US3456588A

US3456588A - Printing press plate cylinder lockup

Info

Publication number: US3456588A
Application number: US625071A
Authority: US
Inventors: George R Brodie
Original assignee: JOHN C MOTTER PRINTING PRESS C
Current assignee: MOTTER PRINTING PRESS Co; JOHN C MOTTER PRINTING PRESS C; JOHN C MOTTER PRINTING PRESS CO
Priority date: 1967-03-22
Filing date: 1967-03-22
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22

Description

July 22, 1969 G. R. BRoDlE PRINTING PRESS PLATE CYLINDER LIOCKU` Sheets-Sheet l Filed March 22 1967 S Si INVENTOR. GEORGE R. BRODIE I l III I .k IAM I I I l II- .x@ IAJU. 1531 -MII AT'OHNEYS IIIM his

July 22, 1969 G. R. BRODIE PRINTING PRESS PLATE CYLINDER IIOCKU 4 Sheets-'Sheet :1

Filed March 22, 1967 s .bm

INVENTOR.

GEORGE R BRODIE his ATTORNEYS July 22, 1969 Filed March 22, 1967 zo cr 761872 64509064 G. R. BRODIE 3,456,588

PRINTING PRESS PLATE CYLINDER LOOKUP 4 Sheets-Sheets -uQ-e-- SOURCE OF AIR PRESSURE INVENTOR.

GEORGE R. BRODIE ATTORNEYS has G. R. BRODIE PRINTING PRESS PLATE CYLINDER LOOKUP July 22, 1969 4 Sheets-Sheet 4 Filed March 22, 1967 5l ...r..... l

INVENTOR.

GEORGE R. BRODIE /x/f/'M his ATTORNEYS United States Patent O 3,456,588 PRINTING PRESS PLATE CYLINDER LOCKUP George R. Brodie, Narberth, Pa., assignor to John C. Motter Printing Press Co., York, Pa., a corporation of Delaware Filed Mar. 22, 1967, Ser. No. 625,071 Int. Cl. B41f 3/54 U.S. Cl. Mil-415.1 17 Claims ABSTRACT F THE DISCLOSURE A lookup for attaching, accurately positioning and tightening a wrap-around type plate on a rotary printing press plate cylinder comprising a pair of clamping assemblies mounted in a longitudinally extending recess in the plate cylinder body for movement of their outermost ends toward each other to draw the plate tightly about the cylinder, an inflatable tube mounted between each clamping assembly and the adjacent wall of the cylinder recess to urge the clamping assemblies toward 4each other to pull the plate tightly around the cylinder, and a mechanism for moving one of the clamping assemblies relative to the other to longitudinally displace one end of the plate relative to the other end. 'Each of the plate-clamping assemblies is composed of a clamping bar and a plurality of movable clamping jaws mounted on the bar, the clamping jaws being movable and being resiliently urged into a position engaging a ange on each end of the plate between coacting plate-gripping faces on the bar and jaws. An actuating bar is provided to simultaneously open up all of the clamping jaws on each of the assemblies.

Background of the invention This invention relates to rotary printing presses of a type employing wrap-around plates and, more particularly, to a novel and improved plate lookup mechanism for attaching, accurately positioning and tightening the plate on the plate cylinder,

A number of types of printing techniques, a particularly important one being offset printing, employ a relatively thin metal, plastic or fibrous plate which is wrapped around a rotary plate cylinder. The plate is fastened to the cylinder by a clamping device, usually referred to as a lookup Many types of plate lookups have been suggested in the past, ranging from those of relatively simple construction, such as a clamp bar that is fastened by screws in a cylinder groove with the'ends of the plate clamped between the bar and the cylinder, to those of very complex construction embodying various adjusting devices, releasable clamps, operating linkages and so forth.

Generally speaking, the relatively simple lookups do not afford any appreciable adjustment of the plate, or if adjustment is possible, it is nonetheless difficult to accomplish. Accordingly, the relatively simple lookups are generally unsuitable for more sophisticated printing machines and operations, notably color work. On the other hand, the previously suggested lookups for use in more sophisticated printing machines, such as offset presses, often have relatively numerous defects arising, basically, out of their complexity. For example, many of them involve a considerable number of adjustments that must be made while the press is shut down and which often take a fairly considerable amount of time. Moreover, the clamping arrangements for these mechanisms frequently require 3,456,588 Patented July 22, 1969 ICC forming a complicated flange structure on the ends of the plates for use in the lookup, or special clamp bars must be welded onto the plate. Often, a given lookup assembly is designed to provide optimum operation for a particular characteristic, and as a consequence, other features of the lookup are adversely affected by the inordinate attention given to one or another specific feature. For this reason, versatility is sometimes sacrificed for the sake of providing one or more specific functional features.

