US1214904A - Art of and apparatus for casting fluid metals. - Google Patents

Description

H. H. DOEHLEH.

ART OF AND APPARATUS FOR CASTING FLUID METALS.

APPLICATION FILED MAR-2311915.

Patented Feb. 6, 1917.

HERMAN H. DOEHLER, or BnooKIirN, NEW YORK, ASSIGNOR T DOEI-ILER DIE oAsrrNe coNrANY, or BROOKLYN, NEW YORK, A oonronArroN or NEW roan.

mar or A D APPARATUS FOR, CASTING FLUID METALS.

ament.

" York, have invented certain new and useful Improvements in the Art of and Apparatus for Casting Fluid Metals, of which the following is a specification, reference being had therein to the accompanying drawings, which form a part thereof. 7

- My invention relates to an art of, and apparatus' for, casting fluid metals and more particularly to improvements in the art and apparatus patented to me in- Letters Patent No. 973,483, dated ()ctober 25 1910.

In the aforesaid Letters Patent, a ladle containing a measured quantity of moltenmetal was mounted in a pressure chamber and after the closing of the chamber the' metal was poured by the inversion of the ladle, and air under pressure was substantially simultaneously admitted to the chamber so as to deliver the molten metal to the die under conditions which 'would insure- -the formation of asolid partition of molten metal, flowing under gravity, between the pressure chamber and the die. By the method of said patent, splashing of the metal was avoided and the air used in forcing the metal was prevented from entering the 'body of the metal or being imprisoned therein in a manner to cause the presence of blow;holes in the casting. Furthermore, the air used in forcing the metal into the die was not in contact therewith for a suflicient interval to oxidize the metal nor in contact with any portion of the metal entering into the casting.

The method and apparatus of my aforesaid patent has been found to produce highly satisfactory castings but has not been found suited to cheaper grades of work owing to the fact that the operation of the apparatus and the practice of the method were essentially slow by reason of the manner of in-- troducing molten metal to the apparatus.

By my present invention, I am enabled to secure all of the advantages of my patented process while at the same time delivering the molten metal to the pressure chamber sufficiently rapidly and in the desired quantities to permit rapidity in the making of castings. I am also enabled to deliver metal substantially free from oXids and Specification of Letters Patent.

the requisite fluidity thereof;

Patented Feb. 6., ill ilt.

Application filed March 23, 1915. Serial No. 16,340.

other'dross and to preserve in the metal to be used for each casting the proper fluidity to insure soundness in the casting.

The essentials of my present invention are the control of the volume of the molten metal to be delivered to the die; the timely measurement and separation of the desired volume from the melting-pot and its maintenance at the desired temperature to insure the interposition of a solid mass of the metal between the means forcing it into the die and the die while it is confined in a constrictedpassageway, and the application of pressure to the fluid metal while in the constricted passageway and while it is flowing by gravity into the mold. e

In pressure die casting, the charging of the die is a substantially instantaneous operation and it is essential that the entire vol ume of the molten metal be delivered to the die at substantially the same instant and in substantially uniform condition and a solid mass. It has also been found desirable to apply the pressure forcing the metal into the mold under conditions within the control of the operator so as to permit the application of an increasing pressure which will reach its maximum when the die is substantially filled withthe metal.

The invention consists primarily in the art or method of casting fluid metals consisting in maintaining a mass of molten metal about a chamber having a downwardly opening discharge port in the bottom thereof adapted to communicate with the ingate of a metal die, delivering the molten metal from said mass to said chamber from a point intermediate the to and bottom of said molten mass and in su cient quantity for a single casting, sealing said chamber against the ingress of molten metal when the desired quantity has been introduced thereto and applying pressure to the metal contained in said chamber while it is flowing therefrom to the die; and in such other further steps and practices and in the novel features of construction of, and comratus utilizing compressed air adapted for use in the practice of my improved art or method.

Fig. 2 is a like view of a similar apparatus utilizing a reciprocatory plunger as the forcing medium; and

Fig. 3 is a like view of a still further, modification combining similar characteristics of each of the apparatus shown in Figs. 1 and 2.

Like letters refer to like parts throughout the several views.

