[1]2 2 6 9 9 @ 1 1 5 United States Patent Office Patented Jan. 11, 1955 2,699,115 5 ROTARY OFFSET PRINTING PRESS WITH GRIPPER CAGES WiDiam W. Davidson, Jr., Evanston, DI. Application May 2, 1950, Serial No. 159,591 10 18 Claims. (Cl. 101- 232) Rotary lithographic presses of old usuauy included 15 three cylinders, namely, a plate roll, a blanket roll and a platen rofl. The plate roll carried the plate which was dampe ned and inked by running past dampening and inking rolls, and then printed the image on a blanket on the blanket roll. The blanket then printed the image 20 on the sheet being printed while it was backed up by the platen roll. Twocylinder lithographic presses have been known for many years and have recently met with considerable favor. In these the plate and platen are on opposite sides 25 of one large drum. The blanket roll, of half this size, makes a first revolution against the plate to receive the ink image, its next revolution rolling against the platen to print a sheet which pasges between thern. For dependable quality, this form of tw o-cylinder 30 press requires a gripper bar to pass through the bite between the drums at the correct time to carry the sheet into the desired registration with the blanket during its printin g revolution. Various rneans for accomplishing thig have been used. When the gripper bar is mounted 35 on the blanket roll it is of no aid in stripping the sheet from the blanket. When it is mounted on the large drum, it is of no aid in stripping from that drum if that drum is occasionally used for direct printing of the sheets, and other fatilts are encountered in any event. Chain-car- 40 ried grippers have been used, but chams are noisy, egpeciall y after wear, wear the sprockets, change their own length with wear, present registration difficulties in some instances, and have other faults. Accor ding to the present invention, the gripper bar is 45 carrie d through the printing bite and away from both rollg by a rotary rigid cage including a pair of rims or rings lying just beyoiid the ends of the blanket roll and having a larger diameter. Such rings run quietly, substantial ly without wear or other change, may be timed 50 accura tely by direct gearing and have other advantages. Some advantageg flow from the fact that the rigidity and constancy of the gripper cage permit feeding the sheet to the grippers at a point remote from the bite and spaced from both rolls. This in turn has two qtiite 55 differe nt advantages: (a) The registration feed roll mechanism can be simplified because the increased room availa ble for it peri-nits the use of one or more large feed rolls or segments of rolls, and (b) The accegsibility of the cylinders for washing and other servicing can be in- 6ocreased. The axis of the blanket drum necessarilk passes through the circle surrounded by the rim peripherieg. This necessarily poses a problem of motinting and driving the blanket drum. Two solutions have been shown, 65 though others as well as various combinations of these two will readily suggest themseives. According to one, the rims are carried by hubs at their centers, running on stationary stiib shafts, the inner ends of which shafts are extended inwardly to form a solid stationary bracket be- 7o tween the rings. The blanket drum is rotatably supported by arms extending from this bracket and driven through one of these arms from a gear carried by the hlib of one of the rings. According to the other solution shown, the rims are mere annular or hubless rings 75 rotatably carried by peripheral bearing wheels. The usual support and drive for the blanket drum extends through the center hole in the ring. Additional objects and advantages of the invention will be apparent from the following description and from 80 thedrawings. 2 Designation of figures Figure I is a soniewhat diagrammatic, vertical, sectional view taken longitudinauy through one form of the press chosen for iflustration, Figure 2 is a plan view, partly broken away, of the structure seen in Figure 1, Figure 3 is a fragmentary, horizontal sectional view taken approximately on the irregular line 3-3 of Figure 1, Figure 4 is a fragmentary, somewhat diagrammatic vertical sectional view taken approxhnately on the line 4-4 of Figure 3, showing also the use of a second gripper unit, Figure 5 is a somewhat diagrammatic detail view showin one form of the drive for the feed roH mechanism, 9 Figure 5-A is a diagrammatic representation of