US2539383A

US2539383A - Inking mechanism for printing presses

Info

Publication number: US2539383A
Application number: US573841A
Authority: US
Inventors: Davidson William Ward
Original assignee: Davidson Corp
Current assignee: Davidson Corp
Priority date: 1941-08-11
Filing date: 1945-01-22
Publication date: 1951-01-30
Anticipated expiration: 1968-01-30

Description

Jan. 30, 1951 w, DAVIDSON 2,539,383

INKING MECHANISM FOR PRINTING PRESSES Original Filed Aug. 11, 1941 6 Sheets-Sheet 1 INVENTOR.

Jan. 30, 1951 w, w, DAVIDSON 2,539,383

INKING MECHANISM FOR PRINTING PRESSES Original Filed Aug. 11, 1941 6 Sheets-Sheet 2 5A 3 Z d T INVENTOR. 7am Wzrnfla'mdsora LQ WYW Jan. 30, 1951 w. w. DAVIDSON INKING MECHANISM FOR PRINTING PRESSES .6 Sheets-Sheet. 4

Original Filed Aug. 11, 1941 INVENTOR. Wilda/7a flaz/jafso/z ATTYS.

Jan. 30,- 1951 w. w. DAVIDSON INKING MECHANISM FOR PRINTING PRESSES GSheets-Sheet 5 Original Filed Aug. 11, 1941 w w k wwhm l l w @N mww wxww wkm M Jan. 30, 1951 w. w. DAVIDSON INKING MECHANISM FOR PRINTING PRESSES Original Filed Aug. 11, 1941 6 Sheets-Sheet 6 INVENTOR.

Patented Juliso, 1951 INKING MECHANISM FOR PRINTING PBESBEB William Ward Davidson, Eva'naton, 111., minor,

by memo assignments, to Davidson Corporation, a corporation of Illinois Original application August 11, 1041, Serial No.

Divided and this application January 22, 1945, Serial No. 573,841

' 4 Claims.

My present application is a division of my earlier application, Serial No. 406,328, iiled August 11, 1941. now Patent No. 2,387,750, dated October 30, 1945.

The present invention relates primarily to a novel inking unit or mechanism for a printing press, for example, of the type fully shown and described in my above referred to patent.

It is an object of my present invention to provide an inking mechanism for eil'ectively breaking up the ink and distribute it evenly over the printing plate.

A preferred feature of my invention resides in providing a ductor cutout to avoid excess inking when the press is running without supplying sheets and to clean up the rollers when the itively, arranged for offset lithographic printing with which the inking unit of my present invention is embodied;

Figures and ID are diagrammatic views of the press and conveyor table. respectively, ar-' ranged for direct letter press printing and showing the inking mechanism of my invention diagrammatically with respect to such modification of the press;

Figure 2 is a vertical sectional view taken substantially along the line 2-2 of Figure 1A, looking in the direction indicated by the arrows;

Figure 3 is a detail vertical sectional view taken substantially along the line 3-4 of Fig ure 2;

Figure 4 is a longitudinal vertical sectional view taken approximately on the line 4-4 of Figure 2, looking in the direction indicated by the arrows;

Figure 5A is another vertical longitudinal sectional view taken approximately on the line 5AIA of Figure 2;

Figure 5B is a fragmentary view showing the cutout position for ducking apparatus of the ink ductor roll of the inking mechanism;

Figure 6A is a generally horizontal sectional 2 mately on the line lA-IA of Figure 3, the top of Figure 8A being at the right in Figure 3;

Figure 6B is a generally vertical sectional view taken approximately on the line lB-OB of Figure 6A; and

Figure 6C is an exploded perspective view of the oscillating mechanism herein disclosed for the vibrator roll.

Before considering the detail structure of the inking unit of my present invention, it is believed that it will be helpful to refer first to the diagrammatic illustrations shown in Figures 1A to 1D for a general description of the press with which the inking unit of my present invention has been embodied.

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.

GENERAL ORGANIZATION A. Lithographic oflset printing (Fig. 14)

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 the rotatable stop fingers E, sheet B may be jogged against a side guide, against which it is also urged by the diagonal tape, to assure proper lateral 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 some 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 view of the inking mechanism taken approxie is lower feedroll to move the sheet toward the bite s,sso,sss

of the cylinders while the 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 1, 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. Aswiil be seen by reference to Fig. 1A, the water form roller 2l8 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 P 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. 0n 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 drumlike assembly S, and thereupon proceeds around the blanket drum M to a position where it is again opened by a 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 221 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 up the ink and replenish the ink on the ink form rollers for the next application of ink to the printing plate.

