US1961942A

US1961942A - Die casting machine

Info

Publication number: US1961942A
Application number: US470859A
Authority: US
Inventors: Pack Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1930-07-26
Filing date: 1930-07-26
Publication date: 1934-06-05
Anticipated expiration: 1951-06-05

Description

June 5, c P 1,9615942 DIE CASTING MACHINE Filed July 26, 1930 4 Sheets-Sheet l BY 0a AT ORNEYS.

June 5, 1934.

C. PACK DIE CASTING MACHINE Filed July 26, 1930 4 Sheets-Sheet 4 IN V EN TOR.

*a ATTORNEYS.

Patented June 5, 1934 DIE CASTING MACHINE Charles Pack, Jackson Heights, N. Y.

Application July 26, 1930, Serial No. 470,859

28 Claims.

This invention relates to die casting, and more particularly to a die casting machine adapted for the casting of any metal under any desired high pressure.

In my copending application Ser. No. 417,849 filed January 2, 1930, I have disclosed and claimed a novel method and machine for ,die casting.

In accordance with the said disclosure the die is provided with a cup or receptacle for molten metal in addition to the mold impression. This cup is filled manually with molten metal from a separately heated crucible, after which the die is closed, and a plunger, smaller in diameter than the receptacle, is forced into-the receptacle in order to displace the center portion of the metal therefrom into the mold. The plunger is then retracted, the die opened, and the casting and cup-shaped gate ejected.

This method makes it possible to cast any metal, even those of high melting point, at high pressures. The difliculties of close .tolerances are avoided, the machine remains at a low temperature, and chilling of metal around the cup I is provided for, thereby avoiding abrasion and changed at will.

The object of the present invention, generally, is to improvethe diecasting machine disclosed in my prior application while retaining all of the foregoing advantages of the die casting meth- 0d and machine set forth above.

In my prior machine the die and the plunger were both operated by concentrically arranged pistons and cylinders, and this resulted in the machine having considerable height. It' also necessitated the use of a complex arrangement of bushings to prevent oil leakage, and made the plunger'relatively inaccessible for the provision of water cooling. One object of the present invention is to overcome these difiiculties and to provide mechanism for operating the die, and additional mechanism for operating the plunger, which will be separately, independently, and advantageously located with a view to reducing the height of the machine and simplifying and improving the accessibility of the individual mechanisms.

In preferred form the machine employs fixed and movable plates on which the die portions are mounted. To simplify the frame of the machine and to keep the height of the cup, which must be filled with molten metal from an appropriate ladle, constant, it is preferable-that the fixed plate be the lower plate. Inasmuch as the plunger and die operating mechanisms are preferably located on opposite sides of the fixed and movable plates, it then becomes of advantage to 10-- cate the plunger on bottom, or beneath the fixed plate, and to force it upwardly into the cup for the casting operation. This, however, introduces difficulty due to the formation of a fin at the bottom of the cup which tends to wear the plungerwith cumulatively bad effect, inasmuch as it may not be removed when the cup-shaped gate is ejected after each casting operation. Accordingly, further objects of my invention are to prevent the formation of such a fin, and, in the event of its formation, to insure ejection thereof with the gate. To this end, a tapered approach be-. tween the bottom of the cup and the side walls of the plunger is provided when the cup is being filled with metal, so that preliminary chilling of the metal later opposes the formation of a fin. When the gate is who ejected, the plunger'is retracted a substantial distance below the bottom of the receptacle, thereby clearing and releasing the fin so that it is readily ejected with the balance of the metal left in the receptacle. The plunger is then raised to an intermediate position near or slightly above the bottom of the receptacle preparatory to filling the receptacle with a new charge of molten metal. In other words, the plunger is effectively operated in three positions or movements instead of the customary two.

A further object of the invention is to provide hydraulically operated means and relatively simple valve mechanism therefor, for obtaining the desired upward, downward, and intermediate positions of the plunger. For this purpose, 'the plunger is directly connected to a piston arranged to reciprocate between the upward and downward positions. In addition, a movable stop is provided for moving the piston and plunger from the downward to the desired intermediate position, and this stop is preferably actuated by a small auxiliary piston and cylinder located beneath the head of the main cylinder and subjected to continuous pressure which is overcome, when necessary, by the main piston. I

The separable die portions are preferably operated by hydraulicmeans taking the form of a cylinder and piston located on top of an upper fixed plate spaced frohrth lower fixed plate by pillars. A movable plate located between the upper and lower fixed plates carries the upper die portion and is moved by the piston. In accordance with further objects of the invention, this mechanism is arranged to necessitate the use of only a single valve, and this valve is so interconnected with the valves controlling the operation of the plunger as to insure closing of the die prior to the casting movement of the plunger, and movement of the plunger to the intermediate position prior to closing of the die.

