Air-dam for printing press vacuum transfer apparatus
AssigneeHoward W. DeMoore
InventorHoward W. Secor
Life of this patent
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Abstract
A vacuum-type sheet transfer apparatus for a rotary printing press includes an air dam device formed by an elongated plate which is supported on the transfer apparatus housing and extends toward the surface of a transfer cylinder or impression cylinder of the press. Spaced apart openings are formed in the plate and have deflectable elastomeric flaps disposed in the openings to allow the cylinder gripper fingers to pass by the plate. An air dam or seal is formed by the plate to redirect the flow of air to urge sheets, including lightweight and heavy weight stock, to follow a preferred transfer path between the impression cylinder and the vacuum transfer apparatus.
Claims20
A device for use in a printing press in conjunction with a vacuum type sheet transfer apparatus wherein said sheet transfer apparatus includes a housing defining a chamber in which at least a partial vacuum is drawn and sheet support means defining a sheet support path for supporting sheets transferred along said transfer apparatus and urged into engagement with said sheet support means by a differential pressure force caused by said vacuum in said chamber, said device comprising:
- a member extending between said housing and a sheet supporting cylinder of said press and operable to redirect the flow of air toward said chamber such that differential pressure forces acting on said sheet will cause said sheet to transfer from said cylinder to said sheet support means along a predetermined path.
A device for use in a printing press in conjunction with a vacuum-type sheet transfer apparatus wherein said sheet transfer apparatus includes a housing defining a chamber in which at least a partial vacuum is drawn and sheet support means defining a sheet support path for supporting sheets transferred along said transfer apparatus wherein said sheets are urged into engagement with said sheet support means by differential pressure caused by said vacuum in said chamber, said device comprising:
- an elongated plate supported on said housing and extending generally between said housing and a sheet supporting cylinder of said press for redirecting the flow of air flowing toward said chamber such that said differential pressure force acting on said sheet will cause said sheet to transfer from said cylinder to said sheet support means along a predetermined path, said plate including a distal edge disposed in proximity to a surface of said cylinder and plural recesses formed in said plate and intersecting said edge and defining clearance spaces for movement of sheet gripper fingers disposed on said cylinder past said device.
In a vacuum transfer apparatus for a printing press, said apparatus including a housing defining a chamber in which at least a partial vacuum is drawn and support roller means defining a sheet transfer path in said printing press and delimiting at least part of said chamber, the improvement characterized by:
- at least one air dam device associated with said apparatus and extending between said housing and a sheet transfer cylinder of said press and operable to minimize the flow of air between said cylinder and said housing in such a way that differential pressure forces are operable to act on said sheet to urge said sheet into engagement with said support roller means as said sheet passes along said transfer path.
Dependencies are inferred from the claim text.