US2387750A - Printing press - Google Patents

Description

Oct. 30, 1945.

W. W. DAVIDSON PRINTING PRESS Filed Aug. ll, 1941 12 Shegts-Sheet l INV ENT OR.

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PRINTING PRESS Filed Aug. 11, 1941 l2 Sheets-Sheet 2 Oct. 30, 1945. w. w. DAVIDSON 2,387,750

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PRINTING PRES 5 Filed Aug. 11, 1941 12 Sheets-Sheet 5 2V" /76 /77 /76 W /7.9 239 257 249 INVENTOR.

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PRINTING PRESS Filed Aug. 11, 1941 12 Shegts-Sheet 9 30/ d 32 23 234 30/ j/{g Q 4 30? 30 2 30% 25 0 26/ 252 WWW s m lllll IN VENTOR.

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Patented Oct 30, 1945 2,387,750 7 PRINTING mess -William Ward Davidson, Evanston, 111., to Davidson Manufacturing Corporatlo poratlon 0!,Illinois assignma cor- Application August 11, 1941, Serial No. 408,328 12 Claims. (Cl. 101217) .for lithographic offset printing, a plate is mounted on the plate segment, and during one-half the The subject matter of this invention is a twopurpose ,;duplicator capable of doing both direct and olfset printing. For direct printing, the raised type, or so-called "letterpress" process, is ordinarily used; and for offset printing, the lithographic process is-preferred.

Most, if not all, duplicators on the market before this invention were one-purpose machines. They could doetther letterpress printing, directly from a raised type plate to the. sheet being printed, or they could do oflsetlithographic work in which the positive image on the lithographic plate is first transferred to a rubber blanket and then to the sheet being printed. They cannot, however, do both direct and oflset printing.

The ofiset lithographic process is rapidly displacing direct letterpress printing for reasons unimportant here, but there are some printing jobs which, by reason of inherent limitations in the lithographic process, or because of cost, are '20,

almost necessarily performed bythe letterpress process. Printing just a few words in a blank left in'previously printed pamphlets, cartons, and the like is one such instance. This is called im- Large printing shops can afiord to have both but there is a large demand in smaller printing establishments, and in stores, manufacturing plants, business houses, and the like, for a sin- 0 gle, relatively small, moderately priced duplicator capable of doing quality printing by either the letterpress or lithographic processes.

vA two-purpose duplicator designed for and used tial elements and mechanisms of the machine that it is characterized by simplicity, ease of adjustment, convenience of operation, and the speed by which it can be converted from a direct printing letterpress machine to an offset lithographic 45 machine, and vice versa.

To achieve the broad objects of a two-purpose machine, the conventional employment of three printing cylinders is discarded, and, instead, only largely in this specialized field will, in most in- 35 revolution of the large drum the image is transferred tethe blanket, and during the next half revolution of the large drumrthe blanket transfers the image to thesheet being printed. To convert the machine into a direct-printing letterpress duplicator, the platen segment-is removed, and in its place a direct printing letterpress segment is substituted. The plate segment is removed from'the machine and, if ahard platen surface is required, it may be substituted for the blanket, or a steel cylinder may be substituted for the blanket cylinder. The dampening mechanism used when the machine is doing lithographic printing is constructed so that it is selfcontained and may be removed from the machine with little eflort. The entire conversion from lithographic printing to letterpress printing can minutes.

Provision is made so that the head margin for the printed sheet may be accurately determined, whether the duplicator be set for letterpress printing or lithographic printing. To this end, the two segments, carried by the large drum are made angularly adjustable, and means are provided so that their, position with respect to a fixed point on the drum may be accurately determined.

Another outstanding feature of this invention is the manner in which the sheets are fed to the bite of the printing rolls, registered with reference to the printing plate, and then delivered onto a pile with the printed side of the sheet facing up, regardless of whether the machine is doing letter-press printing or lithographic printing. Advantage is taken of the fact that the larger drum is exactly twice the size of the smaller drum, and a chain delivery is used employing but a single gripper bar which grips the sheet prior to the time that the sheet reaches the bite of the printing cylinders and carries it through the bite, stripping it from the ink-carrying transfer surface and finally delivering it to the catcher with the printed side of the sheet facing upwardly, where it may readilybe ,viewed by the machine operator. This positive handling of the sheet by a single set of grippers as the sheet passes through two cylinders are used, one being larger than the '50 the bite or the cylinders results in extremely acother and preferably having a diameter that is twice that of the smaller cylinder. The larger cylinder or drum is provided with removable plate and platensegments, while the smaller drum curate registration and dispenses with the usual set of grippers carried by one of the printing cylinders.

Ihe i throwout mechanismfor automatically carries a blanket. When the machine is-used *55 separating the printing cylinders whenever a be accomplished within the space of a very few sheet fails to reach the bite at the prescribed time is another novel feature of this invention. It is so constructed that it is quiet in operation and is characterized by its relative simplicity. A counter is associated with the throwout mechanism to count the sheets that are actually printed, but the counter is so arranged that the check for the presence of the sheet is completed before the sheet reaches the bite of the printing cylinders.

Provision is made for adjusting the parallelism between the two printing cylinders, and a simple micrometric or slow-motion adiustmentpermits the printing pressure to be accurately determined. The machine is sturdily built and, once these adiustments are made, will hold them over long periods of time.