In the practice of my art or method, I maintain a molten mass of metal of the desired alloy in a melting-pot having submerged therein a' casing forming a subchamber having relatively smaller capacity than the melting-pot, this capacity being proportionate to the mass of metal required for a single casting operation. The chamber is provided with a bottom port adapted to register with the ingate of a die or mold which during the casting operation is positioned immediately below saiduchamber. The molten metal is withdrawn from the mass within the melting-pot at a point intermediate the top and bottom thereof, through a port in the side of said casing, said port having sufficient capacity to permit the rapid flow of the molten metal into the chamber having due regard for the capacity of the mold ingatc which ordinarily is materially constricted as compared with the said chamber. By withdrawing the metal intermediate the top and bottom of the molten mass the metal used in casting is substantially free from the sediment accumulated toward the bottom of the mass and the oxids and other dross which accumulates at the top of the mass. The constriction at the ingate of the die or mold Wlll have the eflect of retarding the flow of the metal under gravity for a suiiicient period to insure the accumulation of a suflicient volume of molten metal in the auxiliary chamber, to form the charge for a single casting operation. The submersion of the said chamber in the molten metal in the melting pot proper, will maintain the fluidity of this measured charge and thus permit the necessary accumulation of metal with out likelihood of variation in the condition of the metal of succeeding charges to an extent to vary the quality of succeeding castings or interfere with regularity in the operation of the apparatus.

When the desired volume of the molten metal has been introduced to said chamber the port of communication between said chamber and the melting-pot is closed and pressure is applied at the top of the molten metal in saidchamber so as to accelerate its rate of flow through the discharge port of said chamber and the ingate of the die or mold. After each charge has been delivered to the die or mold, said die or mold is removed from adjacent the discharge port of said chamber, any metal not entering the said mold forming a part of the sprue of the casting in the opening in the die or mold provided for that purpose; Any metal in excess of that required for a casting and its sprue will remain in the oiftake port of the auxiliary chamber, from whence it may be readily removed by the application of prese sure from within the chamber or by means of a tool used exteriorly of said chamber. I have found it preferable to flare said port outwardly slightly so as to give the proper draw to any metal accumulated in said port.

It will be noted that the port of communication between the auxiliary chamber and the melting-pot cannot become clogged by reason of the fact that the temperature of the wall of the chamber thereabout will be at a temperature at least as high as the fusing point of the molten metal.

It will also be observed that the molten metal may be introduced to the auxiliary chamber after the die is in position relatively thereto and that the manner of i11- troducing said metal is such as to avoid unnecessary delays in forcing the metal after the desired volume has been accumulated into the die or mold. The sole delay between casting operations, aside from those incidental to positioning the die or mold and ejecting the casting therefrom, is that required to deliver a single charge from the melting-pot to the auxiliary chamber which delay is immaterial as the port of communication between the melting-pot and the auxiliary chamber may be made of a capacity to insure rapidity in this charging operation.

WVith every casting operation the entire volume of metal is discharged from the auxiliary chamber, and hence upon the initiation of each casting operation, said chamber is free from any particles of metal or impurities remaining from a preceding operation. v

The capacity of the auxiliary chamber is proportioned to the size of the charge required for a single operation, although the 1 volume of metal admitted thereto may be varied according to the requirements of any particular casting, by varying the duration of the flow of the molten metal from the melting-pot into said chamber. In other words, castings of different sizes may be made by varying the size of the charge delivered to the auxiliary chamber as distinguished from the necessity for using chambers of different sizes for different castings.

The chamber, to insure a small area of molten metal exposed to the forcing medium and a deep mass of flowing metal between the said medium and the die, is preferably nuance ing of the drawings.

Referring more particularly to Fig. 1, I have shown at a a melting pot surrounded by a furnace b'. Said melting pot and said furnace may be of the usual or any desired construction. In the drawings, I have shown the melting pot as closed by a cover 0 supporting the operative parts of the apparatus. -Extending vertically through the melting-pot a so as to be completely surrounded at all times by the molten metal within said pot, is a casing d forming an auxiliary chamber e. This chamber is provided with a discharge port 7 atthe bottom thereof, the chamberbeing flared outwardly Slightly as at f adjacent said port so as to facilitate the removal of any metal which may accumulate in said port by reasonof there being a slight excess of molten metal in the charge introduced into said chamber over that required in making any casting.

' The casing d intermediate the bottom and top of the melting pot a is provided with a port 9 opening into the said melting pot.

Controlling the port 9 is a gate valve 72 slidably mounted in a bearing in the top 0 for the melting pot, said valve being provided with an operating handle h mounted upon said top 0.

Discharging into the auxiliary chamber 6 is a'pipe 6 through which air under heavy pressure may be delivered to said chamber. This pipehas in its length a three-way valve wth casting apparatus utilizing compressed air. 4

At ic I have shown conventionally a metal I mg. said die is shown merely conventionally as any desired rigging may be used for this purpose, it being merely necessary to secure a sufficiently lntimate contact of the said die with the casing 0? about the port fto avoid the squirting of metal between the die and the said casing.

