Vacuum transfer apparatus for rotary sheet-fed printing presses

A sheet transfer apparatus for use with a sheet fed printing press, said apparatus being adapted to be positioned below a sheet delivery conveyor which extends along a sheet travel path from said press to means for receiving freshly printed sheets from said press, said apparatus comprising:

• a frame including means defining an air manifold chamber;
• a plurality of sheet support members for supporting sheets being transferred along the sheet travel path, said sheet support members extending transversely of the sheet travel path and being spaced apart one from the other along the sheet travel path to provide spaces therebetween in communication with said manifold chamber;
• and,
• airflow means coupled in communication with said chamber for drawing air through the spaces between the support members as the sheets are transferred along the sheet travel path.

Sheet support apparatus for guiding freshly printed sheets as they are transported by a delivery conveyor along a sheet travel path between a printing unit of a printing press and means for receiving printed sheets from the printing unit, said apparatus comprising:

• a frame comprising opposed sidewalls, end walls and a bottom wall forming a vacuum chamber, said frame being supported on said conveyor system in proximity to sheet travel path for sheets being transferred from said printing unit to said means for receiving printed sheets;
• a vacuum source coupled to said vacuum chamber;
• and
• a plurality of elongated support members mounted on said frame for supporting sheets being transferred by said conveyor system, said support members being spaced apart from each other along said travel path to provide spaces therebetween for admitting the flow of air into said vacuum chamber from an area generally adjacent to said travel path whereby a differential pressure is created across printed sheets supported by said members as the printed sheets are transferred along said sheet travel path.

A method for controlling the movement of freshly printed sheets as they are transferred from the impression cylinder of a printing press along a sheet delivery path to a sheet delivery stacker comprising:

• providing subjacent support for the freshly printed sheets by a plurality of elongated support members which are spaced apart from each other along the sheet transfer path;
• causing air to flow across the sheet transfer path and through the spaces between the elongated support members thereby imposing a pressure differential across the freshly printed sheets as they are transported along the sheet transfer path;
• and,
• controlling the rate at which air is caused to flow across the sheet transfer path.

A sheet transfer apparatus for use in combination with a sheet fed, rotary offset printing press of the type having cylinder means for applying wet material to one side of a sheet, and a transfer conveyor having means for gripping and pulling the freshly printed sheet from the cylinder means and conveying the sheet along a transfer path to a further processing station of the press, said sheet transfer apparatus being characterized by:

• a frame defining a vacuum chamber having an airflow inlet opening in communication with the vacuum chamber, the airflow inlet opening having an airflow inlet area which is substantially coextensive with a predetermined section of the transfer path;
• a plurality of sheet support members mounted on said frame and overlying said airflow inlet opening, said sheet support members being disposed in side-by-side relation and closely spaced across the airflow inlet opening, thereby defining elongated airflow apertures;
• and,
• means coupled to said chamber for inducing a partial vacuum within said chamber, whereby suction pressure induced within said chamber causes air to flow into said chamber through the airflow apertures between said support members to draw the unprinted side of a sheet being conveyed along the predetermined section of transfer path toward said support members.

A sheet transfer apparatus for use in combination with a sheet fed, rotary offset printing press of the type having cylinder means for applying wet material to one side of a sheet, and a transfer conveyor having means for gripping and pulling the freshly printed sheet from the cylinder means and conveying the sheet along a transfer path to a further processing station of the press, said sheet transfer apparatus being characterized by:

• a frame defining a vacuum chamber having an airflow inlet opening in communication with the vacuum chamber, the airflow inlet opening having an airflow inlet area which is substantially coextensive with a predetermined section of the transfer path;
• a plurality of sheet support members mounted on said frame and overlying said airflow inlet opening, said sheet support members being disposed in side-by-side relation and closely spaced across the airflow inlet opening, thereby defining elongated airflow apertures;
• and,
• means coupled to said chamber for inducing a partial vacuum within said chamber, whereby suction pressure induced within aid chamber causes air to flow into said chamber through the airflow apertures between said support members to draw the unprinted side of a sheet being conveyed along the predetermined section of transfer path toward said support members.