The ink mechanism is constructed to effectively break up the ink and distribute it evenly over the printing plate. A novel ductor cutout makes it easier to avoid excess inking when the machine is running without supplying sheets and to clean For the most part, the drives for all moving parts of the machine are takenfrom the shaft of the larger drum, thereby facilitating manufacturing assembly and adjustment of the timing for the machine.

Considered as a whole, the machine is outstanding for its ability to perform quality printing by either the direct or offset methods, and many other objects and advantages will become apparent as the disclosure proceeds and a detailed description of the various parts of the machine is made with reference to the accompanying drawings, in which:

Figs. 1A and 1B are diagrammatic views of the press and conveyor table, respectively, arranged for offset lithographic printing.

Figs. 16 and ID are diagrammatic views of the press and conveyor table, respectively, arranged for direct letterpress printing.

Fig. 2A is a fragmentary perspective view of the preferred form of the press.

Fig. 2B is an exploded perspective view showing the sheet detector and counting actuator. In assembly, the sleeve I30 is carried by shaft I52.

Fig. 3A is a transverse generally vertical section taken approximately on the line 3A-3A of Fig. 1A.

Fig, 4A is a longitudinal vertical sectional view taken approximately on the line 4A-4A of Fig.

Fig. 5A is a view similar to Fig. 4A but taken about the middle of the press transversely, approximately on the line 5A-5A of Fig. 3A.

Fig. 6A is another vertical longitudinal sectional view, taken approximately on the line 6A-6A of Fig. 3A and showing diagrammatically, in a broken-away portion thereof, the feeder which is controlled through the controls shown in the main portion of the figure.

Fig. 6B is a fragmentary viewshowing the cutout position for ducking apparatus of the ink ductor roll.

Fig. 7A is a fragmentary detail view illustrating the platen throwout and counter mechanisms.

Fig. 7B is a view illustrating the independence of the feeler from the counter when no sheet is present.

Fig. 8A is a generally horizontal sectional view taken approximately on the line Oil-8A of Fig. 8B is a fragmentary view illustrating the adjustability of the main cylinder segments, the calibrations therefor, and the segment holding lock.

Fig. 8C is a detail sectional view taken through with a portion of the frame broken'away for the sake of clarity, the bottom of the figure being at diametrically through the main cylinder and illustrating particularly the means of securing the plate and platen segments thereto.

Figs. 11B and 11C are enlarged fragmentary cross-sectiona1 views showing the bite between the platen segment and the blanket roll, Fig. 11B showing the shims which are used between the platen sheet and the platen segment when a thin paper is being printed, and Fig. 110 showing the same parts without the shims when a thick paper is being printed.

Fig. 11D is a fragmentary sectional view showi'ng the interior of the main cylinder, the view being taken approximately on the line llD--l ID of Fig. 11A.

Fig. 12A is a chart illustrating the timing of the movement of the various parts of the press and showing .the position of each part at any given angular position of the main cylinder; the zero position being the position which it is in when the blanket and plate first come together.

The parts are not in the same positions in all of the figures.

At the outset, it should be understood that the invention may be embodied in many forms, but a preferred embodiment has been illustrated in the drawings and will hereinafter be described in detail.

Before considering the detailed structure of the machine, it will be helpful to refer, first, to the diagrammatic illustrations shown in Figs. 1A to 1D.

In Fig. 1A, the machine is shown set up for offset lithographic work, and in Fig. 10 the machine is shown set up for direct letterpress work. By considering the progress of a sheet of paper through each arrangement of the press and the timed relationship of the various parts Of the machine as they cooperate in applying the image to the sheet, it will be easier to understand the detailed description that follows.

Gnmuu. Oaosmzerrou A. Lithographic oflset priming (Fig. 1A)

Sheet A in Fig. 1A has just been printed, and sheet B is about to be lifted by the suction head of a feeder C, an intermediate sheet already being on a diagonal tape conveyor board D. Upon reaching therotatable stop fingers E, sheet B may be logged against a. side guide, against which it is also urged by the diagonal tape, to assure proper later position. At the same time, or shortly thereafter, a feeler finger F is moved toward the bite of the printing rolls to check that the sheet is in proper position. If for any reason the sheet is not there, the finger F will drop through a slot in the feed board and actuate an arm G, which functions to separate the printing rolls; but, if a sheet is present, it prevents the feeler finger F from dropping into the slot and the printing rolls are held in cooperative relationship. The same movement of the feeler finger F also operates a counter if a sheet is present. Otherwise, the counter is not actuated After the sheet has been brought into end registry with the stop fingers E and has been properly positioned laterally, as the feeler finger F makes its check, the upper of feed rolls H descends upon the sheet, grips it while the rolls are still stationary, and then cooperates with the lower feed roll to move the sheet toward the bite of the cylinders whilethe stop finger E is rotated out of the way.