Summary of the inventori There is provided, in accordance with the present invention, a novel and improved plate lookup having a number of advantages over lookups previously known in the art. More particularly, the lookup constituting the invention includes a pair of clamping assemblies for holding each end of the plate and attaching the plate to the cylinder. The clamping assemblies are mounted in a recess extending longitudinally across the cylinder body for for movement of their radially outwardmost ends t0- Ward each other to draw the plate tightly around the cylinder. Each of the clamping assemblies is preferably composed of a clamping plate extending substantially the entire length of the recess and hinged to a common base plate positioned in the recess. The clamping bar carries a plurality of spaced-apart clamping jaws, and the bar and jaws have coacting gripping faces for engaging and holding a simple turned-in flange on each end of the plate. The clamping jaws are mounted on the clamping bar for movement between a position opening up the plate-clamping space to receive the plate and a position in which the plate is clamped and held between the gripping faces. Preferably, the gripping jaws are resiliently urged to their closed, plate-clamping positions.

The lookup further comprises an actuating bar for selectively opening up the gripping jaws to receive the plate. Desirably, the actuating bar is arranged to open all of the jaws on each of the clamping assemblies simultangeously and, moveover, to operate the jaws of each of the assemblies exclusively of the other. Thus, the jaws on one clamping assembly can be opened up to receive one end of the plate, then closed to clamp the plate in place, followed by operation of the clamping jaws on the other assembly to receive and clamp the other end of the plate.

In a preferred embodiment, each of the clamping assemblies is moved inwardly toward the other to draw the plate tightly about the cylinder surface by forces created by a fluid expandable tube located between the clamping assembly and the adjacent wall of the cylinder recess. In o-rder to locate all plates used on the cylinder in the same position on the cylinder in the circumferential direction, one of the clamping assemblies engages a stop or a series of stops which limit its movement. The other clamping assembly is free to move in a direction to tighten the plate to a desired extent, as established by the forces created by a predetermined inflation pressure in the tube associated with it.

An important feature of the lookup of the invention is provision for adjustment of the plate to properly orient the leading edge with respect to the trailing edge, in other words to properly orient the plate along its diagonal. More particularly, the clamping assembly associated with one end of the plate, preferably the trailing end, is arranged to be moved longitudinally along the cylinder with respect to the other end of the plate, and an operating mechanism is provided'to impart the necessary longitudinal adjustment. The operating mechanism is, moreover, arranged to be operated from outside of the press frame and can be operated not only when the press is shut down but also while it is running. Inasmuch as relative movement between the leading and trailing edges of the plate to obtain the desired registration can also result in a slight cocking of the plate on the cylinder, the clamping assemblies are preferably carried by a mounting base common to both of them which is arranged to pivot about an axis aligned substantially radially of the cylinder. This arrangement permits the entire lockup to pivot out of alignment with the axis of the cylinder to allow for the tendency of the plate to take a slight helical wrap around the cylinder when its trailing edge is brought into alignment with the leading edge in the course of obtaining diagonal registration.

As mentioned previously, the lockup has numerous advantages. For one thing, the lockup enables the plate to be mounted in a very short time, say three minutes, thus minimizing the shut-down time while the press is being set up for another run. Moreover, the lockup permits the plate to be quickly taken off the cylinder, such as to make reprints, and to be quickly remounted, remounting a previously mounted plate taking only about two minutes. The lockup permits the plate to be tightened around the cylinder from both ends, rather than from just one end and accordingly lessens the tendency for uneven tension to be placed on the plate as it is pulled tight. The lockup provides for adjustment of the plate position to obtain proper registration; in this regard, the leading end of the plate is pulled to a xed stop point, so that every plate will be locked up in the same position relative to the plate cylinder body. The plates require only short simple bends on each end which are received in the clamping spaces on the clamping assemblies. The use of inflatable tubes to tighten the plate on the cylinder provides for constant tension on the plate so that any slight stretch in the plate will not release the tightness of contact between the plate and cylinder; in other words, the tensioning mechanism provides a floating action that affords uniform tension. The lockup of the invention is adapted for use with a variety of plates, including ones of various materials and various thicknesses.

