US2637689A - Device for making curved electroplate shells - Google Patents

Description

May 5, 1953 R. R. MYERS, JR

DEVICE FOR MAKING CURVED ELECTROPLATE SHELLS Filed Jan. 21, 1949 2 Sheets-Sheet l WZVMEEE ww a 6M May 5, 1953 R. R. MYERS, JR 2,637,589

DEVICE FOR MAKING CURVED ELECTROPLATE SHELLS Filed Jan. 21, 1949 -2 Sheets-Sheet 2 Patented May 5, 1953 DEVICE FOR MAKING CURVED ELECTRO- PLATE SHELLS Robert R. Myers, Jr., Des Moines, Iowa Application January 21, 1949, Serial No. 71,773

1 Claim.

The principal object of my invention is to provide a method of producing arcuate printing shells for arcuate printing plates without appreciable distortions, thereby making for printing fidelity and accurate color registry in multicolor printing.

A still further object of this invention is to provide a method of producing precision curved printing shells, and thence precision curved printing plates that requires inexpensive equipment.

A still further object of this invention is to provide a simplified method of making arcuate printing shells that is economical and a saving in time, material and skilled labor.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangement, and combination of the various parts of the device, whereby the objects contemplated are attained as hereinafter more fully set forth, pointed out in my claims, and illustrated in the accompanying drawings, in which:

Fig. 1 is a top plan view of the device I use to accomplish my method.

Fig. 2 is a longitudinal sectional view of the device taken on line 22 of Fig. 1.

Fig. 3 is a perspective view of the mold holding means of the device.

Fig. 4 is a side view of the device holding a mold in curved condition in the plating tank.

Fig. 5 is an enlarged cross-sectional view of the device taken on line 5--5 of Fig. 1 and more fully illustrates its construction.

Fig. 6 is a sectional view of a portion of the device taken on line 66 of Fig. 5.

Fig. 7 is a perspective view of a fiat mold prior to being placed in my device.

Most magazines and newspapers are printed by rotary cylinder presses, and require therefor printing plates that are arcuate. The present method is to take a soft fiat metal printing plate and hammer and bend it into a curved plate. Obviously, this is slow and tedious work and the distortion of the printing plate is inevitable. Such original fiat printing plates are usually made by first forming a mold, rendering the mold electro-conductive (accomplished usually by spraying a layer of silver or like metal thereon), the electro-plating of the flat mold to form a metal shell-like replica, the removal of the flat shell, and then making the printing plate by backing it with a suitable thickness of metal. However, it will be noted that the tops of the projections of the printing plate is the printing surface and that when the plate is bent into a curved printing plate the tops of the projections will be spread further apart. This objectionable spreading and further distorting of the printing surface points is caused by the stretching of the printing face surface and the contracting of the back of the plate, necessary in the bending of the plate into an arc. While the use of very soft metal aids in the easy bending of the plate, it really promotes certain distortions and highs and lows are most common. While rotary high speed printing presses have been accepted by all major printers as the ideal method of quantity printing, their main problem has been the obtaining of precision curved printing plates. Usually such printers depend upon commercial plate makers (electrotypers) for his plate supply. As above noted, however, accurate curved printing plates, under present methods of production are almost impossible, due to the stretching and distorting of the printing face and the damaging and distorting of the plate proper when it is bent into a curved plate from a flat plate. This objectionable distortion is even more serious and accentuated in making color plates register and especially is this true when the plates to be made had colored illustrations in combination with type, rules, or like. Obviously, the skeletonized or open portions of the plates do not stretch uniformly with the flat halftone or solid portions. Even in the making of partially accurate plates, the following equipment is used: a bending machine, a special solidifying machine, a special plate shaving machine, a special curved plate proof press, male and female saddles, and

special curved finishing tools for plate correction.-

Besides this, is the time, labor, and material costs.

I have overcome such problems by a simple method and means, requiring few special tools,

and only semi-skilled labor, but producing an accurate precision curved printing shell. In my method I first take a fiat plastic or like mold or matrix [0 as shown in Fig. 7. Such fiat molds are common in the art and the printing face is not at the top of the projections as in a printing plate, but are in the valleys, or between the projections. This fact is important to my method. My first step is to take the mold l0 and curve or bend it into an arc in my device, as shown in Fig. l. The mold has already been rendered electro-conductive. points are between the projections, they will be little, if any affected by this bending action.

Furthermore, such plastic or like molds are Obviously, as the printingflexible and bend readily and uniformly. My device for maintaining the mold in a properly curved condition for plating and forming the shell will be later described in detail. However, it will here be noted that the mold is so held and supported in the electro-plating bath. Copper or like metal is plated on the mold (now in curved condition) to form the printing shell. This shell, when formed, will be curved and have little, if any, distortion, and certainly no stretch distortion of the printing face. This is due to the fact that the valleys of the plastic or like mold were the printing face surface, and were not materially affected by the curving of the mold prior to plating. The printing face points of the replica shell, however, are its high projections, but these are not stretched or distorted because the shell was formed during the plating and formed arcuate and thereafter never bent. Therefore, the replica shell is free from distortions "caused herebefore by bending and stretching the printing plate into a curved condition.

With my method, therefore, it is possible to startthe making of the printing platewith a per fectly curved precision printing shell as distinguished from the heretofore method of starting from .a viiat printing plate and stretching and bending it .intoua curve. In making, duplicate shells, it is merely necessary to run ofi as many shells as desired from the plastic or like mold.

