US3750572A - Printing plate cylinder saddle - Google Patents

Abstract

A printing plate cylinder saddle is provided with construction features for mounting on a printing plate cylinder and for attaching a thin, flexible printing plate. Identical plate engaging assemblies are provided at each end of the saddle and are selectively operable to releasably clamp and interlock the lead edge of the flexible plate in register along the lead edge of the saddle or to interlock and exert a constant tension upon the tail edge of the flexible plate along the trailing edge of the saddle.

Description

United States Patent Etchell et al. 1 Aug. 7, 1973 [54] PRINTING PLATE CYLINDER SADDLE 3,603,255 9/1971 Homer 101/378 3,626,848 121971 T fl t l 101 415.1 [751 fiche", Owners 3,646 886 3l1972 11:02:11; et al. 10 l/378 Bohdan Washchynsky, Westchester, both f "L FOREIGN PATENTS OR APPLICATIONS [73] Assigneez North American Rockwell 1,115,936 6/1968 Great Brltaln 101/4151 Corporamm Pittsburgh Primary ExaminerRobert E. Pulfrey [22] Filed: June 12, 1972 Assistant ExaminerPaul T. Sewell [211 App. No: 261,876 stigma-John R. Bronaugh, Damel H. Dumbar [57] ABSTRACT 2% A printing plate cylinder saddle is provided with con- 415 1 struction features for mounting on a printing plate cyl- 1 0 can inder and for attaching a thin, flexible printing plate. Identical plate engaging assemblies are provided at [56] Reerences cued each end of the saddle and are selectively operable to UNITED STATES PATENTS releasably clamp and interlock the lead edge of the 3,110,255 11/1963 Jeschke et al. l01/415.1 flexible plate in register along the lead edge of the sad- 3,702,098 11/1972 Eburn lOl/4l5.l dle or to interlock and exert a constant tension upon 3,470,817 10/1969 Helmllcher et a1. 101/378 the tail edge f the flexible plate along the trailing edge 3,533,355 10/1970 Wall 101 4151 Ofthe Saddle 3,537,395 11 1970 Prince et al.. 101/378 3,587,464 6/1971 Wessels 101/4151 5 Claims, 6 Drawing Figures PATENIED 7 3. 750.572

sum 3 or 3 PRINTING PLATE CYLINDER SADDLE SUMMARY A printing plate cylinder saddle is provided with means for mounting on a rotary printing press printing plate cylinder and with identical lockup assemblies at both ends of the saddle which are selectively positionable for interchangeably engaging either the lead or the tail edge of a flexible printing plate of the type having lead edge and tail edge flanges formed essentially at right angles to the plate principal surface. Each lockup assembly includes a series of plate engaging fingers and associated interlocking tabs which are movable by means of a convenient manually operable lever between two plate engaging positions. In one position the fingers and interlocking tabs radially restrain and securely clamp the lead edge flange of the printing plate in register position along the lead edge of the saddle. In the other position, the fingers and tabs are adapted to radially restrain and exert constant tension on the tail edge flange of the printing plate. Thus, the lead edge of a plate may conveniently be mounted in register at either end of the saddle and by simply moving two convenient levers it is securely locked in position and placed under a constant tension.

DRAWINGS FIG. I is a schematic end view of a typical rotary printing press printing plate cylinder having two semicylindrical saddles in accordance with the present invention mounted thereon;

FIG. 2 is a developed view taken along the line 2-2 of FIG. 1;

FIG. 3 is a sectional view along line 3-3 of FIG. 2;

FIG. 4 is an exploded view of the flexible printing plate restraining/tensioning assembly provided at each end of the disclosed novel saddle;

FIG. 5 is a perspective view ofa spring element of the FIG. 4 assembly; and

FIG. 6 is a fragmentary perspective view illustrating the flanged edge of a flexible printing plate for which the saddle lockup assembly of FIG. 4 is useful.