a modified arrangement of the parts especially suitable for a table model, and Figures 6 and 7 are fragmentary diagrammatic viewg of a modified form of the invention, showing respectively a vertical longitudinal section and a plan view with parts removed for clarity. Although the law requires a full and exact description of at least one form of the invention, such as that which follows, it is, of course, the purpose of a patent to cover each new inventive concept therein, no matter how it may later be disguiged by variations in form or additions of further improvements; and the appended claims are intended to accomplish this purpose by particularly pointing out the parts, improvements or combinations in which the inventive concepts are found. General description The presses of the present invention include two pregs cylinders 11 and 12, the cylinder 12 being twice as large as the cylinder 11. The cylinder 12 includes a platecarrying portion 13 and a platen portion 14 which roll against the cylinder 11 during successive revolutions thereof. The cylinder 11 has a blanket 16 (Figs. I and 4) which receiveg an ink impression from plate 17 on the platecarrying portion 13 of cylinder 12 and in turn applies this ink impression to a sheet to be printed, backed up by the platen portion 14. The sheet is delivered to the cylinders with proper timing by a gripper unit 18 carried by a cage 20, which in Figs. I to 4 includes wheels or rims 19 at opposite sides of the press. The sheets are successively fed to the gripper -units 18 byregistration feed unit 21. Dampening fluid and ink are successively applied to the plate 17 by dampener assembly 22 and inker asgembly 23. Cam 100 prevents their engaging platen 14. The registration feed roR unit 21, the cage 20, the blanket cylinder 11, the plate and platen cylinder 12, and the dampening and inking assemblies are all driven in timed relationship by means which include gears between the various main rotating elements. The present invention is particularly concerned with the cage structure carrying grippers 18, with the regigtration feed roll unit 21, and with the over-all arrangement of the several elements to provide ready accessibility to all necessary parts of the press. Gripper bar carrier A feature of the present invention is that the gripper 18 rigidly revolves around the blanket cylinder 11, following an orbit larger than the blanket cylinder, so that it may feed the sheet to and strip it from the blanket cylinder. By the expression "rigidly revolving" is meant that the gripper is part of a rigid cage rotating about a fixed axis so that the action of the gripper may be accurately predetermined. Heretofore, grippers which passed around the axis of the ink-applying cylinder have either been carried directly by the cylinder so that they could perform no feeding or stripping ftinction, or they have been carried by chains with the result that their positioning from time to time was not certain to be invariable and various expedients had to be resorted to to obtain reasonably accurate registration of the sheets with the printing cylinders. In the form of the invention shown particularly in Figs. I to 4, the gripper IS is carried by wheels 19, each of
[2]2,699,115 3 which rotates about a stationary stub shaft 26. The stub shafts are rigidly secured to frame members 27, which rnay be either part of the main press frame or an attachmeiit secured thereto. Two metliods of sectirijig the stub shafts 26 have been iil,,israted in Fi.-. 3. At 5 the upper part of the figure, the stub shaft 26 Iias been shon@,n with a flattened portion 23. Such flattened po,-- tions would be provided on the upper and lower portions of the shaft 26 so that !he shaft covld be c,-.n-,ped to a flal seat on frame member 27. Stich clamping 10 could be accomplished eitlier by bolts 29 passing through the shaft 26 or by a claiiip plate engagin.- t(ie tiliper flattened portion of the sbaft. At the bottoiii portion of Fig. 3, the shaft 26 has been shown as having a si)iined en.-agement with the frame member 27. The splin,'@ng 15 gives greater certainty of the absolute ang@,itar rigi@ity reqtiired and is the preferred foriii at present. The wheel 19 sliown it the lower portion of Fig. 3 is provided with gear teeth 31 which mesh mith Pear 32, which is the main -ear for the large cyl;iider 12. 20 Tlius the wheel 19 with its teeth may be deemed a ge.