US2827942A

US2827942A - schultz

Info

Publication number: US2827942A
Authority: US
Priority date: 1953-04-17
Filing date: 1954-01-25
Publication date: 1958-03-25
Anticipated expiration: 1975-03-25
Also published as: US2895529A; FR1083668A

Description

March 25, 1958 SCHULTZ 2,827,942

MACHINE FOR DE-EM dssINc LITHOGRAPHIC PRINTING PLATES 'Filed Jan. 25, 1954 e Sheets-Shet 2 z/seMm/ J. 52404 7.2,

- INVENTOR.

March 25,- 1958 H. J. scHuL'rz I MACHINE FOR DE-EMBOSSING LITHOGRAPHIC PRINTING PLATES Filed Jan. 25; 1954 6 Sheets-Sheet 5 //EMAW J. 5:40.472.

IN V EN TOR.

H, J. JSCHULTZ 2,827,9 42

March 25, 1958- MACHINE FOR DE-EMBOSSING LITHOGRAPHIC PRINTING PLATES 6 Sheets-Sheet 4 Filed Jan. 25, 1954 March 25, 1958 2,827,942

MACHINE FOR DE-EMBOSSING LITHOGRAPHIC PRINTING PLATES Fild Jan. 25, 1954 J. SCHULTZ 6 Sheets-Sheet 5 fi/ge/ww 52 404 72.

INVENTOR.

March 25, 1958 H. J. SCHULTZ 2,827,942

MACHINE FOR DEEMBO SSING LITHOGRAPHIC PRINTING PLATES 'Filed Jan. 25, 1954 6 Sheets-Sheet 6 A seMm/ Sci/a1. 72.

INVENTOR.

BY v

United States p o V My invention relates to a de-embossing-machine, and particularly to a machine for smoothing out embossed areas; ofiset upon the backs of printing plates of the character used in ofiset printing, and restoring the embossed areas to-a required printing level.

The present invention involves improvements upon the machinedisclosed in my copending application Serial No. 349,507, filed April 17, 1953, including improved mechanism for controlling and actuating rollers by which areas embossed upon a printing plate may be pressed back to a prescribed printing level in conformity with prevailing; requirements.

It is among the objects of my invention to provide an improved 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. V i s Another object is to provide a de em-bossing maohinein whicha plurality of. pneumatically operated rollers, each contacting only a small area of a printing plate, are advanced step-by-step across-the intervals between adjacent rollers, p s

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 cylinder on which a: plate is gripped while embossed areas are pressed out, the advance movement occurring at instants when the rollers are notin contact With the plate.

.Another object is to provide a power driven de-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 following description of that form of the invention illustrated in the-drawings. It is to be understood that theinvention is notlim-ited to the embodiment shown in the drawings as it may be embodied in other forms asset forth in the claims.

In the drawings:

Fig. 1 is a plan. view of the machine of my invention. Fig. 2- is. afragmental, partially diagrammatic front elevational View of portions of the machine shown in Fig.1..

Fig. 3" is a fragmcntal perspective view of the righthand end of the machine as shown in Fig. 1.

Fig. 4 is afragmental perspective view of. the lefthand end of. the machine as shown in- Fig. 1.

Fig: 5. a fragmental sectional detail showing one of the de-embossing rollers in engagement with the back of a printing plate.

, Fig 6 isra fragmental plan. view, partly in horizontal section showing the lefthand end of the pressurebar, and its adjusting and" actuating means. a a

' Fig.; 7t is a fragmental view of a portion of the plate carrying cylinder and the plate gripping means thereon.

2,827,942 Patented Mar. 25, 1958 Fig. 8 is a view of the plate gripping means in plate disengaging position. H,

Figs. .9 and 10 are enlarged fragmental sectional views of a portion. of the plate carrying cylinder with a portion of the plate in original embossed and partially deembossed condition respectively.

In the making of printing plates for use in what is known in the art as'the direct image process of offset printiiig, images; of type, photo engravings, and designs of various' kindsar'e impressed by letterpress or other suitable pressure applying means upon the face of a laminated printing plate comprising a sheet of metallic foil laminated upon an impregnated card stock backing. The type and/or engravingsare impressed into the face of the laminated metallic foil to a depth of .00'l to .004; The bashing is of impregnated card stock of fleicible 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; necessary to remiss the inked printing areas to the print ing level of the plate. This operation is referred to herein as the d e-embossing operation, and the machine of the present invention is primarily designed for performing this essential step.

