US965241A - Apparatus for making stereotypes. - Google Patents

Description

J. JQG. SMITH. APPARATUS FOR MAKING STEREOTYPES. APPLICATION FILED APR.1, 1909.

965,241. 0 Patented Ju ly 26,1910.

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' Patented July 26, 1910. lE5 g 38HEETS SHEET 2. XL

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J. J. 0. SMITH.

APPARATUS FOR MAKING STEREOTYPES.

APPLICATION FILED APR.1,1900.

UNITED STATES PA ENT OFFICE.

- JOHN J. o. sMI rH, or PASSAIC, NEW JERSEY, ASSIGNOR T mm M. HAMMALIAN, or

' HACKENSACK, NEW JERSEY.

APPARATUS FOR MAKING STEREOTYPES.

To all whom it may concern:

Be it known that I, JonN J. (1. SMITH, a citizen of the United States, and residing at Passaic, county of lassaic, State of New Jersey, have invented new and useful Improvements in Apparatus for Making Stere- I, otypes; and in order that those skilled in the art may understand, make, and use my 1n- 1 vention I give the, following specification,

reference being had to the accompanying drawings, forming part thereof.

My invention relates generally to the production of cast metal designs but more particularly to makingof new and improved stereotypes for the reproduction by ordinary printing processes of cuts, illustrations, designs, type-matter and the like.

The invention has for its objects the production of stereotypes of special and superior material to that at present generally used; the provision of improved molds and molding apparatus for the making and casting of stereotypes, and the saving of time required to produce stereotypes.

Stereotypes .at present employed are formed, either by casting type-metal against a matrix of papier mach, or by electrotyping on a wax or similar impression, the elect-retype shell being afterward reinforced or backed by type-metal. A great desideratum in the art of making stereotypes has been to produce a stereotype of harder metal than the type-metal or electrotype plates commonly used, which are heavy in weight and soon become defaced by wear and usage.

' Further, since it is desired to reproduce cuts,

' illustrations, type-matter and the like in many different publications in different and remote places and at as nearly the same time as possible, the cost of transportation, particularly where sent by mail, as is frequently done, is, owing to the weight of the ordinary type-metal stereotypes, an item of considerable expense which my invention is intended to overcome. The employment of other metals than type-metals has hitherto been prohibited by the fact that harder and lighter metals suitable'for printing 'purposes require considerably higher temperature for melting, making the use of a papier macho matrix impossible and necessitating the employment of a refractory material for the same. In employing a mold ormatrix of refractory materiahhowever, further dif- Specification of Letters Patent. I Patented July 26, 1910. Application filed April 1, 1909.

Serial No. 487,169.

ficulty is encountered in that such molds are formed of the molding material in a plastic or semi-fluid state from which it hasto dry and harden, and this drying, in order to be sulliciently rapid, requires a heat of about 600 F. Under these conditions fine or. even large cracks make their a1) 'ea.1ance in ordinary m'olds. It will be 0 vious that even the finest cracks, or a slight amount of shrinking or warping will destroy the mold, particularly when it is considered that the metal is cast in the molds under pressure, as it is contemplated with the molds of my present invention.

I am aware that plaster molds have been employed for producing metal castings and stereotypes, but such molds as have heretofore been used have the disadvantage not only of not satisfying the above requirements, but of requiring such length of time to dry them by heat that their use for making stereotypes is out of the questioin'because stereotypes are required to be finished on very short notice, sometimes no more than three or four hours,-a period insufficient even to dry the ordinary plaster mold.

Still a further dilliculty to be overcome with molds of such material is that the material of the mold must be capable of entering the finest lines of a delicate or intricate design and of taking and retaining impression in a high degree of perfection, and also that it must be capable of withdrawal from the pattern without distortion and must separate from the pattern perfectly and clearly.

In the accompanying drawings Figure 1 is an underside View of a mold plate. Fig. 2 is a longitudinal View of Fig. 1. Fig. 3 is a plan view of the base-board with patterns and gate or sprue blocks in position. Fig. 3 is a detail sectional view of a modificarepresenting a mold plate and base-board arranged for molding, with part of the mold plate broken away to show the patterns and gate blocks in position. Fig. 5 is a longitudinal sectional view of Fig. 4. Fig. 6 isa similar view to. Fi 5, showing the mold partially raised off the patterns. Fig. 7 is a view of the underside or interior of the formed mold. Fig. 8 is a plan view of a separating plate forming part of the apparatus used in casting. Fig. 9 is a longitudinal sectional view of Fig. 8. Fig. 10 is a 3 holes 3, t

lon itudinalsectional view of .twomolds wit a separating platebetween, arranged upon a platform of a casting machine.

