Types Of Pulley:Exhaustive Insights

Pulley is a simple mechanical system that helps to transmit the motion of an object via rope, rod, or belt.

Pulley helps change the position and direction of an object easily. It is used only to transfer the object’s motion. It does not provide energy for the object to move. This post is concentrated on the types of the pulley.

Types Of Pulley

There are several types of pulley that are very helpful to carry the motion. The three basic types of the pulley are;

Let us study these in detail.

Fixed pulley

It is one of the types of pulley system which has a pulley attached to a fixed arm and a rope is holding the weight is moving over the pulley. The fixed pulley is designed such that the wheel and the axel situate in one edge.

fixed pulley
Free body diagram of Fixed Pulley

Working of a fixed pulley

When you pull the rope on one side, say downward, the other side of the rope moves in the upward direction. The force that you apply to pull the rope downward is equal to the force that you exert to lift the same object by your hand. In this case, the direction of force changes.

Moveable pulley

In this type of pulley consisting of a rope whose one end is fixed and other is set free to pull. This rope crosses over the pulley, which is attached to an object.

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Free body diagram of Moveable pulley

Working of moveable pulley

When the free end of the pulley is pulled down, the pulley slide over the string and uplift the object, this pulley is beneficial if you are at a higher altitude and the object is below your level. Moveable pulleys will work as wheel, if both the end of the string is fixed to the arm. In that case, when the force is applied, the object moves along the string.

Compound pulley

It is a type of pulley composed of both fixed and moveable pulley in a single system. It is employed to lift the heavy object. This pulley makes you exert less than half of the energy.

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Image credits:  Image by Muhammet Ali ÇETİN from Pixabay 

Working of compound pulley

Since it has both fixed and movable pulleys, it makes the object lighter and becomes easy to lift. For this process, you need much speed. The compound pulley is also called as “Combinational pulley system.”

Other than the above three types, there are several types of pulley. The secondary types of pulley are

Block and Tackle pulley

Block and tackle or simply tackle pulleys consists of two or more pulleys in a single system held by a rope or cable. This particular type of pulley is used to lift the massive body.

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Image credits: Image by Muhammet Ali ÇETİN from Pixabay

Working of block and tackle pulley

Several sets of pulleys combined together to form a block. This block, along with a rope crossing over the pulley, is called a tackle. These blocks are paired in such a way that one pulley is fixed and another is to be moveable. The load is attached to the moveable arm of the pulley. The rope provides mechanical support to the system and boosts the tension force on the rope to lift the massive body.

This type of pulley is commonly used in boats, cranes, and sailing ships.

Step pulley

A step pulley consists of several pulleys of various diameters fixed to one arm. It is arranged in such a way that it looks like a step, so the pulley is named a step pulley.

Working of step pulley

Step pulley is provided with a belt. The belt is changed from one step to another step to monitor the speed of the system. Step pulleys are always operated in pairs. When the belt of the one pulley is changed, the belt of other pulleys is also changed simultaneously.  These pulleys are employed to regulate the speed of the pulleys.

This types of pulley is commonly equipped in the machines such as drilling machines, lathe machines, etc.

Cone pulley

It is a type of pulley that acts in pairs. Cone pulleys are usually narrow and cut into two parts. The pulleys are arranged as the broad end of the one cone is facing the narrow end of the other one. It is provided with a belt that moves with the pulley and controls the speed of the system.

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Free body diagram of cone pulley

Jockey pulley

A jockey pulley consists of a wheel at the top edge and a belt attached to it. This type of pulley is also used to regulate the speed of the machinery.

Working of jockey pulley

Jockey pulleys are fitted with five pulleys, which are operated by coupling with other pulley. While running the machine, the belt may become loose and slip from the pulley. The third pulley, a self-controlled pulley, is used in pairing with the two pulleys to overcome this problem.

V groove pulley

This typical types of pulley consists of a “V” shaped belt is used to move over the two pulleys. This is particularly equipped in automobiles and electric motors to transmit power between the parallel axels of the pulley.

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Image credits: Image by b0red from Pixabay 

Working of V-groove pulley

The V belt used in the system provides the mechanical linkage. This delivers excellent speed and load capacity to the system. Heavy load increases the efficiency by transmitting power through the belt, which is responsible for reducing friction.

Conveyor pulley

Conveyor pulleys are used for the driving purpose equipped in the countershaft of the machines. It consists of broad and flat belts on their face.

Working of conveyor pulley

It is type of pulley consisting of a roller and a flexible disc. The conveyor belt helps to change the direction of the pulley and provides tension. The disc and the roller are fitted in the end-to-end connection, which allows for rolling over the conveyor motors. These are used in the oil engine and electric motors.

Belt pulley

It is the most inexpensive pulley used in the computer printers, papermakers, and textile industries.

It consists of a flat belt that moves over a flat pulley. It is operated at high speed and uses low power. The torque acting on the pulley is more, so that, if the belt slipped, there would be very little damage to the equipment.

The belt pulleys are further classified into three types, they are

Split pulley

It is a type of pulley. It is made up of cast iron, consisting of two parts, one is a face, and another is a hub. These are versatile pulley,   operates efficiently in all size of the pulley. It is mainly used in saw machines and oil extraction.

Wooden pulley

The wooden pulleys are lightweight pulleys made up of wood. These are fitted with adjustable screws to reduce friction.

Paper pulley

In this type of pulley, the inner layer of the pulley is comprised of metal coat and outer layer is coated with the paper fibers. The paper fibers are compressible, and they transfer the motion from the center to the shaft in a short distance.

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