The necessary opening or separation of the portions of the die is dependent upon factors which are more or less independent of 'the over-all dimension of the die including the die box with its ejector and core plates. When a relatively extreme change in size of the die must be accommodated, it is desirable that the spacing between the mean position of the movable plate and the lower fixed plate be variable, and in accordance with another object of the present invention this change is provided for by making the pillars which determine the spacing between the upper and lower fixed plates replaceable, so that pillars of greater length may-be substituted when necessary.

When the height of the die is.relatively small, the opening of the die may be greater than necessary if the piston operating the same is permitted to rise to the top of its stroke. This is waste.- ful of time' and power, and accordingly it is a further object of this invention to make it possible to limit the opening stroke of the die as desired, and variable or replaceable stop means are provided for this purpose.

The die ordinarily consists of an ejector die and a cover die. The ejector die is provided with an ejector plate and ordinarily also with a core plate, and a further object of this invention is to arrange for the operation of these plates. This may be more readily accomplished when the ejector die is made the movable portion of the die, and accordingly in the present machine the die is inverted so that the ejector die is on top of the cover die. cover die, and inasmuch as the cover die is usually small in height relative to the ejector die, this possesses the additional advantages of reducing the elevation of the cup and permitting the elevation thereof to remain constant. Suitable lever mechanism is provided to interconnect the fixed frame of the machine, the movable die, and thecore plate, to cause the core plate to be moved toward the cover die when the die is closed and away from the cover die when the die is opened, thereby providing for retraction of the cores, which lengthens their wear and facilitates ejection of the casting. The upward movement of the ejector plate with the ,ejector die is arrested near the end of the stroke, causing the ejector pins on the ejector plate to eject the casting from the ejector die.

It frequently is necessary to employ side pulled cores. Whenever possible, these are located in the ejector die, and a further object of this invention is to provide for automatic operation of such a side pulled core located in the ejector die. For this purpose a fixed member having inclined bearingsurfaces, preferably in the form of a slot,

is attached to-the frame of the machine and cooperates with a follower riding in the slot and attached to the core. The follower is moved in the slot when the ejector die is raised or lowered, and the inclination of the slot is made proper to cause insertion of the core when the die is closed and retraction of the core. when the die is opened.

Occasionally the nature of the casting is such that it is necessary to employ a side pulled core in the cover die. Such a core must normally be pulled manually, but this isundesirable because the core must be pulled before the die is-opened, and a single misstep will ruin the casting and may ruin the entire die. Accordingly, a further object of my invention resides in the provision of power means for automatically pulling a side pulled core in the cover die. This is accomplished by attaching a detachable hydraulically operated piston and cylinder mechanism to the frame The cup is then located in the of the machine adjacent the core for operating the core. The piping to this cylinder is so arranged that no additional valves other than those ordinarily employed in the machine are necessary, and yet retraction of the core prior to opening of the die, and insertion of the core prior to the operating stroke of the plunger are assured.

Further objects of the present invention center about the manufacture of relatively large die castings. When making small castings the cup or receptacle for molten metal is located at the center of the die, and the mold impressions for the articles to be cast, are distributed around the center gate. When making a large casting, the cup may itself be in the way of the desired mold impression, and it is a further object of the present invention to care for such cases and to make it possible to move the cup, the plunger, and the operating mechanism therefor toward one side or the other of the die sothat an offset gate may be provided. It may incidentally be pointed out that the possibility of obtaining this desired adjustment constitutes another important advantage of the separated mechanisms for operating the plunger and the die employed in the present machine, in contrast with the concentric combined mechanism employed in my prior machine.

At times it is necessary'to make castings which are even larger than those which may be accommodated by the expedient just described. When making relatively long, and slender castings, it

is necessary not only that the die beaccommodated by the machine, but also that metal be fed to the extremities of the die impression before it has time to chill. To provide for the successful manufacture of such castings is still another object of my invention, and for this purpose a plurality of receptacles for molten metal are employed in communication with a single mold, and a plurality of plungers are simultaneously moved into the receptacles in order to displace metal therefrom into the mold. This desired arrangement is preferably provided for without necessitating a special casting machine, by the relatively simple expedient of so designing the individual casting machines that two or more may be assembled at will and rigidly locked together when it is necessary to make a large casting. The similar elements of the machine may be piped together 1 in parallel, or the valve mechanisms thereof may be geared to operate together in order to insure simultaneous operation of the component machines. Any slight differences in this respect are amply taken care of by the fact that it is a single rigid die which is bolted to the fixed and movable plates of the several machines.

