Pulley Systems
The 1:1 Redirect Pulley System
In the illustration to the right we have a rope attached to a load weighing 100kg. The rope has been passed through a pulley which
Pulley systems are used to provide us with a mechanical advantage, where the amount of input effort is multiplied to exert greater forces on a load.
They are typically used for hauling and lifting loads but can also be used to apply tension within a system such as in a Tensioned Line or Tyrolean. This page explains the basic principles of pulley systems and how they work, for information on how to use them in hauling see the hauling systems post.
Force is an influence that has both magnitude and direction, it is usually given in the dynamic unit of Newtons (N). For ease of explanation we have used kilograms on this page. Additionally, the examples on this page do not take into account the effects of angular vector forces or the coefficients of friction.
Pulley Systems
The 2:1 Pulley System
If we take a 1:1 system and turn it upside down it will result in a 2:1 mechanical advantage. Instead of the pulley being attached
Pulley Systems
The 3:1 Pulley System
Here we have a 3:1 mechanical advantage. First one end of the rope is attached directly to the load, this is then passed around an
Pulley Systems
The 4:1 Pulley System
This pulley system provides a 4:1 mechanical advantage. The user is required to apply a force of 25kg to raise this 100kg load, for every
Pulley Systems
The 5:1 Pulley System
With this 5:1 pulley system the user is required to apply an effort of only 20kg to lift the 100kg load. Notice that when the
Pulley Systems
The 6:1 Pulley System
As we continue to apply more pulleys to the system then the mechanical advantage ratio increases. In this system some of the pulleys that have
History of Pulley Systems
The is no direct evidence to support the first documented use of pulleys and pulleys systems however, it is believed that primitive pulley systems were first used around 1500 BCE by the people of Mesopotamia to hoist and move water.
Throughout history the use of pulley systems have been recorded in numerous text and drawings including works by people such as Greek mathematician and engineer Archimedes and also Hero of Alexandria. These early pulley systems would probably have played a significant role in the construction industry where large, heavy loads such as stone blocks and timber would have required moving.