In the modification shown in Fig. :2, the

construction is the same as that shown in Fig. 1 with the exception that the gate 71. is dispensed with and the port 9 is arranged will be determined by :1 such as is usually employed in connection at a slightly higher elevation. In addition to these modifications instead of using compressed air as the forcing medium, I employ a reciprocatory piston m actuated by means of a lever handle m. The-piston m serves to control the port it and at the same time is used to force the metal from the auxiliary chamber into the die.

In the modification shown in Fig. 3, I employ the same gate valve construction shown in Fig. l in conjunction with a piston or plunger 12 and lever handle n similar to that shown in the modification illustrated in Fig. 2.

In each of the forms of the invention shown there is present a melting pot for maintaining a mass of molten metal about an auxiliary chamber having a port therein from which molten metal is permitted to flow until the desired volume thereof is accumulated in said chamber. In each form of the invention there is shown meanswhereby the flow of metal through said port may be controlled so as to limit the supply of metal admitted to the auxiliary chamber to that required for a single charge and to prevent the flow of metal through said chamber when a die is not in position or while the metal is being forced from the chamber into the die.

In each form of the invention shown, the operation consists in positioning adie or mold with relation to the port f and securing it firmly in this position. The port 9 is then opened to permit the molten metal to flow from the melting pot a into the chamber e. When the desired quantity of metal has been delivered to said chamber, which ordinarily the duration of the flow of the metal, the port 9 is closed and that metal already delivered to said chamher and which already is flowing by gravity toward and into the die, is forced either by compressed air or by a piston toward said die in a manner to rapidly accelerate the rate of flow thereof and thus insure a substantially instantaneous filling of the molten metal. Whether compressed air or a plunger is used it is usually desirable to start this acceleration slowly and apply the full pressure toward the end of the casting op eration so as to insure the desired compres- The level of molten metal in the auxiliary lee chamber can never exceed that of the metal in the melting-pot so that at all times any metal contained in the auxiliary chamber is maintained at substantially the same temk perature as the metal in the melting-pot itself. It is this condition which permits the accumulation ofthe molten metal in the desired quantity-in this chamber. F urthermore, this condition permits the use of a piston when desired as there can be no tendency of the piston to freeze, or besoldered, to the wall of the said chamber.

When a piston is used as in Figs. 2 and 3, it may be readily removed from the auxiliary chamber to permit re-finishing to secure the desired close fit within said chamher, or the substitution of a new piston therefor.

It is essential to an apparatus made in accordance with this invention that the auxiliary chamber shall be ,maintained 'at at least the same temperature as the molten metal, and that it should be laced in direct communication therewit through a valve controlled. port so as to permit the measuring of the charge introduced to said chamber.

It is not my intention to limit the invention to theprecise details of construction of the apparatus shown in the accompanying drawings, it being apparent that such may be varied without departing from the spirit and scope of the invention. The method or art herein described may be practised in connection with apparatus other than those shown.

'Having described the invention, what I claim as new and desire to have protected by Letters Patent is 1. The art or method of casting fluid metals consisting in maintaining a mass of molten metal about a chamber having a downwardly presented normally open discha'rge port in the bottom thereof adapted to communicate with the ingate of a die or mold, permitting a measured quantity of molten metal sufficient only for one casting operation to flow from said mass of molten metal through said chamber into the ingate of a die or mold and applying pressure to the metal delivered to said chamber while it is flowing therefrom to the die.

2. The art or method of casting fluid metal consisting in flowing molten metal through an elongated chamber of small dimensions having a normally open discharge port at the bottom thereof into the ingate of a die or mold, limiting the quantity of metal passed through said chamber to that required for a single casting operation, applying pressure to the surfaceof the metal in said chamber when the desired quantity thereof has been delivered thereto to force the entire charge therefrom with each casting operation while it is flowing from the chamber from said mold ingate to the mold and maintaining the metal while in said chamber in a molten state'during the casting operation and until it is delivered in its entirety in the mold or die.

3. The art or method of casting fluid metals consisting in the rapid flowing of molten metal through an elongated chamber of small'dimensions, having a normally open port in the bottom thereof into a constricted ingate of a die or mold thereby delivering a charge to said chamber, checkin the flow of said molten metal when a su cient quantity for a single casting operation is delivered to said chamber, applying pressure to the surface of, said metal within said chamber while said metal is flowing under gravity into the said mold thereby accelerating the rate of flow of said metal into the mold and maintaining the metal in said chamber during the entire casting operation in a molten state until it is delivered to the die ormold.

