US1397607A - Process of making metallic printing-plates - Google Patents

Description

C. N! SMITH. PROCESS OF MAKING METALLIC PRNTING PLATES. APPLICATION FILED OCT. so, 1918.

1 ,397 ,607, Patented Nov. 22, 1921.

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, W w pay/Mg %MZ C. N. SMITH. PROCESS OF MAKING METALLIC PRINTING PLATES.

APPLICATION FILED OCT. 30. I9I8- Patented Nov. 22, 1921.

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c. N. SMITH. PROCESS OF MAKING METALLIC PRINTING PLATES. APPLICATION FILED OCT. 3 01 1918- 1 ,397,607 Patented Nov. 2 2, 1921.

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UNITED STATES PATENT @EFICE.

CHRISTIAN N. SMITH, OF ELGIN, ILLINOIS.

PROCESS OF MAKING METALLIC PRINTING-PLATES.

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$pecification of Letters Patent.

Patented Nomi/2, 1921.

Original application filed May 24, 1917, Serial No. 170,669. Divided and. this application filed October 30,

1918. Serial No. 260,408.

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Be it known that I, CHRISTIAN N. SMITH, a citizen of the United States, residing in Elgin, in the county of Kane and State of lllinois, have invented certain new and use- :lul Improvements in Processes of Making Metallic Printing-Plates, of which the following is a specification.

This application is a division of an appli cation for Letters Patent of the United States, Serial No. 170,669, filed by me in the United States Patent Cities on May 24th, i917, for an improvement in processes of making metallic printing; plates, and apparatus i'or practising such process, and'matter herein described and shown in the accompanying drawings, but not claimed, will be found shown, described and claimed in "said application.

This invention relates to an improved process of making; metallic printing plates comprising an electrotype shell or metallic type plate having;- a metallic backing cast in uniting contact with such shell or plate, and particularly to the process of makingmetallic printing plates which are curved or particylindrical in form, and suitable for use in the operation oi'i' printing by means of such curved or cylindrical metallic printing pla e upon printing presses adapted for their use. My improved process, however, relates to the making of flat metallic printing plates, as well as to the making of curved or send-cylindrical printing plates, and also relates to the making oi indentations in or upon the printing surface of metallic printing plates by means oi. malreready overlays in the form ota coating of chalk or a thin layer of material removably in contact with the metallic shell and with the mold wall during; the operation 0i casting the backing of metal in contact with the shell.

The principal object o'f'this invention is to provide a simple, economical and ellicient process of making metallic printing plates, either flat, or of curved or semi-cylindrical form, comprising a metallic shell, such an electrot-ype shell, having a. backinn of suitable metal cast in contact with such shell.

Other and further objects of the invention will appear from the following description and claims, and from an inspection of the p a rt hereoi'.

In the accompanying drawings, Figure l is a view in side elevation of a mechanism or apparatus suitable for use in making metallic printing plates in accordance with my improved process and invention; and shows a curved or semi-cylindrical mold with its heating chamber in lowered or horizontal position, and with the mold closed or in position'to form a curved molding chamber;

Fig. 2, a view in vertical section taken on line 2, 2, of Fig. 1, looking in the direction of the arrow, with the upper or inner mold member shown in open position in broken lines;

Fig. 3, an enlarged detail sectional view taken on line 8, 3, 01"- Fig. 1, and showing in transverse section the portion of themold chamber and the relatively movable mold members forming the curved mold chamber,

with an electrotype shell or curved type Fig. 5, a view in central longitudinal section, taken on a vertical line through. the center of 2, but with the mold members which form the curved mold chamber raised or vertical position, and with the mold chamber provided with an electrotype plate in'position therein, and a flexible metallic plate removably arranged in position to engage th curved back surface of the electrotype plate and cause the latter to be held in contact with the curved concave Or inner wall of the mold chamber;

6, an enlarged detail view in longitudinal section, taken on a vertical line through the center oi Fig. 2 showing the electrotype plate or shell in contact with the surface of the concave wall of the mold chamber, and with the which is in contact with the back face of the electrotype shell, partially raisedor partially withdrawn from the mold chamber,

flexible metallic plate. 7

backing in contact with the back of the electrotype shell below the bottom edge of the partially removed flexible plate;

Fig. 7, a fragmentary detail view of a portion of an electrotype shell, having a make-ready overlay of chalk or similar material on its printing surface;

Fig. 8, an enlargeddetail view in transverse vertical section, taken on line 8 of Fig.

