US1202933A - Method of backing electrotypes. - Google Patents

Description

THOMAS WEBSTER,` or -NEW YORK, 'i\i. Y.

' METHOD iOIF BACKING ELECTRQTYPES.

Original.appiicatnr'led June 24, l1915,

j To all fio/wm it may concern:

Be it known ,that I, THOMAS .WEsrEii, a citizen of the United States of America, and a resident ofNeW York, in the4 borough of Brooklyn, county of Kings,l and State of New York7 have'invented certain' new and useful Improvements iii Methods of Backing Electrotypes, whereof the following is a specification.

In the methods of backingelectrotypes as heretofore practised, the shell forming the lbody of the electrotype after removal from .the electrolytic bath is cleaned and placed face downward on a backing pan which has a very smooth surface. Then a liquid'backing` metal is poured overthe shell in the panto a depth required for the thickness of the backing d'esired. Then the pan and its contents are subjected .to a cooling operation which solidifies the molten ymetal around the shell and forms the backing therefor. This cooling-operation usually consists in expos ing the pari and its contents to an ordinary temperature for a sufficient tini'e'ofvsayfrom twenty-five minutes to half an hour, or in subjecting the pan and its contents to a blast of air froma` blower whereby the time of cooling is reduced to say five minutes more or less. But in both these methods of cooling the metal of the backing shrinks more or less unequally from the pan and causes irregularities on the' printing surface of the electrotype plate,' \vhioh irregularities must be corrected by a finishing operation before the plate can be delivered in a condition acceptable to the user. This finishing is an expensive and time consuming` step.

The objects of this invention are to shorten the cooling step and to perform it in such manner as to avoid the inequalities referred to and do away With the leveling operation usually required afterthe cooling operation is completed. j i I' In carrying out this invention iii-its pre-l ferred form, the pan containing the shell and the backing material covering it, is subjected to chilling material applied to the bottom thereof, preferably in the form of an absorbent pad saturated with Water. This effects a sudden chilling of the bottom of the lp an andthe cold passes by conduction therethrough and touches the shell and the backing material surrounding it'on the lower face thereof and Causes all parts` of the vcase to shrink toward the pan, andthe Weight Specification of Letters Patent,

Patented Oct. 31, 1916.

ofthe hot molten metal above the shell I serves to press the face of the latter against the pan. 'Under this cooling operation an electrotype is produced quicklyand Without inequalities on its printing face. In the accompanying drawings, .which illustrate a convenient apparatus, for carry.-

ing outthis process, Figure 1 represents a.-

side elevation partly in section of a backing panand cooling pan, theformer con-v taining the shell and backing` material and the latter containing the cooling pad in position preparatory to effecting the cooling operation. Fig.-2 represents a longitudinalsection ofthe pans in operative position foi cooling, the cooling pad being in vcontact 4with lthe bottom of the backing pan.- Fig; 3

represents a modified forni of the apparatus in which the cooling material consists of the water in the cooling pan, thel pad being omitted.

sponding parts in the different figures.

The method may be carried out by an api I paratus comprising a backingfpan l0 for containing the electrolytic shell and the A. Similar reference numbers indicate correbacking material, a cooling pan 20 for containing the cooling material and means for shiftingone of said pans to place the bottom of the backing pan in`contact with the cooling material in the cooling pan. The backing pan l0 is supported by suspension rods l1 or otherwise and has the upper face of its bottom smoothed in the usual manner and the underface thereof exposed ,for contact 'with the'cooling materialifi thecooling pan.

The cooling pan 20, which carries cooling material for contact with the bottom of the and a current may beA maintained through I the pan and the pad mounted therein.

One of the pansis moved by any suitablef means to cause the cooling material inthe cooling pan tol contact with the backing pair. n

The means shown includes a rock shaft 30, arms 31 and 32 fixed thereto, lifting levers 33 and 34 engaging` the cooling pan, links 35 and 36 connecting said arms with said levers and an actuating lever 37 attached to said shaft. l l

In carryingout by meansof this apparatus the cooling step `in the backing method,

the shell 40 of the electrotype is placedl with its printing face downward incontact with the upper face ofthe bottom of the backing pan 10Aand the usual molten metal I45 is poured into said pan, covering said shell,

and the weight'of said Ainetalover the shell presses the latter down against the bottom of the pan. `Th cooling pan Q0 is then` the absorbent pad 25. The hot backing panr coming in contact with the wet cooling pad causes more or less evaporation or vaporization of the water, which increases the coolino' effect. lVater is supplied through the inlet to take the place of that evaporated.

QThe quantity of water maintained in" the cooling pan is such Ithat the pad is thoroughly ksaturated therewith, but the water does not form a layer above the surface of the pad under normal conditions.

The. pad 25 may be omitted if desired as shown in Fig. 3. In thatcase the water or other evaporative liquid' supplied to the cooling box comes bodily intocontact with the bottom of the backing pan containing the shell and backing metal to be cooled; but 'I find it preferable inpractice to bring the evaporative liquid into contact 'with the bottom of the backing pan through-the capillary action of the pad. This is probably due to the fact that the lpad distributes the evaporative liquid to the bottoml of the backing pan through capillary action and permits the passage of air between the fibers of the pad and increases the evaporation of the liquid and thereby intensifies the cooling effect; Y

The advantages of this method of cooling by water contact and evaporation-are that the sudden chilling by conduction through the bottom of the backing pan of the face of the casting causesthe metal 'as it cools toshrink toward and into contact with the upper face of the backing pan, the plates being all shrunk alike and the faces thereof drawn down flat, doing Vaway with straightening iii many cases, especiallyon type and halftones, providing the .backing pan is smooth tinuously moistened felt pad, the casts are i f cooled off in rforty seconds. Thus the capacity of a plant is enlarged and at the saine time the product is improved and the eX-l pense of a.. blower is eliminated'.

This case is a division of my apparatus 'application Serial No. 36,148 filed June 24, 1915. K

I claim as my'invention:

1. The method of backingy electrotypes which consists in'placing the solid shell face downward in Contact with the upper face of the metallic bottom of a backing pan, pouring molten backing metal in said pan to a depth which covers said shell, ,and subjectl ing at once the whole area of the'ybottom of said pan while said solid and liquid metals arel in touch therewith to uniform contact with an evaporative cooling liquid. i 2. The method of backing electrotypes which consists in placing the yshell face downward in contact with the upper face of the metallic bottom of a backing Jan, pouring molten backing metal in'sai pan to a depth which' covers said shell,l and subjecting the bottom of said pan to contact with an absorbent pad containing an evaporative cooling liquid;

3. The method of .backing electrotypes which consists in placing the shell face downward in contact with the upper face of the metallic bottom of a backingk an, pouring' molten `backing metal in lsai pan to a depth which covers said shell, and subject-y ing the bottom of said pan to contact with an-absorbent pad composed of felt and containing an evaporatiw, cooling li uid.

4. That step in the art of backing electrotypes which consists in subjecting the botv tom of afbacking pan containing thev solid 100 shell and the molten 'backing metal while both touch saidbottom to uniform contact over itswhole area with a coolin evaporative liquid; .whereby the face of t e electrotype only isfsubjected to a chilling operation 105 causing the metalto ,shrink'towardthe pan and avoiding irregularities on theface of the electroty e. f

Intestimony thatclaim the foregoing as my inventionyl have signed my name in 11/0 presence of two subscribing witnesses. l

' `THOMAS WEBSTER. Witnesses: i 4

l). Lewis MATTERN, A C. P. GOEPEL.

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