The invention subsequently described herein is disclosed schematically in FIG. I as applied to the printing plate cylinder 10 of a rotary newspaper printing press. The number of printing plates and thus the number of pages to be printed by such cylinder will vary depending upon the size and type of printing press involved but generally such cylinders are adapted to accommodate two plates around and four plates across so that eight pages are printed during each cylinder revolution. Such cylinders may be driven in either a clockwise or counterclockwise direction, as viewed in FIG. 1, depending upon the configuration and webbing of the press, but for the purpose of illustrating this invention it will be assumed that the cylinder will rotate in a clockwise direction as indicated by the arrow.

When printing with thin, flexible printing plates, as distinguished from the more conventional stereotype printing plates, such flexible plates must be mounted on saddles of the required thickness and radius of curvature so that the peripheral or printing surfaces of the plates will be adequately supported and maintained at the proper radius. Two such saddles are indicated as 11 and 12 in FIG. 1 and it will be understood that they are secured to the surface of printing plate cylinder 10 by conventional stereotype printing plate tension lockup means as is well known in the art.

The means whereby the flexible printing plates are secured in position on the saddles is illustrated in FIGS. 2 and 3 wherein the lockup assembly indicated by the numeral 20 is shown as being mounted at the lead edge of the saddle 11 for engaging the lead edge ofa flexible printing plate whereas the identical lockup assembly indicated by the numeral 21 is shown as being mounted on the trailing edge of saddle 12. It will be understood, of course, that identical lockup assemblies are desirably provided at the other trailing and leading edges of the respective saddles also.

All of the assemblies are identical in structure and function and therefore, the following detailed description will be directed to the lockup assembly 20 at the lead edge of the saddle l1 and the same reference numberals will be used to identify corresponding elements in the assembly 21.

As shown in FIGS. 2 and 3 the saddle 11 comprises a semi-cylindrical, generally plate-like body member, preferably formed of lightweight metal such as magnesium or cast aluminum, for example, the inner surface of which is milled away or relieved along the lead edge thereof to accommodate the lockup assembly 20. As may be seen best in FIG. 3, portions 22 of the body member adjacent the lead edge relief are retained and these are provided with undercut scarf notches 23 which are adapted to receive the cooperating cylinder tension lockup hooks for stereotype plates (not shown) by means of which the saddle 11 is locked onto printing plate cylinder 10.

The plate clamping assembly 20 adapted to be mounted in the relieved portion of the saddle body is shown best in FIG. 4, and is comprised of a substantially L-shaped base member 27 which extends across substantially the full width of the saddle, a cover plate 28 which is similar in shape and size to the base mems ber, a slide bar 29, and a support bracket 31. The bar 29 and bracket 31 are sandwiched between the base member and cover plate and are mounted for movement relative thereto for plate clamping purposes.

The slide bar 29 is fabricated from a flat, rectangular metal plate and is provided with a series of three aligned, axially disposed, elongated slots 32 centrally thereof. Adjacent each end and on the side thereof facing the support bracked 31 the slide bar also is provided with rollers 33 which are rotatably mounted on rivets or the like secured to the bar. At one end of bar 29a V-shaped groove 34 is provided to receive the arm 36 of a bell crank lever 37 that ispivotally mounted between the base member 27 and cover plate 28 and it has a second arm 38 which projects sufficiently beyond the edge of the saddle to constitute a manual control lever whereby the slide bar can be shifted laterally for purposes to be explained hereinafter.

The support bracket 31 also is fabricated from a flat, rectangular metal plate and it is somewhat longer and wider than the slide bar. Rectangular openings 39 are formed in the body portion thereof to provide clearance for the scarfed projections 22 of the saddle and at the base thereof the bracket is provided with three elongated slots 41 which are aligned with but extend in a direction normal to the slots 32 in the slide bar 29. The base portion of the bracket also is provided with a diagonally disposed slot 42 adjacent each end thereof and these slots are aligned with and are adapted to receive the rollers 33 of the slide bar in the assembled position. Reverse angled pockets 43 are formed at the ends of the slots 42 and as will become clear hereinafter these pockets serve to maintain the bracket in each of its plate clamping positions.