@r having the same number of teeth and the same pitc,i diameter as the gear 32 so tiiat the two rotate coiistantly at a 1:1 ratio. The far ,@,beel 19 rotales with the gepr wheel '@9, being rigidly coiinected thereto tlirotizli 25 the bar 34 of gripper unit 13 and a second bar 33. The second bar 33 may be a gripper unit like the gripper uiii@ 18 and in sonie forms of the invent;on this may be q,,!- @'te advanta-eous. In the simplest for-tns of the invention, howe@,er, there will be o,.ily oiie grid er unit 18 and the 30 bar 33 Id be merely a brace to help epsure rig:idity of wou th,- g,ipper cage. It will be observed that the two wheels 19, to,-ether with the bar 33 and the bar portion 34 of gripper unit 18, compris,- a rigid rotating cage similar to a squirrel cage. 35 It may be noted at this point that the gripper unit itself is reasonably conventional. li-i addition to the main bar portion 34, it includes a shaft 36 (Fig. 4) whicli car@- ies ,@ripper fin,-Crs 37 and is rocked by crank arm 38 (Fig. 3) carryin.- a cam follower roller 39. Gripper cams 41 40 and 42 opeli the gripper fingers 37 at the desired times and permit them to close under influence of a spring, not shown. Arm 38 may trail and be pushed out by siiitable cams instead of leading and being ptished in by cams 41 and 42, as illustrated. 45 Moit7iti7ig of bleiiilcet cyliizdeiWhen a gripper cage is provided which rotates on stub shafts 26 as in the form of invention in Figs. 1 to 4, it is impossible to extend a shaft for blanket cylinder 50 11 to the main frame members. Accordin,-Iy stub shafts 26 carry bracket arms 43 and 44 integrally connected together by the main carryin.- bracket 46. Preferably the niain carryina brack-et 46, bracket arms 43 and 44, and stub shafts 26 form one castin.- or at least one unitaiy 55 rigid structure so that the stub shafts 26 are not cantilever shafts but are part of a beam structure extending between opposite frame membei-s 27. A shaft 48 for the blanket cylinder 11 is joui-naled iii bracket arms 43 and 4A. Blanket cylinder 11 is keyed ro to shaft 43. At the end of shaft 43 extending througl-i bi-acket arm 44, a p;nion 49 is keyed to the shaft 4@9. This p:nion 49 is driven by pinion 51 carried on aiid keyed to the hub of gear wheel 19. The drive between piniotis 51 and 49 is indirect, throu-,h arl idler pinion 52, as seen r best in Fig. 4. Thus the cyliiider 11 rotates in 'Lhe same direction as the gear wheel 19. The pinion St has twice the number of teeth and twice the pitch diameter as pinion 49 ajid the pinion 51 turns with gear 31 ivhich, as previously st,,ited, turns 1: I with gear 32 and 70 hence the cylinder 11 makes two revoltitions for eacii revolution of cylinder 12. Aligiii2iei7t, pi-essiti-e aiid tlii-oivout pi-ovisioiis A printing press should have -,iii adjustment for aligning 75 the axes of its cylinders to provide uniform printing pressure across the width of the cylinders. It should also have -,in adjti@tment of oiie cylinder toward the other for adjusting the an-,otnt of this iiniform pressure. The means for providin- this latteradi,,istment m,@Ly be a pai-t 80 I of the mechanism used in separating the cylinders whenever a sheet is s](ipped so that ttie blanket NN,ill not print onto the bare platen siirface. In the form of press shown in Figs. 1 to 4, all of these adjustments have been provided in connection with the lar,-e cylilider 12. It 85 4 is not necessary to describe these in detail because the mountiiig could be such as provided in many prior presses. To indicate one 'Lype of known mounting coritemplated, a brief description may be' desirable. An eCCeDtricallybored bushing 56 may be turned to provide the alignment adj@Listinent. This does not shift 'che axis of gear 32 i,otatin.@ on the outside of this bushing and hence gear 32 always meshes properly with gear 31 on wheel 19 and other meshiii- gears. Turnin- bushing 56 does, liowever, shift one end of shaft 57 to prodtice the aligning adjustment. Shalt 57 does not rotate wilh the cylinder 12 biit inay be rotated slightly by lever 58 to vary the spaciiig of ilie cylinders. A slight movement is enougfi for pressure adjustmeiit. A larger movemenl provides the throwout for separation of the cylinders in casc a sheet is skipped. (No attempt has been iiiade to shonv the exact de,-ree or angularity of eccentricily.) For exaniple, lever 58 may be slightly adjusted for presslire adjustment ard connected by linkage to suitab,e pla'Len throwo,,it and sheet sl@,ip detection means. The cylinder 12 is driveii by gear 32 throtigh any type of Oldham coupling, dia.