US2895529A - Schultz - Google Patents

Description

y 2 1959 H. J. SCHULTZ ,895,529

MACHINE FOR DE-EMBOSSING LI GRAPHIC PRINTING PL s BY PRESSING EACH PLATE AGA T A ROTATING CYLIN BY AXIALLY SPACEJD PRESSING ROLLS Filed April 17, 1953 4 Sheets-Sheet 2 INVENTOR ATTORNEYS EIEI 3I July 21, 1959 SCHULTZ 2,895,529

H. J. MACHINE FOR DE-EMBOSSING LITHOGRAPHIC PRINTING PLATES BY PRESSING EACH PLATE AGAINST A ROTATING CYLINDER BY AXIALLY SPACED .PRE'SSING ROLLS Filed April 17. 1953 4 Sheets-Sheet 3 fiEPMd/Vd 6mm r2 INVENTOR 44.4 ATTORNEYS y 21, 9 H. .J. SCHULTZ 2,895,529

I MACHINE FOR DE-EMBOSSING LITHOGRAPHIC PRINTING PLATES BY PRESSING EACH PLATE AGAINST A ROTATING CYLINDER BY AXIALLY SPACED PRESSING ROLLS Filed April 17, 1953 4 Sheets-Sheet 4 IE1 El... IE- K n Illlllll I lin #52444 lNVENT ATTORNEYS 1 Sol-101. 72 OR United States Patent MACHINE FOR iDE-E'MBOSSING LITIHOGRAPHIC PRINTING PLATES BY PRESSING EACH PLATE AGAINST A ROTATINGCYLINDERBY AXIALLY .SPACED .PRESSIN G ROLLS Herman J. Schultz, =Glenview, IlL, assignor, by mesne assignments, to Direct .Image Oifse't Corporation, rEvanston, 111., a corporation rofrlllinois Application Aprill17, 1953, SerialN(349,507

.6 Claims. :(Cl.11'53-.32)

My invention relates to a tie-embossing machine, and particularly to a machine for removing embossing from the backs of printing plates *of the character used in offset printing.

.It is among the objects of my invention to provide a mechanism by which the ridges formed upon the back of a printing plate by the impressing of type and/or'designs upon the face of the plate may be readily pressed out and the design raised to the printing 'level of the plate.

Another object is to provide a "do-embossing machine in which a plurality of spring loaded rollers, each con- *tacting only a small area of a printing plate, are advanced step-by-step across the intervals between adjacent rollers.

Another object is :to provide a de-embossing machine :of the character described, wherein rollers are moved automatically in timed relation to the rotation "of a icylinder on which a plate is gripped while embossed areas are pressed out, the :advance movement occurring at instants when the rollers are not in contacuwith the plate.

Another object .=is to providea power driven tie-embossing mechanism provided with means for automatically stopping the operation when the de-embossing operation is complete, and which may be readily set up manually :for operating upon :each succeeding plate.

The invention also .;has other objects and features of advantage, some of which with the foregoing will be explained in "the fol-lowing description of that form of the invention illustrated .in the drawings. It is to be tundcrstood that the invention :is not limited to the em- .hodirnent shown in the drawings as it may be-enibodi'ed in other forms as :set forth in the claims.

lo the drawings;

Fig. :1 is a plan view of the machine of my invention.

Fig. 2 is a .fragmental perspective view of the right hand end of the machine .as shown in Fig. 1.

Fig. 3 is a fragmental perspective view of the left .hand end of the machine as shown in Fig. 1.

Fig. 4 is a fragmental sectional view of a portion of the plate carrying cylinder and the plate gripping means thereon.

Fig. 5 is a view of the plate gripping means in plate disengaging position.

Fig. 6 is a fragmental sectional detail showing the manner in which one of the tie-embossing rollers is mounted and engages the back of a printing plate.

Fig. 7 is a fragmental plan view, partly in horizontal upon an impregnated card stock backing.

