Arrangement for lateral alignment of sheets

In a device for registering a sheet against front and side stops on the feed table of a printing press having a press drive and having means for cyclically feeding sheets across the table toward the front stop, the combination comprising a suction head recessed in the table adjacent the side stop and having a top surface including a set of openings, means mounting the suction head for movement parallel to the surface of the table with the top surface of the head being maintained flush with the surface of the table, reciprocating means coupled to the press drive and timed with the arrival of the sheet at the front stop for shifting the head laterally in the direction of the side stop and for returning it, a source of suction, first valve means coupled to the source of suction for applying a draft of suction to the head timed with the lateral shifting movement so that the sheet is affirmatively shifted into contact with the side stop, a source of substantially constant air pressure, second valve means coupling the head to the source of air pressure for applying a short puff of air to the openings timed with completion of the shifting movement to free the sheet from the head in readiness for removal of the sheet from the table, an auxiliary nozzle recessed in the table in a position adjacent the head, said nozzle being connected to the source of air pressure and directed toward the side stop and approximately parallel to the surface of the table for producing a moving film of air under the sheet in the direction of the side stop to insure that the sheet remains against the side stop when the suction is no longer effective and until the sheet is removed from the table, a first adjustable throttle valve effectively connected in series with the auxiliary nozzle for reducing the flow of air moving under the sheet in the direction of the side stop to a level sufficient to ensure that the sheet remains against the stop and a second adjustable throttle valve effectively connected in series with the second valve means for reducing the force of the puff of air to a level just sufficient to break the suction and to free the sheet from the head in readiness for removal of the sheet from the table.