US1781939A - Multiple-mixture die-casting method and machine - Google Patents

Description

A. AKERS Nov. 18, 1930.

MULTIPLE MIXTURE DIE CASTING METHOD AND MACHINE Filed'Aug. 11, 1927 4 Sheets-Sheet l A. AKERS Nov. 18, 1930.

MULTIPLE MIXTURE DIE CASTING METHOD AND MACHINE Filed Aug. 11, 1927 4 Sheets-Shet 2 1 llll..

Nov. 18, 1930. A. AK ERS 1,781,939

MULTIPLE MIXTURE DIE CASTING METHOD AND MACHINE Filed Aug. 11, 1927 4 Sheets-Sheet 3 Nov. 18, 1930. A. AKERS 1,731,939 MULTIPLE MIXTURE DIE CASTING METHOD AND MACHINE Filed Aug. 11, 1927" 4 Sheets-Sheet 4 a M M Patented Nov. 18, 1930 UNITED STATES PATENT OFFICE AXEL AKERS, OF CHICAGO, ILLINOIS, ASSIGNOR T QUALITY HARDWARE & MACHINE CORPORATION, OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS MULTIPLE-MIXTURE DIE-CASTING- METHOD AND MACHINE Application filed August 11, 1927 Serial No. 212,178.

relatively thick body of one metal or mixture and a relatively thin lining or covering of another metal or mixture, although two or more alloys or mixtures may be employed in the production of a composite hearing or other article, such as a body layer of 92 per cent. zinc, 7.5 per cent. copper, and 5 per cent. aluminum or miscellaneousmaterials or other metals, and a lining layer of from 50 per cent. to 85 per cent. tin and the balance lead, thereby producing a die casting in which the use of a great quantity ofsome expensive metalsuch as tin in the whole thickness of the bearinginstead of merely in the lining is obviated, and at the same time produce an economical hearing or other article which is practical and efficient as to wearing qualities and which-can be quickly produced.

'Another object is to provide a novel method and apparatus for producing oil grooves or the like in the bearing, the construction being such that thegrooves are automatically formed in the'second layer or lining in the operation of die casting the bearing, the groove-forming device being automatically depressed flush with the surface of the small diameter of the core and automatically projected for producing the grooves in the'second layer before the die casting is ejected.

A further object is to provide a die casting machine having two or more furnaces or melting pots, each having movable ladles or containers for the metals, alloys or mixtures usedin the die casting, which move to dip and fill the same and are then brought into position simultaneously or otherwise to discharge the contents thereof into the molds successively 59 under air or other pressure admitted into the containers to eject the fluid metal from, the containers to inject the fluid metal into the dies under pressure or otherwise, the space in the die mold being enlarged by means of a movable core, having portions of different size or diameter or otherwise for accommodating the layers successively, after which the die is opened and the casting ejected. A still further object of the invention'is to provide for the ejection of the air from .within 60. the die mold in the'casting of the first layer so as to exclude the latter from exposure to air and possible oxidation towhich it is readily susceptible, by sealing all joints or escape openings with the spruce or metal forced into the same and by enlarging the space to receive the second layer, as by means of movement of the core, establishing a substantial or partial vacuum, thereby insuring proper fusion or union between the first or outer layer and the second or inner layer, which would otherwise be seriously interfered with by exposure of the first layer to air and oxidation on the exposed surface to which the second layer is joined.

Another object of the invention is to provide a die casting machine which is automatic in its operation and wl'iichcarries out the successive steps quickly and in sequence for each die casting operation. 4

Other objects and advantages of the invention Will be understood by reference to the following specification and accompanying drawings, in which I have illustrated a selected embodiment of the invention and in which drawings 2 Fig. 1 '"v a side elevation of the businessor mold end of the die casting machine showing the novel construction.

Fig. 2 is a top plan view;

Fig. 3 is a horizontal longitudinal sectional view of the mold with the-core in position for die casting the first layer. I Fig. 4 is a view similar to Fig. 3, with the partsin position during the die casting of the second-layer. x

' Fig. 5 is a sectional view, taken on line 55 of Figure 3, of the mold with the parts operatively assembled or together in the die casting" of the first layer. 1

Fig. 6 is a sectional view taken on line 66 of Figure 3, showing the oil groove employed with the machine to eject the metals into the mold.

