US3534694A

US3534694A - Underside lockup for stereotype printing plate

Info

Publication number: US3534694A
Application number: US729688A
Authority: US
Inventors: Leonard I Tafel; Richard G Karch; Larry G Taylor
Original assignee: Miehle Goss Dexter Inc
Current assignee: Miehle Goss Dexter Inc
Priority date: 1968-05-16
Filing date: 1968-05-16
Publication date: 1970-10-20
Anticipated expiration: 1987-10-20
Also published as: GB1196240A; DE6918082U; CH493335A; FR2008663A1; DE1922732A1

Description

United States Patent [72] Inventors Leonard I. Tafel La Grange; Richard G. Karch, Hillside, Illinois; Larry G. Taylor, Dallas, Texas [21] Appl. No. 729,688 [22] Filed May 16, 1968 [45] Patented Oct. 20, 1970 [73] Assignee Miehle-Goss-Dexter Incorporated Chicago, Illinois a corporation of Illinois [54] UNDERSIDE LOCKUP FOR STEREOTYPIE PRINTING PLATE 12 Claims, 17 Drawing Figs.

[52] 0.5. CI 101/378, 101/415.1 [51] Int. Cl U B41f27/10 [50] Field ofSearch 101/378, 415.1, 382

[56] References Cited UNITED STATES PATENTS 1,831,219 11/1931 Wood 101/378 Primary Exanziner-Robert E. Pulfrey Assistant Examiner-Clifford D. Crowder AtrorneyWo|fe, Hubbard. Leydig, Voit and Osann ABSTRACT: A cylinder for holding a pocketed stereotype plate in a printing press in which the fingers which engage the pockets at one edge of the plate have provision for peripheral register adjustment, while the fingers which engage the opposite edge of the plate hold the plate in tension with continuous spring-pressed, nonretrograde followup. Each tensioning finger is activated by an individual cam block having a first set of cam surfaces to extend the finger and a second set of cam surfaces to advance the finger peripherally, the cam blocks being individually springpressed for independent and constant take-up movement of the tensioning finger. Manual operating and adjusting means are provided at the ends of the cylinder. The mechanical elements are received in longitudinal grooves formed in the cylinder and held in place by cover plates.

Patented Get. 20, 1970 Sheet j l/Leo NVENTORS NARD I. TAFEL Rim/m0 G. KARCH LARRY G. TAYLOR by: I ,,u,r@m

Ar'rvs.

Patented Oct. 20, 1970 Sheet m M VEMTWS LEONARD JZ. TAFEL RICHARD G. MARCH L W G. Mmrm I A 5 F 05f 2 (6941M? M A ull UNDERSIDE LOCKUP FOR STEREOTYPE PRINTING PLATE It is object of the present invention to provide a lockup mechanism for stereotype printing plates which is highly effective and capable of holding such plates securely under tension during long press runs and with constant, individual auto matic, and nonretrograde followup as the plate settles on the cylinder or undergoes slight dimensional changes during continued use. It is another object of the present invention to provide a lockup mechanism of this type which is simpler and more economical than the lockup mechanisms available in the past. It is a related object to provide an underside lockup mechanism which employs simplified parts made to liberal tolerance and which utilizes mounting grooves easily machined in the cylinder body. It is still another object to provide an underside lockup which may be easily and quickly installed in the cylinder, which has universal utility capable of prompt conversion in the field for different plate width and different spacing of the pockets, and which is inherently strong and durable for reliable operation at the highest press speeds. It is yet another object to provide a novel cover plate construction which safely retains the mechanical elements in working position but which may be easily removed and replaced.