During this process of bringing sheet B to the bite of the printing cylinders, the upper or larger cylinder I, which carries a plate J on one peripheral segment and a platen surface on another peripheral segment K, has been rotating to ink up the plate J, and apply the image to the blanket L carried on the smaller or lower cylinder M, where it is ready to be applied to the sheet when it reaches the bite of the printing cylinders, As will be seen by reference to Fig. 1A, the water form roller MS of the dampening unit N applies the dampening liquid to the plate J, and then the ink form rollers of the inking unit apply ink to the plate image. While sheet A is being carried to catcher? by gripper Q of the chain delivery mechanism and sheet B is being positioned by stop fingers E, plate J applies its lithographic image to the blanket L. On the next half revolution of the large drum 1, the gripper Q, actuated by a cam R,'releases the sheet A after turning it upside down around the drum-like assembly S, and thereupon proceeds around the blanket drum M to a position where it is again opened bya cam T to receive sheet B as it is fed forwardly toward the bite of the cylinders. The gripper Q then closes and grips the sheet to carry it through the bite, while the feed rollers H, which have been traveling at a peripheral speed slightly above the peripheral speed of the printing cylinders in order to insure proper registration of the sheet within the gripper Q, releases the sheet and the gripper carries the sheet through the bite and thence around the drumlike assembly S,where it is released into the catcher.

A suitable cam is provided along the margin of the platen segment K to lift the water form roller and the ink form rollers from the platen when it passes beneath these rollers, and it should be noted that during the period that the platen K is passing under the inking mechanism 0 the rollers of this mechanism are continually rotating to break upthe ink and replenish the ink on the ink form rollers for the next application of ink to the printing plate.

B. Letterpress printing (Fig. 10)

For direct printing, the platen segment K would be replaced by a direct printing element which in the illustrated form shown in Fig. 1C is a type-bearing segment U. It will be observed that this is put in the position of the platen rather than in the position of the plate so that it will co-act with the smaller lower cylinder at the time a sheet is fed thereto. In this instance the lower cylinder serves as a platen. In some instances its blanket may be used as a platen surface and in other instances it may be desirable to remove it and apply a harder surface.

When a typographic printing member, such as type segment U is used, no dampening is necessary and hence the dampening unit N of Fig. 1A may be omitted. The plate J will also be omitted and, if the segment bearing it is not also removed, the ink form rollers will be completely out of contact with this segment but will be allowed to come into contact with the type on the type segment U, which will then print directly on the upper surface of the sheet.

Since the upper surface of the sheet is printed, it is desirable to deliver the sheet to the collector P' without turning it over, so that the sheet may be inspected. To this end a special cam V is pro-. vided, as seen in Fig. 10, which opens the gripper Q approximately at the position thereof shown in Fig. 1C or shortly before reaching this posi tion. An ejector roller W is provided to cooperate with the drum-like wheels S to insure continued movement of the sheet A so that it is delivered into the collecting box P' or other suitable receiver. Of course, the collecting box P may be the same collecting box as that shown at P in Fig. 1A moved to a new position.

A modified form of the press for direct printing should also be mentioned. According to this form, the press will print two sheets for each revolution of the large cylinder, or, in other words, one sheet for each revolution of the small cylinder. This is accomplished by providing a direct printing plate or the like on each segment of the main cylinderv I, and modifying the feed and delivery mechanism to feed and deliver a sheet of paper for each plate. Thus, the blanket L would serve only as a platen or could be replaced by a platen. A second gripping unit would be provided in the chain delivery unit midway of the length of the chains from the grip ping unit Q. The cams at the margins of the plates would cause both plates to be inked and, if they were lithographic plates, to be dampened before inking. As each plate approached the platen roll M, a sheet would be fed to one of the grippers and carried by it to the bite where it would be printed by said plate. The sheets could be delivered to the same receptacle or to two different receptacles.

0. Combined offset and direct printing, front and back:

tive plate so that it would produce a negative image on the blanket L, which in turn would print a positive image on the underface of the sheet. The plate in place of the segment K would have a, negative image thereon 50 that it would print a positive image on the upper face of the sheet at the same time that the blanket prints the lower face thereof. Thus, the negative plate in place of the platen K would serve as the plat n for the blanket L, while the blanket would simultaneously serve as the platen for the negative plate. It should be observed that no change is necessary in the feeding or delivery for this arrangement. Of course, the dampening and inking form rollers would be permitted to contact both plates.

DETAILED DESCRIPTION From the foregoing description of the general organization of the press, it is believed that the general operation of the press will be sufliciently clear so that a. detailed description of the various parts may be readily understood.

Pan'rs B To D--PRELIMINARY FEEDING The sheets may be separated from one another by any desirable sheet separator. That which is partially illustrated is a suction feeder of a type which has been manufactured heretofore by the Davidson Manufacturing Corporation. The sheets are lifted up one by one by a suction nozzle H and fed to pull-out rolls l2, the lower of which is constantly driven and the upper of which is accurately positioned with respect to the lower roll by thumb nut I3. IA detector maybe provided for automatically deflecting the sheets from their normal course if more than one is fed at a time.

The entire sheet-separating unit i controlled by linkage I6 driven from a crank pin ll rotating rigidly with printing cylinder I so as to ensure accurate timing of the preliminary feed of the sheets with respect to the movement of the press. In the form of feeder illustrated, the feeder includes pile mechanism for automatically raising the pile of sheets B so that the top sheet thereof will always be at a level suitable for engagement by the nozzle l I.

The pull-out roll |2 pass the sheet on to a conveyor table D which may comprise a belt or belts 2| and one or more preliminary rolls 22. Suitable traction means, such as marbles 23, may be provided for pressing the sheet against the rolls and the belt.