Patented July 21, 1959 ice 2 other suitable means upon the face of a laminated printing plate comprising a sheet of metallic foil laminated The type and/or engravings are impressed into the face of the laminated metallic foil to a depth of .001 to .004" 'The backing is of impregnated card stock of flexible character, and becomes embossed in ridges wherever lines of type, rules, photo engravings, or other designs have been impressed into the plate surface. In order to make the plate usable for offset printing, it is necessary to re-raise the inked printing areas to the printing level of the plate. This operation is referred to herein as the de-embossing operation, and the machine of the present invention is primarily designed for performing 'of the cylinder is provided for intermittently moving the de-embossing rollers lengthwise of the cylinder. The movement is timed with respect to the rotation of the cylinder and plate holding means so as to cause the rollers to advance 'only at times when an inset area of the cylinder and plate passes the rollers. The de-emb'ossing rollers are advanced step-by-step until they have been moved a distance at least equal to the distance between the rollers so that narrow areas of the plate are aligned with the rollers successively until the entire area between the rollers has been subjected to their action. Preferably the machine includes means for automatically stopping its operation when a plate has been fully deembossed. The machine is also provided with meail's for manually re-set'ting the de-e'mb'ossing rollers to operate upon a succeeding pl-ate gripped upon the cylinder.

In terms of greater detail the de-embossing machine of my invention comprises a polished steel cylinder 1 secured upon a horizontally disposed shaft 2, which is journaled upon a suitable supporting frame designated in general by the numeral 3. The cylinder is arranged to be rotated by means of a gear 4. A suitable motor 6 is connected by gear 4 to a suitable reduction gear unit '7 of conventional construction and mode of operation. The motor is electrically connected to a source of power through a control switch 8.

The cylinder 1 is provided with a flattened area 9 extending the full length of the cylinder upon one side thereof. A plurality of grippers 11 are mounted upon a shaft 12 journaled in the ends of the cylinder 1. The grippers may be of any spring resilient type, such as commonly used in cylinder printing presses. The grippers extend outwardly through openings 13 formed in the fiattened area 9 of the cylinder. A gripper operating handle 14 is secured upon the gripper shaft 12 for moving the grippers between open and closed positions, as shown in Figs. 5 and 4 of the drawings respectively. The handle 14 may be held manually with the grippers in an intermediate position while a plate is being adjusted, and may be locked in the closed position by a spring loaded detent pin 15 movable into locking engagement with a hole 16 in the end of the cylinder 1.

A plurality of de-embossing rollers 18 are mounted upon a pressure bar 19 extending longitudinally of the cylinder 1 in spaced relation to one side thereof. The pressure bar is supported by bracket plates 21 carried by and forming part of the frame 3. The bar 19 extends provided with heads 23a which form stops limiting the movement of the bar 19 toward the cylinder 1. The positions of the stops are adjusted by advancing or receding the screw with respect to the inner end of the slots 22. A look nut 25 is provided on each of the screws 23. By tightening the lock nuts 25 against the plates 21, after the screws 23 have been set in desired position, the stops are locked in position'to define the operative position of the pressure bar 19.

The outer adjusting screws 24 are threaded through the portions of the plates 21 between their outer edges and the outerends of the slots 22. The outer end of each adjusting screw 24 is provided with a hand wheel or knob 26 by which the adjusting screw may be moved to a de sired position. The inner ends of the screws 24 extend into the slots 22, and limit transverse movement of the pressure bar 19 along the slots 22 outwardly or away from the cylinder 1. A pair of lock nuts 27 upon each screw 24 adjacent the outer edge of its plate 21 provide means for locking the adjusting screw in a desired position relative to the plate 21 and the bar 19, for holding the bar against transverse movement without interfering with its longitudinal movement within the slots 22.

The de-embossing rollers 18 are mounted in uniformly spaced relation, preferably at intervals of about 2. inches,

along the pressure bar 19. The rollers 18 are mounted between the spaced arms of a yoke 28 upon a bearing pin 29. Each yoke is provided with a stem 31 which extends axially through a bore 32 formed in the pressure bar 19. The end of the stem 31 nearest the yoke provides a bearing area extending into the adjacent end of the bore 32, and forming a sliding fit therewith. The outer end of the stem 31 is of reduced diameter, and is slidably engaged by a sleeve 33 which is threaded into the bore 32 from the outer edge of the bar 19. A spring 34 is mounted over the reduced portion of the stem 31 between the inner end of the sleeve 33 and the bearing portion of the stem 31. The sleeve 33 is provided with head 35 by which the sleeve may be moved to regulate the pressure exerted by the spring 34 against the shoulder formed at the inner end of the bearing area of the stem 31. A nut 36 is threaded onto the outwardly extending end of the reduced portion of the stem 31 for limiting movement of the stem 31 and the roller 18 toward the cylinder 1.