The apparatus for forming the molds com r'ises a frame 1 formed of a metal plate 2 0 any desired orsuitable size-say 16" by. 20 or larger-easily handled and acafter appear. These holes may be tapered thereof an as illustrated in Fig.3 -if desired, so as to give themold composition a better grip to the frame. This will be desirable where other metals thansteel are employed for the frame 1. Plate 2 is also provided with a rim or flan e 4: around its edge on one side secured thereto in any convenient manner, as by riveting, brazing or the like. On one side the rim is'interrupted, as

at 5, forming an opening-or gate for use during the casting operation. This opening '5 is closed, however, in the process of forming the mold, bymeans of a removable block 6, (see Fig. 4) or in any other convenient manner. The perforated plate 2 w1th its rim or flange 4: forms a frame 1, relatively shallow so as to take very little molding material, and so form a thin mold, the strength and rigidity of which is derived from the metallic frame. The frames I have emloyed are not over three-eighths of an inch in thickness, including the plate 2. At each corner the frame is provided with a thumbscrew 7 passing through a threaded opening 7 therein.

For use with the frames 1 I provide a base 8 of somewhat greater dimensions than the frame.

This base may be of wood or any suitable material, or may form the top of a table or work bench. On its upper surface this base is provided with a non-adhesive surface to which the molding material will not ,stick, as, for example, a smooth rubber-sheet 9.

The manner of using the apparatus above described and the process of preparing a mold is as follows:-

I take the pattern or patterns P P of which it is desired to make a stereotype or casting a and fasten the same temporarily on the base 8 by means of brads,.or inany other convenient manner. (See ]3:1g.-3). One or anumjber of such patternsmay be so secured in place, as may be desired, and according to the dlmensions of the mold frame employed.

In the drawings I have shown two patterns,

by way of exam le.' The patterns will, be arranged with s cient space between them to allow for the necessary gates or sprues, as will be understood by any one skilled in the molding or castin art. These ates or sprues are formed iy removably. 'astening to the base 8 blocks or pieces 10 of suitable shape, and of a thickness sli htly greater than the patterns,but of less t ickness than the depth of the mold frame 1 (see Fi Having arranged the patterns and the blocks or plates forming the gate and sprues as above s ccified, 1- coat the faces thereof with a thin lm'of separating medium to insure a clean-separation of the mold from the patterns. For'this purpose I preferably employ good sperm oil, applied to the surface of the patterns with a still' brush so as to reach and coat every cavity and deep line of the pattern. This coating of oil or the like, while necessary to insure clean separation-of mold from patterns, has the disadvantage of increasing the tendency of air to become confined in the cavities and lines of the design, thereby preventing the plaster composition'from enterin and thus producing a defective mold. The re ellent or. antagonistic character of the oi ed surface against the water of the fluid plaster composition tends to keep the latter from fiowin into and occupying the deeper recesses an lines of the pattern. It will be understood that for stereotypes the design or pattern is fine and intricate, presenting many hundreds of small recesses and cavities on a surface less than fiftysquare inches, and in order to produce a successful stereotype a faithful reproduction of every line and cavit of the design is required. Agitation of tie plaster composition, after it has been cast upon the pattern and while still fluid, has been proposed, but this is only effective indesigns which do not present the intricacies of detail possessed by stereotypes and is ineffective for such moldin s. Furthermore, if agitation beattempted or the purpose of removing the confined air in the cavities,

as, for instance, by applying a brush to drive the same out, the oil film becomes removed in places'where reached by the brush,

and this results in the mold composition sticking to the attern and reducing defects. To overcome these di iculties I wet or moisten the oiled surface of the pattern with a fluid which will lie uniformly thereon and not be either repellent or antagonistie to the water of the molding composition.

For such fluid I have found wood alcohol to give goodand satisfactory results. Havs. I f.

.terns and without distortion.

than is required to wet the oiled surface, as an excess of alcohol would be likely to delay the setting or hardcningof the mold. Themold frame is then placed over the prepared patterns and the same is held in position either by arranging weights around its edges or by clampingit to the base, or in any'convenient way.