Reversible bias For various reasons it is sometimes highly desirable to position a sheet by two particular edges, say the top edge of the sheet and the right-hand edge of the printed side of the sheet. If the upper face of the sheet is being printed, the positioning of a side guide 26 at the righthand side of the conveyor table D will be correct and the sheet may be pressed against this side guide either by biasing (slanting) the tapes toward the side guide or by providing a jogger for engaging the far side of the sheet to press the sheet against the side guide, or both. However, it will be observed that if the underface of the sheet is being printed, the edge of the sheet which is the right-hand edge of the top face of the sheet is the left-hand edge of the bottom face of the sheet and would be the left-hand edge of the printed sheet. Accordingly, in order to permit lateral registration by the right-hand edge of the underface of the sheet, it is preferred that the side registration means be reversible. To this end the table D may have incorporated therein the reversible bias features disclosed in my Patent No. 2,190,413, the tape carrying and driving rolls 21 being shiftable about approximately vertical axes along the longitudinal center line of the table, and the belts being shiftable thereon so as to bias the sheet, either to the right as shown in Fig. 1B or to the left as shown in FlghlD. The side guide 26 is preferably interchangeable between the two sides of the machine.

Instead of relying on a biased conveyor table D, a jogger may be used for pressing against one side edge of the sheet, preferably pressing it against a. side guide on the other side of the sheet. If it is desired to have the jogger optionally effective in either direction, this may be accomplished by having a single jogger reversible on a rod and providing means for changing the timing of the reciprocation of the rod so that at the proper time it can be made to jog the sheet in either direction. Of course, the side guide could be shiftable to either side as in the case of the side guide 28 of Figs. 13 and ID. of course, a press may have both reversible bias and reversible jogging.

Paars E TO H--FINAL Fsnnmc The parts E to H and their control may be substantially the same as those illustrated in my prior Patent No. 2,246,508. Preferably they are all controlled by cams rotating rigidly with one of the printing rolls so that utmost accuracy of timing is ensured. As seen best in Fig. 4A, the pressure roll 30 (of feed rolls H) is raised by cam 3| operating through lever 32, an angle bar 33, which may be considered as a shaft, being pivoted at 35. The angular position of the cam 3| with respect to the other control parts is such that while the pressure roll 30 is raised, a sheet will be fed under it against stop fingers E. The stop fingers E are carried by shaft 34 which also has feed roller 36 rigid thereon, as seen best in Fig. 2A.

The shaft 34 and with it the stop fingers E and the feed roller 36 are jointly driven as seen best in Fig. 6A. The shaft 34 carries a pinion 31 which is driven by a gear segment 38 carried by a pivoted lever 39, the follower roller 40 of which is urged against cam 4| by spring 42 compressed along slide rod 43.

As cam 4| rotates, it will swing lever 39 and gear segment 38 downwardly, rotating stop fingers E and feed roller 36 in an advancing direction. The shape of the cam 4| is such as to accelerate the sheet smoothly and rapidly so that, before the grippers Q close upon the sheet, the sheet will have reached a speed slightly in excess of the speed of the grippers Q so that the sheet will be buckled slightly against the registration stops of the grippers Q.

After the grippers have closed on the sheet, the cam 3| raises pressure roller 30 so that the sheet may be drawn freely by the grippers. After raisin of the pressure roller 30, cam 4| rotates to a point where it permits spring 42 to push the gear segment 38 upwardly, rotating the stop fingers E and feed roller 36 back to the starting position in time for the next sheet to be fed against the stop fingers E.

PAn'rs I To K-LARGE CYLINDER The construction of the large cylinder I is probably seen best in Figs. 3A. 5A, and 11A to 11D. The end walls of the cylinder are formed by discs 46 which are rigidly mounted on a shaft 41 journaled (with ball hearings) in the press frame. Platen K and plate holder 48 for plate J comprise segments which are suitably secured to the discs 48 spanning the space between them, and are provided with suitable stiffening ribs, as clearly shown in the drawings. I

The preferred securing means for the segments is seen best in Figs. 11A and 11D. A socket screw 8| countersunk into the plate holder 48 passes through a slot 82 in the rimli of each disc 48 and screwsinto a nut 54. As seen by comparing Figs. 11A and 11D, the nut is especially shaped to conform to the inner face of rim 58 and is elongated so that it can easily be prevented from turning by engagement with a shoulder 55 at the side thereof. A plate 56 is preferably secured to the rim 53 and provided with a flange 51 to retain the nut in place before the screw 5| is screwed into it, or while the plate holder 48 and the screw 8| are removed. A pin 58 is provided in the nut 84 to facilitate shifting the nut circumferentially along the rim 53 to position it for alinement with the screw 8| as the latter is about to be inserted.

The elongated slot 52 permits shifting the plate holder 48 with the plate thereon circumferentially of the discs 48 for the purpose of adjusting the head margin on the sheet being printed. It is merely necessary to loosen the two screws 5|, one for each disc 48, and the segment 48 may be slid the length of the slot 52. When the segment 48 has been moved to its new position so that the head ,margin on the printed sheet will be correct, the two screws 5| are again tightened and the segment 48 is firmly in place.

