Industrial Engineering

Types of pulleys and their working

Pulleys are mechanical components that allow motion to be transferred from a shaft to a belt or rope and vice versa. The most simple and frequent power transmission mediums are pulleys and belts. A pulley is a wheel on a shaft that is used to alter the direction of a belt and support power transfer between the shaft and the belt. To hold the cable or belt, a pulley features a groove inside the flange around its circumference.

A rope, cable, belt, or chain is the main component of a pulley system. “Driver Pulleys” are pulleys that are fixed on a shaft or pulley and move other pulleys. “Follower Pulleys” are the pulleys that are moved by the driving pulley. Pulleys come in two sizes: small and large. Using large and small pulleys, we may simply raise or reduce the speed of power transmission in terms of gears and shafts.

Types-of-Pulley-System

In this article, you’ll learn the various types of pulleys and how they work.

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Types of Pulleys

The various types of pulleys include:

  • Fixed pulley
  • Movable pulley
  • Compound pulley
  • Block and tackle pulley
  • Step pulley
  • “V” groove pulley
  • Cone pulley
  • Jockey pulley
  • Round pulley
  • Fast and loose pulley
  • Conveyor pulley

Compound pulley

A compound pulley, for example, is made up of fixed and moveable pulleys that make the weight lighter and allow you to adjust the force’s direction. These types of pulleys are good for really big loads, but you may need a lot of speed to complete the task properly.

It’s made to ensure that the effort you’re putting in is less than half of the actual load. These devices are commonly used on construction sites and on cranes that hoist large materials like concrete and steel. A combined pulley system is another name for it.

Block and tackle pulley

A block and tackle pulley is a mechanism that uses rope or cable to connect two or more pulleys to raise heavy loads. These pulleys are stacked in a block and then connected such that one is stationary and the other moves with a load. The rope is threaded into the pulley to provide a mechanical advantage, which increases the force delivered to the rope. These pulleys are commonly employed to raise enormous weights or to impart a large amount of force in either direction.

Fast and loose pulley

These types of pulleys are used for machines that need to be started or stopped quickly. These are two little pulleys that are mounted on a countershaft in pairs. A ‘key’ or some other medium is used to tighten one pulley on the countershaft, while another pulley is inserted through a provision for free rotation.

The belt is installed on the tight pulley when the machine is to be operated. A quick pulley is a name given to this type of pulley. The belt is slipped onto the independent pulley, also known as a loose pulley when the machine is to be turned off. Its key advantage is that we may turn off the machine while the main shaft, which is powered by an electric motor or an oil engine, continues to rotate. The belt can be slipped using a lever.

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Conveyor pulley

These types of pulleys are used as a driving pulley on the countershaft of machines that have a single electric motor or oil engine, as well as a single countershaft. Their faces are constructed to be as large as possible, and they wear flat belts.

A conveyor pulley is used in the conveyor system to help shift the conveyor belt’s direction, operate the belt, and supply tension to the belt. Rolling shells with flexible end discs and locking assembly make up these. They are mounted on a motor at one end of the conveyor or adjacent to it.

Step pulley

This type can be described as a collection of pulleys. The faces of the pulleys are fashioned into step pulleys, with pulleys of various diameters fixed in the order. A stepped pulley gets its name from the fact that it looks like a set of steps.

It’s employed in situations where the driven pulley’s speed needs to be increased or decreased for various duties, such as drill machines and lathe machines. They’re frequently used in pairs.

“V” groove pulley

On the face of this pulley, a groove in the shape of the English letter “V” has been cut. Electric motors and vehicles both use it. With these pulleys, a specific “V” shaped belt is needed. More than one “V” groove is cut in some pulleys. These pulleys are utilized for power transmission in heavy-duty applications. There are fewer risks of power slip when more than one “V” belt is used.

Cone pulley

These types are tapered and utilized in a pair of two pulleys (pairs). On two pulleys, a comparable taper is carved. These are connected in such a way that the large end of one is opposite the small end of the other, causing a shift in speed as the belt moves. We can acquire adequate speeds for various jobs with the help of this pulley.

Read more: Understanding pulley and belt

Fixed pulley

The rope is tied to the object and the pulley is attached to a fixed location in this form of pulley system. The fixed pulley’s wheel and axle are designed to fit together. It is made out of a single drum that is attached to a single location.

One side of the rope is pulled downwards, while the other is pulled upwards. You pull it down with the same force as if you were lifting the object by hand. However, the force’s direction is altered. This is advantageous since you can push with your own body weight when you draw down.

Movable pulley

The rope is attached to the fixed point and the other end of the rope is left free in this type of pulley. The thing that has to be moved is hooked to the pulley. The rope moves when you pull it, and the pulley lifts the object. This approach is ideal for elevating an object that is underneath you to a higher level.

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Because the object can travel along the rope if a force is given to it, the system works like a wheel and axle if both sides of the movable pulley system are fixed and the rope is stretched between fixed locations.

Jockey pulley

 

One issue that frequently arises when using these pulleys is that their belts get loose and slip over time, resulting in a loss of power. A third pulley is utilized with the pair of two pulleys to solve this problem, as illustrated in the diagram. It’s known as a jockey pulley. This pulley is a self-regulating pulley that tightens the belt when it loosens.

Round pulley

On the face of this sort of pulley, around the groove is carved. It is controlled by round belts or ropes. It can also be manufactured in the same way as a step pulley.

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Conclusion

The common types of pulleys used in industrial applications are the ones listed above. You must have encountered most of them as an engineer. That is all for this article, where the various types of pulleys are being discussed.  I hope you get a lot from the reading, if so, kindly share with other students. Thanks for reading, See you around!