6, looking in the direction of the arrow, and

showing the electrotype shell in the mold chamber with a make-ready overlay in contact with the printing surface'of the shell, and withthe flexible metallic sheet in contact with the back of the electrotype shell, be-

j fore the operation of pouring in the molten metal;

Fig. 9, a similar enlargeddetail sectional view, showing the electrotype plate and the make-readyoverlay in the mold and pressed. tightly in contact with the concave surface of the curved mold by the metal poured into the mold and allowed tocome into contact with the shell upon theremoval of the flexible sheet of metal; and

Fig. 10, a view in elevation of a device for making fiat metalhc printing plates in 'accordance with my inventionwith parts broken away'and omitted to show the mold chamber and contents.

In constructing a mechanism suitable for use in practising my improved process of making metallic printing plates, 1. provide a main frame 1, having uprights 2, 2, provided with bearings 3, 3, in the upper extremities of said uprights. The side frame members thus formed means of transverse frame members 1 and 5.

A pair of main mold members, comprising a lower or outer mold member 6, and an upper or inner mold member 7, adapted to form a mold chamber 8 therebetween, which chamber is semi-cylindrical in form, is provided and. mounted in the main frame in such a manner as to permit the mold cham-.

ber to be opened and closed, and to permit the movement of the connected upper and lower mold members 6 and 7 to raised and lowered positions alternately, desired. The lower or outer mold member 6 is'provided with trunnions or stub shafts 9 which project outward laterally in opposite directions on opposite sides of said mold member and are journaled in the bearings 3 in the upright frame members 2. (See Figs. 1 and 2.)

The upper or inner mold member 7 is pivotally connected in operative engagement with the lower mold member 6 by means of hinge members 10 on the upper mold member, hinge members 11 on the lower mold member, and pintles or horizontal pivots 12, which connect said hinge members 10 and 11 in such a manner as to permit the upper are connected by mold member to swing into position to open and close the mold chamber as desired. The upper mold member 7 is shown in closed or mold chamber-forming position in full lines in Fig. 2, and is shown in broken lines in said figure in the position'which it would occupy when the moldchamber is open, or in position to permit the removal of a printing plate upon the completion of the process of making the same, and to permit the insertion of a metallic electrotype shell into position in the mold chamber, and the placing of the flexible barrier sheet hereinafter described, in position;

A curved marginal gage bar 13 is mounted in position to form an end marginal wall f the mold chamber; and straight marginal gage bars 1 1, 14:, are removably mounted in position to form removable side marginal walls of the mold chamber. The curved end marginal gage bar is removably supported in operative position upon the lower mold members 6, by means of studs 15, 15, which are anchored in the lower mold member 6, and sockets or slots 16, 16, in the gage bar 13, which are adapted to admit and engage the studs 15 whenthe gage bar is in osition to form the removable end wall of the mold chamber. The end gage bar 13 is provided with grooves or dovetailed mortises 17,at or near itsopposite extremities, and each of the gage bars 14; is provided with an endwise projecting tongue or tenon 18 adapted to fit snugly but removably, in the corresponding groove 1'2. Each gage bar 14: is also provided with One or more studs 19, each of which is adapted to be removably inserted in a corresponding recess 20 in the mold member 6. The studs 19 are, by preference, tapered, and the apertures 20 are similarly are provided with marginal recesses 21 on tapered. The gage bars 141 the inner sides thereof and adjacent to a outer mold member 6. These recesses open inward or in the direction of the'interior of the mold chamber 8, and are adapted to engage the edges or margins 24 of a flexible metallic barrier plate 25, which is removably mounted in the mold chamber. The margins of the barrier plate 25 are in sliding engagement with the grooved gage bars 1 1-; and its curved or end margin 26 is movable into and out of position to be engaged by the longitudinal. groove 27 in the curved gage bar 13. (See Figs. 2, 3, 1, 5, and 6.)

