Abstract: A power sieve has a generally planar and longitudinally extending frame having upstream and downstream ends and a pair of laterally spaced side members extending longitudinally between the ends, a generally planar screen spanned longitudinally within the frame, and a plurality of longitudinally spaced and substantially parallel beater beams underneath the screen and having beam ends juxtaposed with the frame side members. Respective horizontally extending leaf springs each have one end secured to the respective side member and another end secured to the respective beam end. Thus the beams can move generally vertically on the springs. Respective beater arms extending generally parallel to the screen from the beater beams have outer ends engageable with the underside of the screen.