Apparatus for handling sheets

Claim 2

In a sheet-handling apparatus, sheet-delivering means, a first sheet-gripping conveyor driven to successively feed said sheets forwardly at a faster speed than the speed at which the same are delivered by said means, said first conveyor including means spaced downstream from said first-named means for forming a nip in the first conveyor at which the sheets are initially gripped by the first conveyor, a second conveyor downstream of said first conveyor, disposed above the path of travel of the sheets carried by the first conveyor, and driven at the same speed and direction as such first conveyor for receiving sheets from said first conveyor, said second conveyor having periodically operated means thereon for grasping and pulling forward the leading end of each sheet while permitting the trailing end of the sheet to sag downwardly appreciably, and a third conveyor partially overlapping the second conveyor and disposed substantially below the level of the sheet-grasping means for receiving sheets released by the sheet-grasping means at the forward end of the sEcond conveyor, said third conveyor being driven to forward sheets at a speed which is appreciably lower than the sheet-forwarding speed of the first and second conveyors, whereby there is formed on the third conveyor a stream of overlapped sheets in shingled relationship with the leading end of each sheet lying above the trailing end of the previously fed sheet.

Claim 3

Sheet-handling apparatus according to claim 1, wherein the first conveyor comprises opposed synchronously driven belts with opposed sheet-engaging runs, the ends of the belts rearwardly of said runs being appreciably spaced from each other, and the nip-forming means comprises means for pressing the opposed runs of the belts toward each other at a location forwardly of the rear ends of the belts.

Claim 4

Sheet-handling apparatus according to claim 2, wherein the nip-forming means comprises opposed rolls disposed with their axes transverse to the lengths of the opposed sheet-engaging runs of the belts, said rolls engaging the surfaces of the respective belts which are opposite the sheet-engaging surfaces thereof.

Claim 5

Sheet-handling apparatus according to claim 1, wherein the second conveyor comprises a belt having said sheet-grasping means thereon at one zone thereof, and comprising drive means for the belt which positively maintains it in synchronism and in phase with the sheet-delivering and the first conveyor.

Claim 6

Sheet-handling apparatus according to claim 4, wherein the belt of the second conveyor has spaced cogs thereon, and comprising sprockets which mate with said cogs over which the belt is entrained, and wherein the means to drive said belt comprises means for driving at least one of said sprockets.

Claim 7

Sheet-handling apparatus according to claim 4, comprising means for selectively disconnecting the drive means for the belt of the second conveyor, whereby to permit the adjustment of the position of the sheet-grasping means thereon relative to the sheet-delivering means.

Claim 8

Sheet-handling apparatus according to claim 1, wherein the second conveyor comprises an elongated vacuum chamber extending along and above the path of travel of the sheets, said vacuum chamber having a hollow body with spaced side and end walls forming an enclosure with an open lower end, and a belt having a longitudinally extending run thereof bridging and substantially closing the lower end of the vacuum chamber, the belt being driven so that said run of the belt travels downstream, wherein said sheet-grasping means comprises at least one opening through the belt providing communication between the interior of the vacuum chamber and the underside of said run of the belt, and comprising means to subject the interior of the vacuum chamber to reduced pressure.

Claim 9

Sheet-handling apparatus according to claim 7, comprising drive means for the belt of the second conveyor which positively maintains said belt in synchronism and in phase with the sheet-delivering and the first conveyor.

Claim 10

Sheet-handling apparatus according to claim 8, wherein the belt has spaced cogs thereon and said drive means comprises sprockets which mate with said cogs over which the belt is entrained.

Claim 11

Sheet-handling apparatus according to claim 9, wherein the cogs on the belt are on the surface thereof which is opposite its sheet engaging surface.

Claim 12

Sheet-handling apparatus according to claim 7, comprising means for adjusting the length of the path through which the sheet-grasping means is operative to retain the forward end of a sheet being fed thereby.

Claim 13

Sheet-handling apparatus according to claim 11, wherein the means for adjusting the length of the path through which the sheet-grasping means is operative comprises means forming a transverse partition closing the forward end of the vacuum chamber, and means to adjust said partition longitudinally of the main body of the vacuum chamber.

Claim 14

Sheet-handling apparatus according to claim 7, comprising a plurality of similar generally parallel vacuum chambers each having a belt cooperatinG therewith, and comprising means mounting the vacuum chambers and belts for adjustment laterally toward and away from each other to accommodate the apparatus to the handling of sheets of different widths.

Claim 15

Sheet-handling means according to claim 13, wherein the means for mounting the vacuum chambers is so constructed and arranged as to permit the laterally outer vacuum chambers and belts to be adjusted so that they diverge in a downstream direction, whereby the forward ends of sheets fed by the belts may be laterally tensioned by the laterally outer belts.

Claim 16

Sheet-handling apparatus according to claim 1, wherein the third conveyor comprises means at its forward end for supporting the overlapped sheets while they continue to travel, and at least one drop roll disposed above the supporting means selectively to form a nip therewith, and means periodically to raise the drop roll from engagement with the overlapped sheets as they travel therepast and to lower the drop roll into engagement with such sheets.

Claim 17

Sheet-handling apparatus according to claim 15, wherein the means to raise and lower the drop roll comprises means to lower the drop roll into momentary engagement with the leading edge of each sheet as it travels therepast, to raise the drop roll from the sheet immediately thereafter, shortly thereafter again to lower the drop roll into momentary engagement with the sheet, and thereafter to raise the drop roll until the leading edge of the next successive sheet is presented thereunder, whereby to eliminate wrinkles from the sheets.

