US2940387A - Sheet delivery means for rotary printing press - Google Patents

Description

`)une 14, 1960 H. A. PRITCHARD SHEET DELIVERY MEANS FOR ROTARY PRINTING PRESS 2 Sheets-Sheet 1 Filed Aug. 2l, 1958 INVENTOR. Hon/AA20 Affe/ramen Arron/#Ey June 14, 1960 H. A. PRITCHARD 2,940,387

SHEET DELIVERY MEANS FOR ROTARY PRINTING PRESS 2 Sheets-Sheet 2 Filed Aug. 21, 1958 INVENTOR. /rowA/ao A faQ/ranma 56.3 .BY l

Arme/vs ys SHEET DELIVERY MEANS FOR ROTARY' PRINTING PRESS Howard A. Pritchard,Hiram, Ohio, assigner to Harrislntertype Corporation, Cleveland,.0hio, a corporation of Delaware Filed Aug. 21, 1958, Ser. No. 756,357

7 Claims. (Cl. 1131-133) This invention relates. to improvements in sheet delivery, i.e., delivery from a printing press. or other high speed sheet handling machine. In particular it relates to delivery from printing presses in whicha sheet is printed for each revolution of the impression cylinder of the press.

ln sheet fed pressesY it is common to take the sheets from the impression cylinder, which may be the last impression cylinder in the. case of a multi-unit press, by meansof a chain conveyor equipped with gripper assemlies which grip each sheetv as it leaves the. impression cylinder and carry the forward end over a delivery pile support, the grippers being opened at the proper time to deposit the sheet on the pile,

The delivery conveyor may comprise a. pair of sprockets over which the conveyor chains run, the arrangement being such that the gripper pads of the gripper assemblies move in a curved path that meets the surface of the impression cylinder. Heretofore the diameter of the delivery cylinder about which the gripper assemblies travel has been the' same as the diameter of the impression cylinder and these cylinders have been rotated one to one.

ln accordance with the present invention, the diameter oi the delivery cylinder isdouble that of the impression cylinder. A number of important advantages result from that relation.

The printed side of the sheet is toward the delivery cylinder. When the latter cylinder is the same size as the impression cylinder, the distance between the pointV where the front edge of the sheet passes through the line of print and the point where the front edge f the sheet moves tangentially away from the delivery cylinder as the chains move away from their sprockets is relatively short as compared tothe length of a full length sheet being printed. The gripping portions of the sheet grippers travel faster in the circular portion of their path about the delivery cylinder than after leaving the cylinder sprockets owing to the fact that pitch lines of the chain sprockets are smaller in diameter than the arcuate paths of the sheet gripping portions of the grippers and the sheet line. If this slower rate of travel begins before the rear edge `of the sheet passes the line of print, the reduced speed of the front edge, unaccompanied by a reduction of speed of the trailing edge, may permit the rear portion of the sheet to cling to the ink on the printing cylinder somewhat past theline of print, thereby causing the sheet to move relative to the surface ci' the delivery cylinder, resultingV in smudging of the printed image. if the delivery cylinder is positioned in a manner to avoid this eect the general design of the nted States Patent 0 siderably, but alsov adds, to the expense of the entire mechanism.

in contrast, when the delivery cylinder is of a diameter twice that ofA theimpression cylinders, as in thepresent invention, the diihcultis. experienced, as,` above noted, are avoided. Eventhoughthe sprocketsmay be made smaller in diameterA than the surfaceA of thedelivery cylthe tail end'of the -sheet will `still pass through the print line beforeV the frontend begins itstravel onthe straig'ritaway because of theA relatively long path around the double size delivery cylinder. Secondly, it isv not necessary to resort ,to sprocketshaving a. radius the same as that of the cylinder surface in order to avoid the speed change at the. time the front edge. of the sheet enters the straightaway, because with` the larger size delivery cylinder the speed' change will,r come after the teil end ofthe sheet passesthe line of print.

One object of the invention, Iktherefore, isthe provision or a. sheet delivery means wherein the delivery cylinder is twice the diameter of the impression cylinder, and a nih-surface delivery cylinder is., so. constructed as` to cause a minirnurnamount of oifsettiugand smudging of the printed' side ofthesheetwhich faces the cylinder.

Another object is` theY provision of asheet delivery in which marking.. or smudgingofthe sheets resulting from the change, of speedf of` the, sheet` as the forward edgeA thereof entersjhe straightaway` of the conveyor, is. avoided.

Another object is to. provide. a printing press delivery. having an endlesschain conveyor,- passing around. a; delivery cylinder of'tWice the diameter. of the impression, cylinder of the press, whereby the. full length of, the

sheet travels at printingspeed, throughout the, timeA thatVA the sheetis, being printedlby. the. impression cylinder and` its cooperating printing cylinder.

