US1487839A - Method of and apparatus for forming printing plates - Google Patents

Description

L. W. CLAYBOURN March 25 METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES Filed June 24, 1921 Shets-Sheet 1 w. IN V N L. W. CLAYBOURN METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES .March 25 March 25 L. W. CLAYBOURN METHOD OF. AND APPARATUS FOR FORMING PRINTING PLATES 1o Sheets-Sheet 5 Filed June 24 1921 www Nu m as 3 March 25 1924- 1,487,839

L. w. CLAYBOURN METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES Filed June 24. 1921 10 Sheets-Sheet 4 NEW 6 Q NM s Wm a N 7 March 25 1924.

. L. w. CLAYBOURN METHOD OF'AND APPARATUS FOR FORMING PRINTING PLATES .March 25 1924. 1,487,839

L. W. CLAYBOURN METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES Filed June 24. 1921 10 Sheets-Sheet 6 "Hi-4 0 f? 112 5 W571, v 4x1 20 4. 152 $9 9 #1497 E I x 40 3 E l 4z 1 a 205g g ,g! 10 53 n 1/ Z 10:" ,/Z i My; 101

March 25 1924.

. L. w. cLAYBouRN METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES @w SQ N Na R Mare]; 25', 1924." ,L. W. CLAYBQURN METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES- l0 Sheets-Sheet 8 Filed June 24, 1921 March 25 1924. 1,487,839 w. cLAYBou N Y METHOD OF AND APPARATUS FOR FORMING-PRINTING PLATES- Filed June 24,

1921 10 Sheets-Shegt 9 N Wm ll/Ill!!! I 6- MM March 25 1924- L. W. CLAYBOURN METHOD OF AM) APPARATUS FOR FORMING PRINTING PLATES Filed June 24, 1921 10 Sheets-Sheet 10 a iwgm Patented Mar. 25, 1924.

PATENT OFFICE.

LESLIE w. CLAYIBOURN, or MENASHA, WISCONSIN.

METHOD OF AND APPARATUS FOR FORMING PRINTING PLATES.

Application filed June 24, 1921. Serial No. 480,073.

To all whom it may concern:

Be it known that I, LESLIE W. CLAY- BOURN, a citizen of the United States, residing at Menasha, in the county of lVinnebago and State of Wisconsin, have invented certain new and useful Improvements in Methods of and Apparatus for Forming Printin Plates, ofwhich the following is a speci cation.

My invention relates to method of and apparatus for forming printing plates into curved form, or for changing the curvature of the printing plates, desirably for adapting them for use upon plate cylinders of difl'erent diameters, or for changing their original curvature, or for heat treatment of the curved plates My invention is applicable, for instance,

in reforming or recurving printing plates previously curved by employment of my inventions in method of curving printing plates and printing plates curved thereby, shown, described. and claimed in my Letters Patent of the United States No. 1,318,967,

dated October. 14, 1919, orby means of the apparatus for curving printing plates shown, described and claimed in my Letters Patent f the United States No. 1,318,- 968, dated October 14, 1919, and 'is also applicable for curving or reforming printing plates initially made or formed by other methods and in other manners.

The printing plates to which my invention is particularly applicable are curved printing plates arranged to be attached to plate cylinders in multi-color "printing presses, or for rinting books, or other printing. The plate cylinders of printing presses are of different diameters, and it is desirable to reform a printing plate of g a given radius of curvature into a printing plate having a different radius of curvature so asto employ the same printing plate on rotary plate cylinders having different diameters.

I' have further found that curved printing plates, due to the compressive actions thereon during printing, or to corrective methods employed on the printing plates in order to cause proper printing of their printing surfaces, or for other reasons, becomehard or crystallized, either as a whole or in spots, or-of uneven molecular consistency, It is, one of the objectsof my invention td' so treat printing plates of this character as to anneal the same'while not limited to printing plates thus formed,

but is applicable to printing plates having printing surfaces regardless of how the same are formed.

It is the object of my invention to curve printing plates 'in such manner that a stretching or disarrangement of the printing surfaces of the printing plates is avoided, and distances and arrangements between printing lines in the printing surface are maintained, in order that the printing from the printing plates before and after being subjected to my improved method and, apparatus is the same, and registry between the printing lines is maintained.

The invention consists in heating the printing plate so as to render the backing. .material thereof readily pliable, but preferably compressively resistant,,and, while heated, curving the same into the desired curvature; further, in heating the printing plate, causing curvature or changing of curvature thereof while heated by resilient. pressures exerted throughout both surfaces enveloping pressure upon the printing platewhile cooling.

My invention consists, further, in applying the heat at the inside of the curvature of the printing plate to be operated on, for rendering the printing plate of increasing pliability toward its backing surface, whereenveloping presby, inrecurving the printing plate, the printing surface of the printing plate is maintained in cooler and in more resistant condi tion than its backing to maintain the original printing condition of the printing plate; further, in quickly changing the curvature of the printing plate while in such heated condition; further, in applying envelopingdrawing pressure upon the printing plate so treated while supported upon the sector of a cylinder of substantially the diameter of the plate cylinder on which the printing plate is to be employed; and, further, in subjecting the printing plate so treated to a cooling agency while under said enveloping drawing pressure.

