US2291188A - Apparatus for forming composite curved printing plates - Google Patents

Description

A. LENGEL 2,291,188

APPARATUS FOR FORMING COMPOSITE CURVED PRINTING PLATES July 28, 1942.

Filed Feb. '7, 1941 2 Sheets-Sheet 1 INVENTOR. Ines/er z. LEA/GEL A TTOHNCX ayw%.

July 28, 1942. A. L. LENGEL 2,291,188

APPARATUS FOR FORMING COMPOSITE CURVED PRINTING PLATES Filed Feb. 7, 1941 2 Sheets-Sheet 2 INVENTOR. 4485m- L. Len/ea 94 1/2 A r TORNEY.

Patented July 28, 1942 U-iTED- STATE :TENT OFFICE APPARATUS FOR FORMING COMPOSITE CUR-VED PRINTING PLATES 15 Claims.

This invention relates to 1 cylindrically curved sheet metal printing platesof thetype which are secured to a similarly curved rigid shellto form a composite unit adapted formounting directly on the type cylinder of a'rotary printing press in place of the usual curved-stereotype plates as used in newspaper printing, so that the printing may be done from the original engraved or'rather etched plates instead of from stereotypes 'or electrotypes made therefrom.

The'principal object of the'invention is to provide an improved cylindrically curved composite plate of the 'kindabove set out and apparatus for producing'it.

Other'ieatures and advantages. of the improvement will appear in the following description and accompanying drawings:

In the drawings:

Fig. 1 is a perspective view'of one of the improved cylindrically curved composite printing plates as produced by my apparatus.

Fig. 2 is a plan View of the apparatus with its dies in closed position asseen before folding the margins of the thin printing plate over the edges of the rigid supporting-shell.

Fig. 3 isa longitudinal cross section of the apparatus of Fig. 2 as seen from the line 3-3 thereof.

Fig. 4 is an enlarged cross section of Fig. 2 taken along the line 44 thereof.

Fig. 5 is an enlarged fragmentary section of the base or concave die member showing the construction of the disappearing centering pins.

Fig. 6 is an enlarged fragmentary section showing the means of securing the margins of the thin printing plate to the edges of its rigid'supporting shell.

Fig. 7 is a view similar to that of Fig. 6 but showing a modification in the manner of securing the thin printing plate to its rigid supporting shell.

Fig. 8 is an enlarged detail of one of the cornets of the rigid supporting shell showing the thin printing plate extending thereover.

'Fig. 9 is an enlarged'perspectiv'e view of one of the link guiding blocks.

Figs. 10 and 11 are respectively front and side views of the hook for clamping the dies closed;

Fig. 12 is a plan view of the'handwheel' stop.

Fig. 13 is a fragmentary section taken along the line I 3-4 3 of Fig. 2.

Before describing the invention it may be said that it is not new to secure a thin flexible printing plate around a rigid press cylinder, or first to a rigid curved plate for thereafteriattaching the latterto the cylinder of a printingpress, the same having been used principally on lithographic presses for years, and more recently some work' has been done in, connection with the similar mounting of half tonean'd'similar typographic plates, but which by reason of their thickness and lack of flexibility have required rolling or forcible bendingto the proper curve before attaching to the press cylinder or intermediate support. My improvement is to eliminate several of the difiiculties involved which have heretofore prevented the wide-use of such curved original plates on rotary typographic presses.

In the practice of my invention'wit-h a so-called half tone relief plate, or its equivalent in having an ink roller supporting rdot structure on its printing surface, the plate is etched on a very thin flexible sheet of'metal such as a zincsheet about .032 of an inch thick, and whichsheet will readily assume the curve of the printing cylinder or intermediate curved supporting shell without any forcible bending operation, as it will conform thereto by merely wrapping it about the cylinder. However, instead of proceeding in this customary manner and meeting the' difficulties of accurately locating the: plate and main taining the desired register, especially as is required for color work where several successive plates are used, I provide a curved press or clamping device which may be termed a pair of die members though they are not actually used for pressure formingbut only to'hold the plate and its shell in close contact and accurate register during the assembling and securing together of the composite printing plate member.

The base'member'of these dies is formed with a substantially half-cylinder concavity with its open side up, and the other die is a conVexly curved counterpart hingedly' connected to the base member so as to swing into or out of it, in predetermined exact relation, but "when in the nesting position thereis a free space between the 'diesurfaces exactly equal to the combined thickness of the thin flexible printing plate and the thickness of a sheet of paper of definite thickness or weight, plus the thickness of the rigid curved supporting shell, the latter being about .410 in thickness, or so that the combined thickness of theshell with its plate will be'the same as the curved stereotype plates for the particular printing press for which the composite p'lateis wanted.