In terms of broad inclusion, the machine of my inventi'on 'comprises a. power driven cylinder upon which a flexible offset printing plate may be held for rotative movementv past a set of t le-embossing rollers yieldably pressed against the plate with suflicient pressure to press back embossed areas impressed in the flexible backing of the plate during the making thereof. The pr essing back of these ridges causes the inked printing areas on the face of the plate to be raised back to the printing level of the plate. Mechanism actuated by the i ot a tion of the cylinder is provided for interrn ittentlymoi irig 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 canse the rollers to advance only at times when an inset arealof the cylinder and plate passes the rollers. The deembossing rollers are advanced step-by-step until they have been moved a distance at least equal to the distance between therollers so that narrow areas of the plate ate 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 means for manually re-setting the de-embossing rollerslto operate upon a succeeding plate gripped upon the cylinder.

Interms of greaterdetail' the de-embossing machine of my invention comprises a polished steel cylinder 1 secured upon a horizontally disposed shaft 2, which is journalled 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. s A suitable motor 6 is connected to gear 4 through a suitable reduction gear unit 7 of con ventional construction and mode of opera tion. The motor'is electrically connected to a: source of power through 'a control switch 8L 7 s The cylinderl is provided with a flattened area 9'. extending the filll length of the cylinder upon. one side thereof. A plurality of gripperslf are mountediupon'a shaft l2' journalled in the endsofthe; cylinder 1'. The grippers may be of' any spring resilienttype, such' as i nionly used in cylinder printing. presses. The g'ri' extend outwardly through openings 13 formed adjacent the leading edge of the flattened area 9 01? the cylinder; A gripper operatinghandle I4 is secured upon 'thejgr'ipj; per shaft 12' for'rnoviiig the gribpersptw'een open and closed positions, as shown in Figs. 8 and 7 of the drawings respectively. The handle 14 may be held manually with the grippers in an intermediate position while a plate isbeing 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 shoulder 17 isformed upon the cylinder along the trailing edges of the openings 13 to provide a stop by which a printing plate may be properly aligned upon the cylinder for engagement by the grippers.

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 through slots 22 formed in the bracket plates 21, and is movable within the slots both longitudinally and transversely. The bar is mounted substantially parallel to the side of the cylinder 1, and is positioned within the slots 22 between inner screws 23 and outer adjusting screws 24.

The inner screws 23 are threaded into the plate 21 at the ends of the slots 22 nearest the cylinder 1, and are provided with heads 23a which form stops limiting the movement of thebar 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 lock 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 outer ends 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 desired 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 provides 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 yokes 28 upon bearing pins 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 lock nut 34 is threaded onto the outer end of each sleeve 33 to secure it in adjusted position upon the bar 19.

Lock nuts

36 and 37 are threaded onto each stem 31 adjacent the outer end of its sleeve 34 to limit .the axial movement of the stern toward the cylinder 1. Each inner nut 36 is initially adjusted to accurately limit the movement of the stem upon which it is threaded, and the outer nut 37 is then tightened against the nut 36 to lock the nuts in their adjusted position upon the stem.

A plurality of pneumatic cylinders 81 are mounted upon a bracket plate 82 extending rearwardly from the pressure bar 19 to which it is secured for movement therewith. Each cylinder 81 is provided with a forward cylinder head 83 having a bearing portion 84 through which a reduced extension .86 of the corresponding stem 31 is slidably axially movable. The cylinders are secured members 90 are connected to the rear cylinder heads 88 by means of suitable couplings 91 through which pneumatic pressure may be introduced into the cylinders. While it is contemplated that air. pressure will be employed, the term air as herein used is intended to include any compressible medium.

In the embodiment illustrated, each cylinder 8 is provided with a bellows 92 expansible by air pressure introduced into the bellows through the passage 89 against the resistance of a compression spring 93 enclosed within the forward end of the cylinder. The extensions 86 of the stems 31 are secured to the forward end of the bellows, and are actuated thereby as piston rods movable through the cylinder heads 83 to transmit pressure to the de-embossing rollers 18. 'Mov'ement of the-stems 31 and rollers 18 is limited in the forward direction by engagement of the lock-nuts 36 with the sleeves 33, and

, in the rearward direction by engagement of the yokes 28 with the bar 19. Rotation of the stems 31 and yokes 23 is prevented by an aligning plate 37 secured to the upper surface of the bar 19 and extending forwardly therefrom to overlie the rearward ends of the yokes 28 throughout their range of movement.

The lower ends of the tubular members 90 are connected into a manifold 94 by suitable couplings 96. Air from a suitable source, not shown, is delivered to the manifold 94 through a hose connection 96a provided with a manual pressure control and relief valve 97 mounted in an accessible position upon the frame 3. The hose 96 is preferably connected to a main supply connection 98 through a suitable pressure equalizing and control valve 99 by which air from a supply at relative high pressure may be delivered at a constant pressure substantially lower-than the supply pressure. Air cleaners or

purifiers

100 and 101 are preferably provided to remove moisture, dust and other undesirable elements from the air before delivery to the manifold 94. Since the valves 97 and 99 and

purifiers

100 and 101 are of conventional character, and the specific structurethereof forms no part of the present invention, a detailed description of these devices is herein unnecessary, and those parts are illustrated only diagrammatically.

