The stone crushers consist of two plates one job being fixed and other being mount by pitman mechanism due which the crushing can be done in one stroke due small moment of jaw plates for crusher. these two plates form a taper chute so that material can be crushed, as the load acts on the plates its wearing rate is high hence high wear resistant material is used generally magnese still are used a heavy flywheel is use to crushed the tough materials which provides the required inertia. Double Toggle jaw crushers may feature hydraulic toggle adjusting mechanisms.

It is shown below Figure it works on reduction of weight of swing jaw plate by reduction of energy consumed in crushing by using “Point Load- Deformation Relationships along with interactive failure of rock particles and Design of Jaw Crusher Plates” point loading various sizes of materials

As the rock particles comes between the fixed and moving plate it get crushed hence the design of plates must be improved worked in design of jaw crushers which impart an impact on a rock particle placed between a fixed and a moving plate. this faces of plate made up of hardened steel it may be flat or corrugated.

As the reciprocating action removes the moving jaw away from the fixed jaw the broken rock particles slip down, but are again caught at the next movement of the swinging jaw and crushed. This process is repeated until the particle sizes are smaller than the smallest opening between the crusher plates at the bottom of the crusher (the closed set). For a smooth reciprocating action of the moving jaws, heavy flywheels are used in both types of crushers.

Jaw crusher is a kind of size reduction machine which is widely used in the mining and aggregates industry.between jaw plates and material particles brings the inevitable and serious wear to the jaw plates during the jaw crusher operation, which not only decreases the efficiency, but also increases the cost and the energy consumption of the jaw crusher. The movement of the moving jaw is described in detail. The breakage force is tested in the experiment and some information on the particles flow is gained by analyzing the force distribution. Based on the movement analysis of the moving jaw and the crushing force distribution analysis, the jaw plates wear is analyzed on a macroscopic level. The result of the wear analysis can explain some of the phenomenon in practice. With the rock material breakage character taken into consideration, the blindness brought by the traditional empirical designing can be greatly decreased.