Other objects and advantages of the invention will be apparent upon reading the attached detailed description and upon reference to the drawings in which:

FIG. 1 is a general perspective view of a printing cylinder embodying the present invention;

FIG. 2 is an end view of the cylinder of FIG. 1, partly broken away;

FIG. 3 is an enlarged fragmentary section taken transversely through the cylinder showing one set of the lockup mechanism with tensioning fingers retracted;

FIG. 3a is a fragmentary section based on FIG. 3 but showing the fingers extended;

FIG. 4 is a fragmentary elevation taken along the line 4-4 of FIG. 3;

FIG. 5 is a fragmentary top view of the structure shown in FIG. 3 with the cover plates removed and the tensioning fingers retracted;

FIG. 5a is a view based on FIG. 5 but showing the cover plate in place and the fingers extended;

FIG. 6 is a fragmentary perspective, partially diagrammatic, showing a finger in retracted position and with plate lifter in the engaged position;

FIG. 6a is a perspective view similar to FIG. 6 but showing the finger moved forward for engagement with the pocket in the plate and showing the plate lifter in the disengaged position;

FIG. 7 is a fragmentary section showing lifting of the plate by the plate lifter;

FIG. 8 is an enlarged fragmentary section taken along the line 8-8 in FIG. 5;

FIG. 9 is a fragmentary section looking along the line -9 in FIG. 8;

FIG. 10 is a top view of a registering finger block showing the angular accommodation to adjacent pockets in the plate;

FIG. 11 is a fragmentary perspective showing the register adjusting means, in simplified form;

FIG. 12 is a diagram showing the insertion of the trapezoidal cover plates and retaining wedge block into the surface of the cylinder;

FIG. 13 is a view looking along the line 13-13 in FIG. 9, showing the cover plate profile; and

FIG. 14 is a plan view of a riser cam showing the provision for endwise adjustment.

While the invention has been described in connection with a preferred embodiment, it will be understood that the invention is not limited to the particular embodiment shown and that we intend, on the contrary, to cover the various alternative and equivalent constructions included within the spirit and scope of the appended claims.

Turning now to the drawings, and particularly to FIGS. 1 and 2, there is shown a printing cylinder 20 having a first set of alined fingers 21 for engaging a printing plate at its registering edge, and a second set of alined fingers 22 for engaging the opposite, or tensioning, edge. Each of the plates, indicated at 23, 24, respectively (FIG. 2), extends halfway around the cylinder. The cylinder may be two. four, or six pages in width, accommodating plates side by side, but only one half ofa four page wide cylinder has been illustrated. Each plate has a series of pockets 25 milled along its underside adjacent the straight edges of the plate as shown in greater detail in the prior Crafts U.S. Pat. No. 2,474,889. In the underside lockup procedure, referred to as tension lockup, a plate is held on the cylinder with the registering fingers 2i engaging a set of pockets and with the fingers being peripherally adjusted to establish register. The second set of fingers 22 is then advanced into engagement with the pockets 25 at the opposite edge of the plate so that the plate is held in sustained tension snugly on the surface of the cylinder. Attention will first be given to the portion of the lockup mechanism which operates the fingers 22 for tensioning of the plate.

Formed in the cylinder is a longitudinal groove 30, having

parallel walls

31, 32, housing all of the elements required for tensioning and takcup and having a flat bottom surface 33. Spaced along the groove 30 are a series of cum blocks 35, one for each of the fingers 22. Such cam blocks are of hollow, boxy

construction having sidewalls

36, 37 slidable against the walls of the groove 30 and an end wall 38. Supported by the cam blocks are finger blocks 40, of which the fingers 22 are an integral part. Each of the finger blocks has a sloping back surface 4I,-the purpose of which will shortly appear, and is held in place by means of a cover plate 42 having apertures, such as shown at 43, through which a finger 22 may project.

In accordance with the present invention, riser cam surfaces are provided in the bottom of the groove having axially facing ramp surfaces for elevating the cam blocks as they are moved in the axial direction so that the fingers 22 are elevated into projecting position and angled way surfaces are provided between the cam blocks and the finger blocks so that upon movement of the cam blocks in the axial direction the finger blocks are advanced chordwise moving the fingers into the corresponding pockets in the printing plate. Thus turning to the drawings and particularly to FIGS. 46, a riser cam 50 is secured to the bottom of the groove and has axially facing

ramp surfaces

51, 52, each of which terminates in

flat plateau surfaces

53, 54. The ramps are engaged by cam follower surfaces, 55, 56, formed on the bottom of the cam block 35. At the top of the cam blocks, angled way surfaces are provided in the form of a ridge 57 which engages a groove 58 on the underside of the finger block. The right-hand edge 59 of the finger 22 striking the edge of the aperture 43 in the cover plate, obstructs axial movement of the finger block with the resulting relative movement at the way surfaces serving to convert axial movement of the cam block into chordwise clamping movement of the finger.