B. Letterpress printing (Fig.

For direct printing, the plate 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 plateso that it will co-aot 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 provided, as seen in Fig. 1C, which opens the gripper Q approximately at the position thereof shown in Fig. 1C or shortly before reaching this position. An ejector roller W is provided to cooperate with the drum-like wheels 8 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 others 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 cylinder 1, 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 couldbe 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 gripping 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 ofl'set and direct printing, front and back With the form of the press illustrated, both the front and the back faces of a sheet could be printed simultaneously by a special arrangement. For this purpose the offset plate J would be left in place and the platen segment K would be replaced by a segment bearing a direct-printing lithographic plate. The plate J would be a positive 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 so 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 platen 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 PARTS B TO D-PREIMHNARY 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 noz- 8 a. II and fed to pull-out rolls II, the lower of which is constantly driven and the upper of which is accurately positioned with respect to the lower roll by thumb nut II. A detector may be provided for automatically deflecting the sheets from their normal course if more than one is fed at a time.

The entire sheet-separating unit C, as shown in Figures A and 5B, is controlled by linkage l5 driven from a crank pin I1 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 II.

The pull-out rolls i2 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 25. may be provided for pressing the sheet against the rolls and the belt.

Reversible bias l'br 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 25 at the right-hand 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 Fig. 1D. The side guide 25 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 log the sheet in either direction. Of course, the side guide could be shiftable to either side as in the case of the side guide 22 of Figs. 18 and 1D. Of course. a press may have both reversible bias and reversible jogging.

PARTS E TO HFINAL FEEDING The parts!!! to H and their control may be sub stantiallythesameasthoseilhistratedinmy prior Patent No. 2,248,508 and my above referred to Patent No. 2,387,750

PART OINKING UNIT Proper distribution of the ink is one of the most important considerations .in designing a press and it is to the inking unit that my present invention is directed. The ink is carried in an ink fountain "I, seen best in Fig. 4. The ink fountain roll 232 rotates in contact with the ink in a clockwise direction, as seen in Fig. 4, 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 253 which ad- Justably press a ductor blade 254 toward the fountain roll 252. A ductor roll 221 bears against fountain roll 252 during a portion of each cycl during which portion the fountain roll 222 is rotated slightly to supply ink to the ductor roll 251. The ductor roll 221 then shifts to pass a new supply of ink to roll 255. from which it is passed to rolls are and 2, all of which serve as distributor and break-up rolls. the roll 24f in turn supplying the ink to ink form rollers'242.

Each of the form rollers 242 is mounted on a pair of links 243, best shown in Figure 3, and is adjustable with respect thereto, to obtain correct pressure between the form rollers 242 and the roll 2. The links 242 are pivotal on shaft 244 of the roll 2, and each link is adjustable by a screw 245 bearing on a normally stationary cam 241 to control the pressure of the form rollers on the plate or other surface being inked. The cams 241 may be turned by a handle tohold the form rollers out of contact with the surface that they would otherwise ink. Each form roller 242 is provided at each end witha lift-off roller 245, which rides on one of the cams 221 of the plate and platen cylinder I to lift the form rollers away from the platen surface as more fully described in my above referred to Patent No. 2,387,750. Cam 241 may have four positions, the 90 position either way from that shown raising one form roll only.

The ink fountain roll 232 is carried by shaft 245. which may be driven by pawl-bearing plate 25L Plate 25l is, in this instance. driven by a link 252 which in turn is driven by an eccentric 255, which is mounted on stud shaft 254 and rotated thereon by sprocket 256 driven by chain 251 from sprocket 255, which rotates with the large cylinder 1.

Distributor roller 24! 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. 6C. The shaft 244 is oscillated angularly by a yoke 259, which in turn is oscillated by link 25l (Fig. 3), which is oscillated by an eccentric 252 rotating with the eccentric 253. The shaft 244 carries rollers 255, each of which rotates on a pin 254 screwed radiallyinto the shaft 244. A sleeve 255 slides on shaft 244 and is provided with spirally disposed slots 251 in which the rollers 255 ride. The sleeve 255 is prevented from turnin by engagement of longitudinal slots 255 therein with blades 255 on a fixedcollar 21!. As the shaft 244 oscillates angularly, the rollers 252 likewise oscillate angularly in the slots 251, and since the sleeve is restrained from rotation by blades 255 it must, under the influence of' rollers 252 in slots 251, oscillate longitudinally of II the shaft 2.

. As seen but in Fig. 6B, the sleeve 233 is provided with an internal sleeve 212 having an angular flange 213 thereon. Oscillator or vibrator roll 24l is provided with a hub portion 214, having a bearing 213 rigid therewith, which rides on sleeve 212 between flange 213 and sleeve 283. Thus, the roll 2 may rotate on sleeve 212 but must oscillate with the sleeve 283, its oscillation being longitudinal of the rolls and of shaft 244. The roll 2 is driven through gear 21! fast thereon, which is driven in any suitable manner by the drive mechanism of the press.

