8levers and linkages
Levers and linkages are some of the simplest machines and form the basis for countless more complex mechanisms. While levers are mostly used to provide a mechanical advantage that allows us to move heavy loads, linkages are mostly used to transform one type of a motion into another. Both are common in everyday life: If you have ever played on a seesaw or used pliers, you have relied on levers and linkages.
A basic lever is simply a beam that has one point of support in the form of a hinge or a pivot, as shown in Figure 8-1. We will call this point a fulcrum. A lever also has input and output forces. We will call the applied, or input, force the effort and the reaction force the load. Finally, we will call the sections ...