The rollers are yieldably pressed inwardly toward the cylinder by the springs 34, the degree of pressure being regulated by adjustment of the sleeves 33. Each roller 18 is freely rotatable upon its pin 29, which is positioned parallel to the axis of the cylinder 1. Rotation of the stem 31 within the bore 32 is prevented by a plate 37 secured to the bar 19 and overhanging the inner edge thereof sufficiently to engage the squared ends of the yokes 28 without limiting the axial movement of the stem 31 within the bore 32. The nuts 36 are adjusted to a position such that the yokes 28 are spaced from the adjacent edge of the bar 19 slightly more than the maximum height of any ridge or obstruction likely to be encountered upon a printing plate, but not enough to clear the plate 37, as best shown in Fig. 6 of the drawings.

At the end of the machine opposite the motor drive, the cylinder shaft 2 extends through the adjacent bracket plate 21, and is provided with a pinion 38 meshing with a gear 39 secured in driving connection with a cam lift 40 and journaled upon a shaft 41 which extends outwardly from the bracket plate. A housing 42 shields the pinion 38 and the upper part of the drive gear 39.

A jack shaft 43 is mounted in vertical position upon a pair of bearing brackets 44 secured to the end bracket ispivoted upon a: plate 51, which in turn is pivoted upon the shaft 43 between the ratchet 48 and a retaining collar 52. -An arm 53 is secured to the plate 51, and is provided with a cam engaging roller 54 which engages the cam face of the cam lift 40. As illustrated, the cam face is formed upon the outer end of the cam lift 40. The cam face is preferably designed with two high points 45, positioned apart (one of the high points being concealed by the cam roller 54in Fig. 3 of the drawings). The first high point 45 is arranged to cause the. pawl 49 to advance the ratchet 48 a distance equal to half a notch. The second high point is twice as high as the other high point to cause the pawl to advance the ratchet through the remaining half notch so as to complete the movement through a full notch for each rotation of the cam shaft 41. The cam rises abruptly to each high point 45 to give a quick power stroke, and recedes gradually from each high point to permit a relatively slow return movement. A tension spring 56 is connected at one end to the plate 51 and arm 53, and at the other end to the bracket plate 21 for normally holding the cam roller 54 against the cam. A tension spring 57 is connected at one end to the plate 51 and at the other to a pin 58 carried by the pawl 49 for holding the pawl in engagement with the ratchet 48. A knob 59 is secured upon the upwardly extending end of the jack shaft 43 for manually rotating the shaft independently of the pawl and ratchet for setting the bar in a desired position. The pin 58 provides a handle by which the pawl 49 may be held out of engagement with the ratchet 48 to permit manual movement of the bar 19 to the left.

A feed board 61 is mounted above and toward the rear of the cylinder 1, to receive and support a printing plate preparatory to its introduction into the machine.

The operation of the machine is briefly as follows:

While the power is turned off at the switch 8, the hand wheels 26 are turned to back the outer adjusting screws 24 away from the pressure bar 19 sufiiciently to permit the bar, and the de-embossing rollers 18 carried thereby, to be moved to an inoperative position with the rollers .18 entirely clear of the cylinder 1. This may be accomplished by loosening the outer adjusting screw at the left hand end of the machine only enough to allow the bar 19 to swing about the pinion 46. The adjusting screw 24 at the right hand end of the machine is secrewed outwardly to a point which will permit outward movement of the bar 19 sufficient to cause the de-embossing rollers to be spaced from the cylinder a distance substantially greater than the thickness of a printing plate. The knob 59 is then turned to move the bar 19 to the left to a normal starting position.