The lower mold member 6 is provided with an outer wall 28, which is located on the outside of the lower inner mold chamber wall formed by said mold member 6; and is provided with a space 30 between said lower inner wall and said outer wall and forming a heating chamber adapted to enable the mold member 6 and the outer wall of the mold chamber to be heated in an efiicient wall, are also provided.

manner. The outer wall 28 of the heating chamber is provided with strengthening rlos 31 on the outside of said wall; and strengthening ribs 32, located on the inside or the The upper or inner mold member 7 is also, by preference, provided with a heating chamber 38, the outer wall of which is formed by a curved wall portion 84 0f said inner or upper mold memher 7. Ribs 35, which may be integral with the wall 34, and inner ribs 36 between the heating chamber wall 34: and mold chamber wall 37, serve to brace and strengt en the inner mold member 7.

Securing means is provided :torsecuring the upper and lower mold- members 7 and 6 in mold chamber-forming position. The securing means for this purpose, when constructed as shown in the drawings, may consist of a plurality of laterally projecting lugs or clamping members 38 upon and in rigid relation to the marginal portion of the upper mold member 7, and clamping screws 39, pivotally connected with the adjacent margin of the lower mold member 6 by means or lugs 40 and bolts er, and having clamping nuts 42 mounted in threaded engagement with the said clamping screws, respectively, and adapted to be screwed into and out of securing engagement with the clamping members 38, respectively, when the screws are moved into position to extend into recesses l8 in the clamping members 38.

Laterally projecting bosses are provided, which are by preference, integral with the marginal portion of the upper mold member 7 and a shaft or axle 4-5 is rotatively mounted in these bosses in position to extend over the adjacent marginal portion of the lower mold member 6, and one or more eccentrics or cams 4-6 are mounted upon, and, by preference in fixed relation to and adapted to rotate with such shaft, and in sliding engagement with the adjacent marginal surface or" the mold member 6. One or more handles or levers l? are mounted in fixed relation to the shaft and eccentric mechanism, for operating the same to raise the upper mold member '7 with respect to the lower mold member 6 in opening the mold chamber. When the lever and eccentric mechanism is in the position shown in Fig. 2, the mold chamber walls in parallel relation, or in the position which they should occupy during the operation of casting. It is obvious that by turning the eccentric and lever mechanism downward and in the direction indicated by the arrow in Fig. 2, the upper mold member 7 will be raised with respect to the mold member 6, to a suihcient extent to release the upper mold member from engagement with the casting contained in the mold chamber upon the completion of the operation of casting a printing platein the chamber.

burners,

hi eans is provided for supporting the pivoted mold-comprising mold members 6 and 7-in horizontal or lowered position, as shown in Figs. 1 and 2, and in vertical or raised position, as shown in Fig. 5, and suitable means for heating both of said mold members, and means for cooling the mold, all adapted to enable the mold to be swung to lowered or horizontal position and to raised or vertical position, and to be opened and closed with facility. pivotally mounted upon the main frame by means of a transverse shaft 49 to which the lever is fixed by means of a set screw 50, or other suitable securing means; and one or more stop arms 51 are secured in fixed relation to the rock shaft 49 in position to move into and out of supporting engagement with shoulders 52 on the lower mold member 6. (Eco Figs. 1 and 2.) Bosses or shoulders 53 near the opposite extremity of the mold member 6 are adapted to rest upon the transverse frame member 4 when the mold is in horizontal position. It is plain that the raising of the lever 48 will release the stop arms 51 from engagement with bosses 52 and permit the pivoted mold to be swung from horizontal position, as shown in Fig. 1, to vertical or raised position, as shown in Fig. 5. A handle 54upon the end of the mold member 6 is used for raising and lowering the mold. The means for heating the heating chambers 30 and 33, and thereby heating the mold chamber and its contents, when cei'istructed as shown in the drawings, comprises a plurality of Bunsen burners mounted in position to discharge heated gas into the heating chamber 30 of the mold member 6. These burners are connected with a source of gas or fuel supply by means oil a pipe or conduit 56 and a flexible pipe or conduit 57, adapted to permit the movement of the mold without disturbing the connection with the fuel supply.- Controlling cocks or valves 58, which may be or" any ordinary, desired or well known form, are