Another object is to permit` the use of,` delivery, cylinder sprockets of lesser diameter than the delivery cylinder diameter, without the, position of the delivery cylinder about its impressioncyl-inder being controlled by the length of the sheets, andwithout a change inI speedV between the leading andV tail. edges oi the sheet. while the sheet is undergoing printing.

An ancillary object, is topermit use. of, such sprockets. while still employing a cylinder. having, a., full, surface.

Still another object. is. the, provisionY oi' asheet deliveryY for a multicolor printing press. having double sizel transfer'cylinders in whichthe.4 delivery cylinder is the same size as the transfer cylinders and may. be mounted, in. the frame of the machine to bear the same relation tothe last impression cylinder as each transfer cylinder bears` to the preceding impression cylinder, thereby promoting efficiency and. economy in construction.

Other objects and features of novelty will appear as l proceed with the description of that embodimentV of the invention, which, for the purposes, of the present application, I' have, illustrated in the. accompanying drawings, in which: v

Fig. 1 -is a sidev elevation of a multicolor offset printing press equipped with ak sheet;l delivery constructed in accordance with the invention;

Fig. 2 is a 4fragmental, elevational view on a larger scale showing the delivery cylinder and chain conveyor,v

the View being taken substantially on the line 2-2 of carrying bearings for shafts 13, '.14 and 15 upon which are mounted plate, blanket and impression cylinders 16,V v

'17 and 13 of conventional form, each of these cylindersY being of the Ysame size, as isthe usual practice. Each unit -is .alsoprovidedwith dampening means 19 and 111king means 20fof conventional character.

secutive printing units there ,are positioned additional frame members 21 vin which are carried bearings for shafts 22 thatrsupport transfer cylinders 23 of double the sizeof the impression cylinders 18. VEach of the Y YBetween the V'side Yframe members 11 and 12 'ofy con- I transfer cylinders'ZSV has tworsets of diametrically op- Y positely positioned grippers 24. v The grippers 24 are, of course, adapted to take sheetsfrom'one impression cylinder 18 and transfer them tothe grippers 25 of the next impression cylinder. The shafts 22 of the various Vunits, arerdsposed'in a common horizontal plane, V,and the same cylinders. Preferably the plane of shafts is somewhat Y, above that of the shafts 22." The machine as thus far described isjwell' known inthe art.-

'The sheet delivery'of the'present invention'departs ,fromV Ythe'onventional sheet' delivery. Itv comprises in its pre'- ferred form frame members 21', similar in al1 essential respects'to the framemembers V21 for the ,transferlcylin- Y ders. These frame members 21"'contain bearings -for a shaft r2.2IV I that lis similar to the shafts 22 and is inthe same horizontalplane with shafts 22. ".The shaft 22 therefore bears the same relationshipY to the shaft 15 of the last im#V pression'cylinderas Yeach shaft 22 of a transfer cylinder bears tothe shaft 15 of the last Vpreceding impression forward edge will be slowing'down somewhat as'it leaves its curved path around the delivery cylinder, thatcondition comes too late'to affect the printing, and no marking or smudging occurs. Y

Having thus describedmy invention, I claim:

l. In a sheet fed printingpress, in combination, ian im- Vand a delivery cylinder with which the impression cylinder cooperates having sprockets around which the end- ,I less conveyor and its grippery assemblies travel, saiddething is; true 'of thershafts 15 of thervarious impression livery'cylinder lbeing oftwice the diameter of the m- V'pression'eylinder and the distance along the sheet path between the Vpoint at whichth'e endless conveyor leaves the'delivery cylinderrand the line' of print between the impression and printing Ycylinders being greater than the length of thernaximum size sheet to be handled by 'the Y press,whereby Vthe tailof a sheet willkhave passed the line of print beforelthe'g pper 'assembly kholding its lead- Y Y ing edge has left the delivery cylinder.

' 2. YIn a.pri11tin'g"press, V a"printing unit embodying an Aimpression cylinder adapted to receive a'sheet.- for each revolution'thereof and carry 'it through a printing station, and delivery means for receiving sheets from the im- -V pression cylinder comprising a sheet delivery'cylinde'r in cylinder. The,construction and erection of the completeV Y machine is thereby simplified, and the cost maintained Y proportionately low.