While the pressure bar is thus rendered inactive and lnoperatlve, the gripper handle 14 is moved to raise the grippers 11 to their open position, as indicated in Figs. 2 and 5 of the drawings. A printing plate 62, having embossed ridges 63 on its back, and which has previously been placed upon the feed board 61, is then slid from the feed board onto the cylinder with its lower edge moved under the outwardly projecting ends of the grippers 11. In order to receive the printing plate, the cylmder is moved to substantially the position indicated n Figs. 1', 2 and -3 of the drawings with the flat face 9 n substantial alignment with the feed board. The cylinder is inched along to that position by momentarily closing a circuit through the motor 6 a suflicient numberof times to bring the flat face 9 to the desired position. For this purpose, I provide a switch 66 mounted ad acent the main control switch 8, and connecting the source of power to the motor through a resistance element 67. The switch 66 is of the push button type, and is operated to close a circuit momentarily through the resistance and the motor suiiicient to give a slight forward turning movement to the cylinder.

The printing plate 62 is positioned on the cylinder 1 with its lower edge seating against a pair of stops 68 on the cylinder. The grippers 11 are then turned to closed position for clamping the edge of the plate against the flat surface of the cylinder as indicated in Fig. 4 of the drawings. The grippers are locked in this closed and clamping position by engagement of the pin 15 with the detent hole 16.

The pressure bar 19 is next moved back to its operative position with its inner edge against the heads of the inner adjusting screws 23. The outer adjusting screws are then advanced to hold the pressure bar in its operative position with sufficient pressure to assure alignment, but not great. enough to cause any material resistance to the longitudinal movement of the bar relative to the cylinder. The inner adjusting screws 23 are initially set so that the bar 19, when in its operative position, will be substantially parallel. to the surface of the cylinder 1, and spaced sufficiently therefrom to permit the de embossing rollers to be resiliently pressed against the back of. the printing plate. The degree of pressure exerted by the springs 34 may be regulated by means of the threaded sleeves 33, to meet varying requirements; and clearance is allowed between the yokes 28 and plate 37 for permitting outward displacement of the rollers sufiicient to prevent damage to the plate or to a roller in event an incompressible projection or obstruction car ried by the plate is encountered during the operation of the machine.

When the machine has been thus set up in readiness for operation upon a plate, the switch 8 is closed and the motor 6 set in operation to rotate the cylinder 1. As the plate 62 is carried past the de-embossing rollers 18, each roller is pressed by its spring 34 against the back of the sheet. The rollers are narrow, preferably about A; of an inch. As the ridges 63 on the back of the plate 62 are moved under the rollers 18, they are pressed back to substantially the level of the unembossed areas of the plate. Each roller contacts only a narrow band of the plate and of course smooths out only those portions of the ridges which pass directly under it.

As the cylinder 1 is rotated, the pinion 38 is moved to actuate the cam drive gear 39 and cam lift 40. Preferably the gear 39 and pinion 38 have a two to one gear ratio so that two full revolutions of the cylinder 1 and pinion 38 are necessary to impart one full revolution to the drive gear 39 and cam lift 40. As the first of the two high points 45 of the cam 40 is moved into engagement with the cam roller 54, the arm 53 is displaced and the pawl 49 is moved to advance the ratchet 48 one half notch. This movement of the ratchet operates through the jack shaft 43 to cause the pinion 46 to advance the rack 47 and pressure bar 19 a corresponding amount. The second or higher high point next advances the ratchet another half notch, thereby causing the ratchet to be advanced a full notch for each rotation of the cam shaft 41. The high points of the cam 45 are so positioned with respect to the cylinder 1 and its flat face 9 that each forward impulse is imparted at exactly the moment when the flat face 9 passes the line of de-embossing rollers 18. At that instant, the printing plate, being held fiat against the fiat surface 9 by the grippers 11 is not touched by the rollers, and hence the rollers can be shifted without being dragged over the surface of the printing plate.

Continued rotation of the cylinder 1 causes the pressure bar 19 with its de-embossing rollers 18 to be advanced step-by-step from left to right lengthwise of the cylinder 1, until a distance at least equal to the intervals between the de-embossing rollers has been covered, Preferably, the degree of movement at each step is only about half the width of a roller so that the area contacted by each roller at each step overlaps the area previously covered by the roller during the preceding step. For example, assuming a de-embossing roller having a width of about /s" the rollers are preferably advanced in steps of about Since the rollers are advanced one step for every revolution of the cylinder, each of width of the printing plate will be moved under a roller twice. As the rollers are advanced, the embossed ridges 63 on the back of the plate are smoothed out gently and uniformly progressively across the plate until the entire surface has been smoothed out. At the same time, the impressions on the face of the plate are raised to the printing level. The edges of the rollers 18 are preferably rounded or beveled to guard against the forming of ridges on the back of the plate.

