US2974587A - Splice trip for gravure press - Google Patents

Description

March 14, 1961 F. H. M ARTHUR SPLICE TRIP FOR GRAVURE PRESS Filed July 5, 1957 2 Sheets-Sheet 1 ATTORNEY 5 2 Sheets-:Sheet 2 F. H. M ARTHUR SPLICE TRIP FOR GRAVURE PRESS March 14, 1961 Filed July 5, 1957 wkammk INVENTOR F04 ro/v 6 M40 ,4? 77/0)? ATTORNEYS 2,974,587 Patented Mar. 14, 1961 2,974,587 SPLICE TRIP FOR GRAVURE PRESS- Fulton H. MacArthur, 9 Rudd Court, Glen Ridge, NJ.

Filed July 5, 1957, Ser. No. 670,257

3 Claims. (Cl. 101-184) This present invention relates, in general to rotary printing presses, and in particular to rotary gravure printing presses wherein the printing is done by intaglio-engraved cylinders, and the material to be printed upon is in the form of a web which travels through the press over the engraved cylinders.

In such presses, superimposed printings or impressions are made upon the web in one or in a plurality of colors at each printing station in a succession or battery of printing stations, and it is necessary to secure and maintain proper register of the successive impressions, both longitudinally and laterally of the web. When a large amount of web stock is to be continuously handled by such presses or press batteries, it is necessary to splice the end of one web supply to the beginning of the next web supply, and any such splice will result in a local abnormal thickness of the web. For fine quality impressions, it is essential that uniform strong pressure he maintained between the printing cylinder and the pressure roll at each printing unit or station, but damage to the web and to the printing cylinder can result whenever the extra thickness of a splice passes through the machine. Damage is particularly noticeable in high-speed machines employing high-pressure contact between the printing cylinder and the pressure roll.

It is, accordingly, an object of my invention to provide an improved printing press of the character indicated.

It is another object to provide an improved printing press in which damage can be avoided when a splice passes through the machine.

It is a further object to achieve the above objects in a continuously running press battery, without loss of synchronism of the respective. printing cylinders at successive printing stations or units.

It is also an object to achieve the above objects with a press in which, no matter how many printing stations or units, the loss of web material occasioned by passage of a splice through a continuously running machine may be held to an absolute minimum and may be localized substantially only to the effective length of the splice.

Onother object is tov achieve the above objects with a mechanism which will in no degree affect a given precision-set web-path length between printing stations, so that perfect register may be assured both before and after each printing unit accommodates a web splice.

Other objects and various further features of novelty and invention will be pointed out or will occur to those skilled in the art from a reading of the following specification in conjunction wit-h the ccompa'nying drawings. In said drawings, which show, for illustrative purposes only, preferred forms of. the invention:

Fig. 1 is a view in side elevation of a multiple-unit printing press incorporating'featu-res of the invention;

Fig. 2 is a view in end elevation of one of the units of Fig. l, certain parts being broken away and shown in section, as along the lines 2-2 of Fig, 1;

Figs. 3 and 4 are simplified diagrams, schematically structure 22 supporting further guide indicating alternative automatic control mechanisms of the invention; and

Fig. 5 is a similar diagram for a further alternative control mechanism.

Briefly stated, my invention. contemplates application to ro-togravure printing presses of the type in which the impression to be transferred by printing is engraved upon a printing cylinder, and the impression is transferred to a web by pressing the web between the printing cylinder and a pressure roll. For high-speed presses, relatively high contact pressure is required between the pressure roll and the printing cylinder, thus tightly squeezing the web as it passes through the press, and in accordance with my invention, I provide for automatically relieving this pressure by displacing the printing cylinder and pressure roll with respect to each other upon detection of an oncoming abnormally thick portion of the web, such as a splice between the end of one web supply and the beginning of another. Probe means for detecting abnormal thickness in the oncoming web may be mechanical or electrical and may employ mechanical, electrical or other control for the transient relief of contact pressure on the web.