As shown at the top of Fig. 11A, the platen K Shims With a two-cylinder press in which the large cylinder carries both the plate and the platen, there is a serious problem in providing proper pressures for both of these members. When the plate prints onto the blanket, there is no paper between them, and, when the blanket prints onto the paper on the platen, a different pressure may be desired and furthermore the sheet of paper may be of one thickness in one Job and of a very different thickness in another job. Accordingly, some provision must be made for obtaining the correct pressures under the varying conditions. Furthermore, the peripheral speeds of the plate surface and the blanket surface must be the same to avoid minute smears, called gear marks, inprinting on the blanket, and the peripheral speed of the blanket surface and the sheet surface being printed must be the same to avoid like smears or gear marks in printing the paper.

As described hereinafter, the axes are normally positioned at the correct distance apart to provide the desired pressure on the blanket.

As seen best in Figs. 11B and 110, the correct pressure for printing the paper A is obtained, without disturbing the optimum spacing of the axes for the blanket, by providing shims may be secured by a countersunk bolt 6| passing through the platen K and screwing directly into rim 53. However, when the platen is replaced by a type-holding plate, it is desirable to be able to adjust the plate for head margin adjustment as has been described with respect to plate holder dinarily be preferred that the adjustable securing means illustrated at the bottom of Fig, 11A

be also used at the top of Fig. 11A for the platen and for the type-holding plate which replaces it.

Segment lock In order to facilitate adjusting the segment 48 (or the type segment) for head margin adjustment, a lock arm 63 (Fig. 4A) is pivoted to a bracket 84 carried by crossbar-$58 of the main frame and is provided with a pin 85, which, as shown in dotted lines in Fig. 4A, may be inserted in a hole 68 provided in segment 48 for the purpose. With the lock pin 65 thus in place, the segment is held against turning so that the head margin adjustment may be made simply by tuming one of the handles 81 which turn the press. The handles 61 are rigidly mounted on a shaft 88 on which is also rigidly mounted a pinion 88 which meshes with lower cylinder gear II.

It may be noted, incidentally, that the shaft 88 is-part of the main drive for the press, being driven by motor driven belt 12 which extends along pulley 73 on shaft 68.

Head margin calibrations Adjustment of the head margin may also be facilitated by providing calibrations 18 (Fig. 8B) on one of the discs 48, which calibrations may be visible through a cutout 11 in the edge of plate holder 48.

48. For that reason it will or- 8| between the platen K and a platen sheet 82. Although only two shims have been shown, there are preferably several shims of a variety of thicknesses so that shims may be removed corresponding to the thickness of any sheet being printed. Thus, with a thin sheet of paper A the shims removed may be equal to its thickness, and with a thick sheet A being printed the shims removed may be equal to its thickness. In this way the total thickness of the sheet of paper being printed, the platen sheet 82 and any shims being used will always be a predetermined thickness. The printing pressure will ofcourse depend not only on the thickness of the sheet being printed and the sheets 8| and 82 but also on the resiliency and the thickness of the blanket L and of course the spacing of the platen K from the blanket holder 84. However, with a given blanket and with a correct spacing of the platen K from the Pears L To MSMALL QYLINDER As seen in Fig. 3A, the smaih lower cylinder M may be cast in one piece, that is, with its peripheral portion 86, end portions 81 and hub flanges 88 integral. The-hubs 88 may be provided with bearing sleeves 88, which run on hearing portions 8| of a shaft 82. The shaft 82 may be provided with trunnions 83 and 84 eecentric to the bearing portions 8i, and journaled in bushings 88 and 81, which are rigidly secured to the main frame except for adjustability of bushing 86, described hereinafter.

As will be evident from Fig. 7A, a slight rotation of the shaft 92 about the axis of trunnions 83 and 84 will shift the cylinder M toward or from the upper cylinder I. The shaft 82 is held at a given angular position by a collar 88 rigid therewith, and seen best in Fig. 3A, which in turn is normally rigidly secured to latch disc 99, which in turn normally bears against pivoted latch arm IOI (Fig. 7A), which is normally held in latching position by means described below.

Pressure adiustment During printing the latch disc 99 is held in the position shown in Fig. 7A. The angular position of the shaft 92, and hence the spacing of the cylinders I and M, may therefore be adjusted by shifting collar 98 with respect to latch-disc 99. This may be accomplished manually after loosening screws I03, which normally hold them locked together. It is preferred that a screw I04 be provided for facilitating a micrometric adjustment between the latch disc-99 and the collar 99 for determining the pressure of the plate J on the blanket'L with utmost accuracy. As previously mentioned, the pressure of the blanket L on the printed sheet is determined by shims 3|.

Uniformity of pressure along the line of contact may be obtained by loosening screw I06 (Fig. 3A) and turning bushing 96. Screw I06 passes through a slot in the flange of bushing 96. The bore in 96, in which the trunnion 93 is journaled, is eccentric with the outer surface of the bushing 96, so that rotation of the bushing 96 will move one end of the shaft 92 toward or from the large cylinder I, thus producing a unifo m pressure irrespective of manufacturing variations.

AUTOMATIC Crnmnss Tnaowour When a sheet app oaches the stop fingers E it slides on top of a table II I (Figs. 2A and 'IA) comprising a sheet of metal. This table is provided with a cut-out slot I I2. A detector or feeler I I3 is reciprocated along this slot, and is pivotally mounted and so weighted that its leading end II4 will drop into the slot if no sheet is present, but will be supported by the sheet if one is present.

