Types of Hoists
Hoists is a device used to lift or move loads by utilizing technological advantages so the lifting ability becomes very large. The lifting force is obtained from changes in energy mechanically, hydraulically, pneumatically and electrically. Here are some types and how the hoists work based on the mechanism and operating systems :
1. Manual Hoist
The working principle of the manual hoist (Chain Block or Lever Block) is similar to a pulley that changes the direction of the force so that the work done easier. Several pairs of gears of different sizes are used to gain mechanical advantage when the operator exerts force by pulling a chain of hoists or by pressing a lever. The force will be transmitted by pairs of gears to produce a greater force to lift heavier loads. With giving a smaller force at a longer distance then at a shorter distance will produce a greater force. The advantages of manual hoist compared to other types are cheaper, easy to use, easy to repair and maintain and does not require electric current. While the drawback is since it uses a manual force through the gears then for lifting or lowering the load takes more longer.
2. Hydraulic Hoist
Hydraulic hoist uses an oil-based piston mechanism that works according to Pascal’s Law. Pressure applied to liquid substances in a confined space will be passed on in all directions. By applying force to a small amount of compressed liquid, the force is transferred to a much larger surface area on the other side. Because using the piston media to lift or down the load, so the lifting height is limited. A lever is used to increase or decrease its height.
3. Pneumatic Hoist
Pneumatic or air hoist use air pressure to provide the force needed to lift a load. Operators operate through the pendant control to lift or down the load. The advantage is it does not require electricity, the weight is lighter, more resistant to dirt, dust, steam, high temperatures and humidity. While the drawback is that it is more difficult to control the speed.
4. Electric Hoist
Electric Hoist is a types of hoists use a wire rope or chain mounted on a drum equipped with a rope guide / chain guide. The drum is connected to an electric motor and a gear box so it will spin to lift or down the load. A brake system is used to hold the load when the hoist is at off position (the electricity is cut off). The pendant control has an emergency button that will automatically cuts off the power. The hoist will stop operating and the brakes will work automatically. At the present, we can supply hoist products between the capacities from 250 kg to 200 tons with different types and lifting heights.
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