-raminatically represented at 59. Ilrefe@-ably, the driven i-in,- 60 of the Oldl,,,,,i-ii coupling is adjustably connec'(cd to the end plate 61 of cylinder 12. Thus a bolt 62 iiiay extend tlirough an arcuate slot 63 in ring 60 and screw into the end plate 61. Ti.-fiteni,,ig the bolt 62 locks the cotipling ring 60 and the end plate 61 provides adjustment of the angtilar relationship between cyliliders It ,)nd 12. Tfiis adjlistme-tit vai-ies ttie position on the blaiiket of tl-lc imi)ression placed thereoii by the plate. I-Iejice t'iiis provides a head-mar,,in adjustment of the p,.inting on the sheet. The circumferent',al extent of the platen must be lodg enough to accommodate the desired len.-th c)f sheet, regardless of this adjustment. Hence with this type ofhead-margin adjtistment, it is desirable to have the platen somewhat Ion.-er th-cin the plate-carrying portion, the gripper i-init 18 while gripping the sheet lying entirely within the miniinum i-adius of the printiiig surface of blanket 16. The gripper bar 34 can have a lon,@er seat with a steeper slant than shown in Fig. 4 so the paper will extend back from a pont close to that radius. Preferably, a second slot 64 is pi-ovided in the di-iven ring 60 approximately diametrically opposite the slot 63. This permits shiftin.- the cylinder 12 180-degrees witli respect to gear 32 so as to caiise the plate to enea.-c the blanket cylinder 11 durin.@ the part of the cycle wlie,,i the platen would othera,ise have engaged it. Th,"s change may be desirable for direct lithograph or for letter-press printing, as described under the heading "Operation." Access to screw 62 may be facilitated by ircuate slot 65 in gear 32, Haizd ivheel In preparing for a press operation or in cleaning the press afterwards, it is desirable to be able to turn the press by hand. The form of the press thus far described does not have, in conjunction with the parts so far described, ,t rotating shaft extending throu,-h the frame on which a hand wheel can be mounted. However, another 1: I shaft (not shown) would be provided in this constructioii to mount a hand wheel and to operate throw-off mechanism represented by lever 58. A hand wheel could be mounted elsewhere, as by ,),3 using a rotating drive shaft, such as one carrying a small pinion iiieshi-@ig with gear 32 for drivin.- the Dress. For illtistratioii, a hand wheel 66 has been shown. Sh ie Ids Shields 67 and 68 are preferably provided to prevent accidents such as thrusting a fidger ahead of the rotatin.- bars 33 and 34. Shield 67 may be fixed, but shield 68 should be movable to afford @iccess to drum 11. Preferably a microswitch 69 breaks the eirciiit of the press driving motor whenever shield 68 is raised, to prevent operation of the press when shield 63 is open, except by hand wheel. Of course, gears and the like would also be shielded, as in common practice. Registr(itio7i leed roll iiiiit i An important feature of the present press is that the dependable uniformity of cooperation between the gripper unit 18, the blanket cylinder 11, and the plateplaten cylinder 12, together with the over-all arrange-
[3]5 ment of the several elements of the press, permits feeding the sheet to the gripper unit at a point substantially separated from the cylinder 11 as seen best in Figs. 1 and 2. This in turn permits some advantageous changes in the registration feed roll mechanism, chiefly because of the fact that space is plentiful. For example, the fi-,lal feeding of the sheet into the grippers may be accomplish,-d by a feed segme-.it 71, the length of which inay be adjustable, as illustrated, if desired. Thus the feed segment 71 may include an auxiliary portion 72 wliich is adjustable wi@h respect to the main or leading portion by means of a screw 73 operating through a slot in the main portion 71. Because the length of movement of the sheet under the control of the feed segment 71 is controlled by the length of this segment, no controlled operation of the pressure roller 74 to grip and release the sheet is required. Hence the pressure rolier 74 may be nominally stationary, being constantly urged toward segment 71. When segment 71 passes away f-rom roll 74, the latter moves only slightly, its support being limited in movement by a stop, the spacing as to segment 71 being adjustable. In practice, there would be a plurality of segments 71 across the width of the machine, each with