Fig. 9 is a perspective view of an oil groove forming member.

Fig. 10 is an end elevation of a die cast half-bearing produced by the machine, and

Fig. 11 is an inside elevation ,or bottom View of the bearing shown in Figure 10 and illustrating the oil grooves.

Referring to the drawings in detail,11 in-' dicates a table or frame supported onlegs 12, this table being the usual table employed in connection with die casting machines of the horizontal type, although it is to be understood that the invention is not limited in its application to this particular type of machine but may be applied with equal facility,

so far as the combination of parts and principles involved are concerned, to machines of the vertical or other type. Mounted in an opening 11 centrally of the table are two or more melting furnaces or pots 13 and 14, heated by electric heating elements or otherwise, as indicated at 15, and having at the top suitable bearings 16. The furnaces or pots 13 and 14 may have suitably apertured lugs for bolting the same to the top of the table 11, as indicated at 17, and the furnaces taper toward the opposite ends, as shown more particularly in Figure 2 of the drawings. The bearings 16 take a pivot or shaft;

on which the springs are mounted to rest on the shanks 21 which also receive the bolts to insure the proper seating of the ladles against the die mold and permit adjustment and equalizing of the tension. These ladles are adapted to dip in the molten metal in the furnaces or pots 13 and 14 and are curved on such an are that when they are raised, they will fill with. the metal through the mouth portions thereof. It is to be understood that the ladles may be actuated by the mechanism usually employed for raising the pot or ladle modified as described, or otherwise. Communicating with the ladles orcontainers 19 through the openings 23 by means of hose or pipes 27 and 28 is a control valve 29 whichmay be constructed as shown in Figure 8. As illustrated, the valve is of the cylinder or piston type having a cylindrical casing with an inlet 30 at one end and an inlet 31 at the other for air under pressure and having an exhaust.

axially with respect thereto. A piston 35 is movable in thecylinder or casing 28 and has a reduced, central portion and enlargements 36 at the ends, providing an intermediate annular opening 37. This piston is adapted to be actuated by a stem or rod 38 which passes through a suitable packing gland 39 in the 18 on which are pivotally mounted against open end of the casing 29 and is preferably endwise movement, as by spacing sleeves or' openings 20 in the-shanks 21 thereof. The ladles or containers 19 are of hollow formation and are cut on a concavo-convex arc with a hollow containing space 22 having an internally threaded opening 23 communicating with its inner end and having at its outer end an apertured plug or mouth portion 24 adapted to engage suitable inlet orifices or recesses -in the die molds, as: will be later described.

The opposite ends of the ladles 19 have the shanks 21 extended downwardly beyond their curved portions and connected by a link 25 through equalizing springs 21' with a lever 26 :fulcrumed intermediately and adapted to be oscillated by a suitable means such as an eccentric roller, or otherwise, as is common in the art, for moving the ladles .ontheir pivots'simultaneously from a normally lowered position to raise or swing the same upwardly and by engagement of the roller with the lever to momentarily hold the ladles detachablyrengaged with the piston as indiis connected by a short link 41 to the upper end of a lever 42 fulcrumed intermediately at 43 and having the lower end pivoted to one end of arod 44 extending along the side of the machine and actuated by a cam or disk having an adjacent recess and raised portion successively disposed on its periphery so that the inlets and-outlets are successively coveredand uncovered to their respective ladles and to hold the valve in a neutral position during the greater portion of the time when the ladles are lowered.

The die mold arranged onthe table over the furnaces and ladles consists of a stationary section 45 and a movable section 46 properlv formed to conform and produce the article to be die cast, such as a half-bearing, as shown in the drawings. The cavity or space within the mold for receiving the metal of the die casting is designated at 47. In Figure 5, the sections of the mold are shown together and receiving a core 48, shown for constructional purposes as being formed of. two sections'held together at 49. This core has a large end 50 with a somewhat reduced portion 51 and a still smaller portion 52.