To the accomplishment of the foregoing and such other objects as will hereinafter appear, my invention consists in the die casting machine elements and their relation one to the other as hereinafter are more particularly described in the specification and sought to be defined in the claims. The specification is accompanied by drawings in which:

Fig. l is a partially sectioned side elevation of a die casting machine embodying my invention;

Fig. 2 is a horizontal section taken between the separable die portions;

Fig. 3 is a similar section taken through a machine having a different die, necessitating a side pulled core in the cover die; 1

Fig. 4 is an elevation showing the core plate mechanism;

Fig. 5 is a partially sectioned elevation through the ejector die mechanism; 1 I

Fig. 6 is an enlarged section through the cup and plunger in intermediate position;

Fig. 7 is a similar section through the cup and plunger in casting position; i I Fig. 8 is a side elevation of a multiple machine for the manufacture of large castings; and

Fig. 9 is a side elevation of the valve mechanism.

Referring to the drawings and more particularly' to Fig. 1 thereof, the.present die casting machine comprises separable die portions A and B/a cup or receptacle formolten metal C, and a plunger D smaller in diameter than the receptacle for displacing metal therefrom into a mold impression in the die. The plunger D is operated by appropriate mechanism E, while the movable die portion B is operated by appropriate mechanism F. The mechanisms E and F are septher be noted that it is preferred to make the lower die portion A the fixed part' of the die, although this necessitates that the plunger D be located at the bottom of the machine and operated upwardly into the receptacle C.

The mechanism E is preferably hydraulically operated and comprises a main cylinder 2, and a piston 4 reciprocable therein and actuating a piston rod 6. Plunger'D is rigidly attached to the upper end of piston rod 6 by means of threads 8. The plunger may be unscrewed and replaced by another, if it is desired to change the diameter thereof or in the event of excessive wear. The plunger is hollow and is provided with water connections 10 to which flexible water piping 12 may be attached. A relatively slender tube 14 is threaded into the upper end of piston rod 6 in order to insure circulation of water at the upper end of plunger D even though the connections 10 are made relatively far down the plunger so as not to interfere with the upward reciprocation thereof.

The effective water cooling chills the plunger and prevents it from welding to the cast metal.

The accessibility of the plunger D, making it readily possible to water cool it, and, if necessary, change it, are advantages obtained as a result of using separated mechanisms for operating the plunger andthe die. Another advantage is a saving in over-all height of the machine,

' inasmuch as-the strokes of mechanisms E and F are independent, and allowance for one need not be made in the other as is thecase when concentric hydraulically operated pistons and cylinders are employed. Complicated systems of bushings. and packing. glands in order to seal the concentric elements are dispensed with. The

' upward movement of the plunger tends to force the molten metal in the direction in which it is to flow, instead of in the opposite direction.

When using a bottom plunger, such as the plunger D, difllculty arises because of the formation of a fin at the bottom of the receptacle. The upper end of the plunger should be given a slight taper, say ten to twenty thousandths of an inch in three inches, so that it may be retracted from the. cup-shaped gate formed during the casting operation. This means that when. the plunger is moved downwardly to the bottom of the receptacle there is a clearance of ten to twenty thousandths of an inch present, in which metal will be forced when the plunger is operated, thereby forming a fin of metal which is tightly wedged between the plunger and the opening at the bottom of the cup in which it reoiprocates. This fin causes excessive wear on the plunger, and the difficulty is apt to be cumulative inasmuch as the fin'may not be removed with the gate at each casting operation.

I have found. that this diificulty may be overcome-by moving the plunger downwardly below the bottom of the receptacle in order to clear and free the fin so that it is readily removed with the gate. The plunger, however, must be brought to a point near the bottom of the receptacle ,before a fresh charge of molten metal is poured therein, and the operating mechanism E, for the plunger, is therefore designed to make selectively available three positions or movements of the plunger, upward, in order to displace metal from the cup for casting, downward, below the bottom of the cup, in order to facilitate ejection of thegate, and intermediate, near the bottom of the cup preparatory to filling the same with molten metal.

In the present arrangement'the effective stroke of piston 4 in cylinder 2 is made sufficiently great to move the plunger between the desired upward and downward positions. In addition, a stop 16 is provided which is reciprocable in the head of cylinder 2, and which, in its upward position, determines the intermediate position of piston 4 and consequently of the upper end of plunger D. Stop 16 is preferably actuated by a piston 18 reciprocating in a small auxiliary cylinder 20 mounted. directly beneath the head of main cylinder 2. To simplify the valve mechanism of the machine, the area of piston 18 is made relatively small, and is at most a substantial amount less than the effective area of the upper side of piston 4.. The lower side of auxiliary cylinder 20 may then be directly connected through

pipes

22, 24, and 26 with a source of compressed fluid here exemplified by the main oil supply pipe 28. The upper and lower ends of the main cylinder 2 are connected to valves in a valve system generally designated G, through piping indicated by the dotted

lines

30 and 32. For the downward position, the pressure on the upper side of piston 4 overcomes the resistance of stop 16, while for the intermediate position both ends of main cylinder 2 are permitted to exhaust, in which case the pressure on the auxiliary piston 18 becomes effective.

