A manual chain hoist is a hoist that uses a chain for a lifting medium and does not have an electric motor for lifting power. A hoist is a device that is used for raising a load off a surface, usually for the purpose of moving it onto or off a conveyance. It consists of a drum or lift wheel wrapped with a chain or cable that is raised by a pulley. A lifting hook on the bottom of the hoist is used to attach a load.
The main components of a hoist are the lifting medium and the power type. Chain is a common lifting medium because it is very strong for its size and it does not kink or fray. Chain comes in many sizes, from thinner than a pencil to thicker than a tree. All of these sizes can be found in different chain hoists.
A manual chain hoist, as the name implies, use a chain as the lifting medium. The individual links of the chain are matched to gear teeth in the lift and suspension wheels to keep the chain from slipping. A ratchet mechanism is often included to hold the load suspended in the air after it is lifted.
Wire cable is the other common lifting medium used in hoists. It is generally considered less reliable than chain and can become snarled or kinked. Wire cable also is more likely to rust and break, and it can whip around dangerously when it breaks. In a manual hoist where the operator is close to the load being lifted, a chain is considered to be safer and more reliable than a cable.
A manual chain hoist is used where the load to be lifted is light, electric power is not available or a power unit would be too expensive. Each of the pulleys in a chain hoist multiplies the lifting advantage. With 10 or more pulleys in a hoist, one person can lift an extremely large amount of weight.
Simple chain can be made of connecting metal rings. Chain showed up early in mankind’s use of metal. There are drawings of a manual chain hoist being used to draw water from a well in about 255 BC. Leonardo da Vinci’s drawings in the 16th century show advanced chain hoists with chains that have roller bearings.