The base die member is provided with plate locating meanswithin it which accurately position the thin printing plate when the latter is merely pushed or rather sprung into it by hand with its printing side facing the die (a sheet of paper having first been inserted in the die cavity to protect it). The rigid supporting half-cylindrical shell has in the meantime been attached to the convex surface of the other die member while swung to open position for accessibility, and the die members are then closed to swing the convex side of the rigid shell snugly within the concave side of the sheet metal printing plate, and the die members are tightly latched together. No great force is required on the die members as the weight of the upper or convex member and its tightening latch is suflicient to insure perfect contact of the thin plate with its convex supporting shell.

When in such position in the dies the thin printing sheet extends at both of its straight ends beyond the straight ends of the supporting shell and means is provided for simultaneously folding these extending ends directly across the ends of the supporting shell and securing them thereto, and after which the upper die member is swung out on its hinges and brings with it the completed composite printing unit, i. e. the rigid supporting shell with the thin flexible printing sheet firmly secured to it in predetermined registered position, and which unit is then released from the outer die to which it was clamped and is ready for similar clamping to the printing press cylinder in the same way as a standard curved stereotype plate.

In the drawings Fig. 1 shows the completed unit consisting of the rigid half-cylindrical shell I which is preferably made of steel of an overall size and with its curved ends beveled off at 2 exactly the same as a standard curved stereotype plate to fit in the clamps of a rotary printing press. On the convex side of the rigid shell is the'thin flexible printing plate 3 held smoothly and tightly therearound by screws or special fastening means 4 passing through the inwardly folded straight end margins 5 of the sheet. The corners of the rigid shell are rounded at 6 where the sheet is bent over them for two reasons; first, to prevent cracking the sheet, and second to cause the ink roller of the press to ride up somewhat gradually to the printing surface instead of striking an abrupt corner, for attention is called to the fact that in the preferred form of my composite printing unit as applied to typographic printing there is a printing dot structure such as on half tone printing plates, which is coextensive with the entire surface of the plate on its rigid support and that the dot structure extends not only over all etched areas large enough to require them as an ink roller support to prevent inking the bottom of the necessarily shallow etched portions of so thin a plate, but the smallest or minimum printing point dot structure extends over the margins and the curved corners 6 as well and as shown at I in the greatly magnified view of Fig. 8. This is an important feature which permits the use of such a, thin flexible typographic printing plate, and without it the plate would have to be the thicker stifi metal plates as generally used for half tone blocks, as forcible bending to form, and also routing of all large blank areas would be required, and which latter is not possible on the thin flexible plates used in my unit. My composite curved printing plate unit therefore differs basically from any prior curved printing plate with which I am familiar.

Figs. 2, 3 and 4 show the main features of construction of the unit assembling apparatus and in which 8 is the base or lower die member formed with the substantially half-cylinder concavity 9 and with the outwardly extending shelves l0 along its upper edges, upon which the longitudinally extending folding bars II are slidably positioned.

The base member 8 is preferably a rigid iron or steel casting accurately machined on its surfaces 9 and I0, ribbed as at l2 and provided with a foot flange l3 having holes M for holding down bolts.

The thin printing plate cut accurately to rectangular size is shown at 3 sprung within the concavity 9 of the die member and with its printing face against a sheet of paper l5 and accurately sidewise located by the four marginal pins 16 resiliently urged upward by springs 11, and endwise located by overhanging lips 18 which project inwardly from the confronting edges of the margin folding bars I l a distance about equal to the thickness of the printing plate 3 and under which lips the accurately cut plate is pushed when it is placed into the concavity of the die.

The margin folding bars H are slidably held down upon the shelves III by overhanging guide plates l9 at opposite ends and a similar plate 20 at an intermediate point.

The upper or convex part of the die is a rigid substantially half-cylindrical casting 2| reinforced with deep ribs 22 finished on its face to exactly the same diameter as the rotary printing press cylinder for which the printing plates are intended and it is provided along one arched edge with a fixed overhanging lip 23 beveled to match the beveled portion 2 of the rigid supporting shell I and provided with a couple of similarly beveled clamps 24 which engage over the bevel at the opposite edge of the shell and which may be moved inward to clamp the shell, or outward to release it by turning the handwheels 25 or screws 26 which are threaded through the vertical wall 21 of the die member and upon the enlarged bare shanks of which screws the clamps are slidable, and further similarly guided on pins 28 to prevent the clamps from turning.

