Abstract: A rotating drum debarker is provided which includes a conveyor chute to feed logs to the drum. The drum includes lifters and reinforcing rings. The improvement in drum design is obtained where the reinforcing ring at the inlet and/or outlet of the drum has an inside diameter greater than the free inside diameter of the drum.

Abstract: A plurality of rigid first comminuting elements are located in a container for material to be comminuted, and are stationarily mounted with reference to the container. A plurality of second comminuting elements are also located in the container and each of these confronts at least one of the first elements with spacing from the same. Resiliently yieldable springs mount each of the second elements for swinging movements relative to the first elements, so as to crush material in the gap by cooperation between the first and second elements. A drive is provided for imparting vibratory swinging movements to the second elements.