System for slowing continuously arriving sheets before stacking

摘要

A succession of sheets are delivered by a main conveyor in a direction at high speed to a braking station and are thereafter piled up by a stacker. A braking apparatus at the station has an endless braking belt having a section of predetermined limited length formed with throughgoing belt holes and a section of substantially greater length that is substantially imperforate. A support holds the belt in the station with a stretch of the belt generally aligned with the direction and positioned to receive the sheets from the main conveyor. A suction box underneath the stretch has a face engaging the stretch, formed with throughgoing suction holes, and having a length in the direction shorter than the length of the imperforate section of the belt. A drive advances the belt such that the stretch moves in the direction at a periodically varying speed with the belt holes and suction holes only aligning periodically. Air is drawn in through the belt holes and suction holes only when same are aligned to draw the sheets down against the belt.