mounted in position to control the supply or fuel to the burners Burners 59, which may be in the form of ordinary Bunsen are mounted in position to communicate with and heat the heating chamber 33, and are connected with a source of fuel or gas supply by means of a fuel supply pipe or conduit 60, which communicates with a conduit 61. which is, by preference, in the form of a flexible pipe, and is adapted to be connected with a tank or main, or other suitable source of fuel supply, and to permit the movement of sen burners attached.

valves 62, are mounted trol the supply of gas or fuel to the burners 59. A set of burners 63 is also provided and mounted, by preference, in such position that they will be directly beneath the upper mold Controlling cocks or in position to con A trip lever 48 is the mold with the Bunlower mold member 7 known type and may be stationary,

member 7 when the mold is open, andsaid upper mold member is swung away from the 6to open horizontal position, as shown in broken lines in Fig. 2. These burners 63 maybe in the form of Bunsen burners of any desired, suitable well and are connected with a fuel supply conduit of pipe 6%, which is adapted to be connected with a gas supply pipe 65, leading to a suitable source oi fuel supply. It is obvious that the burners attached to the mold member 6 are adapted to heat the heating chamber and the walls of the mold chamber in an efficient manner, and to enable stationary the mold member 6 to be burners beneath dispensed with. V

In order to provide means for cooling the mold chamber and mold quickly and in an eiiicient manner nozzles 66, 66, are mounted in aosition to discharge cold air into the heating chamber 30, and are connected with a suitable source of air supply by means or pipes 67 and68, which may berin the form of flexible pipes or rubber tubing; and one or more air nozzles 69, which be stationary, are mounted in position to discharge a cold air into the heating chamber 33 of the suitable source of air supply.

are removably upper mold member 7 through an opening or, openings 70. The nozzle or nozzles 69 are connected with an air pipe or conduit 71, which is adapted to communicate with a The stationnozzles 69 are adapted to enable cool air chamber 33 when (See ary to be introduced into the the mold is in vertical position. Fig.5.)

The chamber'33 is provided with a suitable number of ventsor outlets 72, at its upper extremity, and the heating chamber 30 is also provided with similar outlet passages 73 at its upper extremity.

In Fig. 10 is shown a mechanism for use in the practice of my improved process of making flat metallic printing plates. This device comprises an upper mold member 74: and a lower mold member 7 5 operatively connected by means of hinges 76, having pintles 77. The upper mold member forms one wall 7 8 of a flat mold chamber and the lower mold member 75 forms the other wall 7 9 of the mold chamber 80. Gage bars 81, 8:2 and 83 mounted in position to form the marginal walls of the mold chamber and are provided with longitudinal marginal grooves which are adapted to engage and hold removably in position in chamber a flexible barrier plate 8 1, which is, by preterence, formed oi": sheet metal and is adapted to engage and cover the entire back surface or a metallic electrotype shell, when such shell 83, is placed in position in the mold chamber, and to enable the barrier plate to be pressed against such electrotype shell by molten metal introduced into the the mold mold chamber. And the barrier plate or sheet 83 is adapted to be removed from the chamber and from between the molten metal and theelectrotype shell, when the mold, and the electrotype shell and barrier plate arein raised or vertical position, by gradually raising the barrier plate and permitting the molten metal to flow beneath the bottom edge otthe barrier plate and into unitingcontact with the electrotype shell, during the operation or gradually raising and removing the barrier plate 'edgewise from the mold.