'Ihethree position operation of plunger D insures that any fin formed at the bottom of the cup will be removed with the gate. Further precaution is taken to lessen the formation of such a fin in its incipiency, to explain which, attention is directed to'Figs. 6 and 7. In these figures it will be observed that the receptacle or cup C is substantially larger in diameter than the plunger D, and that the inner wall of the cup 36 is generously tapered in order to facilitate removal of the cup-shapedgate. The bottom of the cup is indicated in Fig. 6 by the dotted line 38. The position of the upper end of plunger D during the ejection of the casting is indicated by the broken line 40,. and this, it will be observed, is a substantial distance below the bottom of the receptacle. The intermediate position of the plunger D, bringing the upper end v thereof 42 of the plunger is slightly above, say a quarter of an inch, rather than flush with, or below the bottom of the receptacle. The clearance between the receptacle and the plunger at the bottom of the cup is made relatively slight, say at most a sixteenth of an inch, thereby forming a thin, annular groove 44 around the bottom of the cup. The plunger D is water cooled by connections previously described, and the cup C is Water cooled by means of an annular jacket 46 surrounding the cup through which water is circu- .lated by means of connections 48 best shown in Fig. 1. The cup and plunger both being at a relatively low temperature, molten metal when first poured in the cup is exceedingly rapidly chilled before it has time to reach the bottom of groove 44. When the plunger is elevated, the previously cooled metal in groove 44 tends to effectively prevent the flow of molten metal between the plunger and the wall 50 in which it reciprocates.

The cup illustrated in Fig. 7 is a modified form in which the annular groove 52 at the bottom of the cup, corresponding to the groove 44 in Fig. 6, is tapered to run into the plunger. The groove 52 is of the order of magnitude of a quarter of an inch in height and a sixteenth of an inch in width at the top thereof. tion and mode of operation of this groove is the same as that already described. It may be mentioned that surface tension in the molten metal tends to prevent the groove from initially filling up, and this is followed by rapid chilling which forms a seal against the subsequent formation of a true fin between the plunger and the bearing surface 50 of the cup.

Reverting now to Fig.1, the mechanism F for opening and closing the die comprises a cylinder 56 mounted on and supported by a fixed plate 58, here formed integrally with the cylinder 56. Fixed plate 58 is spaced from lower fixed plate 60 by pillars 62. In the present machine only two pillars are employed in order to make the die of the machine as accessible aspossible. The upper die portion B is detachably mounted on a movable plate 64 moved by a piston 66 through "a piston rod 68. The diameter of piston 66 is selected to obtain sufficient area in excess of the area of the lower side of the piston to keep the die portions A and B tightly compressed together during the casting operation in spite of the relatively large area of the die which may be subjected to the full casting pressure. The total effective force on piston 66 is made safely in excess of that which may be encountered at the die, in order to prevent or minimize the formation of fins at the parting line of the die.

The effective area on the lower side of piston 66 is designed to obtain sufficient upward force to elevate the die B and the movable plate 64 to which it is attached, as well as to operate ejector plate and core plate mechanism later described. The diameter of piston rod 68 then works out to be nearly as great as the diameter of piston 66. This construction possesses several advantages. In the first place, the volume of oil and consequently the hydraulic power consumed may be minimized if the effective area on the lower side of piston 66 is not made excessive. In the second place, the difference in area between the upper and lower sides of the piston becomes so great that it is practicable to admit pressure continuously to the lower end of cylinder 56 and to use only a single valve controlling the fiow of oil to the upper end of the cylinder. The lower end The funcof cylinder 56 is connected to the high pressure pipe 28 through a pipe 70 connected to the pipe 26 previously referred to. The upper end of cylinder 56 is connected through pipe '72 with one of the valves in the valve system G.

The valve system G is best shown in Figs. 1, 2, and 9, and comprises a valve box or chest '76 provided with three sets of valves X, Y, and Z. The precise construction of the valve chest and valves may be conventional and forms no part of the present invention. It need only be briefly mentioned that the valve box is suitably partitioned, and the valves and piping so interconnected that the pipe 72 may be effectively connected to either the high pressure oil supply pipe 28 or a low pressure exhaust pipe 78 by operation of valves X; that the pipe 32 may be effectively connected to either the high pressure oil supply pipe 28 or the low pressure exhaust pipe 78 by the valves Y; and similarly, that the pipe 30 may be connected to either the high pressure oil supply pipe 28 or the low pressure exhaust pipe 78 by the valves Z. The valves X, Y, and Z are respectively operated by

cam followers

80, 82, and 84 which in turn are respectively operated by'cams 86, 88, and 90, all mounted on a shaft 92. Shaft 92 carries a sprocket gear 94 interconnected by a sprocket chain 96 with a sprocket pinion 98 mounted on a countershaft 100. Countershaft 100 may be rotated by either the manually operable crank 102 or by an electric motor 104 connected to the countershaft 100 through pinion 106 meshing with gear 108 carrying sprocket pinion 1 10 driving sprocket chain 112 meshing with sprocket gear 114 mounted on the countershaft 100.