If no sheet is present and the reciprocating feeler II3 drops into the slot II2 it will. upon its movement in the direction of the moving sheet, engage and actuate an arm IIB mounted on a shaft III. The shaft H1 is normally urged by a spring IIO toward the position shown in Figs. 2A and 7A. with arm "6 resting a ainst cross bar II 9. When actuated by the feeler II3 the shaft turns a pin I 2I thereon to the right (counter-clockwise), thus putting tension on spring I22 to urge the latch arm IOI downwardly. Normally spring H8, in urging shaft II! to its normal position, acts through it to urge pin I2I against shoulder I23 of fitting I24 by which latch r arm IN is carried, thus urging the latch arm into the engaging position shown in Figs. 2A and 7A. The fitting I24 is pivotally carried by a fixed sleeve I26, which also forms a bearing for shaft H1. The sleeve I26 is carried by the main frame and is provided with a slot I21 for receiving the pin I2I. The pin I2I in turn holds the fitting I24 on the sleeve I26.

It is evident that the feeler I I3 must be driven in synchronism with the press, and with such timing with respect thereto that the feeler II3 will be reciprocated in its feeling direction, forwardly of the direction of sheet movement, while a sheet, if properly fed, is present over the slot I I2. To this end the feeler is preferably actuated by a cam on the main cylinder I, and it has been found most convenient to connect it to lever 32 by a link I28 pivoted to lever 32, and adjustably positioned in an eye I28 which is pivoted to a short arm I29 rigid with arm I29. As seen best in Fig. 2B, the arms I29 and I29 are both rigidly mounted on a sleeve I30. The sleeve I30 pivots freely on shaft I52 carried by the main frame. This control of the feeler through lever 32 has the incidental advantages that the feeler H3 is moved forwardly at a time when it will aid in ensuring firm contact of the sheet against the stop fingers E as the pressure roll 30 is lowered onto the sheet, and the feeler H3 is not moved rearwardly until the sheet has already been gripped by the grippers of the chain delivery unit so that proper registration is ensured.

The instant when the feeler detects the absence of a sheet at the slot H2 is not the proper time for a throwout or the separation of the cylinders, since at this instant the cylinders may still be printed the preceding sheet. Release at the time of detection is prevented by'the pressure of latch shoulder I3I on latch arm IOI, this pressure resulting from the tension of spring I32 on lever I3'3 which is pivoted to the main frame at I34. Lever I33 is connected to latch disc 99 by an adjustable link I36.

Just before the proper instant for a throwout movement, a cam I31 on shaft 41 of the large cylinder I acts on cam roller I38 to pivot lever I33 counter-clockwise, as seen in Fig. 7A, and relieve the pressure of latch shoulder I3I on latch arm IOI. If the throwout shaft III was actuated as a result of the absence of a sheet, the spring I22 will now draw'the latch arm down out of its position for engaging the shoulder I3I. At this time the reducing portion I39 of cam I31 will reach the cam roller I38 and release the lever I33, so that it will be drawn clockwise by spring I92, thus shifting latch disc 99 in a counter-clockwise direction, and with it the shaft 92. Rotating the shaft 92 in a counter-clockwise direction about its trunnions 93 and 94 will thus cause the lower cylinder M to drop away fromthe upper cylinder I so that, as the cylinders continue to rotate, there will be no contact between them, and hence no offsetting of ink from the blanket on the cylinder M to the platen on the cylinder I.

The throwout occurs shortly before the platen on cylinder I reaches the line of contact with cylinder M, and, after the platen has passed this line of contact,'cam I31 will again act upon cam roller I38 to actuate lever I33, link I36, and latch disc 99 to turn shaft 92 in a clockwise direction to restore cylinder M to its printing position. If in the meantime a sheet has been supplied at the proper time for the ensuing impression, the feeler II 3 will have been held out of the slot H2 and the spring I22 will no longer be holding the latch arm IOI down. Instead, the spring II8, acting through shaft I I1 and pin I2I, will be urging the latch arm IOI upwardly, and as soon as the latch disc 99 has been turned by cam I31 to a latching position the latch IOI will slip up behind the latching shoulder I3I, th'us holding the Parts in the printing position even when the reducing portion I39 of cam I31 would otherwise allow them to shift again to the throwout position.

Silent stop It will be observed that each time a sheet is missing, spring I32 will cause a sudden movement of lever I33 in a clockwise direction, as the steeply reducing portion I39 of cam I31 passes under roller I38. In inking up the press without starting the sheets, or in like situations, this sudden shifting of lever I33 each revolution would result in a noisy press unless the lever I33 were stopped quietly. According to the present invention a substantially silent stophas been provided. the nature of which is seen best in Fig. 7A.

A stop roller III is rotatably carried by a pin I82, which is secured to link I83, pivoted at I to the main frame. Spring I45 urges the link I83 in a counter-clockwise direction, pressing the roller I ll against lever I33. When the high portion of cam I31 suddenly rides out from under the followerroller I88, the lever I33 does not strike a rigid stop but, instead, shifts the stop roller III, with which it is already in contact, to the left or in a clockwise direction, thus pivoting the link I43 about its axis at I. The link I43 is of such length that lever I33 is limited to its proper movement and the cam roller I38 does not strike against low point of cam I31. It will be observed that the lever I33 is stopped without having any moving parts strike a fixed part. Hence the throwout operation of the press will be substantially silent.

