Physics

Pulley system-Types|Mechanisim|Application

The Pulley system started working for the first time in 1500 BCE by Mesopotamians to move water. A pulley can be considered as a simple wheel with a belt or rope, where the power is transferred to the belt to change the direction of the belt movement. Pulley can be used for simple purposes like cloth-line, blinds, flag hoisting, etc. But for heavy-duty purposes, a system is used like in gym equipment, the construction industry, etc. In this article, we look at the mechanism, types, and application of the pulley system.

What is a pulley?

It is a wheel on a shaft or axle which is designed to support the movement and change the direction of the taut belt or cable.
It may have grooves between the flanges around the circumference to locate the belt or the cable.
They are used to provide mechanical advantages for applying large forces.
Sometimes they are operated as a set of pulleys assembled independently on the same axle to form a block.

What is a pulley system?

For supportive movements, a wheel on a shaft or axle is designed which changes the direction of the cable or a belt and also it transfers power between the shaft and cable or belt.

The pulley system has a support frame that does not transfer power to a shaft that is used to exert force and to guide the cable in specific directions.
The supporting frame in the pulley system acts as a block which is called a sheave.
Pulley system circumference is surrounded by flanges that contain grooves for locating the cable or belt.
This whole system is driven by rope, chain, cable, and belt.
They are assembled in such a way that they will have high efficiency to transfer power from one shaft to another.

Mechanism of pulley system:

It has a unique mechanism of working heavy loads with ease by using ropes and wheels. Working mechanism of the pulley system depends on the different types of pulley used:

Fixed pulley

It does not move or rotate in any direction.
It contains a wheel but is a fixed wheel.
Requires less space for operating.
The amount of force applied to the system is the same as the weight of the pulley.

Movable pulley

In this, the wheel can move and rotate, and less force is required compared to the weight of the object. Construction cranes are the most common examples of movable pulleys.

Compound pulley

It’s a combination of a movable pulley and a simple pulley which is called a compound pulley.
It is designed in such a way as to reduce the effort in half of the weight of the loads.
This type is used in cranes to lift up heavy types of loads.

Block and tackle pulley

This type consists of two or more pulley which is attached to cable or rope for lifting up heavy weighted loads.
They are assembled in form of a block and have one movable pulley and one fixed pulley.

Rope pulley system

It consists of one single fixed pulley and two movable pulleys which are attached to the hook and one end is attached to a pulley and another to the winch.
It consists of a single rope to transmit force from one to another.

Application of pulley system:

In elevators to bring it up and down.
In exercise types of equipment.
In cranes for a construction site for lifting and placing heavy materials.