Arrangement for applying compressed air to underside of sheet on feed table of printing press

摘要

A sheet feeding assembly for a printing press including a feed table having a set of front stops and which is inclined downwardly so that a sheet travels toward the front edge of the table where it is temporarily retained in registered position. A port connected to a source of compressed air extends through the table at a position spaced from the front edge of the table. A rear feed plate is seated on the table upstream of the port and a front feed plate is seated on the table downstream of the port, the plates being substantially coplanar with their respective front and rear edges in proximity and uniformly spaced with respect to one another. The front edge portion of the rear feed plate is undercut to form an overhang which defines a transversely extending air conducting cavity which overlaps the port so that an air blast is directed at an angle upwardly and forwardly of the table to lubricate the passing sheet and to urge the sheet in the direction of the front stop. The rear plate is adjustably shiftable to vary the spacing between the plates thereby to vary the rate of discharge of the air. A manually adjustable cam elevates the front edge of the rear plate to a variably upraised position thereby to vary the angle of discharge of the air against the sheet.