In accordance with another aspect of the present invention, a threaded actuating rod is provided which extends through clearance holes in the cam blocks with each of the cam blocks having a nut and associated coil spring, positioned around the rod, on one side of the cam block for moving it in a direction to tension the plate and a nut spaced on the opposite side for moving the cam block in a direction to release the plate upon reciprocating the rod between alternate positions and with the rod being free to move radially with the rise and fall of the cam blocks. Thus, for the purpose of moving the cam blocks 35 endwise, we provide a threaded actuating rod 60 which extends through openings formed in the end walls 38 of the cam blocks. For moving the cam blocks in the plate tensioning direction, each cam block has an associated nut 61 and coil spring 62, with the spring being preferably recessed in the hollow of the block. For moving the block in the plate releasing direction, a nut 63 is provided. These nuts may be rotated for purposes of axial adjustment when the assembly is removed from the groove 30 for adjustment to accommodate various plate widths. but the nuts are dimensioned to engage the walls 3 1 32of the groove to preventariy change in adjustment after the assembly is installed. While separate nuts serve to move a given cam block in its opposite directions, the nuts between adjacent cam blocks may, as shown. do double duty.

Means are provided for manually moving the actuating rod between its alternate positions while accommodating the rise and fall of the rod with the cam blocks. For this purpose an actuator block 70 is provided at the end of the actuating rod having a radially extending slot 71, which is engaged by a crank pin 72 secured to a rotating socket 73 which is engageable by a manual operator in the form of an allen type wrench 74. A plunger pin 75 is provided in rotating socket 73 to prevent the removal of the wrench 74 when the lockup is in any but the locked position. It will be apparent to one skilled in the art that the plunger pin may also be controllingly coupled to the press control circuits (not shown) in such a way as to prevent operation of the press until the wrench is removed from the socket.

In carrying out the invention, a series of rotating plate lifters are used for lifting the tensioned edge of the plate clear of the cylinder automatically when the actuating rod 60 is moved in the plate lifting direction. Moving the actuating rod in the appropriate direction causes the plate lifter to rotate into disengaged position as the plate is secured. Thus we provide a series of rotatable plate lifters 80 each having a pinion 81 engaged by a longitudinally extending rack member 82. For coupling the rack member to the actuating block 70, at the end of the rod, the block is provided with a pin 83. The latter is received in a radially extending slot 84 for the purpose of accommodating the rise and fall of the actuating rod.

In operation, it will be assumed that the finger blocks occupy their recessed positions corresponding to FIGS. 3, 4 and 6. Under such conditions, the cam blocks are fully seated in the riser cams and are moved to the left, as viewed in FIG. 6. Since the finger is obstructed against any appreciable amount of axial movement, relative movement at the way surfaces 57, 58, causes the finger block to be retracted, with the sloping surface 41 on the back thereof engaging a sloping surface 85 in the cylinder to ensure that the finger block is positively retracted into recessed position. After the printing plate has been placed in position, with the pockets thereof registering with the fingers 22, the wrench 74 is thrown through 180 of arc causing advancement of the nuts 61, compression of the coil spring 62, and simultaneous axial movement of the cam blocks in the right-hand or clamping direction. As the

ramps

51, 52 are encountered, the cam blocks are cammed upwardly. The cam blocks then move across fiat plateau surfaces 53, 54. The relative movement at the angled way surfaces 57, 58, causes the finger blocks to be simultaneously elevated and moved forward and then moved chordwise to advance the fingers 22 into the pockets of the plate. At the completion of the throw of the wrench, the coil springs 62 are highly compressed as shown in FIG. 6a to place the plate under tension, but with sufficient travel remaining to accommodate register adjustments. The crank pin moves to a centered or toggled position thus blocking return movement of the actuating rod. Any settling of the plate during the first few revolutions of the press, or any elongation of the plate during a sustained run results in immediate takeup movement of the fingers by reason of the energy stored in the springs so that the plate is kept under sustained tension. The angling of the way surfaces 57, 58 is preferably sufficiently shallow so that the chordwise movement of the finger blocks is nonretrograde. The fact that the crank pin 72 is received in an approximately vertical cam slot 71 in the actuator block permits the actuating rod 60 to move bodily in the radial direction without affecting the operation of the crank.

