Rotary crushers for quarries or ore mines can grind up to 3500 t of material to the desired grain size in one hour. For this purpose an eccentric bearing bush generates a rotary-oscillating movement of the crusher axle, thereby constantly changing the gap
between the crusher jaws and the crushing cone. For grinding the set gap continuously moves along the inside perimeter of the crushing room. With a longdistance sensor in the hydraulic cylinder the crushing gap can be exactly adjusted by raising and lowering the axle.