its pressure roller 74, and all of which may be adjustable laterally across the width of the machine. The pressure rollers 74 may be mounted independently or on a common shaft. The sheets may be fed to the registration feed rolls in any suitable manner, as by a suction feeder, not shown, which delivers the sheets to a biased conveyor 76 which aligns the sheets by pressing them against a side guide 77 (Fig. 2) and with this alignment feeds the sheets to the bite between segmetits 71 and pressure rollers 74. The lateral registration of the sheet is acco-tnplished by the side guide 77. The longitudinal registration may be accomplished by using the bite just mentioned to stop the sheet at the desired position. Alternatively and perhaps with a little greater certainty of accuracy, the sheet could be stopped for longitudinal registration by stop fin.-ers 80 carried by the segments 71 or their shaft 79 and extending down beside pressure roller 74. These stops should come to rest just ahead of the bite between pressure rollers 74 and segments 71, so that the sheet can get to the stops. The sheet may be urged against the stops by driven rollers 78 against which it is pressed by marbles. Some such marbles may be positioned to bear on the tapes of conveyor 76. Shaft 79 may be driven in any suitable manner for giving it the required movement. This movement should include a smooth acceleration from its position at rest to a speed appropriate for feeding the sheet against the stop fingers 81 on the gripper bar assembly 18. The segments 71 should maintain a peripheral speed at least equal to the speed of the gripper bars until the trailing segment portions 72 have passed from pressure rollers 74 so as to release the sheet. For illustration, Figs. I and 2 show sectors 71 in the starting position or position of rest, although this is not in keeping with the positions of other parts of the press. One form of drive for feeder shaft 79 is seen in Fig. 5. A cam 82 carried by gear 32 operates a lever 83 which in turn operates a link or bar 84. Member 84 may merely be pivoted to a crank arm on shaft 79 or it may inc'ude a rack portion at its end, meshing with a piniop on shaft 79. The shape of cam 32 would be somewhat different in the two instances because of the varying mechani_ cal advantages in the case of the crank arm and the constant mechanical advantage in the case of the rack and pinion. No attempt has been made to show the exact cam shape for the illustrated form. It may be noted at this point that with the form of the invention shonvn in Figs. 6 and 7, where there are shafts extending through the frame, the cam 82 may be omitted, the member 84 being drive.Ti by a crank pin eccentrically positioned on the end of this shaft. In that event, however, it is not possible to have the driving niovement of the member 84 stop as abr,uptly as with a cam and hence a greater total movement of the segments 71 will need to be provided to allow a gradual slow-down after release of the sheet. The timing of the closing of the grippers can preferably be controlled as indicated diagrammatically by slide 84'. Delivery The gripper bar to which the sheet has thus been accurately fed will carry the sheet into registration with the 6 blanket cylinder 11. The gripper wiff maintain the grip on the sheet, however, and draw it away f-rom this drum. It may be found desirable to provide stripper guides 85, to help keep the sheet drawn out. In the form of the invention shown in Figs. I to 4, they may be carried by bracket arms 43 and 44. When the gripper bar has reached the desired position, preferably after stripping the en@ire sheet from the blanket, the follower roll.er 39 will encounter the cam 42 and open the grippers to re10 lease the sheet. Preferably the cam 42 is adjustable over a wide range as indicated by slide 85', to vary the titne of release. The sheet may then fall and slide by gravity into a pan 86 or other collecting or discharge means. One or more looselymounted rods 87 (Fig. 1) maybeprovided 15 for making sure that the sheets are not thrown past the collector 86. It will be observed that the sheet is thus delivered printed-side up, assuming that it was printed by the blanket cylinder 11 in an offset process. A perforated pipe 87' or a nozzle may direct compressed air 20 against the upper face of the sheet to help strip it and move it to collector 86. The connecting hose may pass through bore 101 (Fig. 4). If the sheet is printed by direct process so that the side faci-ti.