My invention consists, further, in heating the printing plate while located between curved pressure-resistant resilient. bands; further, in changing the curvature of said bands with the printing plate therebetween to' change the curvature of said printing in arranging said bands with the printing plate therebetween about a' mold and applying enveloping pressure upon the outer band to force said bands with the printing plate therebetween toward said mold; further, in providing pressure-resist ant members of substantially the thickness of the printing plate between said bands to resist crushing of the printing plate; further, in providing pressure-resistant mem-- bers between said bands upon which to supportthe edges of said printingplate to resist stretching of said printing plate; further, in providing interchangeable supports or molds of different curvatures; further, in providing molds of diameters representing respectively the original curvature of a the printing-plate; further,

and the desired whereof correspond prmting plate-and the desired curvature of in providing an the respective ends to substantially the curvatures of said respective molds, repre-' senting respectively the original curvature curvature of the printing plate; further, in providing intermediate molds of changing dimensions, exemplified and stepdown intermediate molds; and, further, in bending a printing plate having a printing shell of, intermediate resistance to flexure and a backing material of less resistance to -flexure between pressure-resistant resilient materials, as, for instance, steel bands, of

intermediate mold,

' greater resistance to flexure.

y invention consists, further,in novel means for causing transference of coaction between the printing plate and the heating mold and the printing plate and the cooling mold; further, in providing novel mold supporting and operating devices; further, in providing novel interchangeable arrangementsof molds; and, further, in novel parts and arrangements. and combinations of parts hereinafter more claimed.

The invention will be further readily understood from the following description and claims, and from the drawings, in which latter Fig. 1 represents a perspective view of an fully described and exemplifying apparatus illustrating my inand showing the outerband in drawn relation.

Fig. 3 is a similar view, with the parts arranged for heating the plate, the outer band being lowered, and the apparatus arranged for imparting greater curvature to the printing plate, that is, decreasing the lengthof its radius of curvature.

Fig. 4 is a perspective view of. the same arrangement of apparatus, the printing plate being shown curved to greater curvature, and the outer band raised for. exposing the printing plate. I a

Fig. 5 is a front end elevation of the apparatus arranged asshown in Fig. 1, with the outer band lowered and the bands in drawn relation.

Fig. 6 is a front end elevation of the same. Fig. 7 is arear end elevation of the apparatus arranged as shown in Fig 2.

Fig. 8 is a central vertical longitudinal section of the apparatus taken on the line 8--S-of Fig. 6. I

Fig. 9 is a detail of the clamp for the cooling mold, shown in side elevation in release position.

Fig. 10 is a vertical cross-section of the apparatus, taken on a line corresponding to the line 1010 of Fig. 8.

i Fig. 11 is a central vertical longitudinal section of the apparatus, taken on a line corresponding to the line 1.111 of Fig. 6', but showing the molds of equal diameters.

Fig. 12 is adetail in axial section, showing a releasable connection for the hose.

Fig. 13. is a front elevationrepresenting the means for securing the swinging end of the outer'band.

Fig. 14 is a horizontal section of the same taken on the line lit- 14 of Fig. 13.

-Fig. 15 is a vertical sectional detail of the same, taken on a line,-corresponding to the line 1515 of 14. Y

Fig. 16 is a vertical sectional detail of the same taken ona line corresponding to the line. 1616 of Fig. 14:

Fig. 17 is a vertical sectional'detailof line 17 -17 of Fig. -14.

the same, taken on a line corresponding to the.

Fig. 18 is a vertical sectional detail of the same, taken on a line corresponding to the line 18-18 of Fig. 14.

Fig. 19 is a rear elevation of the rear ends of the bands and their connections, partly broken away.

Fig. 20 is a taken on the line 20-20 of Fig. 19.

Fig. 21 represents an enlarged cross-section, taken on the line 21- 21 of Fig. 2, partly broken away, showing the relation of parts when formi a printing plate provided with margina bearers.

Fig. 22 is a similar View, partly broken away, showing the operation upon a finished printing plate provided with marginal edges for coaction with usual securing hooks.

Fig. 23 is a cross-sectiom'taken onthe line 2323 of Fig. 5, showing the positioning means for the resistance bars.

Fig. 24 is a longitudinal section of the same, taken on a line corresponding to the line 2424 of Fig. 23. v

Fig. 25 is a plan view detail of the same.

Fig. 26 is a perspective view of one of the clamping members for positioning the resistance bar, in association with the resistance bar shown dotted and partly broken away.

Fig. 27 is a cross-sectional detail, taken on a line corresponding to the line 27-27 of Fig. 23; and,

Fig. 28 is a plan view of one of the cooling molds with the top wall thereof removed, and shown in section on a line corresponding to the line 2828 of Fig. 21-.

In exemplifying my invention, it may be instanced that the printing plate is to be re curved to an arc of less curvature, as exemplified in Figs. 1, 2, 5 and 8, or to an arc of greater curvature, as exemplified in Figs. 3 and 4, or that the are of curvature is to remain the same, as exemplified in Fig. 11.