As the actuating rod 60 is moved into the plate releasing direction (to the left as viewed in FIG. 6), the pin 83 which engages the rack 82 urges the rack to the left, rotating the plate lifters into engaged position as shown in FIG. 7, thereby lifting the plate clear of the cylinder surface and facilitating removal. Conversely, when the actuating rod is moved in the clamping direction. i.e.,to the right, the plate lifters 80 are all rotated out of the way as shown in FIG. 6a.

Turning next to the mechanism at the opposite or registering edge of the plate, and which serves to operate the fingers 21, such mechanism is contained within a narrow groove which is formed at the other side of wider groove 130 and having

parallel walls

91, 92 and a flat bottom surface 93. Spaced end to end within the groove 90 are registering finger blocks 95, each of which carries a pair of registering fingers 21. The finger block 95 is maintained in its seated position in the groove by means of a cover plate 96 having apertures 97 which are alined with corresponding pockets in the registering edge of the plate.

In accordance with the invention, the finger blocks 95 are made slightly narrower than the groove 90 in which they are received, and an adjusting screw is provided in each of the finger blocks, and bearing against the wall of the groove, for a small amount of circumferential adjustment. The finger blocks 95 are freely slidable in the groove 90 to permit alinement of the fingers 21 with the apertures, a rack being provided for simultaneously engaging pinions on each of the adjusting screws permitting register adjustment regardless of the axial positioning of the finger blocks. Thus taking the finger block 95 shown in FIGS. 5, 8 and 9 as representative, the finger block 95 has an adjusting screw 100 which is received in a -hole 101 centrally threaded in the block. The screw has a thrust plate 102 at one end and a pinion 103 at the other, the pinion being locked to the screw by means of a nut 104. For meshing with the pinions 103 of adjacent finger blocks, a longitudinally extending rack 105 is provided which is received in axially extending recess 106. The rack is positioned by means of an adjusting pinion 107 at the end of the cylinder having a shaft 108 which is engageable by a suitable wrench and having a dial 109 which is calibrated in terms of circumferential shift. Seated in the same longitudinally extending recess 106 is a second rack which is used to adjust the register of the ad jacent or in this case the inner, plate, this rack being positioned by a pinion 117 having a shaft 118 and calibrated indicating dial 119.

It is one of the features of the present construction that the finger blocks 95, being narrower than the groove in which they are received, and having an adjusting screw projecting from the center thereof, are free to adopt a skewed position within the exaggerated limits indicated at 121, 122, thereby enabling the finger block to accommodate itself to small amounts of nonalinement between adjacent pockets at the registering edge of the plate. This balances the forces applied by the adjacent fingers 21 and avoids the setting up of localized stress. To prevent the finger block 95 from rattling, the finger block may be recessed, as shown in FIG. 5, for reception of small coil-type expansion springs 123, 124 which exert a reaction force against the wall 92 of the groove.

When installing a plate, the

racks

105, 115 are moved in a direction to move the finger blocks 95 backward through the limited available distance. The plates are hooked over the registering fingers 21, following which the

racks

105, 115 are adjusted to establish an initial condition of register. Following this the wrench 74 at the tensioning edge of the plate is thrown to extend and engage the fingers 22 with their respective pockets as has been previously described.

As has been noted it is one of the features of the present construction that the two

adjacent grooves

30, 90 are formed at the bottom of the shallower groove 130, the edges of which are undercut to define supporting ledges accommodating cover plates of generally trapezoidal cross section which are locked in place by a retaining wedge block. Thus, referring to FIG. 12, a cylinder 20 has a shallow groove formed therein having undercut

lateral edges

131, 132 defining

side ledges

133, 134, which are alined with a central ridgell35. The cover member 42 has a tapered edge 137 while the cover member 96 has a, tapered edge 138, which are inserted into the undercut regions as shown in FIG. 12. When the cover plates are in place a retaining wedge block 140 having tapered surfaces 141, 142 is placed between them, the wedge block being clampingly secured by a series of retaining screws MS received in tapped holes 146 in the central ridge. It will be apparent that when the wedge block is clamped in place, the tapered surfaces thereon urge the cover plates into their seated positions on the side ledges, the entire cover assembly being securely fastened by only a limited number of screws 145 to permit quick and easy disassembly.