- drum 14 is printed, it is preferably delivered 25 'to the collector 88 so as to have its printed side up in this instance. in this case, cam 41 which will have been removed or shifted axially from active position during offset printing, will be placed approximately as shown in Fig. 4, so as to release the sheet in time for it to pass 30 to the right of deflector 89 wllich in this instance will be shifted to the dotled line position seen in Fig. 1. Deflector 89 is notched to permit gripper fingers 37 to pass through it. A stripper 90 ensures the stripping of the sheet from the printing surface on cylinder 12. Preferably, draw35 off rolls 90' are provided, at least one of which is driven, to draw the sheet safely ftom the printing surface, once it has entered the bite betwee-,i these draw-off rolls. With letter-press printing, there is usually nodifficulty in drawing the sheet from the type. With direct lithography, if 40 delivery ijito collector 88 should prove uncertain and therefore troublesome, cam 41 could be removed, deflector 89 shifted, and the sheet delivered into collector 86. In fact some models, esn,ecially table models, may be made with only collector 86. The only objection to 45 this would be that the printed face wotild be down, thus catisin.- sor@ic di.McL,.Ity of inspection. Alodif7cation with hitbless gripper cage 50 Figs. 6 and 7 diagrammatically represent a modified form of the invention in xvhich the gripper cage is of a b.ubless type and consists of the two rings 91 fastened together by tbc two bars 33 and 34. These rings 91 are in turn carried by peripheral type rotary bearing units 55 92 which consist of free turning wheels, the peripheries of which are shaped to hold, both radially and axially, the peripheries of tie rings 91. Each of them is mounted on a stub shaft rigidly held in frame 27. There are three of t@.ese bearin.- un;ts 92 for eacli of the rings 91. At 60 Icast one of each group of the bearing wheels rotates on an eccentricaliv adiustable hub for adjustment of the tightness with which tie wheels fit the rings 91. If at least two bearing wheels of each group are provided with s.iiftable Pxes, they may b-. used for accurately position65 ing rings 91. Tnstead of engaging t,-ic outside of rings 91, the bearing u.-iits 92 rqay engage the i-tisidp. edge, if preferred. With cilher of these arrapgements, the center of rings 91 may be left open so thgt a shaft 93 for blanket cyliider 11 70 -ay extend through the rings to frame members 27. This construction has soi--ne advantages over the constrlction of Figs. I to 4. For example, assembly may be some@,@ihat easier. Also the pi@oblem of obtaining s@ifflcient riaietity in tlie mounting of blanket cylinder 11 is 75 avoided, since it ca.n be mounted in substantially the usual way. In Pddition, cylinder 12 may be mounted on a rot-,iting si-iaft 94 which n-tay extend throaph the frame members 27 to provide hand wheel 96 at or,.e end and external cams and the like at the other end for actuating SO various other parts of the mechanism. The various adjustments and movements of one cylinder with respect to the other, together with the Oldb,,im coupling, may readily be applied to cylinder 11. This avoids any disturbances in ttie i-elationship between cylin7 85 der 12 and its inking and dampening assemblies. Cylin-
[4]7 der 11 is then driven by a gear 97 (through an Oldham coupling if the cylinder 11 is shiftable) which meshes with gear 32. The gear 32 is in this instance sufficiently wide to mesh also with gear ring 93 carried by the adjacent ring 91 of the gripper ca.-e. Of course two narrow 5 gears 32 could be provided in place of one wide gear. Figs. 6 and 7 are considerably simplified by the - omission of parts. For example, gripper opening cams 41 and 42 have been omitted for simplicity. In this instance, these cams could be carried directly by a frame member 27 10 by means of brackets extending in through a ring or rings 91. Alternatively, the shaft 36 which actuates the grippers or the crank arm 38 thereon could extend outside the gripper cage to be operated by cams outside of the cage. Space for this is most easily found on the side "5 remote ftom the gears, namely, the side at the top of Fig. 7. This would add torque drag at that side however, and is not preferred at present. Assenibly 20 The form of the invention shown in Figs. 6 and 7 needs very little discussion of the assembly except to note that the ca.