Manual Hoists and crawl
Manual chain hoist is quite a simple device especially looking at the huge amount of weight that it can lift. Manual hoists are made from stern, high grade steel that provides safety and reliability when lifting extremely heavy loads. Manual hoist can be classified in 3 different part categories, which are lifting chains, lifting mechanism and hooks.
How a manual chain hoist works:
The science behind a chain hoist is exceptionally basic and have been utilized for lifting overwhelming loads for quite a while. Chain hoist uses a mechanical advantage to convert small force over a long distance to large force over a short distance, this is possible by using a number of larger and smaller gears in the chain hoist system.
To lift a load, chain hoist operator needs to pull down the hand chain, this turns the cog and axle which goes through the lifting mechanism. Inside the lifting component are numerous gears which increase the mechanical work applied when pulling the hand chain for a number of times utilizing gear ratio, allowing to effectively lift loads with different ton capacity.
So when the hand chain is pulled, the cog which is rotated by the hand chain turns the drive shaft and gears which turn the load chain sprocket, this likewise turns the load chain that is looped over the load chain sprocket and lifts a load. Larger gears move slower than smaller gears, however create more force, this is the reason why chain hoist lifts load very slowly in comparison to a hydraulic hoist. Toward the end of the lifting chain is a grab hook, which allows to effectively attach and detach a load. Most chain hoist lifting mechanisms have a ratchet or braking mechanism that keeps the load from slipping back, however allows to lower a load by pulling the opposite side of the hand chain.
Some of the advantages of using manual chain hoist are that they don’t need electricity, oil or other resources to function. They are obviously cheaper than electric or hydraulic hoists. Lastly, they are also simple to use and to repair and maintain.