The printing plate is exemplified at 31, and may be of any desirable kind or nature, and comprises a printing surface 32 and a backing face 33. It may comprise a printing shell 34, for instance of electro-deposited metal, such as copper, and a backing 35, of backing material of suitable composition. The backin material may be a mixture of lead, tin and antimony, in the proportion of ninety pounds of lead to five pounds each of tin and antimony, the fusing point of the mixturebeing approximately 600 d Fahrenheit. The printing shell when of copper would have a fusing point of approximately 1900 degreesFahrenheit.

Heat is applied to the printing plate of such a degree and for such duration as will render the printing plate readily flexible but preferably insuflicient' to render the same readily crushable. The heat is preferably applied from the inside of the are on which the printing plate is formed, so as to apply horizontal section of the same,

the heat from the inside or backing surface of the printing plate toward the outside or printing surface of the printing plate, with the object of rendering the printing plate progressively more pliable toward the backing Surface, and leaving that portion of the plate toward the printing surface less pliable, in order toprovide less resistance to flexure at the bottom or supporting side of the printing plate, than at the printing side, with the effect that upon curving the printing plate, the distances between printing lines are not disturbed and the printing sur-. faice is maintained in its original printing condition. i x

The printing plate may be exemplified as approximately three-sixteenths of an inch thick, as is usual in printing plates of this character.

I have found that subjecting a prin'tin plate of this character to a temperature 0 five hundred and fifty degrees Fahrenheit for a duration from fourto six minutes by application of the printing plate to a heating element, for instance, a heating mold, of such temperature, and preferably interpos ing a layer of thin paper, for instance, a thin book paper, which has been previously saturated in an oil, as a usual lubricating oil, between the backing face of the printing plate and the heating element, that a condition of flexibility in the printing plate such as I have described above will be obtained. The heat imparted to the printing plate at its rear face in this manner may be instanced as somewhat less than five hundred degrees Fahrenheit, for example, four hundred and fifty to four hundred'and seventyfive degrees Fahrenheit.

The backing material may be other than that above instanced, for instance, gutta percha. or other material which is rendered readily pliable by heat without rendering the same readily crushable. The condition of the material for the printing plate de- 21. If desired, the printing plate may be in completely trimmed condition, with its backing face shaved, when subjected to my improved method and apparatus. as by having its marginal bearers removed, and each of its marginal edges provided with a bevel edge 38 for coaction therewith by any usual register hooks, all as more fully shown and described in my aforesaid patent, or the said' bevel edges may be omitted and the edges be perpendicular or radial with relavature and is subjected to the heat of a heating mold 44, preferably from the inside of the arc of the printing plate, for which purpose the heating mold may be provided with fuel pipes 45', extending lengthwise in the interior of the same, having suitable openings 46 for the flames, for instance, of gaseous fuel, fed to the pipes, for instance, through air mixers 4:7, and regulated by valves 48, communicating with a manifold 49, to Which a flexible hose 50 for gas-supply is relcasably secured, for instance, by a releasable coupling 51. A sheet-metal plate 52, as of copper, is preferably interposed between the flames and the body of the heating mold, to equalize the heat. A sheetmetal plate 53, as of galvanized iron, is preferably placed under the burners to shield the support or carriage on which the molds are placed, from the heat. The fuel pipes may be supportedin the end walls 54, of the heating mold.

The printing plate is preferably supported between an inner band 61 and an outer band 62, arranged to be separated for receiving the printing plate and arranged to be placed in substantially concentric relation with the printing plate therebetween.

Thus the front end of the inner band is fixed to a cross-bar 63, as by being received in a slot 64 therein, and having securing means, as rivets 65, passed through the lower front margin of said band and the walls of said slot. Brackets 67 are secured to said cross-bar, as by bolts 68. Rods 69 are pivoted in bearings 70 of said brackets, the heads 71 of the rods resting on said bearings. The rods have adjustable connection with a slide 75, adjustable for moving the bands toward and from .the coacting faces of the molds.

The slide is exemplified as comprising boxes 76 movable up and down in guideways 77 in the ends of the machine frame 78. A cross-trunnion 79 has its ends located .in the boxes. Collars 80 are received about the cross-trunnion. The rods 69 have adjustable connection with said collars, as by having their ends threaded, as shown at 81, and received in threaded sockets 82 of the collars, clamp-nuts 83 fixing the parts in adjusted positions.

The rear lower marginal portion of the innerban'dis provided with tails 86, shown as extensions of the band, to which one of the ends of the springs .87, shown as helical springs, are secured, the other of said ends being fastened to the slide for normally exerting a downward pull upon the rear'end of the inner band. This latter connection is shown effected by connecting the lower ends of the springs to lugs 88 on collars 89 on the cross-trunnion.

