wheel and Axle

The wheel and axle is a simple machine.

The traditional form as recognised in 19th century textbooks is as shown in the image. This also shows the most widely recognised application, ie lifting water from a well. The form consists of a wheel that turns an axle and in turn a rope converts the rotational motion to linear motion for the purpose of lifting.

By considering the machine as a torque multiplier, ie the output is a torque, items such as gears and screwdrivers can fall within this category.


The doorknobs is an example of the same form as the water well, the mechanism uses the axle as a pinion to withdraw the latch.

The simple Chain Fall is another example. Here the user pulls on the wheel using the input chain, so the input motion is actually linear.

The Screwdrivers is an examples of the rotational form. The diameter of the handle gives a mechanical advantage (compared to a screwdriver with no handle!)

Gears are examples of the rotational form.