Suitable means is provided for connecting the mold members 74 and 2" 5, which may consist 01 one or more clamps having clamping jaws 85, pivoted to the lower moldmember by means of pivots 86 and lugs 87 and having clamping screws 88, for engaging and securing the upper mold member in closed or me l-chamber-forming position. The lower mold member 75 has trunnions 89 fined thereto and journaled in suitable bearings in supporting framememb'ers 90. The mold member 75 has a heating chamber 91 and the upper mold chamber 92. The heating chamber 91 has openings 93 in the bottom of said chamber, and the heating chamber92 has openings 94 in its bottomend, and both of said chambers are provided with vents or outlet openings 95 at their upperextremities. A set of burners 96 is provided, which may be in the form of a suitable number burners, of any suitable known'type, which may be connected with a gas supply pipe or conduit 97, mounted in position to communicate with a suitable gas supply. conduit 98,

adapted to be connected with a source of gas One or more air nozzles '99 are supply.

d scharge coolair member 'Zt has a heating.

oi ordinary Bunsen 92, respectively,

a metallic electrotype shell 101 which is made in the usual and ordinary manner in common practise and well known to those skilled in the art to which the invention relates. lit is therefore deemed unnecessary to describe the process or method of making such electrotype shells or plates in detail herein.

The electrotype shell is placed in the mold chamber with the printing face, or face on which the type characters arelocated, in contact with the mold. chamber wall formed by the lower mold member. When the metallic printing plate to be made is to be in curved or semi cylindrical form, the mold chamber is of curved or semi-cylindrical form, as shown in Figs. 1 to 6, inclusive, and the electrotype shell is placed in contact with the concave surface of the lower mold chamber wall, as shown in Figs. 3, 5, and 6. The flexible metallic barrier plate or sheet 25 is placed in the mold chamber in contact with the back of the electrotype snell, and in position to entirely cover the back of the shell. The margins or edges of the metallic barrier sheet are mounted in sliding engagement with the hingitudinal slots 21. of the side gage bars let; and the bo tom edge of said sheet extends into the curved slot in the bottom of the curved gage bar 13 as already suggested. The mold chamber is then closed by swinging the top mold member 7-which has by preference been previously heatedinto mold chamber-tforming position, as shown in Figs. 1 and 3, and in full lines in Fig. 2. The mold members are then clamped together, and the bottom mold member having also been previously heated, the mold is tipped from horizontal position to vertical position in which csition it is shown in Fig.5. The mold chamber, and also the flexible metallic barrier sheet 25, and elect-retype shell 101 are thus in vertical position, and the barrier plate, which covers the entire back surface of the electrotype shell is inposition to permit molten metal to be introduced into the mold chamber between the barrier sheet 25 and the mold chamber wall formed by the upper mold member. Molten metal suitable for forming a backing for the electrotype shell-rwhich shell is usually of copper and has, of course, been previously tinned, or

covered on the back with a coating of tinisintroduced into. the mold chamber fillin the chamber back of the barrier plate, and pressing the flexible barrier plate snugly against the back of the electrotype shell. It should be noted that the metallic barrier plate and electrotype shell should be thoroughly heated and are in fact thoroughly heated when the mold chamber walls are heated, and previously to pouring the molten metal. The flexible barrier plate having thus been placed into snugly fitting contact with the electrotype shell by the action of the heavy molten metal, the flexible barrier plateis withdrawn gradually from the mold chamber and from between the molten metal and the 'electrotype shell, by gradually raising, the flexible barrier plate, while the plate and shell are in vertical position. During theo 'erationol raising or withdrawing the fiex'ibefbarrier plate, the molten metal comes gradually and progressively into contact "with the back' of the tinned electrotype shell and below, the bottom edge of the upwardly moving flexible barrier plate. The portion of the electrotype shell which is engaged by the flexible barrier sheet during the operation of raising the barrier sheet thus held evenly and uniformly in contact with the moldjchamber wall by the weight of the moltenjmetal ,baclrof the barrier sheet, and a th barrier h e is it l he ten barrier sheet at two or more the electrotype shell or metal below the lower edge of the barrier sheet comes in contact with the heated tinned back surface oi the electrotype shell and unites with the electrotype shell progressively as the barrier plate is raised. and with the shell, forms a complete metallic printing plate which is in one integral piece, and which has an even and uniform printing surace of exactly the desired curvature or cylindrical form required for its use in the operation of printing.