The outer bandhas fixed connection with a cross-bar 91, as by having its rear lower:

to clamp the rear lower end of the inner band and the rear lower end of the outer band together, the eccentrics being shown operating upon the rear extensions of the inner band. If it is desired to have free movement of the rear end of the inner band relative to the rear end of the outer band, the eccentrics are unclamped, placing the rear end' of the inner band under the action or tension of the springs 87.

If it is desired that the rear ends of the inner and outer bands shall be connected or shall move together, the eccentrics are clamped upon the rear end of the inner band, thereby connecting the said rear ends of the inner and outer bands. The pressure of the eccentrics is, however, such as to permit relative slipping between the rear end of the inner band and the rear end of the outer band upon sufiicient drawing action being exerted upon the cross-bar at the rear end of the outer band, or upon undue stress being exerted upon said eccentric connection, as in changing the curvature of said bands with a printing plate therebetween. This cross-bar is provided with brackets 101, to which rods 102 are secured, the other ends of the rods being secured to the slide 75, there being preferably an adjustment between the slide and the cross-bar. This adjustment is effected by rotatively supporting the rod in a bearing 103 in the bracket, providing the rod with a head 104 above the bearing, and with a threaded end 105 received in a threaded socket 106 of a collar 107 about a cross-trunnion, a jam-nut 108 securing the parts in adjusted positions.

The outer band is arranged to be raised and lowered with relation to the inner band,

for access into the space between the bands, accomplished by providing a free end, shown as the forward end of" the outer band, with a cross-bar 111 fixed to said free end, as in a rabbet 112 of the cross-bar, by means of rivets 113. The cross-bar 63 and the cross-bar 111 are arranged to be united for combined movements, for instance when are shown on brackets 116 fixed to the crossbar 111 by means of bolts 117, and have handles 118 for manipulating the swinging end of the outer band.

'I prefer to provide locking means to lock said forward ends of the hands together,

for combined movements of said forward ends, shown accomplished by means of bolts 121, 122, respectively slidable in grooves 123 of the brackets 116, being guided in said grooves by the walls of said grooves and the cross-bar 111, and in bearings 124, shown as formed by means of blocks, secured to the cross-bar 111 by means of screws 126, and received in keepers 127, extending from the cross-bar 63 outwardly into range of said bolts, and shown formed on blocks secured to the cross-bar 63 by means of bolts 128.

The bolts 121, 122, are operated by means of a handle 131, rotatable in a bearing 132, fixed to the cross-bar 111, and having eccentric articulations 133 with the proximate ends of said bolts, so that rotation of the handle will move the bolts lengthwise for either looking or unlocking relation.

The bands are preferably crushing-resistant resilient bands, for instance of spring sheet steel, and are arranged in substantially concentric relation when the res ective ends of said bands are secured toget er, I

' with said bands spaced apart substantially the thickness of a printing plate.

The bands are arranged to be raised and lowered with relation to the molds, and means are also preferably provided for causing separating movement between the forward ends and the rear ends'of said hands,

when the bands are being raised for decreasing the curvatures of said bands, that is, arranging their arcs as the sectors of cylinders having longer radii, the said lower ends approaching each other when said bands are lowered, for imparting greater curvature to the arcs of said bands, that is, arranging them on sectors of cylinders having less diameter, in order to accommodate molds of various diameters and permit ready axial movements between the molds and the bands.

In order to guide the lower ends of said bands, I provide the cross-bar 6-3 with studs 135, about which rollers 136 are journaled, and provide the cross-bar 91 with studs 137 about which rollers 138 are journaled. The

rollers 136, 138, are respectively guided on guideways 139, 140, arranged slantingly so machine, to cause approach between the lower ends of the bands when the bands are lowered, and to cause separation between said lower ends when the bands are raised.

The raising and lowering of the bands are shown accomplished by means" of raising and lowering the slide 75, shown accomplished by fixing screw-rods .141, 142, to said boxes, as by pins 143, said screw-rods being 'shown provided respectively with right-hand threads and left-hand threads. The screw rods are guided in bearings 144, 145, fixed to the machine-frame. Nuts 146, 147, have threadedengagements with the respective screws and are shown formed in the bores of bevel- gears 148, 149, with which bevel- gears 150, 151, respectively, mesh, the latter bevel-gears being secured to a crossshaft 152, journaled in bearings 153 fixed to the machine-frame;

A bevel-gear 156 is fixed to an operating shaft 157, journaled in bearings 158 fixed to the machine-frame, and meshes with the bevel-gear 148. The operating shaft has a hand-wheel 159 fixed thereon, by means of which the trains of gears, including the nuts, are rotated for raising or lowering the slide 75, whereby the resilient bands are raised or lowered with relation to the molds.

The collars 80, 107, have rocking move ment on the cross-trunnion to accommodate the approach or recession between the lower ends of the bands, the rockable collars being held in endwise relation on the trunnionshai 't by means of collars 161, fixed to said cross-trunnion by set-screws 162.