-e 20 is put in place while some of the rollers 92 are removed and before the shaft 93 for cylinder 11 is - inserted. 2;) In the assembly of the form showii in Figs. I to 4, the cylinder 11 is mounted in bracket arms 43 and 44 before this unit is mounted on a frame. After insertion of shaft 43 and after mountin- of -ears 49 and 52, gear 30 wheel 19 is applied over one @'tub s'haft 26 and the other wheel 19 over the other stub shaft. The gripper carrying bar 34 and the bar 33 may previously have been rigidly secured to the gear wheel 19 and may now be sectired to the other wheel 19. Tiiis entire assembly is now secured - to the frames. If a splined connection of stub shaft 26 3, to the frame is used, the frame member on one side of the machine will have to be left unattached to the remainder of the frame until the splines have been slipped in place. Opel-atioil 40 Although the operation of the press will be relatively evident from the previous description, a brief - explanation of its operation may be helpfiil. In the case of offset printing, a properly etched or -10- otherwise treated plate 17 is applied to the plate-carrying portion 13 of cylinder 12. The press may be rotated with the main cylinders spaced apart until the plate is properly inkcd by running successively against the form rollers of the dampening and inking units 22 and 23. A @0 pile of sheets to be printed will have been placed on the primary feeder, not shown. When it is started, sheets will be delivered to conveyor board 76 in properly-timed relation to the operation of the press. The sheets will be laterally registered by side guides 77 and will come to 55 rest against stops 80 or the alternative stop means comprising the bite between segmer@ts 71 and pressure rollers 74. At the proper time during each cycle of the press, segment 71. will be pivoted by means of cam 82 in Fig. 5 and will feed the sheet into the gripper unit 18 as the 60 latter approaclies the uppermost portion of its orbit. Tfie gripper 18 will carry the sheet into the bite between cylinders 11 and 12. The sheet may be carried over guides (not sbown), if desired, but this is believed not necessary because the turning of the leading edge of the 05 sheet tends to bow the paper upwardly and avoid premature contact with cylinder 11. In the meantime, the blanket on cylinder 11 will have received an ink impression from plate 17 with whi@-h it will print the adjacent face of the sheet, the opposite face of the sheet supported 70 by platen 14. Cam 41 having been removed, the -,ripper will carry the leadiiig edge of the sheet to the far side of cage 20, sti-ipping the sheet from the blanket. Cam 42 will then re'lease gripper fingers 37 so that the sheet will be deposited in collector 86. 75 For direct printing with the same gripper unit 18 and the same timing of the feed of the sheet, screw 62 in Fig. 3 will be removed and cylinder 12 rotated approximately 180 de.@rees after which screw 62 will be replaced, this time passing through slot 64 instead of slot 63, from 80 which it was removed. The platen 14 with its cams 100 need not be totiched as the cams will throw the form rolls out as before. The offset plate 17 will be replaced with a direct lithograph plate or a suitable relief plate. When properly inked, it will print directly on the adia85 cent face of the sheet. Cam 41 in Fig. 4 will be applied so that the gripper will release the sheet in tirne for it to pass to the ri-ht of deflector 89 (swung to the dotted line position of Fig. 1) and it will be delivered to the collector 88 printed face up. Both portions of roll 12 may be used for direct printing if two gripper units IS are provided and a sheet fed to each, and no cams 100 used. Thus if two different direct plates are used, a two-page letter or form may be printed and collated. Additioital features aizd advantages Although, for purposes of simplification, the shaft 48 in Fig. 3 has been shown with a relatively simple type of mounting, it may, if preferred, have the more complex type of mounting illustrated for the shaft 57, the shaft then being stationary except for adjustment and throwout movements. This may be preferred in order to leave the cylinder 12 invariable as to its axis. The chief problem in providing the shaft 48 with the shiftable axis is to control said shaft. This can be accomplished, however, by providinr,, a bore 101 in one or both of stub shafts 26 through wliich a