This core is fixed at its outer end to a plate 53 which is laterally adjustable and secured at 54 to a slide'55 which slides laterally on a track 56 of a bracket 57 bolted to the table, which serves to guide the core horizontally. For actuating the core, the latter may be operatively connected at its outer end with an arm 58 fixed to a shaft 59-bearing in the bracket 57 at the side of the table and adapted to be actuated by cams or other means suitably actuated by the mechanism of the machine in properly. timed relation with the other mechanism for moving the core inwardly between the sections of the mold and for successively moving or stepping it outwardly in the successive steps of a plurality in the. die casting operation when two or more metals, alloys or mixtures are forced or ejected into the mold cavity for producing the articleto be die cast, as will be particularly described in connection with a half-round hearing, although it is to be understood that various other articles may be made in substantially the same manner.

' The movable section 46 of the die is adapted to be actuated by means ofa slide mechanism 60 actuated by a suitable cam, drum and toggle mechanism on the machine and hav ing a stationary part 61 boltedon the table, or otherwise, and braced by the rod 62. Die blocks or shoes 63 are fitted against and secured to the movable and stationary sections 46 and 47 and the die block of the movable section has a sleeve 64 to take a plunger 65 with connected plates 66 at the inner end thereof within the chamber of the die block, and has push-out pins 67 to engage through corresponding openings in the sectiou 46 to eject the article produced :in the machine from the mold. An oil hole forming pin 68 also may be provided in the section 46 to supplement oil groove forming means, as will be later described.

.The mouths or orifices leading into the cavity-'48 of the mold and which are flared to conform to the mouth portions 24 at the outlet ends of the ladles or containers 19 are designated at 69 and have neck portions 70 with one of which a sprue lock or valve'7l cooperates. This sprue lock passes through the sprue .72 at the neck part 70 and is adaptedto be actuatedby suitable rack and pinion or other mechanism common in the art for reciprocating the lock or valve which inciden-- tally serves to move the sprue v72 along for discharging the latter and simultaneously acting as a plug or valve to close the cavity and prevent-the passage of metal of the effective fusion or union between the layers of the article such as wouldbe prevented by surface oxidation and the formation of a powder or loose coating on the exposed surface if it were subject to exposure to air and consequent oxidation. t is also understood that this partial vacuum is sealed by closing of the jointsbetvveen the mold sections or special escape slots or openings provided for this purpose, owing to the air and sprue being forced out between the joints of the sections of the mold when the metal under pressure is forced into the cavity thereof "during the first step of die casting operation. Bythis means, the joints between the sections are efi'ectively sealed and the cavity rendered practically air-tight before the second layer or lining ofJthe article is formed.

The cavity 47 isadapted to receive the first mixture or layer 73 when the core is in theposition shown in Figures 3 and 5, said cavity having deeper portions at the ends to produce the end flanges 74 of a half-bearing. In this position, the ladies or containers 19 in the pots 13 and 14 have been dipped and raised to fill the same with the molten metal and to bring the mouth portions 24 thereof against the orifices69, after which, air under pressure or otherwise isadmitted into the ladle to inject the metal into the cavity 47. This is admitted into the pot containing the first layer mixture only, through the inlet 75 of the valve 29, invvhich position the piston 35 has beelrshifted to the right from the. position shown in Figure 8 to uncover the outlets I313 4 and 7 to displace the portion 51 and the shoulder or lip 76 from the layer 73 so that the smaller portion 52 of the core is in alignment with the cavity 47and the first layer 73. In this position, the lip or shoulder 76 remains within and seals the space formerly occupied by the large part 50 of the core 48 at the left-hand end between sections 45 and 46, and the lip orshoulder 7.7 seals the space 78, and the second ladle or container-'19 Within the pot 14, having also been swung against the orifice 69, air is admitted through the .plpe 79 into the valve 29, and the piston-35,

having been moved to the left to again un-v cover the outlets 33 and 34, air enters the inlet 31fa-nd the pipe 27 through the outlct ifl for ejecting the habbitt orother mixture. of

molten metal from the ladle, and allows'air in the other ladle to escape to the atmosphere through the port 33 and exhaust It is to be understood that the pipes 27 and 28 are connected to the inlet openings 23 ot' the ladles and that the discharge of the metal is through -'the outlet orifices at the mouth portions 24 of the ladles. The cavity being entirely sealed, oxidation of the ex posed surface of the layer 73 is absolutely prevented, and during the shifting of the piston 35 compressed air in the ladles exhausts through the port 32 to the atmosphere. Obviously, the movement of the piston 35 is in timed relation to the other mechanism so that the parts are operated'in proper sequence. The babbitt or other mixture forming the innerlayerof the article die cast by the machine, such as the bearing indicated, is shown at 80. \Vhen this is formed, the die mold is opened while the core has its smaller portion of di''- ameter opposite the cavity, by movement of the movable section 46 with respect to the stationary section 45. After this, the push-out Y pins are operated to displace the casting, the

ladles having been previously lowered and the sprue lock or valve having been retracted or backed up to open the inlet portion of the orifice 69.