Means are provided for positioning the printing plates between the bands, shown accomplished by means of resistance bars 166, 167, extending parallel with the axis of curvature of the mold and arranged to. be positioned so that the marginal edges of the printing plate contact and are supported by said resistance bars, the adjustments being preferably such as'to prevent spreading of the printing plate to maintain printing relation of the printinglines and to prevent crushing action uponthe printing late. The resistance bars are also preferably rounded at their upper faces, as shown at 168, so as to avoid the presenting of sharp corners or angles to the outer band and thereby prevent injury to said outer band. The resistance bars are preferably of such thickness as to place their upper faces in the circle of the cylinder in which the printing surface of the printing plate is located when on the mold, representing, for instance, a thickness equal to the thickness of the printing. plate plus the oil-sheet under the printing plate.

' The positioning of the resistance bars is shown accomplished by providing resilient supporting strips 171 at the respective ends of the inner band, shown fixed to said inner band at the median portions of said strips, as by rivets 172. These strips flex with the flexure of the inner band, and are shown as of under-cut form for forming dovetails 173.

As'the flexure of the inner band and said.

strips takes place, there is longitudinal movement between the respective ends of said strips and the band. To permit such longitudinal movement and at the same time cause the strips to remain close to the inner band, the ends of the strips are provided with slots 174 extending lengthwise of the strips, the respective lengthwise walls of said slots being formed as T-slots, as by providing the walls of the same. with rabbets. A complemental block, shown as a dove-tail'block 175, is received in each of said slots and is fixed to the inner band, as by means of a rivet 176.

The resistance bars are provided at their respective ends with rabbets 179, forming extensions 180 received over the flexure strips 171. These extensions are provided with slots 181 extending lengthwise thereof, forming walls received in grooves 182, of clamping members 184. 5185, respectively, provided with grooves 186, 187, received at the respective sides of the under-cut or dovetail edges of the flexure strips. A clamp screw 188, journaled in one of the mating clamp-blocks and having threaded en agement 189 in the other of said clamp-b ocks, clamps the mating clamp-blocks to the flexure strips. The resistance bar is caused to move with the clamps lengthwise of the flexure strips 'by means of the slot and tongue connection between the slotted ends of said resistance bar and the flexure strips,

and is held in position when the clamping members are clamped to the flexure strips. When it is desired to heat the printing plate, it is placed between the flexible resilient bands and the bands are drawn about the heating mold. When proper heating of the printing plate has been effected, the bands are raised,'with the heating mold between them to permit transference of the printing plate to a forming mold 191, which may be arranged on a curvature of greater diameter, less diameter or substantially the same diameter as the heating mold. I have in Figs. 1, 2, 5, 6, 7, 8 and 10, shown the forming mold as of greater diameter than the heating mold, while in Figs. 3 and 4, the forming mold is shown of less diameter than the heating mold, and in Fig. 11 the forming mold and heating mold are shown of equal diameters.

Heating molds of different diam ters may be employed, as instanced by comparing the heating molds of Figs. 1 and 2 with the heating molds of Figs. 3 and 4, and forming molds of different diameters may also be employed, as illustrated, by comparing the from its end complemental to the heat-- a ing mold toward its end complemental to the forming mold, as shown in Figs. 1, 2, 5 and 8. \Vhen a forming mold of less diameter than the heating mold is employed, an intermediate mold decreasing in diameter from its end complemental to the heating mold toward its end complemental to the forming mold, is employed, as shown in Figs. 3 and 4, and when the heating mold and forming mold are of equal diameters, an intermediate mold having the'same curi ature throughout is employed, as shown in The forming mold is preferably provided with means for quickly cooling the printing plate formed thereover, shown accomplished by providing the forming portion of the forming mold with a jacket for water or other cooling fluid, comprising longitudinal channels 195, 196, extending lengthwise at the respective sides of the forming mold, and cross channels 197 formed by ribs 198 connecting said lengthwise channels. Valves .201, 202, connect with said respective chan nels, one of said valves being an inflow valve and the other an outflow valve. Hose- 203, 204., have releasable connections 205 with said valves for ready release of the hose in case it is desired that an interchange in the forming molds take place.

I have found it desirable for convenience that both the valves be closed, with the cavifluid, before' interchange of molds takes place, in order to prevent pocketing of air in the cavities, whlch pocketing of air may also beprevented by first filling the molds when standing on end, with the valves extending upward.

In order to provide convenient transference of coaction between the molds and the bands, I have provided a carriage 211, arranged to travel back and forth under the bands. The carriage is provided at its under side with a longitudinal groove 212, in which a toothed rack 213 is located. A pinion 214 meshes with the rack, and is fixed to an operating shaft 215, journaled in bearings 216 in the frame, and having an operating hand-wheel 217 fixed thereto. The carriage is guided by ribs 220, coacting with guideways 221 of the main frame, and I is preferably supported on rollers 222, journaled on studs 223, fixed in bearings 224 in the main frame. The end pairs of these rollers are shown located in brackets 225 of the main frame. The carriage is provided with stops 226 arranged to contact stops 227 on the main frame to limit endwise movements of the carriage.

The carriage is provided with shoulders 231 extending lengthwise thereof and forming positioning shoulders for positioning and centering the molds with relation to the carriage and with relation to each other.