Obviously, each of these shells will be exact duplicates in both indicia and curvature. In the old method of making curved printing plates it would .be physically impossible to produce exact duplicates inasmuch as the bending and stretching-of the flat printing plates would produce different distortions in the various plates being bent and stretched.

Af-ter'my arcuate shell is made it is backed with suitable material such as lead, electrotype backing metal, or like. This may be accomplished by injection molding, centrifugal molding, or like and the finished product is a precision curved printing plate. As "the plate is cast in a curved shape, requiring no later bending. or stretching, it need not necessarily be formed of the relatively soft electrotype backing metal. A much tougher or harder backing metal may be used. The curvature of. the plate will depend upon the curvature-of the device used to hold the mold while the shell is being plated thereon. Different presses have different diameters therefore requiring: plates of different curvatures. This is easily provided by having frame holding devices of different varying degreesof arc. Bymy method little, if any, work is required on the resultant printing plate before it is placed on the press.

I will now describe my mold holding frame device in detail. The numeral M designates an elongated trough member arcuate in cross-section, as shown in Fig. 5. The degree of arc of this member will depend 'upon the degree of are required of the finished printing plate. meral I2 designates a curved collar secured to the inside upper end of the portion II. This member l2 extends transversely of the length of the member H and has its lower portion spaced apart from the inside of the member I i to provide a downwardly extending curved slit opening 53 at the top of the trough, as shown in Fig. 2. At the bottom inside of the member 1 I are a plurality of spaced apart upwardly extending finger members M, as shown in Fig. 1.. free end portions spaced apart from-the inside of the trough member H, to provide a receiving The nu- These fingers have their.

'4 space l5 under each finger. To use this portion of my device it is merely necessary to take the flat mold l0, manually force it into the trough H (which will accordingly curve it as shown in Fig. 5), slide the upper end of the mold into the curved slit I3 until the bottom end of the mold clears the fingers l4, after which the mold is slightly slid downwardly into the spaces l5 below the fingers It. By thisarrangement the curved slit I3 will hold the upper end of the mold in curved condition and adjacent the curved inside of the trough and the fingers M will hold the lower end portion of the mold in curved condition and adjacent the curved inside of the trough. Reinforcing bands l6 may be placed around the outer side of the trough. The collar band 12 may be of transparent material so that the operator may easily view the position of the upper end of the mold resting in the curved slit iii. The numeral i1 designates a bracket member secured to the upper end of the trough. This bracket member has a portion l8 parallel to the length of the trough and in a plane above the inside center of the trough. Above this portion 18 is a curved depression I 9, and below which is a handle portion 2b as shown in Fig. 2. The numeral 2.! designates a handle portion hinged to the bracket and whichhas a curved jaw portion 22 adiacent the portion 19. A spring means 23 yieldinglyholds the jaw 22 toward the depression is. This jaw 22 and depression [9 are designed to detachably embrace the supporting rod 25 of a plating tank 25 and suspend the device with the mold in the tank as shown in Fig. 4. The numeral 25 designates .a headed stud on the portion I8. 'Ihe numeral 21 designates a spring tongue having a bayonet slot 28 detachably engaging the stud 26, as shown .in

Fig. 1. After the plastic or like mold has been placed in the trough this tongue is latched on the stud 2.6 with the .free end of the tongue yieldingly engaging the electro-conductive treated face of the mold. This action holds the mold,

against undesirable movement in the trough, and

inasmuch as it and the bracket l8 are of con-' ductive metal, electrical contact will be established between the mold face and 'the rod 24 which.

is in the electrical plating circuit. The trough portion Ii, member [2, and fingers [-4 are ;pref-,

erably of plastic composition. After a suitable shell hasbeen formed on the face of the mold the device is removed from the plating tank. and

the resultant curved printing shell is removed from the mold. To remove the mold from device it is merely necessary to detach the tongue 21, slide the mold upwardly to clear the fingers I4, and then slide it from the curved slot 13 under the band collar [2.

My method of curving the mold and holding it in such curved condition at its two ends that [2 are capable (with the trough H) of forcing and holding. the end edges of the mold throughout their lengths in a perfect arc, thereby main-' taini-ng correct curvature of the mold while it is being plated to form the printing shell. Some changes may be made in the construction and arrangement of my method of and means for making curved electroplate shells-'- without departing from the real spiritv and purpose of my invention, and it is my intention to cover by my claim, any modified forms of structure or use of mechanical equivalents which may be reasonably included within their scope.

I claim:

A holding device for maintaining a flexible fiat mold having relief indicia in a curved condition during the plating of a shell thereon, said holding device comprising, an impervious trough portion arcuate in horizontal cross-section, a collar on the upper end of said trough overlapping and spaced apart from the inside of said trough, said collar having its length arcuate to conform with the inside are of said trough and overlapping the upper marginal edge portion of said mold for detachably holding the same in curved condition and closely adjacent the inside of said curved trough portion, a bracket secured to said trough member having a raised flat portion, a headed stud on said flat portion, a spring tongue extending into said trough and yieldingly engaging said mold and having a bayonet slot for detachably engaging said stud, and a spring clamp means connected with said bracket for connecting the same to the support rod of a plating tank.

ROBERT R. MYERS, JR.

References Cited in the file of this patent UNITED STATES PATENTS

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