Should it be desired to form oil grooves in the bearing, such means may be providedin the form of a groove forming member or maker 81, shown in Figures 3, 4, 6, 7 and 9.

.This member has four rings 82 at the proper angle and provided with bottom recesses 83,

the ends of which are extended to produce under-cut portions 84 adapted to receive and retaint-herein an arcnate spring 85, these parts being fitted in a slot or seat 86 in the reduced portion 52 of the core 50 so that when the core is in the position shown in Figures 3 and 6, this groove-forming member is depressed into the small. portion of the core flush with the operative surface thereof. \Vhen the die mold is closed, and after the zinc or first layer has been formed, the core is shifted laterally to move the small diameter 52 opposite the same as shown in Figure 4. In this position, the spring 85 st-raightens and forces the member 81 out into the recess 78, so that when the inner layer 80 is produced it will have the grooves 87 therein produced antomatically in the die casting operation. Incidentally, it will be noted that the rings 82 of the groove forming member close the openingwhere the pin 68 is positioned so as to form the oil hole 88.

This operation is continued for the die casting of each part or article, and it is, of course, to be understood that the shape of the article determines the shapeof the concavity in the mold. It also is to be understood that the cores may be slid laterally from one or both sides and that the number of furnaces or pots for the molten metals or mixtures may be increased and that a movable ladle is provided for each pot. The elements 15, while described as electric heating elements of resistance wire, can be substituted by other-heating means. In the formation of the oil grooves,

when the core is partly drawn out to permit "the projection of the oil maker or groove forming member 81 by the spring 85, the die mold is closed and the bearing or other article is ejected after the mold has been opened, due to the movement of the section 46 away from the section 45. This permits the core 48 to be pushed into its original position, as shown in Figure 3, and the closing of the mold section 46 against the section 45 depresses the groove forming member 81 into the recess of the small core portion 52, so that the portion 51 is in posit-ion to permit the formation ofthe layer73. This operation may be quickly carried on to economically produce an article of composite metals or mixtures having two or more layers. The devices may also be applied to standard machines for die casting, such as the type illustrated in Figures 1 and 2 with the novel features applied thereto.

Die casting machines, especially those of the horizontal type to which the invention is I shown applied, are usually controlled by a hand lever. Such a machine is operated by a belt pulley running at about R. P. M. with a shaft driving pinion meshing with an integral gear resulting in a speed of 9 R. P. M. of drums controlling the operation or about 6% seconds per cycle of operation. The drums are right and left-hand due to outer cam arrangements and are bolted together with fitted bolts having a filler between the drums. The sides of the drums are provided with cam-ways in which disks run, one disk being fastened on each side of a lever which fulcrums on the end plate of the bed plate of the table and the other end transmits a vertical or downward motion to two levers, one on each side of the first lever, from which motion is transmitted to a toggle. One end of the toggle is fastened to the bed plate fulcrum stand and the other end to the main slide. When the drums revolve, the slide moves backward and forward toward and away from the stationary die holder or block. 'After the die mold has been fastened to the stationary and movable die holder and the drums have been revolved so that the toggle is in a straight line position, then the metal is forced into the die mold under pressure. While the drum is revolving, the die mold is closed, the metal containers rise into position, the cores are located, and the air pressure turned on automatically, after which the air is released, the containers dropped, the die mold opened, and the casting ejected from the die mold. The sequence of operation with the present machine is as follows:

