Chain hoist is a mechanical device used for lifting heavy loads of objects and equipment. It is made with a pulley, which is held together by a closed chain. The closed chain forms a loop, which makes it easy to be pulled by hand.
There are several large and small pulleys located throughout a chain hoist. There is one large and one small pulley are situated on the same axle, as well as a mobile pulley that holds the load in place.
For the load to be raised with the chain hoist, the closed chain has to be pulled. When it is pulled, the large pulley draws in more chain than what is released by the smaller side. From here, the lifting process begins.
Although the history of pulleys is unclear, it is known that primitive methods were employed to move heavy objects around. One of the early attempts at a pulley system was the single fixed pulley, which failed because friction prevented the wheel from being turned. Rope pulleys, which were commonly used for pulling water out of wells and are still in use today, are thought to have been invented next.
The function of lever hoist and chain pulley hoist is the same , both are used for lifting and handling load by manual operation . The difference is that , the chain pulley hoist is driven by pulling the hand chain, which is commonly used to lift weight vertically , While the chain pulley hoist is carried by rotating the lever , mostly used to move heavy objects horizontally.