How it Works: Chain Hoist

It is really cool that you can lift so much weight with so little force!

Operation

If something is too heavy to lift by hand, there are several ways to use the power of mechanical advantage to lift it. 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, chain hoist, or car jack. Each uses a simple mechanical linkage to increase force by increasing travel.

Force x Distance = Work. Unless you have been exposed to monster amounts of gamma radiation and wear purple pants, you can't lift a car directly. But, to get the same work done (lift the car six inches), you could input a smaller force over a greater distance by using a jack and moving the handle back a few dozen times.

Massive Gear Reduction

This hoist uses a three stage reduction to increase the force you output manyfold

The first reduction is between the gear connected to the input shaft to the larger diameter middle stage gear. The second reduction is from the middle stage gear to the output. The third reduction can be found in the difference in diameter between the large diameter input wheel and the small diameter output.

Also interesting is how tiny the one-way ratchet can be that holds the load up when you let go of the input chain, since it is on the low-force end of the gearbox.

It is a very simple machine, and it is simply amazing that you can lift so much weight with one hand.