The elements thus far described are assembled as a unitary structure by means of rivets 44 and 45 which extend through apertures provided therefor in the base member 27 and cover plate 28. The rivets 44 also extend through the outermost of slots 32 and 41 in the slide bar 29 and bracket 31, respectively, and they are provided with spacers 46 which fit snugly without binding in the respective slots 32 and 41 and serve to maintain clearance between the base member and cover plate so that the slide bar 29 and support bracket 31 are caused, when actuated, to move at right angles relatively to each other. The rivet 45 also passes through an opening 47 provided in the bell crank 37 and constitutes the pivot axis for said lever.

After assembly of the unit as just described, it is removably mounted to the saddle by means of the bolts 48 which pass through openings in the base member and cover plate as well as spacers 49 and the ends thereof are received in tapped holes provided therefor in the saddle. The center bolt 48 also passes through the base member and cover plate and it carries a spacer 49 which is adapted to fit snugly in the center slots 32-4l of the slide bar and bracket, respectively.

From the description thus far, it will be evident that when the bell crank 37 is pivoted in a clockwise or counterclockwise direction corresponding lateral movement will be imparted to the slide bar 29 which motion is permitted by the elongated slots 32 whereas said slots coact with the spacers 46 and 49 to prevent the slide bar from moving in a circumferential direction. Due to the coaction of the rollers 33 of the slide bar in the diagonal slots 42 of the support bracket 31, the latter will be moved back and forth in a circumferential direction between its two plate clamping positions, the elongated slots 41 permitting such circumferential movement while coacting with the spacers 46 and 49 to preclude lateral movement of the bracket.

For the purpose of radially restraining, clamping, and tensioning a flexible printing plate on the saddle, one edge of the support bracket 31 is projected beyond the base member 27 and cover plate 28 and is provided with a series of plate tentioning fingers 51 and interlocking fingers 52 extending across the full width thereof. Such fingers are preferably fabricated from a strip of spring steel which is bent into a generally Z- shaped configuration haveing a base portion 53, a vertical wall 54, and a finger portion 56. The finger portion 56 and wall 54 are slotted as at 57 thereby forming two tension fingers 51 which are separated by an intervening finger 52, the latter being bent at an angle relative to the wall portion 54 such that it projects somewhat ahead of the tension fingers 51 as indicated more clearly in FIG. 3. In those portions of the vertical wall 54 forming part of the tension fingers 51, interlocking tabs 58 are punched from the spring steel so that they project rearwardly with respect to the fingers 51 and they are bent at an obtuse angle or sloped with respect to the vertical wall as is more clearly indicated in FIG. 3.

All of the respective fingers and tabs across the full width of the support bracket obviously may be formed from one continuous piece of spring steel but it is preferred to form them as independent elements each of which consists of two tension fingers and an intervening locking finger. In such case, four such elements normally are required for a standard size saddle and they are mounted in aligned relation along the projecting edge of the support bracket 31 as illustrated in FIG. 4. In the preferred construction, the base portion 53 of each finger element is sandwiched between the bracket 31 and one leg 55 ofa bar 59 of L-shaped cross-section and both the finger element and the bar are secured in position on the bracket by means such as the rivets 60. The bar 59 is mounted over the finger element in a manner that the other leg 55a thereof extends parallel with and closely adjacent to the vertical wall 54 of the finger element and it serves to protect the tension fingers 51 against damage as well as to reinforce the fingers as they move to the plate clamping position as will be explained hereinafter. It will be noted that the leg 55a of the L-shaped bar is cut away in the area adjacent the interlocking finger 52 so that said finger can project forwardly of the tension fingers 51 and thereby perform its intended function.

For use in conjunction with the present saddle lockup means, the printing plates are pre-bent and punched in a manner as indicated in FIG. 6. As shown, the edges (leading and trailing) of the plate 61 are bent inwardly at substantially a angle relative to the body thereof to form a flange 62 which in turn is provided with two series of slots 63 and 64 respectively. The slots 63 are located so that they will coincide with a groove 66 formed in the end face of the saddle 11 and they are adapted to have coaction with the locking tabs 58 to radially restrain the lead edge of the plate in register position on the saddle. The slots 64 on the other hand are located substantially at the junction between the flange 62 and body 61 of the plate and they are adapted to have coaction with the interlocking fingers 52 to radially restrain the trailing edge of the plate in position.

