Class 3 (see Figures 7-8 and 7-9): The effort is located in
the middle of the lever and the load and the fulcrum at its
Figure 7-9: A boom of a crane is an example of the class 3 lever, with the
load and the fulcrum at its ends and the effort applied to its center (in this
case, by a pneumatic cylinder). Class 3 levers have a mechanical advantage
less than 1, meaning that they require plenty of effort but can move loads
over large distances. This is favorable when it comes to pneumatics, which
can exert huge force but have limited reach.