Jaw crushers have been around for almost 175 years. All jaw crushers are distinguished by the presence of two plates, one of which is fixed and one that swings open and then closes, concurrently trapping and crushing material between the two surfaces. There are three types of jaw crushers: Blake, Dodge, and Universal. They are classified according to the location of the pivot point of the swinging jaw. The most common type of jaw crusher today is the Blake crusher, patented by Eli Whitney Blake in 1858 (Weiss, 1985). The Blake crusher pivots at the top and comes in two forms: the double toggle and the single toggle. The single toggle is taking over most new applications due to lower cost 5
and higher capacity (Stansell, 2003).