control member may be passed to operate gears or links for turning the shaft 48 for throwout atid pressure adjustment purposes. If the shaft 48 is to b-. shiftable, the gear 49 wotild be positioned between drum 11 and bracket 44, bCiDg carried on a bushing sim,@'lar to bushing 56 and being connected to the cylinder 11 through an Oldham coupling. Gear 49 would then be connected to gear 51 through a pair of gears on a common shaft, the common shaft passing through and bein-. journaled in bracket 44. It will be observed that with both ilIListrated forms of the invention, there is very little torque resisting the rotation of the ring 91 or wheel 19 more remote from the driving teeth 31 or gear 98. This torque is only the frictional torque of its mouiiting and the torque resulting from a part of the pull exerted on the sheet. It is believed therefore that providing sufficient rigidity in the cage 20 so that this wheel or ring will not appreciably la.- behind its more directly driven counterpart will present no problem. It may be noted, however, that, if found necessary, gears may be provided on both sides of the gripper cage. It will be observed that the upper portion of both cylinders 11 and 12 are thoroughly accessible with both illustrated forms of the press. This is a highly desirable feature because it facilitates cleaning and otherwise servicing the cylinders. It should be understood that with some types of short-run printing, it may be necessary to clean the blanket cylinder quite frequently and also to put on and take off plates frequently. The cylinders have been shown arranged with their axes approximately in a horizontal plane. This provides exceptionafly good accessibility from above. In addition, it facilitates moving the paper generally horizontally toward the press in the preliminary feeding without obstructing accessibility to the upper side of the blanket cylinder. Nevertheless it may be desirable in some instances to shift the relative positions of the axes. For example, raising the top of cylinder 11 to the level of the top of cylinder 12 as seen in Fi-. 5-A still affords equally good accessibility from above'while leaving more room for a collector below. This is especially suitable in the r-ase of a model designed to rest on a table. The axis of cylinder 11 can be raised to the level of the top of cylinder 11 without @-xcessively impairing access but must not be so high that the gripper cannot deliver the sheet reliably after stripping it. Accessibility is impaired somewhat as the axis of cylinder 11 is lowered below the level of the axis of cylinder 12, but the impairment is not too serious until the bottoni of the cylinder 11 is lower than the bottom of cylinder 12, The pile from which sheets are drawji may be positioned close to cylinder 11 as seen in Fig. 5-A. In that event, the feeder preferably delivers sheets to rollers 78 of the illustrated feed roll mechaiiism. 14-owever, the feed roll mechanism could be omitted with this type of press at least as well as witb otbcr presses, the iiiitial feeder then feediiig directly to the gripper unit 18. Although the cage has been illustrated as including bearing means at each end of the ca@e, it could at least in theory include a bearing means at 'one end of the cage only, the gripper bar extending from that end being unsupported at its far end. Likewise it may be observed
[5]2,699,115 9 that the bearing means at the two ends may be different. For example, the driven end of the cage may be in the form of a wheel supported by stationary stub shaft as in Fig. 3 while the support at -i-lic far end may be by an open-centered ring supported by peripheral rollers as in 5 Fig. 6. In that event, it will probably be sufficient for the peripheral rollers to give only radial support to the ring, not axial support. The term "printing press" is used in the accompanyin.- claims in its broad inherent sense, including all machines 10 making multiple copies by applying ink to sheets and is intended to include the smaller types of machines sornetimes called office duplicators as well as larger pri-@iting presses. Although the invention in its simplified form is especially suitable for office dtiplicators, it has im- 15 portant advantages, especially in more complex forins, for large printing presses. It will be understood that the press will be driven by a motor. Thus gear 32 may be driven by a pinion which may be dri-ven by a belt driven by the motor. 20 I