Claim 18

Sheet-handling apparatus according to claim 16, wherein the means to raise and lower the drop roll comprises cam means driven in synchronism with the third conveyor, cam follower means connected to the means mounting the drop roll, the cam and cam follower means cooperating to raise the drop roll, and spring means retaining the cam follower means in engagement with the cam and periodically advancing the drop roll toward said sheet-supporting means.

Claim 19

Apparatus for handling sheets, comprising a first, higher speed conveyor, means on the first conveyor for grasping and holding elevated the leading end of a sheet and pulling the sheet forward by its leading end, a second, lower speed conveyor disposed below the first conveyor, the second conveyor being so spaced vertically from the first conveyor that the trailing end of the sheet is supported by the second conveyor, means for releasing the sheet from the first conveyor and depositing the sheet upon the second conveyor after at least the leading end and a substantial part of the intermediate portion of the sheet overlie the second conveyor, and means for slowing down the released sheet to the speed of the second conveyor, said last-named means comprising at least one drop roll cooperating with the second conveyor and drop roll controlling means including means for periodically first raising the drop roll to receive the leading end of the sheet between it and the second conveyor and means for thereafter lowering the drop roll into engagement with the sheet closely adjacent its leading end.

Claim 20

Apparatus for handling sheets, comprising a first, higher speed conveyor, means on the first conveyor for grasping and holding elevated the leading end of a sheet and pulling the sheet forward by its leading end, a second, lower speed conveyor disposed below the first conveyor, the second conveyor being so spaced vertically from the first conveyor that the trailing end of the sheet is supported by the second conveyor, means for releasing the sheet from the first conveyor and depositing the sheet upon the second conveyor after at least the leading end and a substantial part of the intermediate portion of the sheet overlie the second conveyor, and means for slowing down the released sheet to the speed of the second conveyor, said last-named means comprising at least one drop roll cooperating with the second conveyor and drop roll controlling means including means for periodically first raising the drop roll to receive the leading end of the sheet between it and the second conveyor and means for thereafter lowering the drop roll into engagement with the sheet closely adjacent its leading end.

Claim 21

Apparatus according to claim 18, wherein the drop roll controlling means comprises means for again raising the drop roll after its initial engagement with the sheet and thereafter again lowering the roll and maintaining it in engagement with the intermediate portion of the sheet for a substantial time.

Claim 22

Apparatus for handling sheets, comprising a first, higher speed conveyor for forwarding a plurality of sheets in flat condition in spaced relationship, a second conveyor travelling at substantially the speed of the first conveyor receiving sheets in sequence from the first conveyor, means on the second conveyor for grasping and holding elevated the leading ends of the sheets as they are presented to the second conveyor and pulling successive sheets forward by their leading ends, a third, lower speed conveyor disposed below the second conveyor, the third conveyor being so spaced vertically from the second conveyor that the trailing end of each grasped sheet is supported by the third conveyor, means for releasing the leading end of each sheet from the second conveyor and depositing it upon the third conveyor after a substantial part of the sheet overlies the third conveyor, so as to form a shingled stream of sheets on the third conveyor wherein the leading end of each sheet as released overlies the trailing end of each previously released sheet, means including a drum at the forward end of the third conveyor for turning over the shingled stream of sheets, and means for slowing down each sheet last deposited on said shingled stream to the speed of the shingled stream of sheets, said last-named means comprising at least one drop roll overlying the turnover drum and drop roll controlling means including means for periodically first raising the drop roll to receive the leading end of the last-deposited sheet therebeneath and means for thereafter lowering the drop roll into engagement with the last-deposited sheet closely adjacent its leading end.

Claim 23

Apparatus for handling sheets, comprising a first, higher speed conveyor for forwarding a plurality of sheets in flat condition in spaced relationship, a second conveyor travelling at substantially the speed of the first conveyor receiving sheets in sequence from the first conveyor, means on the second conveyor for grasping and holding elevated the leading ends of the sheets as they are presented to the second conveyor and pulling successive sheets forward by their leading ends, a third, lower speed conveyor disposed below the second conveyor, the third conveyor being so spaced vertically from the second conveyor that the trailing end of each grasped sheet is supported by the third conveyor, means for releasing the leading end of each sheet from the second conveyor and depositing it upon the third conveyor after a substantial part of the sheet overlies the third conveyor, so as to form a shingled stream of sheets on the third conveyor wherein the leading end of each sheet as released overlies the trailing end of each previously released sheet, means including a drum at the forward end of the third conveyor for turning over the shingled stream of sheets, and means for slowing down each sheet last deposited on said shingled stream to the speed of the shingled stream of sheets, said last-named means comprising at least one drop roll overlying the turnover drum and drop roll controlling means including means for periodically first raising the drop roll to receive the leading end of the last-deposited sheet therebeneath and means for thereafter lowering the drop roll into engagement with the last-deposited sheet closely adjacent its leading end.

Claim 24

Apparatus according to claim 20, wherein the drop roll controlling means comprises means for again raising the drop roll after its initial engagement with the last-deposited sheet and thereafter again lowering the roll and maintaining it in engagement with the last-deposited sheet for a substantial time whereby the shingled stream of sheets in its travel is pressed between the turnover drum and the drop roll.