Although the function of the lockup assemblies should be clear from the foregoing description, a brief explanation of the procedure involved in mounting a plate on the saddle is considered helpful. Assuming that the cylinder 10 (FIG. 1) will be rotating in a clockwise direction, the lockup assembly 20 on the saddle 11 will be in the lead edge position. Referring to FIG. 3, the lever 38 must first be moved in a clockwise direction (as viewed in FIG. 2) thereby shifting the slide bar 29 and therewith the rollers 33 to the right. As the rollers 33 traverse the diagonal slots 42, the bracket 31 will be moved in a circumferentialdirection from its retracted (FIGS. 2 and 3) position wherein the vertical wall 54 of the tension fingers 51 is adjacent the end face of the saddle, to its projected position (see assembly 21, FIGS. 2, 3) wherein said wall 54 is spaced from the end face of the saddle. This will provide clearance for the flange 62 at the lead edge of the plate to be inserted between the face of the saddle and the clamp assembly with the slots 63 therein coincident with the groove 66. It should be noted, although not shown in the drawings, that locating pins or studs may be mounted in the end faces of the saddle and cooperating holes provided in the flanged leading and trailing edges of plate 61 to obtain proper lateral registration of the plate on the press plate cylinder prior to clamping and tensioning.

Once the lead edge of the plate is in position, the lever 38 is moved in counterclockwise direction whereupon the rollers 33 and slots 42 will coact to retract the bracket 31 as the slide bar 29 moves to the left as viewed in FIG. 2. Movement of the bracket 31 continues until it assumes the clamping position as illustrated in FIG. 3 wherein the tabs 58 are interlocked in the slots 63 of the plate and project into the groove 66 of the saddle. In this position the lead edge of the plate is positively radially restrained by the tabs 58 against centrifugal forces acting thereon at high speeds.

The angle of the tabs 58 also serves a secondary but important function. As the bracket 31 is retracted toward its plate clamping position, the leading edge of the tabs 58 will initially engage the upper edges of the slots 63 of the plate 61. As movement of the bracket continues, the angle of the tabs 58 will cause the flange 62 of the plate to be drawn radially inwardly of the saddle until the body portion of the plate is brought into and thereafter maintained in intimate contact with the outer surface of the saddle. This is important because the plate has a natural tendency to spring away from the saddle and if any clearance remains between the plate and the saddle after the plate is locked up in position, it will permit a flexing action which can have an adverse effect upon the printed impression as well as cause premature cracking of the plate during operation.

During the retraction of the bracket 31 the radially disposed wall 55a of the L-shaped bar 59 engages and thus serves to reinforce the relatively flexible fingers 51 so that the tabs 58 will penetrate the slots 63 to the maximum extent and thus positively draw down the plate into intimate contact with the saddle.

After the lead edge of the plate has been radially restrained and clamped into position, the tail edge is secured by the assembly 21 at the trailing edge of the saddle. In this instance, the lever 38 of the assembly 21 would first be moved in counterclockwise direction as viewed in FIG. 2, thereby shifting the slide bar 29 laterally so that the rollers 33 will traverse the diagonal slots 42 and thus retract the bracket 31 and fingers 51 to a position adjacent the end face of the saddle. The tail end flange 62 of the plate 61 is then positioned over the fingers 51 and 52 whereupon the lever 38 is moved in clockwise direction to project the fingers 51 and 52 to the position illustrated in FIG. 3

During their movement to the illustrated projected position the sloped portions of interlocking fingers 52 project through the slots 64 in the plate 61 thereby securing the plate against any centrifugal forces acting thereon during operation of the press and here again because of the angle of said fingers the tail edge of the plate is drawn radially inwardly and maintained in intimate contact with the peripheral surfaces of the tension fingers 51. The latter fingers in turn, are adapted to engage the flange 62 of the plate prior to reaching their fully projected position so that they are bent backward to a predetermined extent upon final movement of the bracket 31 to its fully projected position. As a result, the fingers 51 become preloaded and thus exert a constant, circumferentially directed tension upon the plate to maintain it in intimate contact with the saddle during operation of the press.