The mold havingbeen heated to the proper temperature to enable the molten metal to flow freely andunite with the heated tinned surface of the electrotype shell, the burners are lowered or extinguished, if desired, either before or immediately following the raising of the mold to vertical position, and the introduction of the molten metal for forming the backing for the electrotype shell. After removing the flexible barrier sheet, it is desirable to cool the mold quickly, in order to enable the casting or metallic printing plate to be removed without unnecessary loss of time. This is accomplished in a simple and efiicient manner by simply introducing cold air into the heating chamber through the air nozzles above described. I contemplate cooling the mold chamber by any ordinary and well known cooling means, but prefer to introduce cooling means in the form of a fluid, such as air or wat into the heating chambers or in contact outside of the mold chamber walls.

In practice it is desirable to detachably connect the electrotype shell with the flexible barrier sheet in such manner as to insure the holding of the electrotype shell in exactly the proper position in the mold chamber to obtain the desired curvature without destroying or interfering with the proper registration of the plate or the characters and figures, and highlights and solids with those of other printing plates in connection with which such printing plate is to be used, for instance, in color printing. In order to accomplish this in a simple and etlicient manner, when required, I detachably 0011- nect the electrotype shell with the metallic points by means of a dropof solder 102, soldered to the electrotype shell and barrier plate at asuitable point or points to detachably connect them. A drop of solder near the bottom extremity, and another near the top extremity of the shell and barrier sheet, as indicated in Fig. 3, is suflicient to serve the purpose. The solder should be so placed that it will be melted by the molten metal poured into the mold, in forming the backing for the print ing plate. 7

In order to indent the printing surface of printing plate in a simple and eliicient manner, in connection with the practice of my improved process,

with the .in the mold chamber.

. the art.

it is only necessary to place a make-ready overlay 103, which may be in the form of a coating or thin layer of chalk, or other suitable heat-resisting material, for making an overlay, in the desired position upon the printing surface of the electrotype shel. (See Figs. 7, 8, and 9.) This is 'of course done before Jlacing the electrotype shell The pouring in of the molten metal with the inlay in the position in which it is shown in Fig. 8, and the withdrawing of the flexible barrier plate so as to permit the molten metal to come into uniting contact with the back of the electrotype shell, will cause the electrotype shell to be pressed andbent against the adjacent engaged more or less irregular or uneven surface of the inlay, and into close fconformity with the same, and also against the face of the wall of the mold, as shown in Fig. 9, leaving the desired indentation 105 corresponding with the shape and position of the overlay or overlaid material 103, as indicated in Fig. 9. lt is obvious that the rintin surface portion of the electrotvnej shell thus pressed against and bent into close conformity with the adjacent surface of the inlay 103 and the wall of tie mold, will contain surface irregularities graduations or indentations and more or less uneven or unequal elevations corresponding with the surface irregularities or depressions and elevations on the engaged face of the inlay or inlaid material 103.

Theelectrotype shells or type plates used .in making metallic printing plates in accordance with my invention, are usually of copper, or copper and other suitable metal, such for instance, as nickel, the copper shell being formed in the ordinary or any desired suitable or known manner, for instance, by

depositing the copper or metal upon a mold arranged in an electrotype bath containing suitable chemicals, and embraced within an electric circuit.

tinned in the usual manner well known in The metal which forms the metallic backing for the electrotype shell should be softer than copper, or should have a lower melting point than that of the cop-' per or metal of which the electrotype shell is formed, A metallic compound or alloy containing approximately 92% lead, 4% tin, and 4 6 antimony is suitable for the purpose, and has been found in practice to give entirely satisfactory results.