The molding composition having been prepared, is now poured into the mold or frame through the'opcnings 3. This moldingeomposition must possess the requisite characteristics of withstanding the heat of the molten metal to be cast therein when the mold is formed Without cheekin' or cracking, since the finest crack woul duced on the cast stereotype. This heat will be about 900 F. The molding composition must possess such tenacity that it will, when set, withdraw absolutely clean from the pat- And further it must be of such character that it will en .sion. I have invente ter the finest detail and lines of the design and reproduce a shar. and erfect impres- I a mo ding composition possessing these characteristics and have filed an application for Letters Patent therefor of even date herewith, said appli cation having Serial No. 487,168filed April.

" the top or outer face of plate 2. This leaves the composition filling the holes or openings 3, as shown in Ifigs. 5 and 6 in which the molding composition is represented at M.

- After about ten minutes more, the com position sets sufliciently hard to permit the mold to be removed from the base-board and patterns. This removaltof the mold requires great care. To enable the removing of the mold to be accomplished with certainty, and without damage, I have provided at each corner of the mold plate the thumb-screws 7. By turning each of these screws slightly in succession and to a similar degree, the mold will be lifted from the base-board without any danger of defacing the molded impression, as is clearly illustrated in Fig. 6: The mold may now be placed at once into the drying oven. This oven may be of any suitable kind, heated by gas or other means of heat, to atemperature of about 600 F. The molds sustain this degree of heat without any danger of cracking or any other injury. They are left in the oven for be repro-' a period of from two to three hours, at the end of which time the moisture andwater are all expelled therefrom. The numerous perforations or openings 3 in the mold )late permit ready escape of the moisture an water; and by reason of the fact that the mold material itself, consists of only a thm layer of the molding composition, the time required for drying is reduced to a minimum. After having been dried the molds are ready for the casting operation. It will be apparent that the mold is constituted by the thin.

layer of molding composition which carries the design orimpression, together with the perforated mold frame or plate 2. The latter gives great stiffness, rigidity and strength to the mold, not only protecting it from damage but enabling it to resist the pressure to which it is subjected in the casting operation.

I have contemplated employing molds prepared in the manner above described in machines or apparatus for casting metal under pressure. Machines or apparatus of this type have long been known, and'have been invented by myself and others, (See for instance United States Patents, No. 70,038 granted to Michael Smith, October 22 1867, and No. 477,231 granted to myself and Victor 1a. Smith June 21, 1892, No.-

591,430, granted to me October 12, 1897. In machines of this character the fluid metal is forced into the molds under what is substantially the equivalent of hydraulic pressure, which forces the metal into the fine details and lines of the designs, enabling, thereby, a perfect casting to be obtained.

- In using the molds in the casting operation I employ a separating plate, illustrated in Figs. 8 and 9 by the numeral 11. This plate is similar to the mold plate 2, in that it is provided with perforations or openings 12, similar to the openings 3 of plate 2, and is also stiffened by a rim or flange, 13, around its edges. ]n this case, hou'cver,'the rim or flange 13 is on both sides of the plate 11 as shown in Figs. 1) and 10. This separating plate 11 is prepared by placing it on a base-board and pouring the molding composition through the openings 12 until the composition rises to the level of the upper face of the rim 13, when it is evened off. The result is a plate, as illustrated in Fig. 9, having a central metallic plate 11 with the molding compositions 14 on each side thereof flush with the rim.

In arranging the molds in a casting ma-- 11, is shown in Fig. 10 on the platform 14.

of molding machine; but it will be understood that'any convenient number of molds 1 may be so arranged with a plate 11 be tween-the open faces of each pair. The

" gates 5 of the molds are arranged to'come all in registry with the outlet from the mol-' ten metal receptacle (not shown) of the casting machine. As illustrated in 1g. 1 the gates of the mold are at the right, in registry with a suitable opening or passageway15 in the castin machine. WVhen the desired number of mo ds have been arranged in the casting machine they are clamped together under heavy pressure, as will be understood by those skilled in operating such machines. The casting machine is then operated to force the molten metal through the gates into the molds.

It willbe noted that by having the molds and the intermediate plate of the construction described they are not only of sufficient strength to resist the pressure to which they are subjected, but, what is 'an important consideration, the gases from the molten modifications-may be made by those skilled. in the art, without departing from the inmetal, and also the air in the, casting spaces,

find exit through the porous molding composition filling the holes in the said plates. It will be understood that the molding composition is of a finely porous character, -permeable to gases, particularly under the pressure of the metal forced into the mold.