First, the hand lever above referred to for controlling the operation, is thrown over to the right, which lifts the pulley brake throwing out the automatic stop, and throwing in the countershaft clutch (not shown). The

close the die mold by shifting the movable section against the stationary section, after which the .ladles or containers are lifted into place and air pressure admitted into the zinc or first mixture ladle for forcing the same into the cavity of the die mold. The sprue lock then-closes the inlet aperture of the die I mold, after which the core is moved to dispose its small portion or diameter opposite l5 layer or body of the die casting has been gformed. Air pressure is then admitted into the babbitt or second mixture ladle to exit the molten metal or mixture and produce the inner layer or lining of the die casting and the parts are lowered, after which the die is opened by further rotation of the drum and the raising of the toggle. The sprue lock then backs up and the push-out pins are finally actuated to push out the casting. This operation is repeated by moving the core in, so that its largest'diameter is opposite the cavity of the die mold, which is the first position in the die casting operation. Then the movable section of the die mold moves up to close the die mold by the straightening of the toggle.v This operation is quickly carried on and the ejection of one mixture or metal is almost instantaneously after the other mixture or metal is injected. Obviously, the cavity may be enlarged one or more times to take two or more metals or mixtures, thereby producing a bearing or other article with two or more layers, according to the requirements, though two are usually sufficient. The number of enlargements of the cavity depends upon the number of step portions which the core has. While I have shown a' core which is movable laterally, it isto be understood that it may be moved in any other direction than horizontally and thatthe enlargement of the cavity may be produced in any other suitable manner.

While I have shownand described my invention in a preferred form, I am aware that various chaggis and modifications may be made therein thout departing from the principles of the nvention, the scope of which may be'determined by reference to the appended claims.

I claim as my inventioni v 1. A die casting machine having a plurality of melting furnaces, each having movable metal containers to inject fluid metal into a die under, pressure. 2. A die casting machine having a plurality of melting furnaces, each having movable metal containers, a mold having a'cavity with means for enlarging the same, the 65 containersbeing adapted to be moved'and drums revolve to straighten the toggle and the cavity in the die mold in which thefirst.

brought into position to inject different fluid metals from the furnaces into the-cavity under pressure, and means for actuating said containers.

3. A die casting machine having a plurality of melting furnaces, each having movable metal containers, a mold having a cavwhich are sealed by the metal upon the injection from the first container to expel air from the mold cavity whereby to establish a partial vacuum within the cavity and prevent oxidation of the exposed surface of the metal upon the enlargement of the cavity and .the proper fusion of the second metal therewith.

4. In a die casting machine, a plurality of melting furnaces, movable ladles in each furnace adapted to dip. in the metal thereof for filling the ladles at their free ends, and means for ejecting saidmetals independently.

5. In a die casting machine, a plurality of melting furnaces, movable la es in each furnace adapted to dip in the metal thereof for filling the ladles at their free ends, means for ejecting said metals independently, said means including a valve having inlets for the admission of pressure and outlets connected to the ladles, and means for actuating the valve.

6. A die casting machine having a plurality of melting furnaces, each having movable metal containers, a mold having a cavity, means for enlarging said cavity to take a plurality of layers of metal discharged 5 from the ladles, the containers being adapted to be simultaneously brought into position to inject different fluid metals from the furnaces into the cavity under pressure, and means for sealing the cavity.

7..A die casting machine having a plurality of melting furnaces, each having movable metal containers with outlet orifices, and means connected to the containers to inject fluid metal into a-die mold under pressure.

8. A die casting machine having a pluralitypf melting furnaces, each having movable metal containers with outlet orifices, means to force molten metal from the containers under pressure .at different times, a

separable die mold having a cavity, a core for successively enlarging the cavity to receive successive layers of the molten metal, and means for sealing openings or joints in the die mold upon the formation of the first layer of metal andfor establishing a partial vacuum therein upon enlargement of the cavity to prevent oxidation of the first layer.

. 9. A die casting macgine having a plural- 3 ity of melting furnaces, each having movable metal containers with outlet orifices, means to force molten metal from the containers under pressure, a separable die mold having a cavity, a core for enlarging the cavity to receive layers of the molten metal, and means for sealing openings or joints in the die mold after the formation of the first layer of metal, said mold having an inlet orifice and a sprue lock for closing said orifice.