Referring to Figs. 1 and 2 of the drawings, my invention is shown in application to a rotogravure press comprising a plurality of like printing stations or units 10-11. The units may be mounted upon an elongated bed or flo'or 12 and tied together by elongatcdlframe means 13 at the top. A continuous supply of web material, suggested by the dot-dash line 14, passes continuously from one unit 10 to the next successive unit 11, and through as many more successive units (not shown) as, necessary to accomplish the desired complete color build-up, through successive registered impressions on the web. The web 1 may be of any suitable material, such as paper, cardboard, metal foil, sheet metal, plastic sheet, or the like.

Each of the units 10-11 is shown to comprise spaced side frames 15-16 fixedly journalling a plurality of guide rollers 17-18-19-20 for the web; a pressure roll 21 may also be fixedly journalledin frames 15-16. Associated with each unit 10-11 is an upper frame rollers 23-24-25; for the web space between two adjacent printing units 10-11, a further roll 20' may be adjustably positioned on the elongated frame means 13, so as to determine a precise fixed spacing (as measured along the web 14) between the printing location at unit 10 and the printing location at unit 11. The pressure roll 21 may be of steel, but is preferably finished with a hard rubber or rubber-like surface to provide a cushioned base for the Web as it is squeezed when receiving the impression from a printing cylinder 26. The printing cylinder 25 may be intaglio-engraved and may be continuously inked by known means which form no part of the present invention and which are, therefore, not shown or described.

In accordance with the invention, the journalled support for the printing cylinder 26 is bodily displaceable with respect to support for the pressure roll 21. Normally the printing cylinder 26 is held relatively tightly compressed against the web and against the pressure roller 21, but I provide for relief of this pressure when an abnormally thick portionrof the web, such as the splice 28, passes through the machine. Fig. 1 displays the instant at which splice 28 happens to be running over the guide roll 19 of printing unit 11.

For the machine shown, the printing cylinders 26 for all printing units 10-11 are continuously driven in complete synchronism. For this purpose, a drive shaft 30 extends the length of the machine along one side; at each unit 10-11, shaft 30 drives a power take-off device, as shown at 31 in Fig. 2. The power take-off may include a worm 32 keyed orsplined tothe shaft and driving a wormwheel 33 on an intermediate shaft 34. Meshing gears 35 (on shaft 34) and 36 (on the printing-cylinder shaft 37) complete the drive to the printing cylinder 26. The entire power take-off unit 31 including the gear 35, but not including the gear 36, is securely referenced to the frame member '16, as by bolting a bracket flange 38 thereof to the frame 16.

To provide adjustable positioning for the printing 'cylinder, the opposed ends of the printing-cylinder shaft 37 are supported in displaceably guided trunnions or bearing-blocks 39 in the respective side frames 15-16. For the arrangement shown, in which the printing cylinder 26 is directly beneath the pressure roll 21, both blocks or trunnions 39 are guided for essentially vertical movement, accessible on removal of side plates 40 carried by frames 15-16. The elevating mechanism for trunnion blocks 39 may comprise in each case a crank-pin 41 and link 42 effectively pinned .to the associated trunnion block 39. A shaft 43 ties the cranks 41 for both crank pins 41 to each other and assures synchronism of displacement of the trunnion blocks 39; each of the ends of the shaft 43 is mounted eccentrically of the hub of an angularly adjustable bearing plate or member 43, so that fine adjustment may be made for the frame-reference of shaft 43, and, therefore, also for elevation of the printing cylinder 26.

A hand crank 44 is shown keyed to one end of the shaft 43 so as to permit adjustment when manually setting up printing cylinders at each printing unit. In both units 10-11 of Fig. 1, reference numeral 44 designates the upper position of crank 44 (in which the printing cylinder is elevated for printing contact with the web), numeral 44' designates an intermediate position (in which printing contact pressure is relieved, without disengaging gears 3536), and numeral 44" designates a down or set-up position (in which printing cylinder 26 is dropped low enough to disengage gear 36 from gear 35). A manually releasable stop member 40 is carried by plate 43 to normally intercept crank 44 and limit its movement to one or the other of positions 44-44; upon manual release of stop 40', crank 44 may be shifted to the set-up position 44".

In accordance with the invention, pressure relief between the roll 21 and cylinder 26 occurs automatically upon detection of abnormal thickness in the web, whereupon an actuator 45 throws a crank 46 on the shaft 43 to slightly drop or lower the printing cylinder. A suitable web-thickness probe may simply be an idling roller 47 at the end of a pivoted arm 48; roller 47 rides a margin of the exposed surface of the web 14 as it travels over the guide roll 19, immediately prior to passage under the pressure roll 21. The follower arm 4-8 is shown as a bell crank having an adjustable arm 49, for contact with trip means 50 to control the actuator 45.

