Image Number 5 for United States Patent #4145009.
An impact crusher includes a shell housing, a main drive shaft, a first member mounted on the shaft, and a second member carried on and rotatable with respect to the first member. Impact members act against the inner lining of the housing to crush the material. The impact gap between the impact members and the housing lining is variable in a stepless fashion by a drive mechanism which rotates the first member relative to the second member to thereby drive the impact members radially. In one embodiment each impact member is driven by a pin which extends through the impact member and overlapping elongated holes in the first and second members. In other embodiments, a plurality of linking elements are employed. Weights may be provided to counter-balance the forces in the crusher resulting from the centrifugal forces of the impact members. These weights may also serve as an alternate set of impact members usable when the normal impact members become worn.