The mechanism for cocking the plate, that is for adjusting its trailing end with respect to its leading end, is notable especially for its ability to be adjusted while the press is running. This capability of the lockup is afforded in part by the lack of interdependency between the tightening of the plate by the inflatable tubes and the mechanical clamping of the plate to the cylinder by `the clamp assemblies. The cocking operation is performed by merely closing off the air to the iniiatable tubes, thus loosening the plate on the cylinder, cocking the plate as needed, and then retightening the plate by turning the air back on. During the time that the plate is loosened, it is still firmly attached to the cylinder by the clamping assemblies.

Brief description of the drawings FIGS. 1A and 1B, taken together end to end with FIG. 1A to the left of FIG. 1B, make up a top elevational View of the plate cylinder, sections being broken away to eliminate unnecessary repetition and portions of the cylinder surface being broken through to show interiorly located parts;

FIG. 2 is a view in section taken longitudinally through the lockup mechanism of the plate cylinder of FIGS. 1A and 1B, the section being generally along a plane defined by the lines 2-2 of FIGS. 1A and lB and looking in the direction of the arrows;

FIG. 3 is an end view in section through the plate cylinder taken generally along a plane defined by the lines 3-3 of FIG. lA and in the direction of the arrows;

FIG. 4 is an end view in section taken at another plane through FIG. 1A defined generally by the lines 4-4 and looking in the direction of the arrows, and

FIG. 5 is a section taken through the left (with respect to FIG. lA) shaft of the cylinder and looking to the right, as represented generally by the lines 5 5 of FIG. 1A.

Description of an exemplary embodiment The embodiment of the invention selected for illustration in the drawings and description in this specification is a lockup for a rotary offset press. Referring to FIGS. 1A, 1B and 2, the plate cylinder, which is designated generally by the reference numeral 10, includes a cylindrical main body portion 12 and

shafts

14 and 16 by which the cylinder is journaled by bearings (not shown) in the press frame, of which only a segment of one side member 18 is shown in the drawings. A printing plate 24 which may be of the conventional metal type or more recently developed paper type, is wrapped around the cylinder body and is attached and held tightly in proper position on the cylinder by the lockup mechanism of the invention, which is designated generally by the reference numeral 30. Mounted at the ends of the cylinder body 12 are the

usual bearers

20 and 22. The plate cylinder is of course suitably coupled to the press drive to be rotated in the direction indicated by the arrows on FIGS. 3 to 5.

As best shown in FIGS. 3 and 4, the parts of the lockup mechanism by which the plate is attached to the plate cylinder are located in a recess 32 which extends along the entire length of the plate cylinder body 12. In order to facilitate removal of the lockup without dismounting the cylindrer from the press, one side wall of the recess 32 is constituted by an insert 34 which is tted into an extension of the recess 32 machined out of the cylinder body. The insert 34 is formed with a longitudinally extending setback 36 defining a flange portion 38 which is bored with holes 40 for bolts 42 by which the insert 34 is fastened to the cylinder body. The setback 36 receives a liller strip 44 which is fastened by screws 46 to the flange portion 38 of the insert 34. -In order to provide a perfectly smooth cylindrical surface on the cylinder body, the holes for the screws 46 receive filler pieces 48. If at any time it is desired to remove the insert 34 such as to permit the lockup to be taken out for repair, the llers 48 can readily be drilled out and the strip 44 and insert 34 detached and removed.

The lockup 30 comprises a pair of clamping assemblies CL and CT (clamp leading and clamp trailing) composed of, inter alia, clamping bars 50 and 52 which extend substantially the entire length of the cylinder body and which are mounted for pivotal movement on a base plate 54 by means of

hinges

56 and 58, respectively. The longitudinal adges of the base plate 54 are received in slots and 62 on either side of the recess 32, the overha-nging edges of the slots serving to retain the lockup in the recess.

Each of the clamping bars 50 and 52 carries a series of spaced-apart movable clamping jaws 64 mounted on anges 68 and 70 extending from the inward faces of the

bars

50 and 52, respectively. Each clamping jaw 64 includes a gripping head 72, a rod 74 slidably received in a guide hole in the respective flange 68 or 70 and a spring retainer 76 fastened to the lower end of the rod. A spring 78 surrounding the rod yand located between the retainer 76 and the mounting flange 68 or 70 urges the clamping jaw 64 downwardly along the clamping bar.

