US477231A - smith - Google Patents

Description

(No Model.) 3 Sheets-Shed 1. J. J. O. 82; V. E. SMITH. ABPARATUS FOR CASTING METALS.

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(No Model.) 3 SheetsSheet 2. J. J. C. 85 V. E. SMITH.

APPARATUS FOR CASTING METALS. No. 477,231. Patented June 21, 1892.

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J. J. 0. & v. E. SMITH. APPARATUS FOR CASTING METALS.

No. 477,231. Patented June 21, 1892..

' To all whom it may cmtccrn:

designs, with a sharpness-and perfection equal UNITED STATES PATE OF IC J OllN 0. SMITH AND -VIGTOR.E. SMITILVOF'PASSAIO, NEW JERSEY; SAID JOHN J. C. SMITH ASSIGNOR TO SAID VICTOR. E. SMITH.

APPARATUS FOR CASTING-M ETALS.

SPECIFICATION forming part of Letters Patent no. 477,231, dated. June 21, 1892. Application filed April 28,1891. Serial No. 390,729. (No model.)

Be it known that we, JOHN J. 0. SMITH and VICTOR-E. SMITH,eit-izensof the United'States,

residing at- Passaic, in the county of Passaic I and State of NewJersey, have jointly invented new and useful Improvementsin Apparatus forOasting Metals, of whiclrthe following is aspecification.

The invention relates'to a means of producing very light and thin metallic castings, more especially such as are marked with elaborate to electr c-deposits.

, ishing the pressure in front of the advancing 1 Our invention is an improvement on those methods of and'apparatus forjmetallic castin g in which effectivepenetration of the fluid mass to and intimate contact with every part of the matrix is sought to 'be secured by, first, collection and temporary detention of the entire charge of molten metal in a suitable holder above the molds; secondly, prompt, rapid,and continuous transfer ofthe purelymetallic portions of the entire body of molten metal from the bottom of such holder to the matrix-cavities, leavingiimp'nrities in the sprue, thirdly, the-twofoldoperation of increasing the pressure-at. the rear and diminstream of molten metaL' The products .of our invention are greatly superior toanyknown to us except those of the comparatively costly expedients of original engraving or of electroplating 0 can c 'arac are our im rove The s o d h t f p ment will be better understood after a brief reference to the state of the art.

7 For many years past it has been the aim of workers in metal to produce, by means of the comparatively cheap process of casting, mee tallic articles of slight thickness and elaboratedesign, such ashave heretofore been produced either by the costlyexpedient of electroplating or by the still more expensive labor of the engraver.

Whil our present invention is applicableto foun ing or casting operations generally, it has more particular reference to-where it is notonly essential to have perfectly sharp and finished outlines of the most minute ornamental details, but also to combine therewith a required lightness of weight and economy of material-such, for example, as called for in the endless variety of vtable-ware, toilet articles, medallions, and other delicate metallic objects of use, ornamentation, and luxury.

Like articles are usually manufactured out of sheet metal, either by spinning against a pattern or by stamping or. hammering'in dies.v These processes do nottransfer the finer details of the design, which consequently have .to be added by the skilled labor of the chaser or engraver.

,Theobject of our als-''such, .for example, as German silver-of invention is to produce perfeetcastings'in the most refractory met- I anyrequired thinness and with a faithful reproduction of the most elaborate ornamental details. The molds for these fine, delicate, and sharp castings are preferably made of clay pressed on a pattern and then bakedafter the manner set forth'in Letters "Pat-- cut No. 70,038, granted to Michael Smith 00- means of which the metal collected in a conveni'ent cylinder can beinjected almost stantaneously to every part of the matrlxspaces. This purpose is accomplished by applying suction, which absorbs and carries tober 22, 1867. An apparatus-is needed by away the air and gases from the matrix-spaces through the substance of the said baked-clay molds, while, on the otherhand, pressure'isapplied-to expedite the entrance'of the metal and its prompt and effective permeation to every part of said spaces.

Furthermore, it is requisite that the molds be so. effectually sealed and clamped that escape of metal from the matrix-spaces is avoided. v

Referring to the accompanying drawings, which form a part of this specification, Figure I is a'perspective view of a casting apparatus' adapted tocarry out our said method. g Fig. II is a vertical longitudinal section ofsuch apparatus in itsclosed condition, the

charging-cylinder being shown in act ofreceiving its charge of metal. Fig. III is alike cylinder taken at a later stage. inthe operation, the pressureof the forming-piston hav ing broken through the asbestus diaphragm,

thus allowing the metal to pass through the gate into the matrix'spaees, communication having been previously opened from the out-' tus and vacuum-chamber.