I COUNTER It is customary to provide a counter I 5I for counting the sheets printed. In the illustrated I58 and aids the return spring in urging the return of the parts.

It is very desirable that the counter count only actual sheets printed, not revolutions of the press. This is accomplished in the present invention by having the crank arm I55 actuated by the feeler III, but actuated by it only when a sheet is present. As shown in Figs. 2A and 7A, feeler H3 is provided with an arm I51, which has a, dog I58 at its end. This dog is positioned, when a sheet is present, to strike a dog I59 at the bottom of crank arm I58. In short, when a sheet is present the reciprocation of feeler II 3 causes dog I 58 to engage dog I59 and turn crank arm I58 and shaft I52 to operate the counter I5I through linkage I53.

When there is no sheet present, the feeler II3 pivots so as to fall into slot H2, and this pivotal movement raises dog I58 so that it passes over dog I59, as shown in Fig. 7B, and thereby avoids actuating the counter mechanism.

From Fig. 7A is will be seen that dogs I58 and I59 have their engaging faces inclined at such an angle that once they have come into engagement the feeler II3 can no longer pivot under influence of its weight with respect to lever I29. The result is that as the lever I29 swings to the position shown in full lines in Fig. 1A, it will raise the feeler I I3 to the position in which it is shown in full lines in the same figure. This is advantageous, since it raises the feeler II3 off of the sheet before the forward movement of the feeler II3' ceases, thereby preventing any dragging of the feeler II3 on the sheet. Because of the inclination of the faces of dogs I58 and I59, the dog I59 must come to rest sufiiciently far forward of the corresponding resting position of dog I58 so that the feeler II3 may pivot freely as it feels for the presence of a sheet.

It will usually be preferred to have the feeler Ill come to rest on top of the table III ju t to the right of slot II 2 (Fig. 7A) so that as a sheet passes under it it'will merely have to tip the feeler by the thickness of the sheet. Accordingly, it is necessary for the dogs to be sufliciently separated so that the feeler II3 can move to the position of slot H2 and still be free to pivot.

The position of dog I58 is determined by the In using the press for direct printing the dampening unit is preferably removed, as seen in Fig. 10, so as to increase the visibility and accessibility of the parts which are being used. Likewise, in substituting a type-carrying segment for the platen it will usually be most convenient to remove the dampening unit for accessibility if, as in the preferred structure, the dampening unit is readily removable.

As seen best in Figs. 6A and 100, the dampening unit is provided with a separate frame "I, having notches I12 at the bottom of each side thereof each of which flts on a pin I13 carried by the main frame. The only other means of support is in connection with collars I 15, one on each side of the dampening unit at the top thereof, and each of which is rigidly carried by the dampening frame I1I. As seen in Fig. 10D a sleeve I19 is threaded through the collar I14 to be adjustable therein, and is locked by a lock nut I11. Sleeve I15 rests on boss I19, and its adjustment of the sleeve I18 accurately determines the position of the dampening unit with respect to the cooperating parts of the main press. A socket screw I18, screwing into boss I19 in the main frame, holds the dampening unit firmly in place.

. The dampening unit includes a fountain or fountain pan I8I carried by the frame members, having an upwardly opening tubular mouth I62 into which the neck of a bottle of dampening solution is inserted to maintain the dampening solution, which is mostly water, at a predetermined level in the fountain I8I. A fountain roll I83 is carried by the main frame in a manner seen clearly in Fig. 10A, and has its lower portion submerged in the bath in the fountain. At a predetermined period in each cycle a ductor roll I84 is shifted to the position shown, against the fountain roll I83. It is urged to this position by a spring I86, and, except for a short while on the roll I83, is held against distributor roll I81 by cam I88. Cam I88 is rigid on a shaft I89, which also bears rigid thereon agear I9I meshing with and driven by a pinion I92 (Fig. 6A) rigid on ashaft I 93. The shaft I93 is in turn rigid with a gear I94,

driven by a gear I95 which meshes with and is driven by gear I96 which rotates with the large cylinder I, and is driven by the lower cylinder gear H. The gear ratio of gear I9I and pinion I92 is such that shaft I89 and cam I88 rotate once for each revolution of the large cylinder I.

While ductor roll I84 is held against fountain roll I83, the fountain roll is rotated slightly, the exact amount depending on the amount of water or dampening liquid which it is desired to pick up during each cycle of the press. As seen in Fig. 4A, the fountain roll I83 is rotated by means of a ratchet wheel 29!, which in turn is driven by a pawl 282 carried by pivoted lever 203, which is actuated by a. second pivoted lever 284 urged in one direction by a spring 288 and actuated in the other direction by a cam 281 rigid on the shaft I89. The relationship between the cams I88 and 281 is preferably such that the entire forward movement of pawl 202 occurs while the ductor roll I84 is at rest on the fountain roll I83. The stroke of the pawl 282 is always of the same length, but the amount that it rotates the fountain roll I83 may be regulated by shifting a shield 288 to hold the pawl 292 out of engagement with the ratchet wheel 2IiI during any desired portion of the stroke of pawl 282. The shield 288 is pivotally carried by the shaft 289 of the fountain roll, and is held in an adjusted position by a spring detent 2. A handle 2I2 is provided for moving the shield 298, and, as'seen in Fig. A, a handle 2 I3 is provided for turning shaft 289 and fountain roll I83 by hand when desired, as to wet it when the press is started.