Ink distributing rolls 238 are idler rolls and may be mounted in a very simple manner. Each roll is carried by a shaft 218. As seen in Fig. 5A, the center shaft 218 slips downwardly in slots 218 at each end of the shaft until the center roll 238 comes to rest on the two side rolls 238. There is no thrust on the shaft 218, and hence no bearings are necessary except that the bracket 28l, in which the slot 218 is formed, will keep the roll from gradually shifting longitudinally.

Since there is a lateral thrust on the two side shafts 218, each of them is provided with a bearing block block 282 at each end, these blocks sliding in additional slots in the bracket 28| until the rolls 238 come to rest on the oscillator roll 2. With this arrangement all three of the rolls 238 may be removed easily whenever desired, and no adjustment with respect thereto is necessary. Lateral adjustment could be provided for the right-hand roll 238 in Fig. 4 so as to permit regulation of the distribution of its pressure between

rolls

238 and 2, but this has not been found necessary, slight play being intentionally left in the mounting. Roll 238 is driven by gears 280 and 283 from gear 215.

The ink rollers in the direct train from ductor roll 231 to either form roller 242 are all of different diameters, and the idler rolls are different from any of these, the relations being other than simple multiples. This, together with the constant driving of the ink rolls, ensures maximum breaking up of the ink. The ductor roll is preferably shifted to the distributor roll 238 at the time which will permit maximum rotation of the rolls before the ink reaches the plate, viz: at such time that the fresh ink being passed from roll to roll will reach the position for application to the plate just after the plate has passed said position. Care must be taken, at least if the vibrator has the same cycle as cylinder I, that its eccentric 282 have such angular position with respect to the cylinde I that the cams 221 raise and lower the form rollers 242 at such times as to avoid piling up of the ink on one side of the press. Apparently the best time for the form rollers to shift is approximately at the end of one stroke of the vibrator roll, so that there will be substantially no lateral movement of the vibrator roll for an extended period after the shift of the form rollers. A possible theory is that the shifting of the form roll has a squeegee action producing a thickened line of ink, in which case it is necessary to avoid sliding the thickened line of ink predominately in one direction.

CLEANING THE INKING UNIT To clean the inking rolls a clean-up attachment 284 may be provided. This attachment is in the nature of a tray having slotted brackets so that it can be slid by hand onto a cross-bar or strut 288 (resting also on shaft 254) until its lip 281, in the form of a squeegee, made of an oil-resisting synthetic rubber such as Duprene,"

comes in contact with oscillator roll 24 l. acrews 283, near opposite sides of the tray, are prc-set to limit the squeegee to the proper pressure, and the clearance with the screws removed being too small to allow the metal tray to strike the roll. The clean-up attachment is preferably only half the width of the machine and can be slid back and forth along the bar 283. Cleaning fluid is squirted from an oil can onto the

rolls

238 or 238 while the various printing rolls are being driven, so that the cleaning fluid is mixed with the ink thereon. Then the tray 284 is wiped back and forth along the oscillator roll 2, cleaning the softened ink therefrom. The process is repeated until the inking rolls are clean. In the initial stages of the cleaning it is best to clean only about half the length of the rolls at a time so that the driving traction between them will not be lost by diluting the ink over the whole length at once. The half-width tray tends to make this partial cleaning seem natural.

During the cleaning process it is desirable for the ductor roll 231 to be in contact with the roll 238 all the time. In this way the ductor roll will also be cleaned and the feeding of additional ink from the fountain roll will be prevented. This is accomplished in the manner seen best in Figs. 5A and 5B.

The ductor roll is normally shifted back and forth by operation of cam 288 on shaft 284. The cam 288 engages cam roller 288 on lever 28f, which rocks rock bar 282 by which, as seen in Figs. 3 and 4, the ductor brackets 283 for carrying ductor roll 231 are mounted. It may be noted at this point that the ductor roll 231 is journaled in slotted bearing blocks 284, which slide between bifurcations on the brackets 283, preferably being held therein by spring clips. The ductor of the dampening unit is mounted in the same way.

As seen in Fig. 5A the cam roller 288 is normally urged against the cam 288 by a spring 288, applied to an upper arm of lever 28l, which is a bell-crank lever. The far end of the spring engages a pin on a second bell-crank lever 281 which is pivoted to the main frame. During cleaning of the inking rolls, or at any other time when it is desired to avoid the feeding of ink, the lever 281 is flipped counter-clockwise to the position shown in Fig. 5B, in which position it is seen that the spring 286 is urging the bell-crank lever 28I in the opposite direction, holding the cam roller 288 off of cam 238 and holding the ductor roll 231 against distributor roll 238. The

tension of spring 288 holds the bell-crank control lever 281 in either position to which it is shifted manually. As seen in Fig. 5B, the short arm 288 of the bell-crank lever 281 bears against a bearing boss 288 on the main frame, which boss also serves as a bearing for fountain roll shaft 248. As seen in Fig. 5A, the long arm of lever 281 bears on this boss in the other position.

