US1720430A - Process of manufacturing curved electrotype plates - Google Patents

Description

July 9, 1929- B. J. OBRIAN ET A. l.1,720,430

QURVE ELECTROTYPE PLATES PROCESS OF MANUFACTURING Filed April 20, 1928 2 Sheets-Sheet 111 /1 Il l lll/[Will l 1//1/ l l l 1l l//l l l l l '7 ATTORNEY July 9, 1929- B. J. oBRlAN ET AL,

PROCESS OF MANUFACTURTNG CURVFD ELECTROTYPFI PLATES ,Filed April. 2Ol 1928 2. Sheets-Sheet 1N VENTOR ATTORNEY Patented July 9, 1929.

UNITED STATES PATENT OFFICE.

BARTHOLOMEW J. OBRIAN AND GEORGE E. FUNK, OF KANSAS CITY, MISSOURI.

PROCESS 0F MANUFACTURING CURVED ELECTROTYPE PLATES.

Application filed April 20,

rlhis invention relates to a process of manufacturing curved electrotype plates to be used on rotary type presses, and has for its principal object the reproduction of any engraved or moulded surface, wood cuts, or pages ot composite type in a flat surface to a cylindrical forni suitable Vl'or use on a rotary press, without distortion.

'llhe method now used in making curved electrotype plates is to mould by pressure, the subject that is to be reproduced in lead while inV a flat shape, backing up said lead mould with some suitable reentorcing metal to prevent distortion, then depositing on the surface of the mould by electrolysis, a'thin layer ot metal, such as copper, to torna a shell on which is reproduced the characters to be printed. '.lhis thin shell is removed trom the mould and backed up with type metal to which it is secured by some suitable soldering material. The shell, with its backing is now in a flat shape, and must be curved to lit the printing drum ot the press. ln the process ot curving this plate, the

Q printing surface is distorted, due to the tact that the plate is quite thick (trom threesixteenths to one-haltl inch thiclr, depending on the type et printingpress on which it is to be used), and the outer surface will be stretched, while the inner portion is coinpressed. 'lhis distortion is very noticeable when color printing is to be done, and more than one printing operation is required. I'llhe distortion ot the diilerent color plates is not the saine, and it is impossible to get a proper register ot the colors.

'lhe purpose ot the present invention is to overcome the distortion ot the plate, and thereby produce an electrotype plate that will be an exact reproduction et the original surface.

il further purpose ot the present invention is to make a curved electrotype plate by depositinbT by electrolysis on a mould having' the reverse contour of the finished 'curved' electrotype plate, a thin layer et metal.

t still further object ot the present invention is to malte a thin lead mould ot an engraved or moulded flat surface, then curving said thin plate to the exact torni Qt the itinished curved electrotype plate, said mould then beine; used to produce a shell of metal by electrolysis.

llith these general objects in view, as well as minor objects which will appear during the course of the detailed specication, ret- 1928. Serial No. 271,471.

erence will now be made to the accompanying drawings, which are submitted to more clearly set forth the different steps, in the manufacture of the present curved electrotype plate, in which Figure l, is a perspective view of a lead mould, formed byvpressing said lead against a moulded or engraved flat surface.

Fig. 2is a perspective view of said mould, shown termed to a curved shape in a curved bloclr.

Fig. 3, is an enlarged cross-section taken on line lll-lll ot llig. 1.

Fig. 4, is an enlarged cross-section taken on line lll-ell] ot Fig. 2.

Fig. 5, is a perspective view ot a curved mould with the reentorcing metal in position. I

liig. 6, is a perspective view of said mould with the shell 'Formed by electrolysis thereon.

Fig. 7, is a perspective view ot the printing' side ot the shell, 'removed trom the mould.

lPig. 8, is a cross-section of the .shell positioned in a casting" box with the metal baclringr in position, and

Fig. 9, is a perspective view ot the shell with the reentorcing metal secured to the baclr thereof.

Like reference characters designate like parts throughout the several views, and the numeral 10 designates a lead mould in which has been reproduced the characters from a llat surface. 'lhese characters are usually produced by placing the thin sheet of lead on the surface to be reproduced, and then applying hydraulic pressure to the outer sur- 'lace of said lead sheet, to torni an impression l1, ot said characters therein. rlhe thickness of this lead sheet is preterably about .010 thickness, while the depth ol the impression made by the characters to be printed is substantially .005, thus making the inner surface l2 of the impressions .formed in the lead sheet substantially on the central plane ot said sheet. |llhis is a very important requirement in the manufacture ot the plate, because ot the tact that the bottom surface ot said depressions is the surtace on which .the-printing sui-tace et the electrotype plate is to be deposited, and due to the tact that these bottom surfaces are on the central plane ot the lead sheet, there will be no stretching or coinlnessing of the metal to distort'the printing` tace. rllhere will be a compression ot the face 13, and a stretching of the surface 14, While the metal on the center plane will be neutral. This is a well established principal in the .forming of metals.