The apparatus comprises the following principal parts: The base of the apparatus consists of an air-tight supporting and exhaust box 1 of somewhat greater length and widththan the molds. On this box are stacked the molds 2, their matrix-smaces 3 communicating bychannels t with vertical orifices, which constitute the gatings 5. The molds 2 are preferably of such finely-porous material as unglazed earthenware or plaster-of-paris, and fit each other and the casing-floor with sufficient exactness to prevent intrusion of molten metal between the partings without obstructing the escape of air, vapor, and gases. Upon the stack of molds is placed a coping or platen 6, which has an orifice 6 in line with the gatings 5. The extremity of the box 1, remote from the orifice 6', communicates by orifice 1 with the interior of the mold-case, and by pipe '7, having a stop-cock 7', with a vacuum-chamber 8 of considerably larger capaeity than said box. The pressure in this chamber may be lowerd to the required approximate vacuum by any suitable meansfor example, by a steam-operated ejector 9. Secured to the top of the said coping 6 is a circular elevation or disk 11, having an orifice 11' immediately over the orifice (3". Upon disk 11 is placed a circular mat ordiaphragm 12, of asbestus, of slightly greater diameter than said disk. The disk 11 with its'mat 12 constitutcs the floor or bottom of a forcing, in j cct-' ing,or charging hopper or cylinder 13, which, being fastened to the coping by screws 13, its rabbet 14 fits tightly over and clamps the projecting margin of the said asbestus mat, which is thus made to do duty as a luting or gasket. The said mat also, for the time be ing, closes the passage from the said charging-cylinder into the gatings 5, and thus temporarily prevents entrance of metal to the molds. (See Fig. II.) With this object in view the mat is of sufficient consistence and thickness to resist rupture by the mere weight of molten metal in the cylinder. 14 is a seupper or runner which conducts the molten metal into the said charging-cylinder. From the mat 12 upward to within a short distance of its rim the walls of the said cylinder are lined with a tube 15 of like ashestus matting. This asbestus tube discharges a triple function, namely: It serves by its refractory and non-conducting qualities to conserve the heat of the molten metal, and at the same time to prevent adherence of the latter to the said walls, and as a luting to prevent escape of the metal past and adherence of same to the foreing-piston now to be described.

Fitted to slide snugly but freely in cylinder 13 is the forcing piston 16, which may be elevated and depressed by any suitable device. For example, the rod of said piston may be a rack 17, into which gears a cogged segment 18, having a lever or operating-handle 19. The rack-rod 17 is guided and the cogged segment 18 is journaled in a suitable standard 20, which ext-ends vertically from the coping. Secured to the box 1 by hinges 21' are four side boards 21, which, being secured to the Vertical position shown in Figs. I, II, and III by screws 21 or other fastenings, constitute a flask or casing, which surrounds the stack of molds at sufficient distance therefrom to cured to the ends of the box 1 by hinges 23 are yokes or straps 23, tapped, within which are screws 24, which enable the coping to be forced down firmly upon the mold.

' 25 is an asbestus facing for the piston 16. This asbestus facing coacts with the asbestos tube 15 and the mat 12 to prevent either chilling or adhesion of the metal, and the said disk and tube co-operatc to hermetically close or pack the cylinder against upward escape of the molten metal, the accumulating body of asbestus increasing and becoming compacted in proportion to the forcing-pressure. A tube or bushing 26 of asbestus,whiehlines the passage from the cylinder to the'gatings, completes the provisions for preventing contact of the molten mass with any metallic surfaces.

An eye or ring 27 enables the removal and replacement of the-platen with its associated forcing mechanism through the instrumentality of a suitable crane 28.

The effectiveness of the above -described method and apparatus for the formation of extreme] y light and sharp castings having a solidity,homogeneousness,and a f reedomfrom blow-holes comparable to electro deposited or to rolled metal is largely attributable to,first, the absolute isolation of, the molten mass from metallic surfaces; second, the disconnection of the molten mass from the molds until the instant of inflow; third, the efiective removal of air, vapor, and gases from the ma-' trix-spaces and the pores of the molds prior to and during the inflow by communication with alarge and continuously exhausted vacuum-chamber; fourth, the complete hermetical scaling in of the molten metal from the instant of the application of the forcingpiston.

The above-described illustration of our casting apparatus is susceptible of various modifications. For example, the bottom of the mold-casing may be a solid plate or wooden afford room for a tamping 22 of compactloam up to the level of the top of the coping. Se-

framing and the vacuum-chamber may communicate directly with the casing-space instead of through an exhaust-box.

Any suitable mechanical device may be employed for operating the forcing-piston.

The fastenings of the sides of the moldbut by the piston.

casing may be of any convenient kind, such as snap-bolts, hasps, or hooks.