10. A die casting machine having a plu rality of melting furnaces, each having movable metal containers with outlet orifices, means to force molten metal fromthe containers under pressure at different times, a sepa 'able die mold having a cavity, a core for successively enlarging the cavity to receive successive layers of the molten metal, and means for sealing openings or joints in the die mold upon the formation of the first layer of metal, said die mold having inlet orifices to receive the mouth portions of the metal containers, a valvelcooperating with one of said orifices to close the same after the injection of the first layer of fluid metal, and means for actuating said valve.

11. A die casting machine having a plurality of melting furnaces, each having movable metalcontainers with outlet orifices, means to force molten metal from the containers under pressure at difierent times, a separable die mold having a cavity, a core for enlarging the cavity to receive layers of the molten metal, and means for sealing the die mold upon the formation of a layer of metal, said die mold adapted to receive the metal from the outlet orifice of the metal containers, means cooperating with at least one of said orifices to close the same after theinjection of said layer of fluid metal, means for ejecting the article produced in the cavity upon the separation'of the die mold and means for closing said die mold after ejection .of the article and prior to again receiving the molten metal.

12. A die casting'machine having a plurality of melting furnaces, each having movable meta-l containers with outlet orifices, means to force molten metal from the containers under pressure at different times, a separable die mold having a cavity, a core for successively enlarging the cavity to receive successive layers of the molten metal, means for sealing openings or joints in the die mold upon the formation'of the first layer of metal, said die mold having inlet orifices to receive the mouth portions of the metal containers, a valve cooperating with one of said orifices to close the same after the injection of the first layer of fluid metal, and an oil groove forming member carried by the core.

13. A die casting machine having a plurality of melting furnaces, movable metal containers with outlet orifices near one end, means to force molten metal therefrom under pressure, a separable die mold having a cavity, a relatively movable core for sl'lccessively enlarging the cavity to receive successive layers of the molten metal, means for sealing openings or joints in the die mold upon the formation of the first layer of metal, said die mold having inlet orifices to receive theoutlet orifices of the metal containers, a valve co-operating with one of said orifices to close the same after the injection of the first layer of fluid metal, an oil groove form ing member adjustably mounted in and carried by the corrnormally depressed so as not to project from the surface of the core, and means to project the same into the enlarged cavity when the core is moved, to form oil grooves when another layer of molten metal is injected into the cavity.

14. In a die casting machine, a mold having sections, at least one of which is adapted to be moved relative to the other and having a cavity formed therebetween, means co-acting with said sections to enlarge or restrict the cavity thereof for successively receiving molten metal to produce a plurality of layers joined together by fusion, and oil groove and hole forming members carried by the last-named means and one section respec-- tively.

15. In a die casting machine, a mold having sections, at least one of which is adapted to be moved relative to the other and having a cavity formed therebetwee-n, a movable core co-acting with said sections to enlarge or restrict the cavity thereof for successively receiving layers of molten metal to produce a plurality of layers joined together by fusion, and means for actuating the core.

16. In a die casting machine, a mold having sections, at least one of which is adapted to be moved relative to the'othcr and having a cavity formed therebetween, means co-acting with said sections to enlarge or restrict the cavity thereof for successively receiving molten metal to produce aplurality of layers joined together by fusion, and means for actuating the last-named means. said means having lips or shoulders adapted to seal the cavity in the different positions of enlargement or reduction.

17. In a die casting machine, a mold having a cavity with inlet orifices connlmnieating withcthe cavity, one section being movable toward and away from the other, and a core having step portions engaging corresponding openings in the sections and co-acting with the cavity to enlarge or reduce the same for receiving a plurality of molten metal mixtures for producing an article of a plurality of layers.

18. A die-casting machine havinga plurality of melting'furnaces, a pivoted ladle in each furnace, each with an outlet orifice,

means connected to the opposite ends of the ladles to force molten metal therefrom under 1 pressure, a separable die mold having a cavity, a core for enlarging the cavity a plurality 5 of times to receive layers of molten metal,

means for sealing the joints or openings in the die mold after the formation of a layer of metal, said die mold having one or more in,-

let orifices to receive the outlet orifices of the w ladies, and means for closing said orifices at different times after injection of a layer of molten metal.

19. In a die-casting machine, a mold having sections at least one of which is adapted to be moved relative to the other and having a cavity formed therebetween, a slidable core co-acting with said mold sections to enlarge or restrict the cavity thereof for successively receiving layers of molten metal to produce a plurality of layers joined together by fusion, and means for actuating the core.