After the rollers have been advanced step-by-step to traverse the distance between the rollers, the motor is stopped. For that purpose, a trip 69 .is secured to the end of the bar 19 and arranged to engage the tumbler arm 70 of the switch 8. The adjusting screws 24 are again moved outwardly to permit the pressure arm to be swung to an inoperative position while the de-embossed plate is removed from the cylinder. Another plate may then be placed in the machine for the de-embossing operation.

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

l. A machine for de-embossing printing plates comprising a rotatable cylinder provided with means for holding a printing plate thereon for movement therewith, driving means for said cylinder, a plurality of spaced coaxially mounted rollers of substantially equal widths adjacent the cylinder and independently movable towards and from said cylinder to engage and press the plate against the cylinder during rotation thereof, a spring biasing each of said rollers equally towards said cylinder, and traversing mechanism connected with said driving means intermittently advancing said rollers axially relative to said cylinder a distance less than the width of one of said rollers.

2. A machine for de-embossing printing plates comprising a rotatable cylinder provided with means for holding a printing plate thereon for movement therewith, driving means for said cylinder, a pressure bar extending longitudinally of said cylinder, a plurality of spaced rollers of substantailly equal widths coaxially mounted along said bar adjacent the cylinder and independently movable towards and from said cylinder to engage and press the plate against the cylinder during rotation thereof, a spring biasing each of said rollers equally towards said cylinder, and traversing mechanism connected with said driving means intermittently advancing said rollers axially relative to said cylinder a distance less than the width of one of said rollers.

3. A machine for de-embossing printing plates comprising a rotatable cylinder having an area inset from its surface and provided with plate gripping means positioned adjacent said inset area for holding an edge of a printing plate in an operative position thereon, a pressure bar extending longitudinally of the cylinder in spaced relation to one side thereof, a plurality of rollers mounted in spaced relation along the bar and movable radially of the cylinder into engagement with a plate carried past the rollers by rotation of the cylinder, means yieldably pressing the rollers against the plate, and means timed with the movement of the inset area of the cylinder past the rollers for moving the bar and rollers stepby-step longitudinally of the cylinder for aligning successive portions of the area of the plate with the rollers.

4. A machine for de-embossing printing plates comprising a rotatable cylinder having an area inset from its surface and provided with plate gripping means positioned adjacent said inset area for holding an edge of a printing plate in an operative position thereon, a prespermitting movement of the bar between operative and inactive positions.

In a machine for de-embossing printing plates, the combination with a rotatable cylinder having an inset area and provided with means for gripping an edge of a printing plate within the inset area, of a pressure bar mounted longitudinally of the bar along one side thereof, a pluralityof de-embossing rollers mounted coaxially in spaced relation along the bar and independently yield:

ably pressed into engagement with a plate gripped on, the cylinder, means actuated by the rotation of the cylinder for intermittently moving the bar and rollers longitudinally of the cylinder in timed relation to the movement of the inset area past the rollers, and means for automatically stopping the operation when the bar has been advanced a prescribed distance.

6. A machine for de embossing printing plates comprising a rotatable cylinder provided with means for bolding a printing plate thereon for movement therewith, driving means forsaid cylinder, a plurality of spaced coaxial rollers mounted adjacent the cylinder and independently movable towards and away from said cylinder to engage and press the plate against the cylinder during rotation thereof, means for yieldablypressing the rollers against said plate, and traversing mechanism connected with said driving means for intermittently advancing said rollers axially, relative to said cylinder in increments less than the width of one of said rollers.

References Cited in the file of this patent UNITED STATES PATENTS 161,269 Perrin Mar. 23, 1875 602,926 Zuhlke a Apr. 26, 1898 921,739 Rieske May 18, 1909 1,239,678 Duncan Sept. 11, 1917 1,519,775 Ericksson Dec. 16, 1924 1,934,660 Fair-child Nov. 7, 1933 1,942,986 St. John Jan. 9, 1934 2,048,964 Osborn July 28, 1936 2,355,529 Hawley Aug. 8, 1944 2,827,942 Schultz Mar. 25, 1958

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