I claim: 7 V v p 1. Theprocess of making metallic printing plates, which consists in placing a metallic electrotype shell in a mold, placing a flexible metallic barrier sheet in contact with the back of the electrotype shell in position to.

hold said shell in contact withthe wall of the mold, then introducing molten metal in contact with the exposed surface of the flexi- The electrotype shell is into unitmg contact with the electrotype shell, and then permitting the molten metal electrotype shell to cool.

2. The process of making'metallic print ing plates, which consists in placing a metal lic electrotype shell in a mold, placing "a flexible barrier sheet in contact with the back of the eleotrotype shell in position to hold said shell in contact with the'wall of the mold, then introducing molten metal in contact with the exposed surface of the flexible barrier sheet in position to cause said flexible sheet to be pressed against the back of the electrotype shell by means of said molten metal, then withdrawing the flexible barrier sheet from between the molten metal and the electroty e shell, and then allowing the molten metal and electrotype shell to cool.

3. The process of making metallic printtion. to hold such shell in contact with the wall of the mold, then introducing molten metal in contact with the exposed surface of the flexible barrier sheet and in position to cause the molten metal to press thebarrier sheet against the back of the electrotype shell, then causing the molten metal'to come into uniting contact with the electrotype shell progressively by gradually withdrawing the flexible barrier sheet from between the molten metal and the electrotype shell, and then permitting the molten metal and electrotype shell to cool, and withdrawing v the completed printing plate from the mold 4;. The process of making metallic print 111g plates, which consists in placing ametal 'lic electrotype shell in a mold, removably' mounting a flexible barrier sheet in corn tact with the back of the electrotype' shell and in position to hold said shell in contact with the wall of the mold, heating the mold and its contents, introducing molten metal in contact with the flexible barrier sheet in position to cause the molten metal to press the barrier sheet agamst the back of the electrotype shell, then causing the molten metal to flow into uniting contact with thegraduelectrotype shell progressitcly bj, ally withdrawing the flexible barrier sheet trotype shell, and then permitting the molten metal and electrotype shell to cool, and withdrawing the same from the mold.

5. The process of making curved metallic l curved walls, removably mounting a curved flexible barrier sheet in contact with the back from between. the molten metal and the elecof the curved electrotype shell, in position to hold said shell in contact with a curved wall of the mold, introducing molten metal into the mold in contact with the concave surface of the flexible barrier sheet and in position to cause the molten metal to press the barrier sheet against the back of the electrotype shell, then causing the molten metal to come into uniting contact with the electrotype shell progressively from the lower to the upper extremity of the shell by gradually raising and withdrawing the flexible barrier sheet edgewise from between the molten metal and the curved electrotype shell, and then allowing the molten metal andelectrotype shell to cool.

6. The process of making curved metallic printing plates, which consists in providing a metallic electrotype shell, bending said shell into curved form, placing the curved electrotype shell in a mold chamber having curved walls, removably mounting a curved flexible barrier sheet back of the electrotype shell in position to hold such shell in contact with a curved wall of the mold chamber, introducing molten metal into the mold in contact with the flexible barrier sheet and in position to cause the molten metal to press said barrier sheet against the back of the curved electrotype shell, then causing the molten metal to flow progressively into uniting contact with the electrotype shell by ra'duallyraising and withdrawing the flexible barrier sheet from between the molten metal and said electrotype shell, then allowing the molten metal and electrotype shell to cool, and with drawing the printing plate from the mold.

he process of making curved metallic printing plates, which consists in providing a metallic electrotype shell, removably attaching a curved flexible barrier sheet to the back of said electrotype shell and bending the shell into curved form, removably securing the electrotype shell and metallic barrier sheet in position in a mold chamber having curved walls, introducing molten metal into the mold in contact with the barrier sheet and in position to cause the molten metal to press the barrier sheet against the back of the elec retype shell, and detaching the flexible barrier sheet from the electrotype shell, then causing the molten metal to flow into uniting contact with the electrotype shell progressively by gradually withdrawing the flexible barrier sheet from between the molten metal andthe electrotype shell, and then allowing the molten metal and electrotype shell to cool, and withdrawing the printing plate from the mold.

