US 4,380,331 AGranted

Sheet feeding and aligning apparatus for rotary printing machine

AssigneeMAN Roland Druckmaschinen AG

InventorHermann Fischer

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Abstract

To insure accuracy in feeding a sheet of paper from an overlapped, shingled paper supply on a make-ready table, a suction pick-up picks up the sheet and moves it upwardly for a limited distance of about 1 mm before initiating the forward movement of the sheet to transfer it to a gripper mechanism of a printing cylinder or transport drum while, simultaneously, moving it transverse to the plane of the sheet to bring it into proper alignment with the drum or cylinder gripper mechanism.

Claims10

Dependent claims

Sheet feeding and aligning apparatus to pick up a sheet (20) of a printing substrate, particularly paper, for transfer to a moving sheet transport mechanism and having

a make-ready table (20);
a vacuum suction pick-up and sheet transport element (3) including
a tubular housing (11);
a suction tube (4) movably guided in said housing for telescopic movement with respect thereto;
bias means (16) for biassing the suction tube (4) towards a sheet (20) to be gripped;
and pull-in means (6) for pulling the suction tube inwardly within the tubular housing upon adhesion of a sheet thereto under vacuum applied to the interior of said tubular housing (11), so that the pick-up element (3) will be of variable length,
the pick-up element being positioned for engagement with the leading edge of the sheet (20) located on the make-ready table in aligned position and supported for pivoting movement for transporting a sheet after being picked up;
and comprising
a locking element (23) selectively positionable in said housing (11) to contain telescoping pull-in motion of the suction tube within the tubular housing to a limited distance, and permit, after repositioning, continued telescoping movement of the suction tube within the tubular housing;
and
means for controlling the pick-up motion of the pick-up element (3) in steps
(a) for pick-up of the leading edge of the sheet and lifting the sheet off the make-ready table (2) by the limited distance (R-1 mm) defined by the locking means by foreshortening said length by pulling in said suction tube for said limited distance;
and then
(b) for lifting the leading edge of the sheet for the remaining distance (R-r) and further foreshortening the pick-up element by further pulling in said suction tube upon repositioning of said locking means and pivotally moving said pick-up element to a position required for engagement with the transport mechanism and accelerating the sheet by moving the leading edge of the sheet in a rotary path as the element foreshortens to feed the sheet to said moving transport mechanism.

11 more elements

Dependencies are inferred from the claim text.

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Abstract

Sheet feeding and aligning apparatus to pick up a sheet (20) of a printing substrate, particularly paper, for transfer to a moving sheet transport mechanism and having

a make-ready table (20);
a vacuum suction pick-up and sheet transport element (3) including
a tubular housing (11);
a suction tube (4) movably guided in said housing for telescopic movement with respect thereto;
bias means (16) for biassing the suction tube (4) towards a sheet (20) to be gripped;
and pull-in means (6) for pulling the suction tube inwardly within the tubular housing upon adhesion of a sheet thereto under vacuum applied to the interior of said tubular housing (11), so that the pick-up element (3) will be of variable length,
the pick-up element being positioned for engagement with the leading edge of the sheet (20) located on the make-ready table in aligned position and supported for pivoting movement for transporting a sheet after being picked up;
and comprising
a locking element (23) selectively positionable in said housing (11) to contain telescoping pull-in motion of the suction tube within the tubular housing to a limited distance, and permit, after repositioning, continued telescoping movement of the suction tube within the tubular housing;
and
means for controlling the pick-up motion of the pick-up element (3) in steps
(a) for pick-up of the leading edge of the sheet and lifting the sheet off the make-ready table (2) by the limited distance (R-1 mm) defined by the locking means by foreshortening said length by pulling in said suction tube for said limited distance;
and then
(b) for lifting the leading edge of the sheet for the remaining distance (R-r) and further foreshortening the pick-up element by further pulling in said suction tube upon repositioning of said locking means and pivotally moving said pick-up element to a position required for engagement with the transport mechanism and accelerating the sheet by moving the leading edge of the sheet in a rotary path as the element foreshortens to feed the sheet to said moving transport mechanism.

11 more elements