' To facilitate cleaning of the ink fountain 23f and the fountain roll 232, the fountain may be removed by loosening thumb nut 30| and swinging it and its stud 302 downwardly about crossbar 303, on which they are mounted. With this downward swinging of the stud 302 it swings clear of a forked lug 304, which normally holds the fountain 23f in place. The fountain may then be slipped off of the shaft 248 which it normally engages with its bifurcated forward end.

While I have shown and described what I believe to be a preferred embodiment of my invention, it will be understood that various modifications and rearrangements made therein without departingfrom the spirit and scope of my invention.

I claim:

1. An inking unit for a printing press having a printing cylinder comprising, an ink distributing roller mounted for rotation about an axis parallel with the axis of said printingcylinder, a pair of form rollers, followers associated with said form rollers and engageable with said cylinder for controlling the position of said form rollers with respect to said printing cylinder, link means for each of said form rollers pivotally mounted at one end at the axis of said distributor roller and supporting said form rollers in engagement with said distributor roller, spring means for said link means for biasing the latter toward each other and in a direction for engaging saidform rollers with said printing cylinder, and a four position cam means between said link means operative in one position to engage one of said link means to dispose the form roller and follower carried thereby in an inoperative position with respect to said printing cylinder, in a second position to engage the other of said link means to dispose the form roller and follower carried thereby in an inoperative position, and operable in thetwo other positions to engage or disengage both of said link means to dispose both of said form rollers and the followers carried thereby in inoperative and operative positions, respectively.

2. An inking unit for a printing press having a printing cylinder comprising an ink distributor roller mounted for rotation about an axis parallel with the axis of said printing cylinder, a pair of form rollers, followers associated with said form rollers and engageable with said cylinder for controlling the positions of said form rollers with respect to said printing cylinder, link means for each of said form rollers pivotally mounted at one end at the axis of said distributor roller and supporting said form rollers in engagement with said distributor roller, spring means for said link means for biasing the latter toward each other and in a direction for engaging said form rollers with. said printing cylinder, a four position cam means between said link means operative in one position to engage one of said link means to dis; pose the form roller and follower carried thereby in an inoperative position with respect to said printing cylinder, in a second position to engage the other of said link means to dispose the form roller and follower carried thereby in an inoperative position, and-operable in the two other positions to engage or disengage both of said link means to dispose both of said form rollers and the followers carried thereby in inoperative and operative positions, respectively, and means car-.

ried by said'link means engageable with said cam means for adjusting the spring means to control the pressure of engagement of said form rollers with said printing cylinder.

3. An inking unit for a printing press comprising a fountain roll, a cluster of distributor and form rolls .one roll of which is spaced from and is in parallel-relation with said fountain roll, a pivoted shaft extending between and in parallel rehtionwithsaidfountainrollandsaidoneroll.

a ductor roll carried by said shaft, a bell crank leverfixed to said shaft, a cam follower carried by one arm of said bell crank lever, a cam adapted to be engaged by said cam follower for effecting oscillation of said bell crank lever and said shaft to engage alternately said ductor roll with said fountain roll and said one roll, a manually operable lever, stop means for supporting said manually operable lever in either of two positions, spring means between said manually operable lever and the other arm ofsaid bell crank lever, said spring means in one position of said manually operable lever biasing said bell crank lever to a position in which said cam follower is disposed in the path of said cam, and in the other position of-said manually operable lever biasing said bell crank lever to a position in which said cam follower is disposed out of the path of said cam.

4. An inking unit for a printing press comprising a fountain roll, a cluster of distributor and form rolls one roll of which is spaced from and is in parallel relation with said fountain roll, a pivoted shaft extending between and in parallel relation with said fountain roll and said one roll, a ductor roll carried by said shaft, a bell crank lever fixed to said shaft, a cam follower carried by one arm of said bell crank lever, a cam adapted to be engaged by said cam follower foreffecting oscillation of said bell crank lever and said shaft to engage alternately said ductor roll with said fountain roll and said one roll, a manually operable lever, stop means for supporting said manually operable lever in either of two positions, spring means between said manually operable lever and the other arm of said bell crank lever, said spring means in one position of said manually operable lever biasing said bell crank lever to a position in which said cam follower is disposed in the path of said cam and in the other position of said manually operable lever biasing said bell crank lever to a position in which said cam follower is disposed out of the path of said cam, and said bell crank lever in said other position of said manually operable lever being disposed in position to engage said ductor roll with said one roll of said cluster of distributor and form rolls.

WILLIAM WARD DAVIDSON.

' REFERENCES CITED The following references are 01 record in the file of this patent:

UNITED STATES PATENTS 2,341,020 Curtis Feb. 8, 19