With the flexible printing plate clamped in operative position as just described, it is obvious that reactive forces acting upon the respective clamping and ten- 6 sembly 20, a reactive force will be exerted against the fingers 51 tending to move the bracket 31 away from the end face of the saddle 11, to the left as viewed in FIG. 2. This force coupled with normal vibration under operating conditions would result in the slide bar 29 shifting laterally, due to the effect of the diagonal slots 42 on the rollers 33, thereby relaxing the securing effect of the fingers 51 and tabs 58 on the plate. The same condition would exist with the assembly 21 except that the reactive force would be exerted in the opposite direction.

To preclude such unintended motions, the previously mentioned reverse angled pockets 43 are provided at each end of the diagonal slots 42 which perform a toggling function in combination with the rollers 33 and thus serve to releasably retain the bracket 31 in either one of its plate clamping positions. With reference to FIG. 2 it will be evident that as the slide bar 29 is moved to the left, the rollers 33 will traverse the slots 42 thereby retracting the bracket 31 to its lead edge plate clamping position and during the final movement of the slide bar, the rollers 33 will pass over the apex of the slots 42 and drop into the pockets 43. As a result, the reactive force acting on the bracket 31 and tending to move it in a circumferential direction away from its plate clamping position will merely force the rollers into the pocket 43 and thus lock the slide bar 29 against any unintended lateral movement. The same function is achieved when the assembly is moved to the plate tensioning position as representd by the assembly 21 in FIG. 2, in which case the rollers 33 drop into the pockets 43 at the opposite end of the slots 42 to thereby toggle the assembly in the tail edge plate tensioning position. This arrangement is completely effective to retain the respective assemblies against unintended movement and yet the toggle effect presents minimum resistance against manual movement of the lever 38 so that the need for an auxiliary tool or the like to manipulate said lever for plate clamping purposes is completely obviated.

What is claimed is:

1. A saddle for attaching to a printing cylinder a flexible printing plate having like flanged and slotted leading and trailing edges formed essentially at right angles to the plate principal surface and comprising, in combination: 7

a rigid plate-like body of generally semi-circular cross-sectional configuration defined in part by a pair of longitudinal edges;

attachment means adjacent the concave surface of said plate-like body for mounting said body on a printing press cylinder;

a pair of plate retention members respectively located adjacent said body pair of longitudinal edges and each having alternate extreme positions for clamping and for tensioning;

mounting means securing said plate retention members to said body and restricting'movement of said plate retention members to circumferential directions relative to said body longitudinal edges and relative to said retention member clamping and tensioning positions;

a pair of actuator means respectively connected to said pair of plate retention members and each being mounted for acutatio n to alternately move a cooperating connected plate retention member to said alternate extreme plate clamping and plate tensioning positions; I

first means in each said plate retention member for engaging and radially restraining a printing plate flanged and slotted leading edge and for urging said engaged plate flanged and slotted leading edge against one of said body longitudinal edges on movement of said plate retention member by the connected one of said actuator means to one of said extreme plate clamping positions; and

second means in each said plate retention member for engaging and radailly restraining a printing plate flanged and slotted trailing edge and for urging said engaged plate flanged and slotted trailing edge away from the other of said body longitudinal edges on movement of said plate retention member by the connected one of said actuator means to one of said extreme plate tensioning positions.

2. The saddle defined by claim I wherein each said actuator means comprises an actuator bar element having slots and movable in longitudinal directions with respect to said plate-like body, and wherein said plate retention member connected to said actuator means bar element is provided with diagonal slot elements and with cooperating roller cams each further cooperating with said actuator bar element slots, said roller cam and diagonal slot elements directing forces developed by said connected actuator means from lines along said bar element longitudinal directions to lines along said plate retention means circumferential directions to move the connected one of said retention members to said clamping position and to said tensioning; position when said actuator means is operated to move said mounting means to and from said plate tensioning position.

3. The invention defined by claim 2 wherein said diagonal slot elements are provided at each slot end with a reverse-angle pocket acting as a detent for the cooperating one of said roller cam elements, said reverseangle pockets locating the cooperating actuator means and mounting means in said plate clamping and plate tensioning positions.