This upper die member 2| is formed or provided with a later'ally extending hinge bracket 29 which is hingedly connected by a pin 30 with a similar bracket 3| secured to or formed on the lower die member so that the upper one may be swung into and out of the lower one by means of the Handle 32, and when in the lower or closed position it may be locked as by means of a latch 33 which is pivoted at 34 to the base member and engages over the shank 32 of the handle. The latch is pivoted to an eccentric pin 63 provided with vise handle 64 for tightening after hooking.

The top side" of the upper die member 2| is generally open and across it is a heavy cross shaped plate 35 preferably cast integral therewith and supported on ribs, and which plate, together with marginal ribs 22' holds the curved wall 2| rigid. Pivotally mounted on plate 35 are four link guiding blocks 31 which slidably receive and guide four flat links 39 provided at their outer ends with firmly secured studs 40 projecting downwardly respectively into holes drilled into bars ll. (See Fig. 4.) Blocks 31 are centrally pivoted to the plate 35 as by suitable screws or rivets 38. (See Fig. 9.)

At their inner ends links 39 are pivotally connected at H and 42 to flat gear sectors 43 in turn pivoted at 44 to the plate 35. The teeth 45 of the gear sectors are in spaced confronting .38 1are quite tight fittingiagainst ithe topof the links 39 so'ith'at thel'frictioniset iup willkhold :relation and in mesh with soppositesideszof: aispur pinion-46 which is: securedito a verticalshaft'fl pivotally extendinglthrough plate 351an'd3afhub 36 formed thereon and heldv from withdrawal by a collar. A handwhel49xissecure'd to'the upper end of the shaft 41 and the positioniof the gear segments is so arranged so that a twist of the .handwheel in one direction will pull both folding'bars inward and vice versa. To limit the maximum movement of the foldingibarsll in or out, a handwheel stop arm 50 secured to shaft 41 is provided with adjustable stop screws-'50 which alternately come'against a stop pin 60 projecting from plate35.

Along both inner margins of the foldingbars I I is .a row of 'drilledholes 5I, which, when the bars are pulled to theirinnermost position, will be exactly aligned over a similar row of holes 52 drilled in thefiat .upperedges of the rigid shell, 3. (See Figs'6 and 7.)

In operating the apparatus, whenthe upper die member is swung open, it is lowered to the dotted line 58 in Fig. -3 to rest its thin lower edges upon across support 59 and'against'which the two straight edges of the'rigid shell I will also rest when slipped on the convex surfac'eof the die and clamped in place, as all supporting shells used with .the die will be accurately machined to exactly th'e same size and will be brought into flush relation with the die at the edges by this means and thus insure a'predetermined'position with regard to the thin printing plate'registered in the base die, when the dies are closed. When the two folding bars'II aresimultaneously pulled inwardly from dotted position I I shown in Figs. '6 and? by means of the handwheel, they push ahead of them the straight marginal portions of the printing plate whichlproiect above the upper edges of the rigid shell I to themwardly extending stop lips I8 and hold these margins at right angles'snugly over the edges of the rigid shell to the position shown in Fig. 6. 'In thus holding the margins of the thin printing plate there is a drawing action whichtakes all slack out of the plate and stretches 'it tightly about the convex surface of the 'rigid shell.

After the margins have been folded over, two ways are illustrated for securing the folded margins to the shell. In Fig. 6 the holes 52 are shown tapped "and also countersunk as 'at 53, and when a pointed punch of the character shown at 54 is driven through'the aligned holes 5I and 52 it will break through the printing plate and spread its ragged margin into the countersunk portion of the holes, so that after all are punched the bars II 'may'be backed off sufficiently to permit screws 4 to be inserted to hold the folded margins in place. The ragged margins forced into the countersunk portion of the holes will effectively prevent any :displacement of the margins before the screws are in place.

A variation of the fastening means is shown in Fig. 7 wherein the holes 52 in the rigid shell are of a size and under cut close to their endsas at 55 so that when the punch 54 is driven through the printing plate the ragged margins will be forced outwardly into the undercut portions as indicated at 56 to lock thereunder and thereby dispense with any other securing means, and the thin printing plate together with its rigid supporting shell may be taken from the opened dies as a unit ready for placing on the press cylinder.