The faces of the clamping jaw gripping heads 72 and the adjacent faces of the clamping bars 50 or 52 are angularly related to axes of the rods 74 so that as the clamping jaws are urged toward the flanges 68 and 70, the separation between those faces is reduced to wedge the end of the plate between them. Before being installed on the plate cylinder 10, the ends of the printing plate 24 are bent inwardly to form flanges 24a which are clamped in the spaces between the clamping jaws and the clamping bars. As is apparent from FIGS. lA and 3, for example, the clamping jaws 64 on the trailing clamping bar 50 are staggered with respect to the jaws on the leading clamping bar 52.

An actuating bar 86 for opening up the jaw spaces to receive the plate anges 24a extends substantially the entire length of the recess 32 and has lugs 88 located to engage upon rotation the spring retainers 76 of the several clamping jaws. The bar is rotatably mounted on the base plate 54 by clamps 90 located at suitable intervals along its length. As shown in FIG. 2, the bar 86 has a slot 92 at its left end (with respect to FIG. 2) by which it is coupled to a shaft extension 94 by means of a projection 96 matching the slot 92. The extension extends out through the left bearer where it is suitably secured by a cap 97 to the bearer. A tool 98 (FIG. 5), which includes an operating screw 100 engageable with the cylinder shaft 14, is provided to rotate the shaft 86 to open up the clamping jaws on the respective clamping bars.

More particularly, the tool 98, as it is shown in FIG. 5, is positioned on the end of the shaft extension 94 such that turning of the operating screw 100 in a direction to pivot the tool 98 counterclockwise (with respect to FIG. 5) will rotate the actuating bar 86 counterclockwise and bring the lugs 88 on the right side of the bar (with respect to FIG. 3) into engagement with the spring retainers 76 and will move the clamping jaws 64 on the leading clamping assembly CL upwardly along the clamping bar 52. The jaw spaces are thus opened and the ange 24a of the plate 24 can be readily inserted. The operating screw 100 on the tool 98 is then turned back to return the actuating bar 86 to its initial position and permit the jaws 64 to be urged downwardly by the springs 78 into wedging engagement with the ange.

To open up the jaw spaces between the clamping jaws 64 and clamping bar 50 of the trailing clamping assembly CT, the tool 98 is removed from the shaft extension 94, is reversed end for end with respect to the view in FIG. 5, and the above-described procedure repeated, except that the actuating bar 86 is rotated clockwise (with respect to FIGS. 3 and 5). The clamping spaces of the trailing assembly CT are accordingly opened to receive the trailing plate flange 24a and are closed to clamp the plate by returning the tool to its initial position. The tool 98 is then removed and stored.

When the plate is initially attached to the lockup, it is relatively loosely wrapped around the cylinder body 12 and must be tightened. The tightening of the plate 24 on the cylinder is accomplished by introducing fluid under pressure, such as air, from a suitable source 102 I(repre` sented schematically in the drawings) into

expandable tubes

104 and 106 mounted in

semi-circular grooves

108 and 110 formed in the walls of the recess 32 behind the respective clamping bars 50 and 52. The

inflatable tubes

104 and 106 extend substantially along the entire length of the cylinder body 12 `and are clamped by releasable clamp elements 112 and 114 to end closure pieces 111 and 113 (FIG. 5) adjacent the left 'bearer 20 and to pipe sections 117 and 118 installed in the right bearer 22 (FIG. 2). The pipe sections are led radially inwardly into the cylinder shaft 16 where suit-able passages (shown schematically) are provided to conduct air in from a union (not shown). The source of air pressure 102 is, of course, suitably connected to the union. The details of the -air pressure supply can readily be worked out by one skilled in the art and therefore are not described in detail here or shown in the drawings.