The gear ratio between countershaft 100 and cam and crank shaft 92 is preferably made a reduction of one to five for the following reason.

The present die casting machine is a five step 115 machine in contradistinction to the ordinary die casting machine which is a four step machine. In the ordinary machine the operating steps are:

1. Closing of die.

2. Operation of plunger.

3. Retraction of plunger.

4. Opening of die and ejection of casting.

In the present machine a fifth step is added in order to take care of movement of the plunger to the intermediate position near the bottom of the receptacle preparatory to filling the latter with molten metal. The stages in the operation of the present machine are:

1. Closing of die.

2. Operation of plunger upwardly.

3. Retraction of plunger downwardly below the cup.

4. Opening of die and ejection of casting.

5. Movement of plunger to intermediate position, and filling of cup.

The exact time needed between the various operations listed above is a variable, dependent upon the size and complexity of the casting and various other factors, and is best determined empirically. By making the gear reduction be tween crank 102 and cam shaft 92 one to five, it is merely necessary to initially distribute the

cams

86, 88, and 90 for equal time between stages, and then torotate crank 102 a single full revolution for each stage inthe operation of the machine. If the piece is to be cast many times, the optimum timing between stages is measured, and the cams are then redistributed on shaft 92 in order to properly apportion the desired time intervals. The control circuit of elecstopped automatically after each casting. In

other cases, continuous operation may be found convenient, and in such cases the timing between steps five and one, listed in the above table. should, of course, include suflicient time for removal of the ejected casting and pouring molten metal into the cup.

Valves X control the pressure applied to the upper end of cylinder 56 through pipe 72; valves Y control the pressure applied to the lower end of cylinder 2 through pipe 32; and valves Z control the pressure applied to the upper end of cylinder 2 through pipe 30. Also, pressure is constantly applied to the lower end of cylinder 56 and to the lower end of cylinder 20. To obtain the five desired operating stages enumerated above, the valves X, Y, and Z are turned to either pressure or exhaust in a manner which is best summarized by the following table, in which pressure is indicated by P and exhaust is indicated by E.

r V Valves Operating steps X Y Z P E E P P E P E P E E P E E F limits.

Study of this table will readily show that for step 1,- pressure is applied to the upper end of cylinder 56 in order to close the die. For step 2 pressure is then additionally applied to the lower end of cylinder 2 in order to force the plunger upwardly for the casting operation. ,In step 3 the pressure at the lower end of cylinder 2 is relieved and is instead applied to the upper end of cylinder 2 in order to retract the plunger downwardly to its lowermost position. In step 4 the pressure on the. upper end of cylinder 561s relieved, thereby permitting the constant pressure at the lower end thereof to open the die. Pressure. on the upper end of cylinder 2 is maintained in order to keep the plunger in its lowermost position during the removal of the cupshaped gate' with the casting. For the fifth step the pressure on the'upper end of cylinder 2 is relieved. thereby permittng the constant pressure in auxiliary cylinder 20 to move the plunger to its intermediate position near the bottom of the cup preparatory to filling the same.

The size of the die may vary between wide The die open ng needed depends upon the size of the casting ejected, and in the more usual case of relatively small castings, depends upon thespace needed-to manipulate the ladle for filling the cup. It will be evident that if the die is relatively small in over-all height, the opening thereof w ll be excessively great if the piston 66 is permitted to rise to the top of cylinder 56. Any unnecessary opening of the die causes a direct loss in time and a loss in power due to the wasted volume of high pressure oil later needed to move the piston downwardly for its full stroke. Accordingly, provision is made to limit the opening of the die and the upward stroke of piston 66 to only the necessary amount. To this end, split collars 120 are mounted on pillars 62 at the upper end thereof, and these act as stops for limiting the permissible upward movement of the movable plate 64. When the die is changed to oneof difierent height, the split collars 120 may readily be removed and replaced by others of different dimension in order to compensate for the diiference in die dimension. The same collars might be moved along pillars 62 and lockedby means of the bolts provided thereon, but it is thought preferable in the present case to rely on the direct stopping action of dificrent sizes of collar, rather than the frictional grip of such a collar on the pillar.

In the event of an excessively great change between the

fixed plates

58 and 60 is made variable. This may be done by unlocking the top and bottom nuts 122 on each of the two pillars 62, elevating the upper portion of the machine F, and replacing the pillars 62 with longer ones better adapted to accommodate the new size of die. This type of change, of course, need only be made at rare intervals in order to accommodate a casting of special nature.

