| 摘要 |
A mechanism for registering a sheet against front and side stops on the feed table of a printing press, employing a suction head recessed in the table and reciprocated for lateral shifting movement in the direction of the side stop timed with the arrival of the sheet. The head is connected to a source of suction so that the sheet is shifted into contact with the side stop. The head has intentional play in the direction of feeding movement of the sheet, as measured from a reference position, and is freely rockable about its axis, so that the sheet is free to settle against the front stop at the same time that it is being shifted toward the side stop. A conduit connected to a source of a pressure is provided for applying a short puff of air to the head, timed with completion of the shifting movement, to free the sheet from the head in readiness for removal of the sheet from the table. The return movement of the head is utilized to reverse the play and to restore the head to reference position. In the preferred embodiment of the invention the head is mounted upon a reciprocated slide which is slidable upon a tube which serves as an air conduit. Also in the preferred form of the invention the same drive shaft is employed in a compactly integrated construction to obtain the reciprocating movement and for rotating air valves to insure high speed synchronization. |