In Fig. 3, I show a first alternative control mechanism operating from a source 51 of pressure fluid, such as compressed air. In that event, the trip device 50 may be a distributor valve controlling the function of a doubleacting cylinder which serves as the actuator 45. Normally, that is, for normal web thickness, the follower or probe arm 48 will be at its lowest position to leave the valve 50 conditioned to supply fluid pressure over the tail end of the piston within actuator 45, thus cranking the shaft 43 counterclockwise (in the sense of Fig. l) and driving the trunnion blocks 39 upward to establish printing contact with the web. Upon detection of abnormal web thickness, as at the splice 28, the probe 48 will be elevated so as to depress the control valve 56 and to transfer the supply of pressure fluid to the head end of the piston in cylinder 45, as by way of the line 52. In such condition, the other line 53 will be connected to exhaust at 54, and the shaft 43 will be rapidly cranked clockwise to lower the printing cylinder, thus permitting the thick splice portion 28 to pass the printing surfaces without causing damage.

When the probe 48 falls off the thick spliced portion of the web, the valve 50 is allowed to return to its normal condition, which means that the head end 52 is connected to exhaust, and pressure fluid is supplied in line 53 to the tail end of the cylinder 45. in order that there may be a slight delay in the application of pressure fluid to the tail end of cylinder 45, I show the incorporation of delay mechanism in the line 53; such delay will be understood to allow for the web-travel time between roll 19 and the printing cylinder 26, or in the event of a diagonal splice, the delay may be set to accommodate the full effective length. of the splice. For the form shown, the delay mechanism comprises a throttle valve 55 and check valve 56 in parallel branches of the line 53. This means that, depending upon the adjustment of the throttle valve 55, slow or fast dashpot action can be achieved for. returning the actuator piston to the head end of the cylinder 45, thus elevating the printing cylinder 26 at the end of a selectively delayed interval. On the other hand, when the cylinder 45 is supplied with pressure fluid at the head end so as to drop the printing cylinder 26, the check valve 56 can exhaust immediately to permit fast drop-out.

In the arrangement of Fig. 4, electrical means are shown for automatic positioning of the printing cylinder 26. The probe 60 is shown as the arm of a doublepole, double-throw snap switch 61, supplied from the line 62 and serving to energize one or the other of actuator solenoids 45 and 45", each having an armature linked to the crank 46 on shaft 43; resilient means within switch 61 may continually urge probe 60 to track the exposed web surface. Delay means 63 are shown in the circuit to the solenoid 45". Normally, and with the probe 60 down for normal-thickness web material, the solenoid 45 will be energized so as to crank the shaft 43 counterclockwise and to elevate the printing cylinder 26 into printing position. Upon detection of a web splice, the probe 60 rises and immediately deenergizes solenoid 45" while energizing solenoid 45', to effect quick drop-out of the printing cylinder 26. When the probe 60 rides off the splice, switch 61 de energizes solenoid 45', but the delay means 63 is effective to delay the excitation of solenoid 45" for a short safety interval so as to avoid driving the printing cylin der 26 against the splice, as will be understood.

In Fig. 5, I illustrate an embodiment of my invention in which a single probe 47 for trip 50 serves not only the first printing unit 10 but also all remaining units 1111, etc. in a given battery. The actuating means 45 for unit 10 may be. driven by either of the means already described for Figs. 3 and 4, but the actuators 45 in succeeding units 1111 derive their operating control at appropriately delayed intervals. Thus, delay means 70 connects trip 50 to the actuator 45 of unit 11, and delay means 72 connects delay means 70 to the actuator 45 of unit 11'. Delay adjustments at 7173 are made according to the web length between printing stations and in accordance with the web-running speed through the press. In operation, trip 50 effects drop-out and elevation control for the printing cylinder 26 of unit 10 to accommodate the splice as it passes through unit 10; then, after delay determined at 70, the printing cylinder 26 of unit 11 is dropped out and elevated to accommodate the splice as it passes through unit 11. Finally, the delay at 72 is effective to relieve the printing cylinder 26 of unit 11 as necessary to ac commodate the splice as it passes through unit 11.

