Cone crusher is similar in operation to a gyratory crusher, with less steepness in the crushing chamber and more of a parallel zone between crushing zones. A cone crusher breaks rock by squeezing the rock between an eccentrically gyrating spindle, which is covered by a wear resistant mantle, and the enclosing concave hopper, covered by a manganese concave or a bowl liner. As rock enters the top of the Cone crusher, it becomes wedged and squeezed between the mantle and the bowl liner or concave. Large pieces of ore are broken once, and then fall to a lower position (because they are now smaller) where they are broken again. This process continues until the pieces are small enough to fall through the narrow opening at the bottom of the crusher.
For the most part advances in crusher design have moved slowly. Jaw crusher have remained virtually unchanged for sixty years. More reliability and higher production have been added to basic Cone crusher designs that have also remained largely unchanged. Increases in rotating speed, have provided the largest variation. For instance, a 48 inch (120 cm) Cone crusher manufactured in 1960 may be able to produce 170 tons/hr of crushed rock, whereas the same size cone manufactured today may produce 300 tons/hr. These production improvements come from speed increases and better crushing chamber designs. The largest advance in Cone crusher reliability has been seen in the use of hydraulics to protect crushers from damage from uncrushable objects entering the crushing chamber. Foreign objects, such as steel, have been known to cost thousands of dollars of damage to a Cone crusher, and more costs in lost production. The advance of hydraulic relief systems has greatly reduced downtime and improved the life of these machines.