20. In a die-casting machine, a mold having sections, at least one of which is adapted to be moved relative to the other, and having 5 a cavity. formed therebetween, automatic means cooperating with said sections to enlarge or restrict the cavity for successively receiving layers of molten metal, means for expelling the air from within the cavity, and

means for actuating the first-named means to move it outwardly and to move it in after the die is ejected.

21. The process of making a die cast article composed of a plurality of molten charges which consist in introducing the molten charge in a portion of a molding cavity, sealing said charge from atmosphere causing another portion of the molding cavity to be presented to a charging position and then. introducing another molten charge in said other portion of said cavity to join said charges together. 4

22. The process of die casting which consists in successively enlarging the molding i5 cavity, injecting a plurality of molten metal mixtures into the cavity and utilizing one of said mixtures to aid in sealing the cavity from I atmosphere before the inject-ion of the next mixture thereinto.

23. The method of die casting with a plurality of metals which consists in successively enlarging a molding space, injecting a plurality of molten metal mixtures into said space successively as it is enlarged. expelling the air from within the space at the first inj ection and sealing said space against the entrance of air to provide a partial vacuum therein and prevent oxidation of the first injection upon enlargement of the space for receiving the next injection whereby the two metal injections may be joined together.

24. The process of die casting with a. plurality of metals which consists in filling a molding space with one molten metal under .25 pressure, enlarging the space and then filling the enlargement with another metal under, pressure and at the same time as said space is enlarged interposing a groove forming member in said cavity to cause a groove-to be formed in the metal forced into said enlargement.

.25. The process of die casting with a plurality of metals which consists in filling a molding cavity with one molten metal under pressure, enlargingthe cavity while the metal is still hot, expelling the air from the cavity to prevent oxidation and then filling the enlargement of the cavity with another molten metal under pressure to cause the two metals to be joined together.

26. In a die casting machine, means for defining a molding cavity, receptacle means for molten metals, means for filling a portion of said cavity with a charge of said molten metals, means for presenting another portion of said cavity to a charging position and means'for introducing another of said molten metals in said other portion to join the molten metals in said cavity together.

27. In a die casting machine, means for defining a molding space, receptacle means for molten metal, means 'for injecting a plu rality of charges of said molten metal into said space and means for utilizing one of said charges to aid in sealing the space from atmosphere before the injection of the next charge therein.

28. In a die casting machine, means for defining a molding cavity, receptacle means for molten metal, means for filling the cavity with a charge of said molten metal, means for enlargingthe cavity and means for then filling the enlargement of the cavity with another charge of molten metal to cause said two charges of metal to be joined together.

29. In a die casting machine, means for defining a molding cavity, receptacle means for molten metal, means for filling the cavity with a charge of said molten metal, means for enlarging the cavity, means for then filling the enlargement of the cavity with another charge for molten metal to cause said two charges of metal to be joined together,

.' and means arrangedto be positioned in said cavity prior to the injection of the second charge of molten-metal therein to cause a. groove to be formed in the second charge of metal as it is added to the first charge.

30. In a die casting machine, means for defining a molding cavity, receptacle means for molten metal, means \for filling the cavity with a charge of said molten metal, means comprising a movable core for-enlarging the cavity and means for then filling the enlargement of the cavity withanother charge of molten metal to cause said two charges of metal to be joined together.

31. In a die casting machine, means for definin a molding cavity, receptacle means for mo ten metal, means for filling the cavity with a charge of said molten metal, means comprising a movable core for enlarging the cavity and means for then filling the enlargement of the cavity with another charge of molten metal to cause said two charges of metal to be joined together, said core including a plurality of different sized portions adapted to be successively moved into the cavitv as the two charges are introduced therein.

32. .In a die casting machine, means for defining a molding cavity, receptacle means for molten metal, means for filling the cavity with a charge of said molten metal, means for enlarging the cavity and means for then filling the enlargement of the cavity With another charge of molten metal to cause said twocharges of metal to be joined together,

said enlarging means including a core having a plurality of different molding surfaces adapted to be successively introduced into the molding cavity as the charges are injected in th 't a 8 can y AXEL AKERS.

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