A hand - operated chain hoist is a kind of manual lifting machinery that is simple to use and convenient to carry. The following is a detailed introduction to it: Structural Composition - Hand chain wheel: It is located at the upper part of the hand - operated chain hoist. This is the part where the operator applies pulling force. By pulling the chain, the entire mechanism is driven to operate. - Brake: Generally, a ratchet - pawl - type braking device or a friction - disc - type braking device is used. After a heavy object is lifted, it can reliably prevent the heavy object from falling, ensuring safe operation. - Planetary gear reducer: It is composed of planetary gears, a central gear, an internal gear ring, etc. It has the characteristics of a compact structure, a large transmission ratio, and high efficiency. It can convert the pulling force of the hand chain wheel into sufficient lifting force. - Lifting chain: Usually made of high - strength alloy steel, it has high strength and wear resistance. It is used to directly lift heavy objects. The pitch and load - bearing capacity of the chain vary according to different models. - Hook: It is the component for connecting heavy objects. Generally, it is forged from high - quality carbon steel or alloy steel, and its surface is treated by quenching, etc., to improve its strength and toughness, ensuring that heavy objects can be safely suspended. Working Principle The hand - operated chain hoist utilizes the principles of the wheel - axle and gear transmission. When the chain is pulled, the hand chain wheel rotates. Through the transmission of the planetary gear reducer, the lifting sprocket rotates, thereby driving the lifting chain to rise or fall, realizing the lifting and lowering of heavy objects. During this process, the brake will brake in a timely manner as required to prevent the chain from reversing and ensure that the heavy object remains in the desired position. Characteristics - Simple operation: It does not require a power supply or other complex power equipment. The lifting and lowering of heavy objects can be achieved simply by manually pulling the chain. The operation is simple and easy to understand, and no professional technical training is needed. - Convenient to carry: It has a small volume and light weight, making it easy to carry and transport. It can be used flexibly in various situations, especially in narrow spaces where large - scale lifting equipment cannot be used. - Safe and reliable: It is equipped with a reliable braking device and an overload protection device, which can effectively prevent heavy objects from falling and the equipment from being damaged due to overload, ensuring the safety of the operation process. Selection Key Points - Lifting height: Determine the required lifting height according to the working scenario and actual needs. Common lifting heights include 2 meters, 3 meters, 5 meters, etc. In special cases, it can be customized according to requirements.

- Working level: Select an appropriate working level according to factors such as the frequency of use and the nature of the load. Generally, it is divided into different levels such as M1, M2, M3, M4. The higher the working level, the relatively higher its load - bearing capacity and service life.