4. The art or method of casting fluid metals consisting in maintaining a mass of molten metal about an elongated chamber of small dimensions having a downwardly presentednormally open discharge port in the bottom thereof in communication with a constricted ingate of a mold, flowing metal. from said mass intermediate the top and bottom thereof through said chamber into the ingate of a mold or die, limiting the quantity of metal delivered to said chamber to that required for a single casting operation, applying pressure to the surface of said metal within said chamber while said metal is flowing under gravity into the said mold thereby accelerating the rate of flow of said metal into the mold and maintaining the metal in said chamber during.

the entire casting operation in a molten state until it is delivered to the die or mold.

5. An apparatus for casting fluid metals embodying therein a melting-pot, a furnac about said melting pot, a casing forming 'an elongated chamber of small dimensions elongated chamber of small dimensions within said melting pot, said casing having a normally open discharge port at the bottom thereof opening outwardly of sald melting pot and an intake port within said melting-pot, means supporting a die with its ingate in communication with said discharge port, means whereby the volume of metal delivered to said chamber maybe controlled, and independently operative means whereby said metal may be forced through said discharge port into said die.

7. An apparatus for casting fluid metals embodying therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions within said melting pot, said casing having an outwardly flared normally open discharge port at the bottom thereof opening outwardly of said melting pot and an intake port within said melting pot, means sup porting a die having a constricted ingate in communication with said discharge port, means whereby the volume of metal delivered to said chamber may be controlled, and independently operative means whereby said metal may be forcedthrough said discharge port into said die.

n apparatus for casting fluid metals embodying therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions within said melting pot, said casing having an outwardly flared normally open discharge port at the bottom thereof opening outwardly of said melting pot and an intake port within said melting-pot, means supporting a die having a constricted ingate in communication with said discharge port, means whereby the volume of metal delivered to said chamber may be controlled, and independently operative means whereby said metal may be forced through said discharge port into said die. 1

An apparatus for casting fluid metals embodying'therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions within said melting pot, said casing having a normally open discharge port at the bottom thereof opening outwardly of said melting pot and an intake port Within said melting-pot, means supporting a die with its ingate in communication with said discharge port, a gate valvecontrolling said in take port, means whereby said valve may be actuated to control livered to said chamber through said port, a pipe connection with the chamber in said casing whereby compressed air may be ad mitted to said chamber above said intakeport, and a valve arranged in the pipe for controlling the flow of air therethrough. Y i

10. An apparatus for casting fluid metals embodying therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions the volume of metal dev scribing witnesses,

within said melting-pot, said casing having a normally open discharge port at the bottom thereof opening outwardly of said melting pot and an intake port within said melting pot, means supporting a die with its ingate in communication with said discharge port, a gate valve controlling said intake port, means whereby said valve may be actuated to control the volume of metal delivered to said chamber through said port, a pipe connection with the chamber in said casing whereby compressed air may be admitted to said chamber above said intake port, and a three-way valve arranged in the pipe for controlling the flow of air therethrough. v

11. An apparatus for casting fluid metals embodying therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions within said melting-pot, said casing having a normally open discharge port at the bot tom thereof opening outwardly of said melting pot and ing-pot, means supporting a die with its ingate in communication with said discharge port, a gate VQIXG controlling said intake port, manually operative means whereby said valve may be actuated to control the volume of metal delivered to said chamber through said port, a pipe connection with the chamber in said casing whereby compressed air may be admitted to said chamber above said intake port and a manually operative valve arranged in the pipe for controlling the flow of air therethrough.

12. An apparatus for castingfluid metals embodying therein a melting-pot, a furnace about said melting-pot, a casing forming an elongated chamber of small dimensions within said melting-pot, said casing having a normally open discharge port at the bottom thereof and opening outwardly of said Inelting-pot, and an intake port within and spaced away from the bottom of said melting pot whereby metal will be delivered to said chamber from a point intermediate the top and bottom of the molten metal in the melting-pot, means supporting a die \with'its ingate in communication with said discharge port and means whereby the volume of metal delivered to saidchamber may be controlled, and said metal may be forced through said discharge port into said die.

In witness whereof I have hereunto affixed my signature in the presence of two subthis 17th day of March,

HERMAN H. DOEHLER.

Witnesses 5 O.-A. Sonnonnnn, W. BAUERSCHMIDT.

an intake port within said melt-

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