When the source of air pressure 102 is communicated to the tubes 104 `and 106, the tubes are expanded and provide inward forces against the respective clamping bars 50 and 52 which pivot them toward each other .and draw the plate 24 into tight engagement around the cylinder body. It is desir-able that the leading edge of the plate be accurately positioned with respect to the cylinder surface for uniformity, especially with a remounted plate, and therefore the clamps 90 by which the lockup :actuating bar 86 is mounted on the base plate 54 are provided with stops l116 (FIG. 4) that limit the extent of inward pivoting of the leading clamping assembly CL. The trailing clamping assembly CT is, however, vable to move inwardly lto an extent sufficient -to provide the desired tightness of the plate 24 on the cylinder as established by the force exerted on the trailing assembly by the tube 104.

The lockup of -the invention further includes provision for cocking the plate on the cylinder, cocking being the term used in the art to refer to moving the trailing end of the plate longitudinally across the cylinder in either direction relative to the leading end. As mentioned before, the base plate 54 is retained in the recess 32 by the overhanging edges of the

slots

60 and 62. It is not, however, clamped or otherwise secured to the cylinder, but is simply located in place in the recess 32 by a single locating pin 120 which is mounted in a hole 122 formed in the cylinder and loaded by a spring 126 upwardly into a position norm-ally keeping the pin in la hole 128 in the base plate 54 (FIGS. 2 and 4). Holes 130 are bored through the actuating rod 86 and its mounting clamp to permit a tool to be inserted down through them to depress the locating pin below the lower face of the -base plate 54 so that the lockup assembly can be removed from the recess 32. lnasmuch as the locating pin 120 is the only element of the lockup which xes it in position in the slot 32, it is clear that the base 54 and all of the parts of the lockup assembly mounted on it can pivot about the pin 120 to swing the axis of the lockup out of parallel with the axis of the cylinder.

Although there is no play in the hinges 58 which -mount lthe leading clamping assembly CL on the base plate 54, the hinges 56 which mount the trailing clamping assembly CT have clearances providing for say 1A longitudinal movement of the assembly CT, and therefore longitudinal movement of the trailing edge of the plate 24 with respect to the leading edge of the plate. When the trailing edge is moved in cocking the plate, as described below, the plate tends to take a slight helical wrap around the cylinder, thereby moving the lockup a slight amount out of alignment with the cylinder axis by pivoting it about the locating pin 120.

The mechanism for cocking the plate 24 is best shown in FIGS. 1B and 2. Extending through an opening in the right (with respect to FIGS. 1B and 2) bearer 22 of the cylinder is a coupling bar which has at its left or inner end a pin 142. The pin extends -up between and is engaged on either side by a pair of coacting pins 144 projecting from the inward face of -the trailing jaw bar 50. The outer end of the coupling bar 140 is connected by a shoulder screw 146 to a sleeve 148 which is coupled by a key 150 to the plate cylinder shaft 16 for rotation with the cylinder but is slidable axially along the shaft. The longitudinally outermost end of the sleeve 148 is coupled by means of -a bearing 152 to an actuating ring 154. The actuating ring 154 has internal threads 156 and is threaded onto an externally threaded reaction ring 158 which is mounted by a bearing 160 on the cylinder shaft 16, the bearing 160 being positioned lengthwise of the shaft by split rings 162 and 164. The reaction ring is also prevented from rotating with the shaft 16 by means of a pin 166 extending from an annular collar 168 bolted to the press frame member 18. On the outer` annular surface of the actuating sleeve 154 are teeth 170 which mesh with a gear 172 carried by shaft 174 extending out through the frame Imember 1'8 and rotatable -by a hand wheel 176 (FIG. 1B).

The coupling bar 140 and the sleeve 148 rotate with the cylinder independently of the actuating sleeve 154 and reaction ring 158. The cocking mechanism is, as will be apparent to those skilled in the art, arranged so that the entire cylinder 10 can be adjusted lengthwise. The mechanism is operated to shift the trailing clamping assembly CT, and thus the trailing edge of the plate, longitudinally across the cylinder with respect to the leading edge of the plate by rot-ating the gear 172 using the hand wheel 176, which turns the actuating sleeve 154 relative to the reaction ring 158 so that the sleeve 154 is threaded toward or away from the cylinder body. The longitudinal lmovement of the reaction ring is transmitted through the bearing 152 to the sleeve 14S and thence through the coupling bar 140 lto the trailing clamping assembly CT. By rotating the gear 172 in an appropriate direction, the trailing end of the plate can be shifted in either direction along the cylinder. As mentioned above, the entire lockup is relatively free to pivot slightly about the positioning pin 120 so that the tendency for the plate to assume a slight helical wrap around the cylinder is accommodated.

