Abstract: A sheet stacker includes a belt conveyor having shingled sheets which includes aligned crowned belt pulleys rotating endless belts. A vertically movable table is located such that the conveyor propels the sheets falling downwardly to form a pile of sheets thereon. A fork unit moves inwardly across the stacker as a temporary support during pile removal. A brake and clutch unit is connected to the pulleys. A sheet control includes pivoted fingers aligned with the belts and secured to a shaft. An actuating arm pivots the shaft to move the fingers into engagement with said aligned belts on the downstream side of the pulleys. A pneumatic control provides a conjoint control to actuate said brake and pivot the finger shaft for momentarily stopping sheet movement in synchronism with the actuation of the fork.