, In the present machine the separable die portions A and B are preferably the cover and ejector die portions, respectively. In other words, the die is inverted and operated upside down. This arrangement is preferred for a number of reasons. To begin with, it is desirable that the fixed plate 60, rather than the movable plate 64, be at the bottom of the machine, because this simplifies the direct attachment of the legs 124 of the frame thereto. In the second place, it permits the cup C, which must be in the lower portion of the die, to remain at a fixed altitude. Having determined that the fixed plate 60 is to be the lower plate, it is then desirable to mount the cover die on the lower plate, because movement of the ejector die may. be taken advantage of to operate the ejector and core plates therein. Also, the cover die is relatively small, and constant in height, and therefore keeps the altitude of the cup C substantially constant with relation to the fixed plate 60.

In fact, the cup C, while effectively forming a part of the cover die A, is in reality a separate readily replaceable member mounted directly upon the fixed plate 60. For this purpose the cup is formed with a depending cylindrical portion 126 (see Figs. 6 and 7) which is accurately fitted in one of a plurality of stepped openings 128 in the fixed plate 60. The cup-is further provided with a flange 130 which fits into and forms the cover of the water jacket 46 which cools the cup. The uppermost part of the cup 132 is made cylindrical and equal in height to the thickness of the cover die. The latter is provided with a central aperture 134 (see Fig. 1) which fits tightly and accurately over the uppermost part of the cup 132 and rests upon the fixed plate 60. It may be anchored thereto by means of appropriate lugs held by bolts the heads of which'are located in suitable T slots 136. The cover-die A is, whenever possible, designed to have a perfectly flatand plane upper surface. To this end, the gates and safety for the cup are preferably formed in the ejector die B. Thus, referring to Fig. '7, the upper surface 133 of cover die A is left plane, and'passages for the gates 135, and for the excess of metal, or safety, 137 at the top of the cup are cut into the ejector die B. p

The ejector die comprises a die proper 188 and a die box 140 housing the necessary ejector plate 142 and the usually necessary core plate 144. The ejector die is mounted as a unit on the movable plate 64 by means of appropriate bolts the heads of which may be located in T slots 146.

The operation of the core plate 144 may best be described with reference toFigs. 1, 4, and 5, in which the core plate 144 is shown to be interconnected by levers 150 with the upper fixed plate 58 and the movable plate 64 to obtain a movement of the core plate 144 toward cover die A when the die is closed, in order to insert the cores into position, and away from the cover die A when the die is opened, in order to retract the cores and so to facilitate ejection of the finished casting. More specifically the levers 150 are anchored at one end by a pin 152 to a fixed member 154 mounted on the fixed frame of the machine. This mounting, in the present case, is made at the upper end of member 154 to the fixed plate 58 through bolts 156. The opposite ends of levers 150 carry pins 158 rigidly mounted on or formed integrally with the core plate 144. The levers 150 are mounted at an intermediate point through a bearing 160 fixed in a plate 162 mounted on movable plate 64 through bolts 164. The apertures at the ends of lever 150 are slotted to allow for angularity of the lever.

When the die is opened, the upward movement of bearing 160 relative to fixed pin 152 causes each lever 150 to swing upwardly in the manner indicated in Fig. 1. This causes the movable end of lever 150 to move pin 158 and with it the core plate 144 still further upward and so to cause retraction of the cores mounted thereon. When the die is closed. the downward movement of bearing 160 relative to fixed pin 152 causes the lever 150 to swing downwardly in the manner illustrated in Fig. 4, thereby causing movement of pin 158 and with it the core "plate toward the cover die A, thereby inserting the cores in proper positon preparatory to the casting operation. It should be noted that levers 150 are preferably run in opposite directions for the sake of symmetry. Adjustment of the desired movement of the core plate may be obtained by movement. of the plates 162 relative to the movable plate 64. Thus the elevation of the core plate relative to the die may be adjusted by movement of bearing plates 162 in a vertical direction permitted by slots 166. When a considerable change in amount of movement of the core plate is needed, the bearing plates 162 may be moved sideways along movable plate 64 by transferring the bolts'164 to different ones of the threaded holes 168.

The ejector plate 142 is provided with a pair of catches or lugs 170.- These are designed to contact with a pair of fixed stops near the end of the upward movement of the ejector die, thereby causing a downward movement of the ejector plate relative to the ejector die, resulting in the ejection of the finished casting. In the present case the stops are indicated at 172 and are provided at the upper ends of arms 174 bolted to the lower fixed plate 60 by bolts 1'76. When the die is closed, the ejector plate is raised to the proper casting position by means of surface or stop pins 180 mounted on the ejector plate 142 and contacting directly with the upper face of the cover die A at points not interfering with the desired mold impressions. The length of the surface pins 180 is made exactly right so that the ejector pins will be flush with the surface of the casting during the casting operation. The ejector plate 142 is held against upward movement during the casting operation by pressure exerted thereon through the levers 150 which operate the core plate 144. For this purpose the ends of the core plate nearthe pins 158 are provided with stop screws 182 which may be properly adjusted to bear tightly against the ejector plate when the die is closed, and this adjustment may be retained by lock nuts 184.