The heating molds are provided with angle shoes 232 fixed thereto, and preferably have heat-insulating blocks 233 interposed between the molds and the shoes to heat-insulate the molds from the carriage. The coolingmolds are provided with angle shoes 236 fixed thereto, and preferably have heat-insulating blocks 237 interposed between the molds and the carriage. The intermediate molds are provided with similar angle shoes and similar heat-insulating blocks fixed thereto. The said angle shoes coact with the shoulders 231 for positioning the molds on the carriage.

The heating mold is clamped to the carriage preferably-at only one end thereof, for accommodating the expansion and contraction due to heating and.cooling of the heating mold, shown accomplished by providing the carriage with a lug 243, against which one of the end walls of the heating mold is arranged to be received in a rabbet 244 at the end of the carriage. A bar-clamp 245 is fastened to the end of the carriage, as by a bolt 246, a set-bolt 247 being threaded to the other end of said bar and arranged to contact the end of the heating mold, for pressing said end wall against said shoul- The intermediate mold ispreferably spaced in its position from the heating mold, and it may alsobe spaced from the forming mold, to minimize transference of heat from the heating mold to the forming mold. This is shown accomplished by providing the respective ends of the intermediate mold with lengthwise extending setbolts 249, threaded into the intermediate mold, jam-nuts 250 clamping the set-bolts in adjusted positions. The intermediate mold may also be provided with slots 251 for the passage of air and the discharge of ,heat.-

A releasable clamp' is provided for the outer end of the forming mold, shown as a pivoted bar 254, pivoted on a bolt 255 to a lug 256 of the carriage. This bar has a swinging end which is preferably provided at its inner corner wlth a rounding 257. A pivoted bar 258 is pivoted to said lug on a bolt 259 to form a swinging bar, which is arranged to rest on the bar 254, when the latter bar is in raised position, so as to prevent tilting of the upper bar outwardly. A set-screw 260 is threaded in the latter bar and has a hand-wheel 261 thereon for turning the same. When the heel of If it is desired to release the mold, the setscrew 260 is turned acouple of revolutions to release clamping engagement between the heels of the pivoted bars, whereupon the upper end of the lower bar may be swung outwardly, as by pulling on the pin 262 extendin laterally therefrom, for lowering its hee away from the heel of the upper. bar, whereupon the upper bar may be swung outwardly to completely release the forming mold.

If desired, heat testing devices may be employed in connection with the heating mold, shown accomplished by providing the heating mold with holes 265' extending lengthwise therein, and inserting pyrometer tubes 266 of suitable pyrometer reading or recording devices into said holes. The holes at the inner end of the heating mold, adjacent the intermediate mold, may. register with the slots in the intermediate mold for ready insertion or removal of the pyrometer tubes.

Heating molds, forming molds and intermediate molds of various diameters respectivelymay be interchangeably employed.

In operation, when it is desired to curve or reform printing plates, a heating mold 44 is selected conforming to the initial curvature of the printing plates, allowance being made for the thickness of the inner band and oiled sheet. This heating inold is placed on the carriage and secured thereto, and the fuel hose 50 connected therewith, it being face of the curved or reformed printingplate, this intermediate mold being placed on the carriage adjacent to the heating mold and in line therewith.

A forming mold 191 having a curvature corresponding substantially to the desired curvature of the inner or backing face of the curved or reformed printing plate, allowance being made for the thickness of the inner band and oiled sheet, is placed on the carriage, in line with the other molds thereon, and the releasable clamp placed in clamping position to retain the mold on the carria e. The slide will have been raised su ciently to raise the inner band sufiiciently high above the carriage to permit the placing edges at the front and band toward the heatin of the molds, the rear'end of the inner band having been clamped to the rear end of the outer band.

The locks or bolts 121, 122, and catches orv hooks 11.5 at the swinging end of the outer band-having been released, the outer band 62 is raised and caused to rest in up position against a brace 268 extending slantingly rear'wardly and upwardly from the frame.

The carriage 211 is then adjusted to place the heating mold under the inner band 61, and the inner band is lowered to be proximate to the heating mold, with, for instance, a half inch space between the inner band and the heating mold. The printing plate to be curved or reformed is then placed on the inner band, and the resistance bars 166, 167, are adjusted to contact the marginal rear of the printing plate, parallel with the axis of its curvature. An oiled sheet 2"(0 is preferably placed between the printing plate and the inner band, for instance, a sheet of ordinary thin book paper which has been saturated with ordinary lubricating oil. This has the efl'ect of aiding in transferring the heat and in uni formity of heat imparted to the printing plate, and preventing or minimizing the likelihood of the fusing of the backing material when subjected to heat.

The heating agency in the heating mold has been placed in heat imparting relation. The swinging end of the outer band is lowered and connected with and locked to the lower forward end of the inner band; The slide 75 is then lowered to cause contact of the inner band with the heating mold The eccentric clamp 98 is released. Further lowering of the slide causes enveloping drawing pressure of the outer band upon the printing plate, and of. the printing plate and the inner mold. This relation is preferably maintained until the printing plate is sufliciently heated to permit ready fiexure thereof without, however, being sufliciently heated to permit ready crushing action upon the printing plate by enveloping pressure thereon.