We are aware that Patent No. 70,038 to- Michael Smith describes an injectingcylinder lined with clay and supplied with a clay tam pmg-plug; but such clay plug often proves-unsatisfactory from its 1iabili'ty to be detached in large fragments, which have partially or wholly obstructed the passage of the molten metal into the molds. What was needed and which proves in practice to be entirelysatisfactory was an infusible substance, whose fibrous composition and tough and close packing qualities made it on the one hand capable of remaining intact under the mere weight of themolten metal, and on the other hand of becoming ruptured without entireseparation when to the weightofthe metal isadded a'superimposed external pressure.

We are also awarethat Patent No. 407,696 to one of the present applicants, in association with Charles Grasser, describesa packing diskor gasket of asbestus, said disk hav: ing a central orifice for the unrestricted passage of the metal when forced upward by the ascent of the piston. In this arrangement themolten metal is supported not by the disk,

The disk is not an imperforate one and could not retain the metal even were the apparatus inverted." Its ofiice. is merely that of .a'refracto'ry lining. The imperforate disk of our presenttimprovement,

besides acting as a refractory lining, scrvesto retain the supernatent body of molten metal until the instant when the excess of external pressure enables the metalto rupture and force its way through the-disk. The tough and fibrous'compos'itionof the asbestus mat causes .the' ruptured filaments to remain adherent to the mat-body instead of becoming" detached in fragments and choking the pas-- sage-way, as is the case with such substances as clay or. plu'mbago. 1 1.

following is whatwe claim as new therein and desire 'to secure by LettersP-atent:

1. In a casting apparatus, the combination of a mold-casing, one or more molds therein,

a charging or injectinghopper upon said casing, a means of'applying pressure above the molten metal in said hopper, apassage through the hopper-fioor'into said casing, and an imperforate asbestus mat upon said floor, whose substance is such asto temporarily close said passage, but to become ruptured without-entire detachmentby'the application of exter-.

nal pressure to the upper surface of the molten metal, substantially asset forth.

2. In 'a' casting apparatus, the combination of a mold-casingm'ne or more moldstherein,

a charging or injecting cylinder above the such as to close sai passage against the weight of the supernatentmolten metal and become ruptured without entire separat on on a the depression of the piston,in the manner and for the purposes set forth. O 3.- In a castingapparatus, the combination,

with one or more molds, of a hermetical casin g therefor, a vacuum-chamber, a passage from said casing to said chamber, a charging or injecting cylinder or hopper, a passage from said hopper into said casing, an imporforate asbestus diaphragm of suflicient substance'to temporarily close said passage, and a forcing piston whose depression ruptures salddlaphragm and fills the molds, substantially as setforth. I c I Q 4. In an apparatus forproducing delicate and sharp metallic castings, the 'oombmatlon of a-hermetically-closed mold-casing, one or more pairs of molds therein, a'forcing-piston, the ashestus facing thereof, a charging-hopper which fits and receives said piston,"a passage in the hopper-floor to said mold-casing, an asbestus lining to the hopper-walls,an imperforate asbestus mat that temporarily closesv the said passage, and an asbestus bushing to said passage, substantially as set forth.

5. In an apparatus for producingsharp and delicate castings of metals, the described com bination of one or more pairs of molds; a hermetically-sealed casing therefor, a charging-cylinder, an asbestus'lining to said cylinder, a passage from said cylinder to'lthe interior of said casing and molds,an imperforateasbestus diaphragm which temporarily closes said passage, a forcing-piston which fits said cylinder,.and QJl'RSbOSlillS facing tosaid piston, substantiallyas set forth.

6. In an apparatus for producing sharp and delicate castings in'metal, the combination of the base or box 1, one or more superimposed pairs of molds 2,'the"hingedsides 21, the coping 6, the charging-cylinder 13, supported on 7 Having thus described our invention, the

said coping and having the screws 13 and the-rabbet 14, the disk 11 on the top of said coping, the gate or. passage 11' therein, and

IIO

sealing the junctionof the cylinder with the said coping, a non-conducting support and insulator for said molten metal, and a tempor'ary obstruction between the cylinder and the mold-casing, substantially as set forth.

7. In an apparatus for producing delicate and sharp' castingsof refractory metals, the

combination of supporting exhaust-box l, having a gate or passage 11 in the mold-casing, one or more pairs of molds 2,.perforatedicopformable to said disk and. whose substance is clamp-screws 24, the whole being arranged such as to I support and isolate the molten and adapted id operate as setforth. 7 metal, charging-cylinder 13, having rabbet J OIIN J, 0. SMITH. 1i and fastening-screws 13, asbestus lining 'VIOTOR- E. SMITH.

5 15 of said cylinder, asbestus-faced foi'eing- Witnesses:

piston 16, depressing mechanism 17 18 19, GEORGE P. RUST, hinged casing sides 21, hinged yokes 23, and JULIA 'I. PERRIN.

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