The de-embossing rollers 18 are yieldably pressed toward the cylinder 1 by air pressure introduced into the air bellows 92. V The degree of normal operating pressure is regulated by the valve 99, which may be adjusted to deliver air at any desired constantpressure. The supply of pressure to the manifold 94 and cylinders 81 is controlled by the valve 97 which is operable to deliver air at the predetermined pressure during the de-embossing operation and torelease the pressurefrom the manifold and cylinders when the operation is completed. The operating pressure is, of course, the same in all of'the cylinders, and all of the'rollcrs will be pressed against the cylinder l with the sameforce. 7

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 camlift' 40 journalled 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 jackshaft 43 is mounted in vertical position upon apair of bearing" brackets 44 secured to the end bracket plate 21. A pinion 46 secured to the jack shaft 43 meshes witha rack 47 secured to the pressure bar 19 upon the 'edge nearest the cylinder, along an end portion of the bar which projects outwardly past the brack ct plate 2l. The jack shaft ,43 is rotated by means of a ratchet 48 securedto the shaft '43 and actuated by a pawl 49'. Thepawl 49' is pivoted upona plate '51, which in turn is pivoted upon: the shaft 43 between the ratchet 48' and a: retaining collar 52. An arm 53is 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 came face isaformed upon the outer end of the cam lift 40. Thecam face is preferably designed with two highpoints 45', positioned. 1 80' apart. The first high point 45a is arranged to cause the" pawl 49 to advance the ratchet 48 a distance equal to half a notch. The'second high point 45b is. arranged to cause the pawl to advance the ratchet through the remaining halfnotch so as tocomplete the movement through a full notch for each full rotation of the cam shaft 41. The cam rises abruptly to each high point 45 to give aquick power stroke, and recedes gradually from each high point to permit a relatively slow return movement.

tension spring 56 is connected at one end to the plate 51 and' arm 53, and at the other end to a fixed part of the bracketplate 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 ro e 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 62- preparatory to its introduction into the machine.

lihe op'eration of the machine is briefly as follows:

With the powerturned off at the switch 8, the knobs 26: are turned to back the outer adjusting screws 24 away from the pressure bar 19 sulficiently to permit the bar, and the de=embossing rollers 18 carried thereby, to beimoved 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 lefthand 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 screwed outwardly to a point which will permit outward movement of the bar 19 sulficient to space the de-embossing rollers from the cylinder a distance substantially greater than the thickness of a printing plate. The knob 59is then turned to move the bar 19 to the left to a normal starting position.

While the pressure bar is thus rendered inactive and inoperative, the gripper handle 14 is moved to raise the grippers 11 to their open position, as indicated in Figs. 3 and S 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 extending under the outwardly projecting ends of the grip pers 11. In order to receive the printing plate, th'e cylinder is moved to substantially the position indicated in Figs; 1, 3 and 4 of the drawings with the flat face 9 in 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 number of times to bring the flat face 9 to the desired position. For this purpose, I- provide a switch 66 mounted adjacentthe main control switch 8, and connecting the sourceof power to the motor through a resistance element 67. The switch 66 is preferably of the push button type, and is operated to close a motor circuit momentarily through the resistance to give only a slight forward turning movement to the cylinder each time the push button is depressed.

The printing plate 62 is positioned on the cylinder 1 withits lower'edge seatin'g against'the shoulder 17 on the cylinder. The grippers l1 are then turned to closed position for clampin'gthe' edge" of-the plate against the flatsurfacer of the. cylinder asri'ndicated in Fig. 7 of the drawings. The" grippers are locked: in this closed and clamping position by'engagem'ent of the pin 15 with the detent hole 16. a e

The pressure bar1=9is. 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 alignmentwithout causin'g any'material resistance to the longitudinal movement. ofthe 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 sufiiciently therefrom to permit the de-embossing rollers to be resiliently pressed against the back of the printing. plate. The movement of the rollers toward the cylinder is limited by-nieans of the threaded sleeves 33, which may beadjustedwo meet. varying requirements, such as different thickness. of printing plate," or different degrees of de-embossing'; also, clearance is allowed between the yokes 28 and the bar 19 for permitting outward displacement of the rollers suflicient to prevent damage to the plate or to. a roller in. event an incompressible projection or obstruction? carried by the plate is encountered during the operation of the machine.

