The principle of operation of the lever crushers (jaw crushers) consists of crushing the feed solids between the fixed and the moving jaw. In crusher’s designing stage, it is important to know the load acting on the machine and energy expended on the crushing of raw materials (feed). Determination of force (load) distribution in the working space of lever crusher is the basis for the design of these types of machines (e.g. bodies, drive shafts, pitman). The current methods of determining the crushing forces relate to model processes which are an idealization of real processes. This paper presents experimental studies on the crushing proces of three different materials by flat and profiled crushing plates. Results show a significant influence of the shape of used plates on loads acting in the crusher’s working space.