adjustment screw can be turned to restore the brake to its original, normal setting. Should the primary brake fail, the auxiliary brake will engage to ensure a steady, controlled descent without accelerating the load. This auxiliary brake employs a centrifugal design—a compact, energy-efficient device that remains stationary unless subjected to an abnormal deceleration.

(3) Circuit

The manual pushbuttons in the control circuit are designed for 24-volt low voltage and feature a drop-resistant (water- and oil-proof) cartridge, thereby ensuring reliable operation. In addition, when a three-phase power supply is used, if the wiring sequence is incorrect, the lift limit switch will fail to operate properly; therefore, a reverse-polarity protection device has been incorporated. The principle behind this protection is to employ a phase-shifting circuit that uses relays to disconnect the control circuit in the forward, reverse, and reverse directions.

Conclusion

Low-clearance electric chain hoists are among the most commonly used lifting devices for handling heavy loads in industrial and everyday settings. In response to market demand, manufacturers continuously develop new models to meet evolving needs, earning widespread acclaim from users.