In considering the operation of-the die mem bers, it should be noted-that the guide members folding bars outwardly so' that the inner die member'with its completed acomposite plate can be swung upwardly out of thelower die, the outward movement'of the folding bars is sufiicient to carry'the lips I8 far enough to clear .the upper corner of the printing'plate 3 attached to its curved 'shell I, and this will be assured by turning the wheel as far as permitted by stop pin 60. However, as these lips I8 must overhang and form stops for the upper edges of the curved printing sheet or plate 3 when it is placed in the concave die, means is provided for bringing these folding bars to proper position before putting the sheet in the lower die. This means is shown in Fig. 13 and consists of-a stop block 6| drilled to fit over fixed stop pins 62 to bring the outer edge 65 of the block in position to stop lip I8 when in correct position. To use the block 6|, the upper die member is first temporarily lowered, stop block BI is put in position (as indicated by dotted lines in Fig 2) the handwheel is'turned sufliciently to pull the folding bars inwardly until one of them strikes the strip block, the stop block is then removed, and the upper die swung out again. The bars II are now in position shown in full lines in Fig. 13, (and as shown dotted in Figs. 6 and '7) ready to receive the sheet and the shell for attaching the'two as described. Block BI is provided with a lifting knob 66.

It should be noted that while I have described the dies and the rigid supporting shell generally as half cylinders, they are in fact somewhat less than a half cylinder to make room for the substantially one inch wide stops usually provided on the-printing press cylinder which come between the junctures of each pair of shells secured around the cylinder, as is the case with the regular curved stereotype plates, though for special presses the actual degrees of a circle included in the cylindrical segments may be made to suit. Also the combined thickness of the printing plate and its supporting shell is generally about but this also willlvary for some presses, and any composite plate will always be made to meet the stereotype thickness required for the particular press upon which it is to be used.

The words half-cylindrical or semi-cylindrical used herein and in the claims are intended to include any variation in length of arc of the members as required for various printing presses for which the invention is applicable.

Having thus described my invention, itsmode of operation and wherein it is an improvement over the prior art insofar as the same is known to me, what I claim is:

1. Apparatus for forming cylindrically curved printing plates comprising a convexly curved block substantially 0f half-cylindrical form, means adapted for securing-a correspondingly curved cylindrical shell segment upon the' face of said block, a concave cylindrically curved base into which said block and its shell segment are adapted to be received, means for definitely locating a thin arched printing plate within the concavity of said base, means supporting said block for movement with its shell segment into the concavity of said base to rest upon the arched printing plate therein, and with the straight ends of said plate extending beyond the straight ends of said shell, and means for bending the extending ends of said plate across said ends of the shell.

2. Apparatus for forming cylindrically curved printing plates comprising a convexly curved block substantially of half-cylindrical form means adapted for securing a correspondingly curved cylindrical shell segment upon the face of said block, a concave cylindrically curved base into which said block and its shell segment are adapted to be received, means for definitely locating a thin arched printing plate within the concavity of said base, means pivotally supporting said block for swinging with its shell segment into the concavity of said base to rest upon the arched printing plate therein, and with the straight ends of said plate extending beyond the straight ends of said shell, and means for bending the extending ends of said Plate across said ends of the shell.

3. Apparatus for forming cylindrically curved printing plates comprising a convexly curved block substantially of half-cylindrical form, means adapted for securing a correspondingly curved cylindrical shell segment upon the face of said block, a concave cylindrically curved base into which said block and its shell segment are adapted to be received, means for definitely locating a thin arched printing plate simultaneously from its four edges within the concavity of said base, means supporting said block ior movement with its shell segment into the concavity of said base to rest upon the arched printing plate therein,. and with the straight ends of said plate extending beyond the straight ends of said shell, and means for bending the extending ends of said plate across said ends of the shell.

4. In a structure as set out in claim 1, the printing plate locating means within the concavity of said base including pins projecting out of the concave surface of said base adapted to engage the opposite edges of the plate, and means mounting the pins for resilient protrusion from the base, whereby they may be depressed into the base when the block is in position.

5. In a structure as set out in claim 1, the printing plate locating means within the concavity of said base including pins projecting out of the concave surface of said base adapted to engage the opposite edges of the plate, and means mounting the pins for resilient protrusion from the base, whereby they may be depressed into the base when the block is in position, and overhanging lips at the two straight edges of the concavity of the base against which lips the straight edges of the arched printing plate abut when in position within the concavity.