The distributor roll I81 is mounted on the shaft I93 and driven by it. The distributor roll I81 is in constant rotative engagement with a form roller 2I6, which is carried between two links 2I1, seen best in Fig. 4A, pivoted about shaft I93. The links 2", and with them the form roller 2I5, are urged downwardly, each link by a spring 2I8, the tension of which may be adjusted by turning collar 2I8 on screw 228, the collar normally being restrained from turning by a setscrew. The downward movement of each of links 2" is limited by screw 2I9 bearing against normally stationary cam 22L The cams 22l are rigid with shaft 222, which is preferably provided with a handle 225 for turning it to a position which raises the form roller 2IB to an idle position. When the form roller 2I6 is in the lower position as shown, it may bear against the plate J. Pressure of roller 2 I 8 on the plate could be determined by adjustment of screw 2I9, if it bears against cam 22I. It is preferred, however, to have clearance between screw 2I9 and cam 22I, in which case the pressure will be determined by spring 2 I 8.

The pressure between form roller 2I8 and distributor roll I81 may be adjusted by eccentric bushings 223, which are provided with hexagonal heads for adjustment and are normally locked in place with set-screws. A shaft 224, on which form roller 2I8 rotates, is mounted in the bushings 223, one in each link 2", so that rotation of the bushings will move the shaft toward and from distributor roll I81. The shaft may be drawn out axially for replacement of the form roller.

The form roller shaft 224 also carries a pair of lift-off rollers 228, one adjacent each end of the form roller 2 I 6. Each of these rollers engages a cam 221, carried by the platen segment K. These cams raise the dampening form roller 2I8, and in like manner the ink form rollers, so that neither will touch the platen surface.

Ductor roll I84 and form roller 2I8 are preferably covered with conventional absorbent material. It has been found desirable to use two absorbent materials on the form roller, the inner material being somewhat less absorbent than the outer and tending to take up excess moisture from the outer to form sort of a reserve reservoir for it. The fountain I8I is preferably formed of or lined with porcelain (preferably white, acidresistant porcelain) or some other material which will prevent electrolytic action under the influence of the dampening solution.

Once during each cycle of the press the ductor roll I84 is shifted against the fountain roll I83, which rotates a predetermined amount to feed a predetermined amount of water to the absorbent covering on ductor roll I84. The ductor roll I84 then shifts to rest against distributor roll I81, and the three rolls I84, I81 and 2I8 rotate together to supply the additional moisture to the absorbent covering on roller 2I8 and spread it evenly therearound. The form roller 2I6 applies the moisture to the plate J, the non-image portions of which retaina film of this water or dampening solution.

PART O-INKING UNIT Proper distribution of the ink is one of the most important considerations in designing a press. The ink is carried in an ink fountain 23I, seen best in Fig. 5A. The ink fountain roll 232 rotates in contact with the ink in a clockwise direction, as seen in Fig. 5A, and draws a film of ink therefrom, the thickness of the film at various points along the roll being determined by a series of screws 233 which adjustably press a ductor blade 234 toward the fountain roll 232. A ductor roll 231 bears against fountain roll 232 during a portion of each cycle, during which portion the fountain roll 232 is rotated slightly to supply ink to the ductor roll 231. The ductor roll 231 then shifts to pass a new supply of ink to roll 238, from which it is passed to rolls 239 and 24I, all of which serve as distributor and break-up rolls, the roll 24I in turn supplying the ink to ink form rollers 242.

Each of the form rollers 242 is mounted on a pair of links 243 and is adjustable with respect thereto, as in the case of the dampening form roller 2I6, to obtain correct pressure between the form rollers 242 and the roll 24I. The links 243 are pivotal on shaft 244 of the roll 2, and each link is adjustable by a screw 246 bearing on a normally stationary cam 241 to control the pressure ofthe form rollers on the plate or other surface being inked. The cams 241 may be turned by a. handle to hold the form rollers out of contact with the surface that they would otherwise ink. Each form roller 242 is provided at each end with a lift-off roller 248, which rides on one of the cams 221 to lift the form rollers away from the platen surface. Cam 241 may have four positions, the position either way from that shown raising one form roll only.

The ink fountain roll 232 is carried by shaft 249, which may be driven by pawl-bearing plate 25I in substantially the same manner as shaft 289 of the dampening unit N, with similar control of the amount it is driven. Plate 25I is, in this instance, driven by a link 252 which in turn is driven by an eccentric 253, which is mounted on stud shaft 254 and rotated thereon by sprocket 256 driven by chain 251 from sprocket 258, which rotates with the large cylinder I.

Distributor roller 24I is preferably a vibrator roll, by which is meant that it oscillates from side to side so as to distribute the ink laterally of the press or lengthwise along the rolls. The manner of accomplishing the oscillation is best explained with reference mainly to the exploded view of Fig. 9C. The shaft 244 is oscillated angularly by a yoke 259, which in turn is oscillated by link 26I (Fig. 4A), which is oscillated by an eccentric 262 rotating with the eccentric 253 already described. The shaft 244 carries rollers 263, each of which rotates on a pin 264 screwed radially into the shaft 244. A sleeve 268 slides

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