4. The invention defined by claim 1 wherein said plate retention members each have spring-like finger members oriented relative to said plate-like body in a generally radial direction and extending substantially throughout the longitudinal extent of said plate-like body, said finger members further comprising first finger members engaging the flexible printing plate flanged trailing edge when tensioning said flexible printing plate and having sloped surface portions engaging slots in said flexible printing plate flanged leading edge to radially restrain said flexible printing plate when said actuator means is positioned in said clamping position, and second finger members interspersed with said first finger members along the longitudinal extent of said plate-like body and having sloped surface portions engaging slots in said flexible printing plate flanged trailing edge to radially restrain said flexible printing plate when said actuator means is positioned in said tensioning position.

5. The invention defined in claim 4 wherein said plate-like body is provided with a groove in said body leading edge and with a groove in said body trailing edge, said first finger member sloped surface portions being received in said body leading edge groove when said plate retention member is moved in a circumferential direction to said clamping position.

Claims (5)

1. A saddle for attaching to a printing cylinder a flexible printing plate having like flanged and slotted leading and trailing edges formed essentially at right angles to the plate principal surface and comprising, in combination: a rigid plate-like body of generally semi-circular crosssectional configuration defined in part by a pair of longitudinal edges; attachment means adjacent the concave surface of said plate-like body for mounting said body on a printing press cylinder; a pair of plate retention members respectively located adjacent said body pair of longitudinal edges and each having alternate extreme positions for clamping and for tensioning; mounting means securing said plate retention members to said body and restricting movement of said plate retention members to circumferential directions relative to said body longitudinal edges and relative to said retention member clamping and tensioning positions; a pair of actuator means respectively connected to said pair of plate retention members and each being mounted for actuation to alternately move a cooperating connected plate retention member to said alternate extreme plate clamping and plate tensioning positions; first means in each said plate retention member for engaging and radially restraining a printing plate flanged and slotted leading edge and for urging said engaged plate flanged and slotted leading edge against one of said body longitudinal edges on movement of said plate retention member by the connected one of said actuator means to one of said extreme plate clamping positions; and second means in each said plate retention member for engaging and radially restraining a printing plate flanged and slotted trailing edge and for urging said engaged plate flanged and slotted trailing edge away from the other of said body longitudinal edges on movement of said plate retention member by the connected one of said actuator means to one of said extreme plate tensioning positions.

2. The saddle defined by claim 1 wherein each said actuator means comprises an actuator bar element having slots and movable in longitudinal directions with respect to said plate-like body, and wherein said plate retention member connected to said actuator means bar element is provided with diagonal slot elements and with cooperating roller cams each further cooperating with said actuator bar element slots, said roller cam and diagonal slot elements directing forces developed by said connected actuator means from lines along said bar element longitudinal directions to lines along said plate retention means circumferential directions to move the connected one of said retention members to said clamping position and to said tensioning position when said actuator means is operated to move said mounting means to and from said plate tensioning position.

3. The invention defined by claim 2 wherein said diagonal slot elements are provided at each slot end with a reverse-angle pocket acting as a detent for the cooperating one of said roller cam elements, said reverse-angle pockets locating the cooperating actuator means and mounting means in said plate clamping and plate tensioning positions.

4. The invention defined by claim 1 wherein said plate retention members each have spring-like finger members oriented relative to said plate-like body in a generally radial direction and extending substantially throughout the longitudinal extent of said plate-like body, said finger members further comprising first finger members engaging the flexible printing plate flanged trailing edge when tensioning said flexible printing plate and having sloped surface portions engaging slots in said flexible printing plate flanged leading edge to radially restrain said flexible printing plate when said actuator means is positioned in said clamping position, and second finger members interspersed with said first finger members along the longitudinal extent of said plate-like body and having sloped surface portions engaging slots in said flexible printing plate flanged trailing edge to radially restrain said flexible printing plate when said actuator means is positioned in said tensioning position.

5. The invention defined in claim 4 wherein said plate-like body is provided with a groove in said body leading edge and with a groove in said body trailing edge, said first finger member sloped surface portions being received in said body leading edge groove when said plate retention member is moved in a circumferential direction to said clamping position.

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