After 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 carriedpast the de embossin'g rollers 18, each roller is pressed against the back ofthe 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 came 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 (45a) of the cam 40 is moved intoengagement w1th 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 48 to advance the rack 47 and pressure bar 19 a corresponding amount.

The second or higher high point (45b) next advances the ratchet another half notch, thereby causing the ratchet to be advanced a full notchfor each rotation of the cam shaft 41. The high points of the cam 45 are so positioned with respect to the cylinder land 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 flat surface 9 by the grippers 11 is not touched by the rollers, and hence the rollers-can be shifted longitudinally of the cylinder withoutbeing dragged over the-cur face of the printing plate.

Continued rotation of the cylinder 1 causes the pres sure bar 19 with its de-embossing rollers 18 to be advanced step-by-step from left to right lengthwi'se'of the cylinder 1, until a distance at least equal to the maximum interval 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 thearea' previously covered by the roller during"theprecedlh g until the entire surface has been smoothed out.

.step. For example, assuming a de-embossing 'rollerphaving a width of about /8" the rollers are preferably advanced in steps of about embossed ridges 63 on the back of the plate are smoothed out gently and uniformly progressively across the plate At the same time, the impressions on the face ofthe' 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 and another plate placed on the cylinder for de-embossing.

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

1. 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 adjacent the cylinder, each of said rollers being capable of independent movement towards and away from said cylinder to engage and press the plate against the cylinder during rotation thereof, a fluid pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder, and a flow pressure connection from each of said fluid pressure actuated means to a common source of fluid under pressure.

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 plurality of spaced coaxially mounted rollers adjacent the cylinder, each of said rollers being capable of independent movement towards and away from said cylinder to engage and press the claim and plate against the cylinder during rotation thereof, a fluid 1 pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder, a connection from each of said fluid pressure actuated means to a common source of fluid under pressure, and traversing means connected with said driving means for intermittently and incrementally advancing said rollers axially thereof along said cylinder.

3. 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 adjacent the cylinder, each of said rollers being movable towards and away from said cylinder to engage and press the plateagainst the cylinder during rotation thereof, a fluid pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder, a manifold connected to a source of fluid under pres sure, a connection from said manifold to each of said fluid pressure actuated means, and traversing means connected with said driving means for intermittently and incrementally advancing said rollers axially thereof along said cylinder.

4. A machine for de-ernoossing 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 adjacent the cylinder, each of said rollers being movable towards and away from said cylin- Since the rollers are ad-' 'vanced one step 'for every revolution of'the cylinder,

.d'er to engage and 'press the plate against the cylinder during rotation thereof, a fluid pressure actuated means operatively associatedwith each of said rollers for yieldably pressing its associated roller towards said cylinder, a

connection] from each of said fluid pressure actuated means to a common source of fluid under pressure, and traversing means, connected with said driving means for intermittently'and incrementally advancing said rollers axially thereof along said cylinder, said incremental advances being less than the width of one of said rollers.

5; 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 co-axially mounted rollersadjacent the cylinder, each of said rollers being capable of: independent movement towards andawayfrom said cylinderto engage and press the plate against the cylinder during rotation thereof, a fluid pressure actuated means operatively associated with each ofsaid rollers for yieldably pressing its associated roller towards said cylinder, a manifold connected to a source of fluid under pressure, a connection from said manifold to each of said fluid'pressure actuated means, and-traversing means connected with said driving means for intermittently and incrementally advancing said rollers; axially thereof along said cylinder,

said incremental advances being less than the width of one of said rollers.

6. 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 extendingrlongitudinally 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, a fluid pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder, a connection from each of said fluid pressure actuated means to ,a common source of fluid under pressure, and traversing means timedwith the movement of the inset area of the'cylinder past the rollers for moving the bar and rollers step-by-step longitudinally of the cylinder for aligning successive portions of the area of the plate with the rollers.

7. 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'adj-acent 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 rotationof the cylinder, a fluid pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder,'a manifold connected to a sourceof fluid under pressure; aconnection from said manifold to each of said fluid pressure actuated means, and traversing .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, 9. fluid pressure actuated means operatively associated with each of said rollers for yieldably pressing its associated roller towards said cylinder, a connection from each of said fluid pressure actuated means to a common source of fluid under pressure, and 5 than the width of one of said rollers.

References Cited in the file of this patent the rollers, said step-by-step movements being each less 10 2,355,529

UNITED STATES PATENTS Perrin Mar. 23; 1875 Perry Dec. 14, 1909 Blakesley July 2, 1911 Nash Dec. 28, 1915 Duncan Sept. 11, 1917 Osborn July 28, 1936 Hawley Aug. 8, 1944