It is one of the further features of the present construction that the present cylinder and lockup may be used almost universally for pocketed type printing plates having different spacing between adjacent pockets, different spacing between the pockets engaging adjacent plates, and different spacing between the first pocket and the end of the cylinder. Such ad justment is facilitated by making the riser cams adjustably positionable in the groove at the tensioning edge of the plate and by substitution of cover plates having apertures spaced to correspond with the pocket spacing of the new plate. Alternatively, where the spacing of two adjacent pockets remains unchanged, the same cover plates, having a pair of apertures, may be used but the spacing between them may be changed by interposing a suitable cover plate spacer. The means for adjusting the position of the riser cam in the bottom of its groove may be that shown in FIG. 14, consisting simply of a pair of slots 151, 152 accommodating screws 153, R54, respectively. Where a spacer is employed between the cover plate sections, in lieu of replacing the entire cover plate, such sections may be positioned as shown at 155 in FIG. 13, it being understood that the spacer has the same trapezoidal section previously discussed in connection with FIG. 12.

Thus in a typical conversion, the cover plate structure may be removed. The finger blocks 95 at the registering edge may be simply lifted a slight distance to disengage the rack and moved along the groove to a new position in which the fingers 2ll register with the pockets of the plate of new width. Turning attention to the tensioning edge of the plate, the assembly consisting of the series of cam blocks 3&3, the finger blocks 40, and the actuator rod 60 is removed from the groove which permits the nuts 61, 63 to be rotated into new positions as required to move the cam blocks 35, and the fingers which they control, into registering with the pockets in the new plate. The new positional settings of the nuts 61, 63 may be obtained from a prepared table of distances supplied to the press mechanic. Following this, the cam block assembly may be reinstalled in the groove 30, with the nuts 61, 63, upon reassembly, being registered with the groove so that there is no possibility of a change in the nut adjustment. Following this, the

cover plates

42, 96, with appropriately spaced apertures, and either with or without spacers 155, are reinstalled with the fingers extending through the apertures and with the entire assembly being clamped together by means of the clamping screws 145.

While it is true that the provision for register adjustment is well known in the art and while it is true that means have been previously provided for tensioning the plate with automatic takeup, the present construction permits this mode of operation to be obtained more simply and less expensively than has been possible in the past and with a mechanism which holds the plates with a contstant, automatic, nonretrograde takeup. Not only are the individual parts simply formed and easy to as semble, but tolerances are liberal so that there is no need for precise machining or expensive fitting. The parts are durable and capable of withstanding high rotative speeds. Particularly noteworthy is the ease with which the construction may be adapted in the field for plates of different width or different pocket spacing.

We claim:

1. in a plate cylinder for holding a pocketed stereotype printing plate, the combination comprising means defining an axially extending groove in the surface of the cylinder, a riser cam seated in the bottom ofa portion of the groove presenting a series of axially facing inclined ramps with the ramps topped by adjacent flat surfaces, cam blocks each having two inclined surfaces on its underside for sliding engagement with the inclined surfaces of adjacent ramps on the riser cam and having associated flat surfaces for sliding engagement with the flat surfaces on the riser cam, actuating means including individual springs for simultaneously urging each respective cam block up the ramps and subsequently along the flat surfaces, a finger block slidably mounted on each of the respective cam blocks having an angled way surface engaging the latter and each having a plateholding finger, each of said finger blocks having means for obstructing axial movement thereof so that upon movement of the cam blocks under the urging of the springs the fingers are cammed outwardly of the cylinder surface by the ramps and moved chordwise into engagement with the respective pockets in the sterotype plate.

2. The combination as claimed in claim 1 in which the actuating means for the cam blocks is in the form ofa manually reciprocable rod extending through the cam blocks and having respective abutments in spaced relation thereon and with one end of each block having a hollow recess to seat a coil spring positioned around said rod and effectively interposed between the cam block and the respective abutment on the rod.