When sufiicient pulling pressure has been exerted upon the outer band, the rear ends of the bands are connected together by the operation of the eccentrics 98, clamping of the rear end of the inner band to the rear end of the outer band. In this relation the ends of both bands at the respective sides of the mold are connected together and are under the influence of the slide 75.

As soon as the proper heat has been. imparted to the printing plate, the slide is raised to release pressure of the inner band upon the heating mold. If the forming mold 191 is of greater diameter than the heating mold, the slide is raised sufliciently to receive the forming mold under the bands. The raising of the slide and the spreading released when the inner band has guides 139, 140, causes se aration between the ends of the respective ands and the arranging of the bands on arcs of less curvature, that is, greater radii, with the printing plate in flexible condition between the same, the pressure of the inner band upon the printing plate being outward and the pressure of the outer band being inward, to flex the printing plate upon corres onding curvatures. The raising of the sli e is continued until the curvatures of the bands are sufiicient to permit reception of the forming mold within the arc thereof. The mold carriage is then moved, to move the forming mold 191 within the bands, the increasing diameter of the intermediate mold 193 aiding in spreading and reforming the hands into proper curva-. tures for receiving the larger mold.

As soon as the forming mold has been received within the bands, the slide is caused to descend for again exertin pulling enveloping pressure upon the lands, with the printing plate therebetween, about the new curvature of the formin 'mold for forming the printing plate into its desired curvature. The rigid connections between the slide and the outer ends of the outer band, due to the direct connections of the rods 102 with the rear end of the outer band and the locking connections of the front end of the inner band with the front end of the outer band, causes direct drawing' or pulling upon the outer band which envelops the printing plate and the inner band. If the relative curvatures between the inner and outer bands are such, when such enveloping pressure of the outer band is exerted, as to cause undue strain upon the eccentric clamp connection 98 between the rear end of the inner band and the rear end of the outer band, then such clamp connection will permit yielding between said ends for causing intimate pressure between the outer band and the printing plate, and the smooth arrangement of the printing plate and the inner band about the forming mold. If desired, the clamp connections may be" en drawn down upon the forming mold.

If on the other hand the cooling mold is of less diameter than the heating mold, a raising of the slide suflicient to permit the sliding movement of the carriage thereunder only will be necessary -for permitting the placement of the formin mold under the bands, whereupon the sli e iscaused to descend, for causing changing curvature of the bands while descending which is communicated to the printing p ate between the bands by the opposing forces of the resilient bands at the respective sides. of the printing plate communicated to the printing plate in the manner just described. The bands communicate less curvature to "the printing plate, which is then in hot and flexible condition, the bands being then lowered to cause enveloping pressure of the outer band upon the printing plate. Yielding of the eccentric clamping connection between the rear end of the inner band and the rear end of the outer band is also per-- mitted, or release of said clamping connection is effected, as described in connection with an arrangement where the forming mold is. of greater diameter than the heat ing mold.

crystallized as a whole or in spots, due to the compressive actions of the printing op,

erations or corrective methods for imparting proper printingfsurfaces to the .printing plates. The annealing of the printing plates also takes place when changing the curvature thereof from a given curvature to another desired curvature,

The are on whichthe contact face of any of the molds is formed represents an are equivalent 'to' the arc of curvature of the plate cylinder upon which the printing plate has been used or is to be used, less the thickness ofthe oil sheet and the thickness of the inner band.

The enveloping pressure of the outer band is maintained until the printing plate has been set or fixed in its new curve, which setting or fixing ishastened-by the-applhcation of the cooling liquid in the forming.

mold. 'With water circulating in the cooling mold at a temperature of forty to fift degrees Fahrenheit, the printing plate .wi l be cooled sufficiently in from three to four minutes.

When the forming of the printing plate has been completcd, the free end of the outer band is released. The releasing is readily accomplished upon. a slight raising of the slide 75. the eccentrics having been released, in order to relieve the locks and hooks from pressure. I having been released, the swinging end of the outer band may be thrown upwardlyito rest on the rest 268, whereupon the curved printing plate is removed.

The carriage is then moved lengthwise to v again. place the heating mold under the hands, the slide being manipulated either prior to or subsequent to such movement,

to place said inner band in desired proxim- The locks and hooksity to the contactjface of the heating mold,

the movement and time of movement of the slide depending on 'wheth'er the heating mold is of greater or less diameter than the forming mold. 'The parts will thereby be placed in position for repeating the "operation.

lower ends of the bands and maintain the lc-urvatures of the bands concentric to the' The spread1ng curvatures of the molds. of the guides at the respective sides of the molds outwardly asthey approach the plane of the molds-and the resiliency of the bands cause'the bands to change their curvatures as their bowed median portions approach The guides 139, 140, guide the paths of theand recede from the molds to accommodate themselves to inolds whose'contact surfaces are sectors of cyhnders of less or greater diameters, and-to form spaces within the' bands in which the. molds are readily received.