The ejector die, in addition to the usual ejector pins advantageously placed to eject the finished casting, is provided with ejector pins 186 for ejecting the cup-shaped gate. These are preferably four in number and are best shown in Fig. 7. This figure is interesting in showing how the ejector pins 186 for the gate may be shortened, permitting the metal to be cast in metal risers 188 when difliculty is experienced with .obtaining proper retraction of the cupshaped gate from the receptacle when the ejector die is elevated. Shortening of the ejector pins 186 provides the risers 188, the surface of which increases the pull of the ejector die on the gate.

Occasionally the casting must be provided with a side pulled core. This is, whenever possible, located in the ejector die or on the parting line, in which case it is arranged to move with the ejector die. To obtain automatic operation of such a core, simple apparatus may be attached to the machine in a manner indicated in Fig. 5. A slotted member 190 is bolted to the fixed frame of the machine, preferably to the lower fixed plate 60, by means of bolts 192 at a point alongside of the necessary core 194. A follower 196 is attached to the core 194 and is arranged to ride in the slot 198. During the opening and closing of the ejector die, the follower 196 rides upwardly or downwardly in the slot 198 and consequently is pulled outwardly or moved inwardly, thereby retracting the core 194 when the die is opened, and re-inserting the core when the die is closed, as is desired.

In rare cases the nature of a complex casting is such that it is necessary to provide a side pulled core in the cover die. Such a core may be operated manually, but this is undesirable because a single misstep in which the core is not pulled completely out of the casting before-the die is opened, will ruin the casting and possibly the die. In accordance with the present invention, automatic operation of such a core may readily be provided, by attaching core pulling mechanism, indicated generally at H in Fig. 3, to the machine. This mechanism is preferably hydraulically operated and is so piped to the remaining elements of the machine that no additional valves, or changes in the valve mechanism G previously described, are needed, and yet re traction of the core prior to opening of the die,

and insertion of the core prior to operation of the plunger D are all assured.

In Fig. 3, the cover die A is mounted on the lower fixed plate 60 by means of lugs and bolts anchoredin T slots 136. The cover die is provided with the cup C in the usual manner and may, if necessary, be additionally provided with passages 200 and mold impressions 202 for the castings to be made. One such mold impression 20.4 is shown to be provided with a side pulled core 206. To operate this core a relatively small cylinder 208 is temporarily attached by means of a bracket 210 to the side of plate 60 adjacent the core 206. The cylinder 208 is arranged with the cylinder head toward the die, and the piston rod 212 attached to piston 214 projecting from the end of cylinder 208 opposite the die. The movement of piston rod 212 is transferred to the core 206 by means of a link 216 surrounding the cylinder. The head of cylinder 208 is connected through a pipe 218 to the piping 30 and valves Z controlling the pressure applied to the upper end of plunger operating cylinder 2. The outer end of cylinder 208 is connected through a pipe 220 to the source of compressed fluid and may be connected with the pipe 28 through any of the

pipes

24, 26, or '70. The effective area of ,the

outer or piston rod side of piston 214 is made sufficient to hold the core in place against the casting pressure The difference in area of the sides of the piston is made sufficient to pull the core out of the casting in spite of the constant pressure applied atthe outer side of the cylinder.

With this arrangement a moments reflection will show that pressure is applied to the head of cylinder 208, and the core 206 is retracted when the plunger D is moved to its downward position, which is prior to the opening of the die. The pressure in pipe 218 is relieved, and the core is re-inserted in. place by the pressure constantly applied to pipe 220 when plunger D is moved to its intermediate position preparatory to filling the cup with molten metal which, of course. is prior to closing of the die and upward movement of the plunger. In other words, core 206 is inserted at step 5 in the table previously given, and

the core is retracted during steps 3 and 4 in the said table. It should be appreciated that the reversal of cylinder 208 is intended merely to obtain retraction of the core when pressure is applied to the head of the cylinder, and that the cylinder may therefore be reversed and interconnected with the core through a lever or other device for reversing movement, instead of using the exact arrangement here disclosed.

In Fig. 3 the cup C is-located at the center of the die, and this center gate arrangement is preferable and is ordinarily employed when making small castings which may be distributed around the cup in the die. However, if it is necessary to make a large casting. or a casting of such shape that a center cup will interfere with the mold impression, provisionis made for moving the cup to one side or the other, as may be necessary,

and such an offset or side gate is indicated in Fig. 2. To accomplish this, the lower fixed plate 60 is provided with a plurality of stepped openings 128 each capable of receiving the cup C. The hydraulic mechanism E for operating plunger D is transversely reciprocable on rails 222 formed on the inside faces of the legs 124 of the frame. The'piping to the hydraulic mechanism E is provided with appropriate swivel joints 224 so as to accommodate the desired transverse movement. It will be evident that when dealing with a die necessitating a side gate it is merely necessary to move the cup C from one to the other of the stepped openings 128 for receiving the same, and to correspondingly move the plunger D and the entire hydraulic mechanism E to the important advantages of using separated mechanisms E and F for the operation of the plunger and the .die, in contrast with the concentric combined mechanism emplcyed in the machine disclosed in the aforementioned copending application.