3. The combination as claimed in claim 2 including a plurality of plate lifters spaced circumferentially from said fingers along a line parallel thereto, the plate lifters being in the form of rotatable elements arranged generally radially in the cylinder and each having a cam surface at the upper end thereof for liftingly engaging the edge of the plate and a pinion at t he lower end, a reciprocable rack extending parallel to the reciprocable rod for engaging the pinions for rotation of the plate lifters in unison, and connecting means between the rack and the actuating means for the plateholding fingers for simultaneously moving the rod and rack so that retraction of the fingers is accompanied by lifting of the edge of the plate to facilitate removal thereof from the cylinder.

4. The combination as claimed in claim 3 in which the actuating means is in the form of a throw-over crank having limit positions separated by substantially for defining limits of rod and rack movement between respective positions in which (a) the plate holding fingers are fully engaged and the lifters are fully disengaged from the edge of the plate and (h) the lifters are fully engaged and the fingers are fully retracted from the pockets in the plate to a position feeessed wifhin the surface of the cylinder so that the edge of the plate is raised from the surface of the cylinder and is fully supported by the lifters.

5. in a plate cylinder for holding a stereotype printing plate having pockets along the respective edges, the combination comprising means defining a longitudinally extending groove in the surface of the cylinder, a set of plate registering finger blocks spaced end-to-end in a portion of the groove for holding one edge of a stereotype plate, said finger blocks each having a pair of register fingers thereon with all of the fingers being in alinement and projecting above the surface of the cylinder, each of said finger blocks having an adjusting screw threaded into the center thereof and held captive with respect to the walls of the groove for chordwise register adjustment of the block, said screws having respective pinions alined with one another along one side of the groove, said groove being wider than the blocks for chordwise movement of the blocks as well as intentional skewing play of each block for equalizing the forces applied to adjacent pockets by the fingers on the block, a reciprocable rack extending axially in the groove for meshing with the pinions, manual operating means for adjusting the rack axially for simultaneous registering movement of the finger blocks, and means at the opposite edge of the plate from the register fingers including plateholding fingers having associated take-up springs for engaging and holding the plate in cooperation with the register fingers during rotation of the cylinder.

6. The combination as claimed in claim in which auxiliary antirattle springs are interposed between the wall of the groove and the ends of the finger blocks, said auxiliary springs being sufficiently strong to prevent looseness of the finger blocks in the groove and yet sufficiently weak so as to be readily overpowered to accommodate equalizing skewing movement of the finger blocks when the fingers thereon are engaged by a plate.

7. The combination as claimed in claim 5 in which the finger blocks are provided in two sets alined with one another in a portion of the groove for engagement of adjacent plates arranged side-by-side on the cylinder, the first set having pinions alined in one plane and the second set having pinions alined in an adjacent plane, and separate reciprocable racks of narrow construction arranged side-by-side in the groove and having respective manual operating means at one end of the cylinder for registering adjustment of the sets of finger blocks.

8. in a plate cylinder for holding a pocketed stereotype printing plate, the combination comprising means defining a wide shallow groove in the surface of the cylinder running longitudinally thereof having a bottom and lateral edges, the bottom of the groove having formed therein a pair of narrower longitudinal grooves, said narrower grooves being spaced inwardly from the edges of the shallow groove to form lateral supporting ledges and defining a central ridge between them, sets of finger blocks in each of the narrower grooves each hav ing fingers which project outwardly of the locus of the surface of the cylinder in alinement with one another for engagement of pockets at the leading and trailing edges of a stereotype plate, means manually operable at the end of the cylinder for moving the blocks incident to plate lockup, the lateral edges of the shallow groove being angularly undercut, a pair of arcuately contoured cover plates seated on the respective ledges and ridge and having apertures to permit projection and movement of the fingers, said cover plates being of generally trapezoidal cross section for registering with the undercut edges and to define a wedge shaped space between them, a retaining wedge block filling the wedge shaped space, and means for clamping the wedge block to the central ridge thereby to clamp the cover plates in seated positions against the action of centrifugal force.

