Abstract: In a rotary screen for sorting wood or other particles of a desired size from other particles such as fine, moist, sticky sawdust particles, a plurality of balls are suspended beneath the screening surfaces in a manner such that the gyratory motion of the rotary screen imparts a resonant, pendulum-type motion to the balls, causing them to strike the bottom of the screening surfaces and loosen particles from the screen which would tend to clog the openings therein. The rotary screen includes a collection tray or "dust pan" to catch undersize particles, and a plurality of balls are also suspended beneath the bottom surface of the dust pan to strike it and prevent material build up in the dust pan.

Abstract: A saw tooth insert, for securing to a saw plate, comprises a front cutting surface containing two adjacent grooves extending for substantially the entire height of the cutting face and substantially radially outward from the rotational axis of the saw plate. The lower portions of the grooves end on opposite sides of the saw plate and the upper portions of the grooves form a central cutting edge between them and external cutting edges on each side of the cutting face where the grooves meet the side surfaces of the insert.