The operation of the lockup is as follows: the wraparound plate will have previously been formed with the inturned flanges 24a at each end, the flanges being reasonably accurately located with respect to the image on the plate. The mounting operation is carried out with the

expandable tubes

104 and 106 deated, the source of air pressure having been shut olf.

Using the tool 98 (FIG. 5), the clamping jaws on either one of the clamping assemblies are opened up by engagement upon rotation of the shaft 86 of the corresponding set of lugs 80 with the jaw spring retainers 76. The flange 24a on the plate 24 is then inserted into the clamping space between the clamping jaws and the clamping bar and the jaws are permitted to be urged closed by the springs upon returning the actuating bar 86 to its initial position. The tool 98 is then removed from the shaft extension `94 and turned end for end, and the abovedescribed procedure is repeated to clamp the other end of the plate in the other clamping assembly. The plate is now attached to the cylinder.

rDhe

expandable tubes

104 and 106 can then be inflated to a predetermined pressure providing the desired forces against the respective clamping assemblies to pull the plate 24 tightly about the cylinder. The inward tightening movement of the clamping assembly CL holding the leading end of the plate is performed first, its movement being limited, however, by engagement of the anges 68 on the bar 52 with the stops 116 on the actuating bar clamps 90 (FIG. 4), thereby locating the plate in a predetermined position with respect to the cylinder body. The trailing clamping assembly CT holding the trailing end of the plate is then moved inwardly, by inflating its tube 104, to an extent determined by the force exerted on it by the tube 104.

Circumferential registration of the plate image is obtained by establishing the appropriate relation between the cylinder and the press drive train in a manner well known to those skilled in the art, and similarly, longitudinal registration of the image is provided by moving the cylinder longitudinally, also in a manner known in the art. The plate cylinder is so mounted and coupled to the drive as to permit these adjustments.

Diagonal registration is afforded by cooking the plate by manipulating the cooking mechanism as follows: The air to the

expandable tubes

104 and 106 is turned off and, by means of the hand wheel 176 (FIG. 1B) the sleeve 154 is rotated in an appropriate direction to thread it with respect to the reaction ring 158 longitudinally along the cylinder shaft, thereby moving the clamping assembly to shift the trailing end of the plate with respect to the leading end. It will be recalled that provision for longitudinal movement of the trailing clamping assembly is made in the hinges 56. The adjustment can be made with the press running under printing impression. The longitudinal movement of the trailing end of the plate with respect to the leading end will tend to cause the plate to take a spiral wrap around the cylinder and to move the axis of the lockup slightly out of alignment with the axis of the plate cylinder. This movement is permitted by the pivot mounting of the lockup on the cylinder afforded by the pin 120. After the plate is properly oriented diagonally on the plate cylinder, the air supply to the expandable tubes can be turned on to tighten the plate. It should be observed that the plate can be cocked without shutting down the press and, moreover, is accomplished without shifting the plate cylinder.

Should the need arise, the removal of the lockup from the plate cylinder is readily accomplished without removing the cylinder from the press. To remove the lockup, the inserts 48 (FIG. 4) are drilled out to provide access to the screws 46, and the cylinder insert 44 and ller 34 removed. The retainer cap 97 is taken off to permit the shaft extension 94 to be removed, and the

expandable tubes

104 and 106 are dismounted from the bearers by removing the clamps 112 and 11-4. The shoulder screw 146 connecting the cocking mechanism to the coupling bar 140 is removed and the coupling bar taken out. A tool can then be inserted through the hole 130 to depress the pivot pin below the base of the recess 32, thereby permitting the entire lockup to be withdrawn from the recess.

Thus the invention provides a lockup that enables the plate to be mounted quickly and easily, thereby reducing shutdown time for setting up each press run. It affords precise adjustment of the plate to obtain proper registration, the adjustment being accomplished simply and quick- 1y; diagonal adjustment can be carried out while the press is running. The stops associated with one of the two clamping assemblies ensure that the plate will not slip out of circumferential registration during operation and also facilitate remounting a plate with minimum resetting. Both clamping assemblies pull the ends of the plate into a position inside `the periphery of the cylinder, thus eliminating the possibility of plate-cracking at the lockup points. The invention makes possible a minimum width opening, say 3A; inch wide, on t-he cylinder surface for receiving the plate ends. The hinging of the clamping assemblies to the securely retained base plate at a plurality of relatively closely spaced points along their lengths limits deection of the clamping bars, thereby affording more uniform tightness of the plate on the cylinder.

