Today if we see around the sky line, the only thing that is noticeable is buildings. There are so numerous constructions that have already been made and many more are still going on. Similarly there are so many different industries available that work many different domains. Each of these industries uses the chain hoist in one or the other way. There are varieties of purposes for which this can be applied.
If something is too heavy to lift and it is impossible to carry it by hand so a mechanical assistant is must in this case. The hoist is one of the commonly used devices for powering the mechanical advantage. There is a bunch of heavy machinery that can do the job, like a forklift or monster robot, but we are talking simple machines. Some examples include a pulley system or car jack. Each uses a simple mechanical linkage to increase force by increasing travel.
Work can be defined as the product of Force and Distance. So to get the same work done, you could input a smaller force over a greater distance by using a jack and moving the handle back a few dozen times. The operation can either be carried out manually or electronically. When operated by operated by hand, it needs an operator who will pull down on one of the chain loops on one side of the chain. This will turn a pulley mechanism inside the chain hoist housing. When this pulley turns, it will lift up the end of the other chain which usually has a hook on the end. By pulling down on one chain, the manual hoist is actually able to increase the mechanical work that is being done. This is caused by the gear ratio inside the manual chain hoist.
There are also two gears located out of which one is small and other is big. The two gears are attached, so when one moves, the other moves. The chain is looped over the smaller gear, and then hangs down in a loop. The chain then continues on over the larger gear and down to a point or another loop, depending on the type of hoist you are using. The operator pulls on the section of chain which is looped over the smaller gear.
It is really important to understand the way the Chain Hoist works but it is easier to understand only if you are aware of science and physics.