6. In a structure as set out in claim 1, the printing plate locating means within the 'concavity of said base including pins projecting out of the concave surface of said base adapted to engage the opposite edges of the plate, and means mounting the pins for resilient protrusion from the base, whereby they may be depressed into the base when the block is in position, and

(ill

overhanging lips at the two straight edges of the concavity of the base against which lips the straight edges of the arched printing plate abut when in position within the concavity, two longitudinally extending bars respectively at the opposite straight edges of the concavity of the base and upon which bars said lips are formed, and means mounting said bars for sliding toward one another for bending the extending edges of the plate across the straight ends of the cylindrical shell segment.

7. Apparatus for forming cylindrically curved printing plates comprising a substantially halicylinder concave die member and a convex substantially half-cylinder die member adapted to clamp between them a rigid curved half-cylindrical shell within the concavity of a curved thin printing plate positioned in said concave die member, the concave die member provided with a shelf extending outwardly at opposite longitudinal edges, a .pair of bars respectively on said shelves, means guiding said bars for bodily sliding on said shelves toward and from one another for folding any extending ends of said printing plate inward across the longitudinal rear edges of the half-cylindrical shell, and a row of openings extending through said bars in position to align over a row of holes formed in the rear edges of said shell when the bars are slid inward toward one another, and stop means limiting inward movement of the bars when the holes and openings are so aligned.

8. Apparatus for forming cylindrically curved printing plates comprising a substantially halfcylinder concave die member and a convex substantially half-cylinder die member adapted to clamp between them a rigid curved half-cylindrical shell within the concavity of a curved thin printing plate positioned in said concave die member, the concave die member provided with a shelf extending outwardly at opposite longitudinal edges, a pair of bars respectively on said shelves, means guiding said bars for bodily sliding on said shelves toward and from one another for folding any extending ends of said printing plate inward across the longitudinal rear edges of the half-cylindrical shell, and means comprising a hand-wheel, means rotatably mounting said handwheel on the rear of said convex die member, and links and levers operatively connecting said handwheel to and for operating both sliding bars simultaneously.

9. Apparatus for forming cylindrically curved printing plates comprising a substantially halfcylinder concave die member and a convex substantially half-cylinder die member adapted to clamp :between them a rigid curved half-cylindrical shell within the concavity of a curved thin printing plate positioned in said concave die member, the concave die member .provided with a shelf extending outwardly at opposite longitudinal edges, a pair of bars respectively on said shelves, means guiding said bars for bodily sliding on said shelves toward and from one another for folding any extending ends of said printing plate inward across the longitudinal edges of the half-cylindrical shell, and means comprising a handwheel rotatably mounted on the back of the convex die member, a pinion rotatable with said handwheel, a pair of pivoted gear segments engaged by said .pinion, and links connected to said gear segments provided with pivotal connections to said bars for operating both sliding bars simultaneously.

10. In the construction set out in claim 9,

means frictionally retaining said links in positions of movement, and the pivotal connections of said links to said bars including pins projecting from one of the connecting members adapted to enter holes formed in the other of the connecting members.

11. In the construction set out in claim 9, means \frictionally retaining said links in positions of movement, and the pivotal connections of said links to said bars including pins projecting from one of the connecting members adapted to enter holes formed in the other of the connecting members, said bars formed with a row of holes brought into alignment with a similar row of holes in the extreme outer edges respectively of said half-cylindrical shell when the bars are moved toward one another to a predetermined limit, and stop means prescribing such limit of movement.

12. In a structure as set out in claim 2, a handle projecting from said block at a :point remote from its pivotal support, and means for latching the block to said base when swung into position therein.

13. In a structure as set out in claim 2, means for definitely locating said shell segment upon said convexly curved block when securing it thereto.

14. In a structure as set out in claim 1 said block being a semi-cylindrical shell, a plate extending across the concave side of the shell and tying the ends of its walls against deformation, and means operatively mounted on said .plate for manually operating said means for bending the extending ends of said plate.

15. Apparatus for forming cylindrically curved printing plates comprising a substantially halfcylindrical concave die member into the curved concavity of which a thin flexible printing plate is adapted to be fitted with its straight ends projecting out of the concavity of the die, a substantially half-cylindrical convex die member, means for clamping upon said convex die member a curved substantially half-cylindrical shell, said shell being of a size and curve to fit within the concavity of said flexible printing plate when positioned in the concave die member, and means for clamping the die members together with the shell and plate between them, a pair of flat bars extending respectively along opposite straight edges of the dies when clamped together, means mounting said bars for movement to fold the projecting ends of said printing plate inward across the rear edges of said shell, said bars provided with a row of openings adapted to align over a row of holes formed in the rear edges of said shell, and stop means limiting the inward movement of said bars when the openings and holes are so aligned.

ALBERT L. LENGEL.

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