I claim:

1. In a plate cylinder for a rotary printing press of the type employing wrap-around plates, a plate lockup mechanism comprising a recess extending into and longi- -tudinally across the cylinder body, an elongated base plate mounted in the recess for pivotal movement about an axis disposed substantially radially of the cylinder and in a substantially fixed plane substantially perpendicular to the said radial axis, a pair of independent plate holding assemblies for securing each end of the plate to the base or plate and thus to the cylinder, each plate holding assembly including an elongated holder bar hinged to the base plate for pivotal movement about an axis disposed longitudinally of the base plate and having means thereon for attaching the respective end of the plate to the bar, one of the plate holding bars being xed on the base plate against longitudinal movement thereon and the other plate holding bar being movable longitudinally relative to the base plate along the said pivot axis of the bar on the plate, means selectively engageable with each plate holding assembly for moving its radially outermost end toward the other assembly to tighten the plate on the cylinder, and means coupled to the said other bar of the plate holding assembly for shifting it longitudinally of the cylinder to an adjusteddiagonally registered position on the cylinder whereby the base plate pivots on its pivot axis in free response to the adjusted position of the said other bar.

2. Apparatus according to claim 1 wherein the means on each plate holding assembly for securing the plate to the holder bar includes a plurality of spaced-apart clamping jaws mounted on the bar, the bar and jaws having coacting faces for clamping the plate between them, the jaws being mounted on the bar for movement relative to it between an open position in which the respective plate-clamping faces on the har and the jaws are separated to receive the edge of the plate and a closed position in which the end of the plate is clamped between the clamping faces and being normally resiliently urged to their closed position; and actuating means associated with each assembly fr substantially simultaneously shifting all of the jaws lthereof to open position to receive an end of the plate.

3. Apparatus accordingto claim 2 wherein the actuating means includes an operating member common to both assemblies; and is selectively operable substantially simultaneojlhsly to open all of the jaws on each assembly exclusively bf the jaws on the other.

4. Apparatus according to claim.3 wherein the actuating means includes an actuating bar rotatably mounted on the base plate between the holding assemblies and having elements thereon engageable with the clamping jaws on the respective clamping bars upon rotation of the actuating bars.

5. Apparatus according to claim 2 wherein the clamping jaws of each of the respective plte holding assemblies are mounted for movement along axes aligned on radial planes of the cylinder perpendicular'-to the cylinder axis and defining a common pl-ane extending longitudinally of the cylinder and angularly related to a plane defined by the cylinder axis and the pivotal axis of the respective bar, and wherein the plate-clamping faces of the jaws and bar define clamping spaces which are located on planes forming an acute angle with the said common plane whereby the shifting of the jaws along their axes' opens and closes the clamping spaces by virtue of the angular relationship between the said common plane and the plane of the said spaces.

6. Apparatus according to claim 1 wherein the means for shifting the longitudinally movable bar includes a coupling sleeve mounted on the cylinder shaft for rotational movement with the cylinder andlongitudinal movement along the shaft, a member coupling the sleeve to the said longitudinally movable bar, uand drive means for shifting the coupling sleeve longitudinally of the shaft.

7. Apparatus according to claim 6 wherein the drive means includes an acuating ring coupled to the coupling sleeve to impart longitudinal movement thereto, a nonrotatable reaction element fixed against movement longitudinally of the cylinder relative to a reference plane and against rotation, coacting threads on the actuating ring and reaction element, and means for rotating the actuating ring relative to the reaction element thereby to thread the actuatingrfing along the reaction element `and shift the coupling sleeve, coupling member and longitudinally movable bar relative to the reaction member.

8. Apparatus according to claim 7 wherein the means for rotating the actuating ring includes an operating element exteriorly of the press frame and means coupling the operating element to the actuating ring to impart rotation thereto.

9. Apparatus according to claim 1 wherein the means for moving the plate holding yassemblies to tighten the plate comprises a fluid expandableV tube positioned between each holding assembly bar and the adjacent wall of the recess.

10. Apparatus according to claim 9 further comprising stop means engageable by one of the holding assemblies for limiting the tightening movement of the end of the plate held by it and affording a predetermined circumferential location of the plate on the cylinder.