' On theV shaft 2 2 there ismounted a deliveryicylinder Y or Ydrum 26,',which may have a continuous surface 'rather thanone made up'of a series of disks with' sharp teeth to' berpresented `to the sheets, as Iis common where the transferring relation with Ythefirnpression cylinder andv of a diameter Vwhich is a nftultipleV of the'diameter of said impression cylinder, sprockets turning with said delivery Y cylinder, anrendless conveyorV comprising chains-running n on said sprockets, and a plurality of gripper'v assemblies delivery cylinder is of the same sizeras theimpression Y cylinders; The Vdrum '26 is, of course, keyed to the shaft '22.` It is driven by gear 27 on the last impression cylin'- Y der 18, the teeth of which mesh with the teeth of aY gear 2,8 on the shaft Z2'. On the shaft 22' there are also Ytwo sprockets 29 disposed laterally outward from the bearers 30 on the impression cylinder. Over these sprockets 29 there'run two chains 31 constituting the side elements of f an endless conveyor driven lby the rotating sprockets 29.

The lchains run substantiallyV horizontally over a delivery pile support 40 to deposit sheets thereon in the usual manner. Connecting the side chains 31 there are a series of gripper assemblies, generally designated 32,' each assembly comprising a rod 33 carrying arseries of grippers 34 Yand a rod 35 carrying a like number of, gripper pads 36. Each rod 33Vis rockedby an arm 37, the free end j of which carries a small wheel or roller 38 that isadapted torrengage a fixed cam 39,-whichjcontrolsropening and closing ofthe grippers 34. The cam 39 is, of course, so

located as to enable each set of the delivery grippersV 34 in turn to accepta sheet from the grippers 25 on the impression cylinder when the latter come into transferring position, that is, whenever theycross the plane con- Y necting the two shafts 1'5 andr22.

VThe line ofrprnt between the blanketfand impression cylinders of the ,last unit isindicatedzat P inrFig. 1. "The line at'which the front edge of.` a sheet," after'being im-Y printed, leaves the curved surface ofthe delivery cylinder Iand starts on -what may be termed the straightawayV p 'of the conveyonl is indicated-at S. The distance between these two points along y,the curved path which the sheet must' travel is considerably greater than the length of a sheet which canbe printed onrthe working surface of theY impression cylinderl 18. :This Vinsures thatY theftailV 1 end of the'sheet have Vpassedthrough the line of print P considerablybefore the Vforward edge passes through'V the points.` Hence, although the travel of the carried by said chains, said gripper assemblies being spaced `apart a distance corresponding with the Vcircumference ofthe impression cylinder and leaving said sprockets at a predetermined position to move the sheet from the delivery cylinder, the distance along'the sheet path from the print lineY at said printing station to the point at'which said gripper assemblies leave their sprockets being at least as great as the maximum size sheet to be handled by the press.

3. In a printing press, the structure a's defined in claim 'V2 wherein'said cylinder is a solid surface cylinder.

4. The- -invention set forth in claim 1 wherein the pitch line radiusA of the sprockets is Vless than the radius of the delivery cylinder. r Y

. 5. In a'sheet fed'printing press, in combination, a plurality of same size impressionV cylinders each'having a Yset of sheet grippersand a gap and adapted to receive Asheets on yan impression surface extending from the grip- Y pers around the cylinder'to the gap, a transfer cylinder cooperating with and located between successive impres# Vslon cylinders," said'transfer-cylinders being twice Ythe diameter of the impression cylinders and each of said transfer cylinders having two `sets of gppers spaced 180 Y apart thereon, a printing cylinder cooperating withfeach impression cylinder, Vanddelivery meansv comprising an endless conveyor -for taking sheets from-the last impression cylinder. and transferring them to a delivery pile support and vfurther comprising a' delivery cylinder ofthe sames1zeV as Vthe transferycylindersand havingssprocrkets at its ends about'which. the endless conveyor travels,land

4, said endless conveyor carryingfgrippervassemblies for receiving sheets from thelast impression Acylinder and coni Y veying .them ,forward at printing speed throughout the timethat the sheets are ,beingprnted by the last impressioncylinder, the Vdistance along the sheet path betweenl Ythe point atV which 4said, endless,A conveyor leaves the delivery cylinder and the line'vofprint between the last impression' and Y.printingcylinders being greater. than the length of the maximum lsize sheet to be handled by the s press, whereby the tail of the sheet will have passed said line of print before the gripper assembly holding its leading edge has left the delivery cylinder.

6. The invention set forth in claim 5 Vwherein the delivery cylinder is disposed in the same relation to the last impression cylinder as each transfer cylinder is to its preceding impression cylinder.

7. The invention set forth in claim 5 wherein the axes of the transfer and delivery cylinders are all in the same horizontal plane and the distance between the delivery cylinder and the next adjacent transfer cylinder equal to the distance between successive transfer cylinders, and wherein the axes of the impression cylinders are al1 located in a common horizontal plane.

References Cited in the le of this patent UNITED STATES PATENTS 1,875,869 Hense Sept. 6, 1932 2,002,814 Harrold May 28, 1935 2,554,904 Harrold May 29, 1951

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