It will be seen that I have described an improved printing press construction, whereby spliced high-speed runs may be made in multiple-unit gravure presses with an absolute minimum wastage of material in the vicinity ofthe splice, regardless of the number of units in the entire press. By. relieving pressure at the splice, I assure no transient overloads at the printing region and thus assure'longer life'of the' parts, as well as top-quality impressions immediately following the splice. This also means no possibility of damage to the web so that the web may proceed at constant high speed throughout the machine, and complete register may be maintained.

Since the thickness probe 47 is mounted to track a margin of the Web, the way impaired.

While I have described the invention in detail for the preferred forms shown, it will be understood that moditications may be made within the scope of the invention as defined in the claims which follow.

I claim:

1. In a web-fed printing machine, a plurality of like printing units, a frame means for said units and for quality of the impression is in no .holding' said unitsin fixed relation with each other, a

pressure roll and a printing cylinder for each unit, web- ;feeding and guide means for passing an elongated spliced endless web through said first unit and between the pressure roll and printing cylinder thereof and thence between the pressure roll and printing cylinder of the next succeeding unit, said web-feeding means conducting said web around a portion of the periphery of the pressure roll in each of said units, whereby said web is not conducted around any portion of the printing cylinder in any of said units, said pressure rolls being journalled on fixed axes and the guide means between said units being fixed, whereby the length of said web between pressure rolls of adjacent units may remain a constant, means movably positioning the printing-cylinder axes for each of said units in the direction toward and away from contact with said web at the adjacent pressure roll, common drive means for allprinting cyl-' inders and including at each unit meshing gears driving the printing cylinder associated therewith, and positioning means associated with each unit andresponsive to detected thickness of web material entering each said unit for automatically positioning the associated printing cylinder in pressure-relieving relation with said web upon encountering an abnormally thick portion of the web, the extent of displacement to efiect pressure relief being less than suflicient to disengage the meshing gears of said drive means.

2. In aweb-fed printing machine, a plurality of like printing units, frame means for said units and for holding said units in fixed relation with each other, means for supporting and feeding elongated spliced endless said web and the corresponding pressure roller, and thickness-sensitive probe means responsive to detection of thickness variation at the splice of said web and in transient actuating relation with said actuating means, the sense of controlled actuation being such as to transiently relieve squeezing printing-cylinder contact with said web substantially only for the relatively short intervals during which the web splice passes between successive corresponding printing cylinders and pressure rollers, whereby the flight of the web may continue undisturbed and web life may be substantially prolonged.

3. In a web-fed printing machine having a plurality of printing units for successive printing on a moving Web, frame means to support each of said plurality of printing units and for holding said printing units in fixed relation to each other, a printing cylinder for each printing unit, a pressure roll for each printing unit, each of said pressure rolls being journaled on said frame means on respective fixed axes, a plurality of guide roller means supported by said frame means on respective axes fixed relative to the fixed axes of said pressure rolls and positioned relative to each respective pressure roll so that a moving web is directed about a predetermined portion of the periphery of each respective pressure roll and so that the length of a moving web between pressure rolls of adjacent printing units may remain a constant, means movably positioning each respective printing cylinder relative to the pressure roll for each respective printing unit so that squeezingicontact may be made with a web moving about said pressure roll, drive means to rotate'said pressure rolls and said printing cylinders uniformly, and thickness-sensitive probe means responsiveto detection of thickness variation at a splice in a moving web and in transient actuating relation with said movable positioning means, the sense of controlled actuation being such as to transiently relieve squeezing printing cylinder contact with a web substantially only for the relatively short intervals during which a web splice passes between successive corresponding printing cylinders and pressure rolls, whereby a web may continue undisturbed and web life may be substantially prolonged.

web at uniform velocity and under uniform tension and including at each of said. printing units a pressure roller in arcuate contact on its lower side with said web, each pressure roller being journalled for rotation in a fixed horizontal axis, a horizontally oriented printing cylinder vertically adjustably supported beneath the pressure roller of each said unit, independent-actuating means associated with each printing cylinder for independent- 1y elevating the same into squeezing contact against References Cited in the file of this patent Koch Aug. 2, 1955

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