As shown in Fig. 4, the lead mould 10, which is easily formed to shape, is pressed into a curved block 15, by any suitable means, and due to the softness of the metal will readily adapt itself to the exact contour of said block. The curved side 1G of the block 15 is made of such a degree, that when the lead mould is positioned therein, the curvature of the bottom portion of the impression in said lead mould will be the saine as required by the printing surface of the electrotype plate.

In Figs. 3 and 4, it will be noted that a4 broken line C-L has been drawn which indicates the central plane of the mould sheet. It is not desired to limit the mould to lead, as it may be made vof wax, papiermch, or any other moulding material, suitable for the purpose.

The curved mould is now removed from the block 15, and backed up with a suitable reenforcing metal 17, as shown in Fig. 5. This backing is secured to the lead plate by any suitable means, and serves to prevent` distortion of the saine during the process of depositing a shell thereon. A deposit of copper is now made on the 'lead mould by electrolysis in the ordinary well known manner, to form a shell 18, having a printing surface 19. When it is desired to use the plate for printing a very large number of sheets, a thin deposit of nickel may .first be made, and then a thicker deposit of copper, thus giving the printing surface a harder texture to prevent Wear. The shell is now removed from the mould by inserting a sharp instrument between said shell and mould at one corner, and then pulling on the shell, thereby peeling the same from the mould while in the curved shape. The shell is new placed in a mould 20, as shown in Fig. 8, and is backed up With a type metal 21, which adheres to the concave side of said shell, due to the application of soldering flux 22, such as tin. The thickness of the backing of type metal is usually from threesixteenths to Ione-halt` inch, depending on the type of press on which the electrotype plate is-to be used. Due to the fact that it is difficult to cast a type metal backing of an exact thickness, thebacking is usually cast thicker than necessary, and-then turned down to the proper thickness, thereby giving the printing surface a more accurate adjustment on the printing roll.

It Will be noted that in this process, the printing surface of the electrotype plate has not been distorted by bending from the original surface from Which it was produced, as described above, while in the ordinary process now in use, the printing surface of the elcctrotype plat-c is greatly distorted, due to the fact that the shell is backed While in the flat condition, and then bent to the curved position.

Should it bc attempted to deposit the shell in a iat shape and then form the liat shell into the curved shape, before the backing is attached thereto, it will be found that due to the'hardness of this shell, thc contour of the shell will become irregular and not of uniform curve. Due to the hardness ot the metal and the different thicknesses of the metal, some portions of the shell will be curved, while others will be substantially tlat, thus making it impossible to obtain the, desired printing surface.

Vith this process, it is very evident that several plates may be made for color Work, which will properly register and produce the same result as is now produced on the flat printing press.

lVe do not limit this invention to the process described and shown, as many modit'cations may be made Within the scope of the appended claims without departing from the spirit thereof.

lVhat we claim as new and desire to be secured by Letters Patent is:

1. A process of manufacturing a curved electrotype plate consisting in depositii g on a curved mould a thin layer of metal to form a shell, then separating said shell from the mould., and backing' up said shell with a reenforcing metal.

2. A process of manufacturing a curved electrotype `plate consisting in depositingon a curved mould by electrolysis a shell of metal, separating said shell from the mould and backing it up with a recntorcing metal While in the curved shape.

3. The process of manufacturing curved electrotype plates consisting in forming a mould to the shape that the finished plate is to be, then depositing by electrolysis a coating ot' metal to form a shell having a printing surface on its convex side.

4. The process of manufacturing a curved electrotypc plate consisting in forming a mould to the curve that the finished plate, is to be, backing up said mould with a reenforcing metal. then depositing on said mould by electrolysis a coat of metal to forni a shell having a printing surface on its convex side, then backing up said shell willi reenforcing metal.

5. The process of manufacturing curved electrotype plates consisting in forming an impression of characters in a thin, flat, soft. metal sheet to a depth substantially one half the thickness of said metal sheet, then curving said metal sheet, then depositing b v electrolysis on said curved metal sheet a shell of metal having a printing surface on its convex side.

6. The process of manufacturing curved llfi electrotype plates consisting in forming an impression of characters in a thin, Hat, lead sheet to a depth substantially one half the thickness of said lead sheet, curving said moulded lead sheet, then backing it with a reenforcing metal, then depositing a thin sheet of metal on said moulded lead sheet to form a shell having a printing surface on its convex side.

7. The process of 'manufacturing curved electrotype plates, consisting in forming a curved mould, depositing thereon by electrolysis a thin shell of metal, removing said shell from said mould and reenforeing the back thereof With metal. t

8. The process of manufacturing curved electrotype plates consisting in making an impression in a thin sheet of lead of some moulded or engraved flat surface, forming said lead sheet into a curved shape with the impressions on its concave side, backing up the convex side of said lead sheet With a reenforcing metal7 depositing a thin coat of copper on said lead sheet by electrolysis to form a curved shell having a printing surfaeeon its convex side and then backing up said plate with type metal.

In Witness whereof, We hereunto aiiix our signatures.

BARTHOLOMEW J. OBRIAN. GEORGE E. FUNK.

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