Pulleys are used in a number of different types of mechanisms. The way they essentially work is quite simple, but they can be a big help with tasks that cannot practically be done with human force alone. A pulley consists of a rope or belt pulled over a wheel. The belt is attached at one end to a (usually) heavy object, and at the other end to a machine that pulls it along the wheel.
The easiest method of pulley alignment involves simply looking at the wheel and belt and approximating it. If the belt seems to be slipping, it is pulled back around the wheel and lined up with any grooves that are present or simply pulled tight along the center of the wheel. This method has the most room for error, and is thus not necessarily the most effective.
Pulley alignment with a straight edge is more exact than with the naked eye alone, but it still is not as effective as alignment with a laser. The straight edge method is used when the pulley itself is misaligned, not the belt. A person using this method would hold the straight edge up to the pulley wheels and slowly turn them around. If at any point the grooves for the belt or rope do not match up on each of the wheels, he will even them out with the straight edge as his reference point.
Lasers are the most effective method of pulley alignment. There are numerous types of lasers that can be bought for this purpose, some of which aid in the alignment of the grooves, and some with the sides of the wheels. These lasers will determine the pulley’s precise misalignment. With these measurements one can use lateral and axial jackscrews to realign the pulley correctly. In terms of safety and efficiency, this is the best method.
If pulley alignment is not correct, a number of problems can arise. For one thing, the belt’s improper positioning may result in its wearing thin very quickly, which means a greater cost for the person who is having to install new belts. There is also the chance of the belt sliding off the wheel and a heavy object midway up in the air falling down. Ultimately, incorrect pulley alignment can be not only costly, but dangerous as well.