By reason of the above described improvements I am enabled to produce, in a short space of time, perfect castings of stereotypes, of a fineness and perfection of design which is only attained, so far as I am aware, by the electrotype process, and also to produce such castings within as short or shorter a time than now required for making electrotype plates. The molding composition which I employ, of which the mold is made, is such as to permit the same to be exposed at once to the high degree of heat required to dry it in a short time without cracking or injury to the finest detail thereof. The perforated plate or frame forming part of the mold not only gives the rigidity and strength required, by reason 'of openings 3, but does not interfere with the rapidity of drying, and at the same time eliminates the difficulty usually encountered Ofoccludedgases and air in the molds when casting. Themold plate forming a part of the mold also en ables the mold to be very thin, thereby economizing material, as well as the time required for drying the same.

While I have illustrated and described a particular form of apparatus and mode of operation, it will be understood. that this is by way of illustration only, and not of limitation to the precise details and steps disclosed, since it will be obvious that various vent-ion.

Matters shown and described in the foregoing specification but not especially claimed herein form the subject matter. of

a divisional application, Ser. No. 518,319, filed September 18, 1909.

What I claim is:

, 1. In apparatus for making molds,a frame having si es to inclose the molding space and patterns, and a plate supported by said sides and extending over the space inclosed thereby, said plate provided with a plurality of apertures or perforations through which fluid molding materialmay be poured or ,cast on the )atterns inclosed by said frame and fill said apertures whereby said frame becomes partially embedded in and forms part of the mold produced.

2. In apparatus for making molds, a frame for forming the mold space about the patterns, said frame having a top plate provided witha plurality of holes and uniting with the mold produced to form a part thereof, and means for gradually and evenly lifting said frame and mold from the pat-a terns.

3. In apparatus for making molds,aframe for forming the mold space about the patterns, said frame having a top plate provided with a plurality of holes and uniting with the mold produced to form a part thereof, and lifting screws onsaid frame for raisingjthe same from the patterns.

- 4. A frame for making molds, said frame 0 on at the bottom, having sides slightly hlgher than the height of the patterns to be molded, and a top plate having a plurality of perforations therein to permit the pouring of the molding material therethrough and the escape of surplus molding material.

5. Molding apparatus comprising a base, a non-adhesive surface on said base, and a mplding frame adapted to rest on said base, said frame open at the bottom and having a perforated top plate.

6. Molding apparatus comprising a base for supporting the patterns to be molded, a frame surrounding said patterns and having a perforated top plate, and lifting screws for said frame threaded therethrough and bearing upon said base.

7. A mold for forming castings, .said moldsformed of a set molding material, and a metallic frame supporting said molding material and forming part of the mold.

8. A mold for forming castings, said mold comprising a metallic frame or support having a mold of plaster composition cast and set therein, said frame forming part of the mold.

.9. A mold for forming castings, said mold comprising a set and hardened hydrated molding nnitcrial'hearing the design to be cast, and a :metallic frame partially embedded in, said moldingmaterial.

10. A mold for forming castings, said mold comprising a set and hardenedhydrated molding material bearing the design to be cast, a metallic frame surrounding said molding material on the sides and back, the back of said frame consisting of a plate having perforations therethrough, with: the molding material filling said perforations.

11. A mold for forming castings, said mold comprising ametallic frame having shallow sides and a perforatedback or bottom plate, a set and hardenedporous mold ing material bearing the design to beeast, on said mold said material filling the perforations in said bottom or back plate.

12. A mold for forming castings, said mold comprising a refractory molding material bearing the design, said molding material having partially embedded therein a metallic plate provided with perforations and a rim on said plate and surrounding said molding material.

13. In molding apparatus, a base or supporting plate for the molds, said supporting plate comprising a metallic plate provided with perforations, a flange or r'm around the sides of said plate and proj cting from both sides thereof, and a set and hardened refractory molding material on both sides of said'plate and even with the rim thereof. 7 a i I 14. In molding apparatus a base or supporting plate for the molds, said plate formed of a refractory, porous molding material, and a perforated metallic plate embedded therein, and a rim surrounding said plate and molding material.

JOHN J. 0. SMITH.

Witnesses:

H. C. WORKMAN, H. R. Hosmon.

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