' In practice, curvedprinting plates are sectors of cylinders less than half cylinders. I prefer that the mo-ldshallbe in the form of a sector of a cylinder greater than the usual sectors rc-presented'by the plates and prefer-ably greater than 'a half cylinder, so as to aid in' shaping the resilienttbands beyondthe ends of the curved printin plates upon which they act, as shown at 2 1, 272,

site ends of the respective resilient hands be projected toward the vertical plane in which the axis of the cylinder and the me-- dian line of the crown of the moldare located: that the path of theslideexerting.

the pulling force to draw or pull upon the hands be substantially" coincident "withor parallel to said vertical plane; and that the point of application of said forcebe outside of and distanced from the circle of the cylinder upon which the molds and printing plates are formed. I have found that such relations of'parts aids in proper curving of printing plates.

Having thus fully described my inven tion, what I claim as new, and desire to secure by Letters Patent. is:

1. The method ofcurving a curved printin g plate having an inner backing surface and inFig. 10. I prefer further that the oppo-' an outer printing surface which consists in applying heat to said curved print-ing plate from the inside of the curvature thereof toward said printing surface in a manner to render the printing plate progressivelymore pliable toward said backing surface and less pliable. toward said printing surface, and then applyimc, enveloping pressure upon the heated plate in curved form.

ing surface which consists in applying heat to said printing plate from the backing sur- 'face thereof toward the printing surface- 2. The method of curving a printing platecomprisinga backing surface and a printthereof to render the printing plate prowhile so supported, and causing envelopgressively more pliable towar said back ing pressure by the outer band about said ing surface and less pliable toward said printing surface, and then applying the enveloping pressure of a flexible band under tension upon said heated printing plate about a rigid curved resistance surface of Substantially the desired curvature of the printing plate, whereby'said heated printing plate is curved withits backing surfaceabout said curved resistance surface.

3. The method of curving a printing plate which consists in locating a printing plate between bands, bending saidbands while the printing plate therebetween is in heated state for imparting rogressive curvatures I by said bands to said printing plate, and

then causing enveloping pressure upon said heated printing plate about a resistant curved surface y substantially equal pulling forces exerted across the respective ends of said printing plate upon the median portion of said printin plate.

4. ,The method 0 curving a curved printing plate comprising a backing surface and a printing surface which consists in applying heat to said curved printing latefrom the inside of the curvature thereo in a mannerto render the printing plate progressively more pliable toward said backing surface and leaving said printing surface less pliable, then applying enveloping pressure upon the heated plate in curved form, and

cooling said printing plate from the inside of the curvature thereof.

5. .The'method of curving a curved printing plate which consists in supporting the curved printing plate between substantially.

concentric resilient bands, applying heat to said printing plate while so supported, continuing the supporting of said printing plate between said bands sub uent to said heating, and causing enveloping pressure upon the outer of said bands to curve the printingplate.

6. The method of treating a curved printing plate which consists in supporting the.

curved printing plate between-curved crushing-resistant resilient bands, applying heat to the curved printing plate from the inside of its curvature, continuing the supporting of said curved printing late between said bands, and causing enve oping pressure by the outer band about said printing plate and a curved pressure-resistant surface within the curvature of said printing plate.

7. The method of recurving a curved printing plate which consists in supporting the curved printing plate between substantially concentric curved crushing-resistant resilient bands, applying heat to the curved printing plate, continuing the supporting of said heated curved printing plate be.- tween said bands and initially recurving said printing plate by flexure of said bands wardl initially curved printing plate and a curved pressure-resistant surface within the curva- 'ture of said printing plate.

- printing plate, continuing the supporting of said heated curved printing plate between said bands and initially recurring said printing plate by flexure of said bands while so supported, causing enveloping pressure by the outer band about said initially curved printing plate and a curved pressure-resistant surface within the curvature of said printing plate, and causing cooling of said printing plate.

9. The method of i'ecurving a curved printing plate which consists in supporting the curved printing plate between curved crushing-resistant resilient bands, applying heat to the curved printing plate from the inside of its curvature, continuing the supporting of said curved printing plate between said bandsand initially recurving said curved printing plate by flexure of said bands while so supported, causing enveloping pressure by the outer band about said printing plate and a curved pressure-resist- .ant surface within the curvature of said printing plate, and cooling said recurved printing plate from inside its curvature out- 10. The method of curving a printing plate which consists in heating the printing plate, and causing enveloping pressure thereon about a resistant curved surface by substantially equal pulling forces exerted across the respective ends of the printing plate upon the median portion of the print= ing plate.

11. The method of recurving a curved printing plate which consists in heating the printing plate between substantially concentric resilient bands, flexing said bands for causing pressure at both sides of said printing plate in opposite directions to initially change the curvature of said curved printing plate, and causing enveloping pressure by the outer of said resilient hands upon the initially recurved printing plate about a curved surface of substantially the desired curvature of the recurved printing plate.

12. The method of recurvlng a curved printing plate which consists in heating the printing plate between substantially concentric resilient bands, flexing said bands for causing pressure at both sides of said printing plate in opposite directions to initially change the curvature of said curved printing plate, and causing enveloping

Images