8. The process of making curved metallic printing plates, which consists in providing a metallic electrotype shell, bending said shell into curved form, placing the curved clectrotype shell. in a mold chamber having in contact with the face of the electrotype curved walls, removably mounting a curved flexible metallic barrier sheet in contact with the back of the electrotype shell ant, in position to hold such shell in the desired position in the mold chamber, heating the mold chamber and its contents, introducing molten metal into the mold in contact with the flexible barrier sheet and in position to press said barrier sheet against the back of the electrotype shelhthen withdrawing the flexible barrier sheet from between the molten metal and said electrotype shell, thereby causing the molten metal to flow beneath the edge of the flexible barrier sheet into uniting contact with the electrotype shell, then cooling the mold chamber and its contents, and then withdrawing the printing plate from the mold. V

9. The process of making metallic print ing plates which consists in providing an electrotype shell having a printing surface, placing a make-readyooverlay of chalk or equivalent material upon the printing surface of the electrotype shell, placing the electrotype shell with the overlay thereon in a mold in such position that the printing surface of the shell and the materialforming such overlay are in contact with the wall of the mold, removably mounting a flexible metallic barrier sheet in contact with the back of the electrotype shell in position to hold said shell in contact with the wall or" the mold, heating the mold chamber, introducing molten metal in contact with the exposed surface of the flexible barrier sheet in posh tion to cause the molten metal to press the barrier sheet against the back of the electrotype shell, then causing the molten metal to flow progressively into uniting contact with the electrotype shell by gradually With-l drawing the flexible barrier sheet from between the molten metal and electrotype shell, then cooling the mold chamber and its contents, and then withdrawing the printing plate from the mold.

10. The process of making metallic printing plates which consists in providing a flexible metallic electrotype shell having a flexible printing surface, laying a make-ready overlay of heat-resisting i aterial'upon and in removable contact with the printing surshell, placing the electrotype shell with the removable overlaid material thereon in a mold in such po sition that the printing surface of the metallic electrotype shell and such overlaid material are in contact with a wall of the mold, then bending the metallic shell into conformity with the engaged surface of the overlay by causing molten metal to flow into uniting contact with the back surface of the me tallic shell, then permitting the molten metal to cool and harden, and then remgving the contents of the mold,

mew-hm Mit J19... MM.

a 11. The process of making metallic printmg plates which consists in providing a flexible metallic electrotype shell having a flexible arintin surface olacin a coatin b 7 2:) C

the metallic electrotype shell with offinely divided heat-resisting material in overlaid removable contact with the printing surface of the electrotype shell, to indent the shell, placing the metallic electrotype shell with the removable overlaid material thereon in a mold in such position that the printing surface of the metallic electrotype shell and such overlaid material are in contact with a wall of the mold, then bending the metallic shell into conformity with the engaged surface of the overlay by causing '7 molten metal to flow into uniting contact with the back surface of the metallic electrotype shell, and then cooling the molten. metal and electrotype shell, and removing the same from the mold.

12. The process of making metallic print= ing lates which consists in providing a flexible metallic electrotype shell having a flexible printing surface, placing a coating of finely divided heat-resisting material in overlaid removable contact with the printing surface of the electrotype shell, placing the removable overlaid material thereon in a mold in such position that the printing surface of the metallic electrotype shell and such removable overlaid material are in contact with a wall of the mold, then bending the metallic shell into conformity with the engaged surface of the overlay by causing molten metal to flow into contact with the back of the metallic ele'ctrotype shell, then cooling the molten metal and electrotype shell and removing the same from the mold, and then removing the removable overlaid materialfrom the surface of the electrotype shell. a,

13. lhe process of making metallic printing plates which consists in {providing a flexible metallic electrotype shell having .a flexible printing surface, laying a coating containing a finely divided mineral substance in removable overlaid contact with the mold,and then removlng the removable overlaid material from the surface of the eleetrotype shell.

Signed at Chicago, Illinois, October 28, 1918.

' CHRISTIAN N. SMITH.

W itnesses:

Davin H. FLETCHER, VVILLIAM A. SHELY.

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