11. In a plate cylinder for a rotary printing press of the type employing wrap-around plates, a plate lockup mechanism comprising a recess extending into and longitudinally across the cylinder body, first and second plate holding means mounted in the recess for securing each end of the plate to the cylinder, each plate holding means including an elongated holder bar mounted for pivotal movement about an axis disposed longitudinally of the cylinder and Ihaving an edge remote from the pivot axis located proximate the cylinder surface,V a plurality of spaced-apart clamping jaws mounted on the bar for move- -ment thereon along axes aligned on radial planes of the cylinder perpendicular to the cylinder axis and defining a common plane extending longitudinally of the cylinder and angularly related to a plane defined by the cylinder axis and the pivotal axis of the bar, opposed faces on the bar and the jaws delining clamping spaces adjacent the said edge of the bar, the clamping spaces being located on a plane forming an acute angle with the said common plane, means resiliently urging the jaws in a direction to close the clamping spaces by virtue of the angular relationship between the said common plane and the planes of the said spaces thereby to engage and hold the end of the plate in the clamping spaces, and actuating means selectively engageable with the clamping jaws to move them in a direction to open up the spaces, and means selectively engageable with the respective holding means for urging the holding bars toward each other to tighten the plate on the cylinder.

12. Apparatus according to claim 11 wherein the actuating means substantially simultaneously engages and moves the jaws of each holding means.

13. Apparatus according to claim 12 wherein the actuating means includes an operating member common to both assemblies and is selectively operable substantially simultaneously to open all of the jaws on each assembly exclusively of the jaws on the other.

14. Apparatus according to claim 13 wherein the actuating means includes an actuating bar rotatably mounted in the recess between the holding bars and formations on the actuating bar engageable with the clamping jaws on the respective holding bars upon rotation of the actuating bar.

15. Apparatus according to claim 11 wherein the means for moving the plate holding assemblies to tighten the plate comprises a fluid expandable tube positioned between each holding assembly bar and the adjacent Wall of the recess.

16. Apparatus according to claim 15 further comprising stop means engageable by one of the holding assemblies for limiting the tightening movement of the end of the plate held by it and alording a predetermined circumferential location of the plate on the cylinder.

17. In a plate cylinder for a rotary printing press of the type employing wrap-around plates, a plate lockup mechanism comprising a recess extending into and .longitudinally across the cylinder body, means in the recess for attaching the plate to the cylinder including a base plate extending substantially the entire length of the recess, the base plate being mounted in the recess for pivotal movement about an axis disposed substantially radially of the cylinder and in a substantially xed plane substantially perpendicular to the said radial axis; a pair of independent plate clamping assemblies for clamping each end of the plates separately, each clamping assembly including a clamping bar hinged to the base plate adjacent to its lower end for pivotal movement and a plurality of clamping jaws spaced along the length of the clamping bar and normally resiliently urged into a plate-clamping position in which the end of the plate is clamped between coacting plate-clamping faces of the bar and the jaws, and means selectively engageable substantially simultaneously with all of the clamping jaws on each bar exclusively of the other bar to open up the plate-clamping spaces to receive the ends of the plate; means for pivoting the clamping assemblies to move their radially outermost ends toward each other to tighten the plate including a fiuid expansible tube positioned between each of the clamping bars and the adjacent wall of the recess, and means coupled to one clamping assembly for moving it longitudinally in either direction relative to the other assembly to shift the `diagonal orientation of the plate, the plate shifting means being operable from outside of the press frame and being operable while the press is running; 4the said one clamping assembly being movable longitudinally of the base plate and the other clamping assembly being fixed against longitudinal movement on the base plate whereby the movement of the said one clamping assembly to adjust its posi- 1 1 12 .l tion results in freely responsive pivoting of the base plate 2,775,198 12/1956 Johnson lOl-415.1 and lookup elements thereon. 2,965,025 '12/ 1960 MnellerlOl-415.1

3,149,565 9,/1964 =Norlin lOl-415.1 References Cited 3,151,553 10/ 1964 Norton V,10b-415.1 UNITED STATES PATENTS 5 y y 1,260,470 3/1918 smith er a1 10i-415.1 ROBERT E PULFREY Primary Exammer 2,768,579 10/ 1956 Fics 101-41'51 I. R. FISHER, Assistant Examiner