A chain pulley is a simple mechanical tool to make the physical act of lifting objects much simpler. Consisting of a linked chain, a metal housing and several gears, a chain pulley uses physics and geometry to increase lifting efficiency. This tool is used in industries such as shipping and manufacturing and has been in operation for centuries in one form or another.
The chain pulley uses a variety of chain sizes depending on the job it is built to perform. Thinner chains are useful in jobs that require speed and do not involve lifting massive weights. Large, thick chains, conversely, take more effort to run through the chain pulley system, but they can withstand greater loads. Much thought is put into selecting the perfect type of chain to use in different situations.
A chain pulley housing is the most visible part of the mechanism, and it varies greatly in size. Constructed of durable metals, such as steel, the housing locks the gear wheels into place. They are constructed to withstand large amounts of pressure because the point where the housing is connected to a stable position, likely a ceiling beam or crane, must endure great amounts of strain.
The gear wheels within a chain pulley are what make this system function. Chain pulleys can have anywhere from one wheel to five in many cases. The simplest single wheel design has a chain feeding into the housing and over the wheel and out the other end. By pulling on one end, the chain lifts the object attached to the other end with greater ease than by manually lifting it.
Simple geometric and physical principles dictate that the more gear wheels added to the pulley system, the easier the lifting process. For this exact purpose, a chain can be fed around a housing containing several wheels. When the chain is pulled, each wheel absorbs part of the pressure from the weight and makes the act of lifting the object much easier.
The chain pulley likely has been in use since the time of the industrial revolution or even before, when technology first allowed for the creation of chain links. These tools still are used by industries that demand the ability to lift heavy loads, such as manufacturing or shipping. Also common in the modern use of chain pulleys is an automated electrical wench that does not require humans to do the pulling of the chain.