9. In a plate cylinder for holding a pocketed type stereoplate, the combination comprising means defining an axially extending groove having parallel side walls, riser cams seated in the bottom of the groove, cam blocks fitted in the groove in sliding relation to the riser cams, finger blocks having plateholding fingers and slidably seated on the respective cam blocks, said finger blocks and cam blocks having interposed angled way surfaces and each of the finger blocks having means for obstructing axial movement so that as the cam blocks are moved axially the fingers are moved radially outward and thence peripherally into the pockets of the plate, a threaded actuating rod extending through clearance holes in the cam blocks and having manual means for reciprocating the same between alternate positions, a nut and associated coil spring on the rod on one side of each cam block for moving the cam block in a direction to tension the plate and a nut spaced on the opposite side for moving the cam block in a direction to release the plate upon movement of the rod to its alternate positions, said nuts being rotatable on the actuating rod and said riser cams being positionable along the bottom of the groove for alinement of each cam block and finger with a corresponding pocket in the plate, said nuts being dimensioned for wall engagement to lock the nuts against rotation in adjusted position when the finger blocks and actuating rod are installed in the groove.

10. ln a plate cylinder for holding a pocketed stereotype plate, the combination comprising means defining an axially 8 extending groove in the surface of the cylinder having parallel side walls, cam blocks slidably fitted in the groove, finger blocks having plateholding fingers and seated on the respective cam blocks, a threaded actuating rod extending through clearance holes in the cam blocks and having manual means at one end for reciprocating the same between alternate positions, a nut and associated coil spring on the rod on one side of each cam block for moving the cam block in a direction to tension the plate and a nut spaced on the opposite side for moving the cam block in a direction to release the plate upon movement of the rod to its alternate position, riser cam means interposed between the cam blocks and the bottom of the groove and angled way surfaces including a rib interposed between the finger blocks and cam blocks so that as the actuating rod is moved all the cam blocks are cammed radially outward to produce radial and chordwise movement of the fingers in a direction to engage the pockets in the plate, said actuating rod being free to move radially with the cam blocks and said manual reciprocating means having provision for accommodating radial movement of the rod.

11. in a plate cylinder for holding a stereotype printing plate having pockets along the respective edges. the combination comprising means defining a pair of longitudinally extending grooves in the surface of the cylinder. each of the grooves having parallel side walls, a set of plate registering finger blocks spaced end to end in one of the grooves and having registering fingers thereon to engage the pockets at one edge of the plate, a set of tensioning finger blocks spaced end to end in the other groove and having plateholding fingers thereon, each of said registering finger blocks having an adjusting screw positioned to cause the register finger blocks to move chordwise in respect to the groove for peripheral register and having a drive pinion, a cover plate secured to the cylinder having apertures for passing the registering fingers and spaced to register with corresponding pockets in the plate, said registering finger blocks being movable axially in the groove into positions of alinement with the apertures, a rack extending longitudinally in the groove for simultaneously meshing with all of said pinions regardless of the axial positioning of the registering finger blocks, manual means for adjusting the rack endwise for simultaneous registering movement of the registering finger blocks, and means including tensioning springs at the opposite edge of the plate from the registering finger blocks for moving the plateholding fingers into tensioning engagement with corresponding pockets in the plate to hold the plate between the registering fingers and the plateholding fingers.

12. In a plate cylinder for holding pocketed stereotype printing plates, the combination comprising means defining an axially extending groove in the surface of the cylinder, riser cams seated in the bottom of the groove, cam blocks slidably engaging the riser cams and each having an angled way surface, finger blocks individually associated with the cam blocks and each having an angled way surface on the underside for slidably engaging the angled way surface on the associated cam block, cover plates for obstructing the fingers against axial movement, a manually operated actuating rod extending through clearance holes in the cam blocks, coil springs positioned around said rod for engaging the respective cam blocks, the coil springs being engaged by respective nuts threaded on the rod so that upon moving the actuating rod in the lockup direction the springs urge the cam blocks up and across the riser cams causing the finger blocks to move individually in the pocket engaging direction, the angle of the way surfaces being sufficiently shallow so that the finger blocks undergo follow-up movement in the pocket engaging direction but are blocked against retrograde movement until the actuating rod is moved in the unlock direction to release the mechanism.