It sometimes is necessary to cast a piece even larger than that which may be accommodated with a side gate. This is particularly true if the piece is relatively long and slender in dimension, so that further difficulty may arise in 0btaining a rapid and effective distribution of metal to the remote ends of the casting. In either of these cases the problem may be solved by utilizing a plurality of receptacles or cups for molten metal all gated to the single casting and all com-\ pressed simultaneously by a plurality of plungers. A special machine may be devised for this operation, but in the present case it is preferred that universal machines of the type so far described be so made that a plurality of the machines may be locked together and simultaneously operated, when necessary. A plant which cannot afford the overhead of a special machine used only at long intervals, may frequently find it profitable to accept such special orders when it may use the standard machines already available.

The manner in which two of the machines so far described may be operated together to accommodate large castings is illustrated in Fig. 8. The outerlegs 124 of the machines are left unchanged, but the inner legs are preferably removed and replaced by a common leg 230. The cover die A is bolted to the two lower fixed plates 60, while the ejector die B is bolted to the two movable plates 64. The machines may be piped in parallel to a single valve mechanism such as the valve mech-.- anism G previously described. If the machines were located quite closely together before being combined so that alteration of the oil piping between each machine and its valve mechanism is not necessary, it may be found preferable to simply gear the valve mechanisms together to insure synchronous rotation thereof. Withe'ither arrangement the operation of the machine will be exactly like that-previously described in connection with the single machine, except that when the die is opened two receptacles must be filled with molten metal before the next cycleof casting operation is begun. The castings obtained are improved in character due to the improved distribution of metal obtained when a plurality of sources of metal under pressure are 125 provided. i

The mode of constructing and operating the die casting machine of my invention, and the many advantages thereof will, it is thought. be apparent from the foregoing detailed description thereof. The machine retains the economy of floor space of my prior machine, and yet is greatly reduced in over-all height. The hydraulic mechanism is remarkably simplified by the use of separated mechanisms for the plunger and die, and water cooling of the plunger is readily provided. The upwardly movable plunger force's the metal directly toward, instead of away from, the gates and mold impressions. The formation of a fin due to the use of a bottom plunger is minimized, and ejection of the fin is provided for. Automatic operation of the ejector and core plates of the die, as well as automatic operation for side pulled cores whether in the ejector die or the cover die, are all obtainable. The valve mechanism employed to control the operation of the machine is relatively simple, insures proper sequence of operation, and accommodates hydraulic core pulling mechanism without added complications. The valve mechanism 150 may be manually or power operated, and the manual operation may be used to determine the optimum apportionment of time between the steps in the operation of the machine, and this apportionment may be obtained with the power operation of the valve mechanism. Variations in die height may be accommodated, and even extreme variations may be handled by replacing the pillars of the machine. The castings may be made with either a center or side gate, as may be necessitated by the nature of the casting, and even extremely large or relatively long and thin castings may be manufactured by the use of a multiple plunger machine obtained, if desired, simply by assembling a plurality of single plunger machines in parallel.

It will be apparent that while I have shown and described my invention in the preferred forms, many changes and modifications may be made in the structures disclosed without departing from'the spirit of the invention, defined in the following claims.

I claim:

1. A die casting machine comprising a receptacle for receiving individual charges of molten metal to be cast, a mold in communication therewith for receiving the bulk of the charge of molten metal, and a plunger located below said receptacle and movable upwardly into the receptacle for displacing most of the metal from the receptacle into the mold, said plunger being substantially smaller in diameter than the diameter of the body of metal in the receptacle and having a clearance between itself and the receptacle which at its minimum is substantially larger than the maximum normally permitted clearance used between the plunger and cylinder of die casting machines generally.

2. A die casting machine comprising separable die portions including a downwardly tapered receptacle for molten metal to be cast and a mold in communication therewith, a plunger located below the receptacle and movable upwardly into the receptacle for displacing the metal upwardly from the receptacle into the mold, said plunger being smaller in diameter than the diameter of the body of metal in the receptacle, plunger operating means located below the die portionsv and receptacle for reciprocating said plunger, and means for ejecting the resulting casting and together with it the solidified residue when the die portions are separated.

3. A die 'casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger movable upwardly into the receptacle for displacing the metal from the receptacle into the mold, said plunger being smaller in diameter than the diameter of the receptacle, and means to position the plunger slightly above the bottom of the receptacle, the bottom of said receptacle being tapered toward the side of the plunger.

4. A die casting machine comprising a' receptacle for molten metal to be cast, a mold in communication therewith, a plunger substantially smaller in diameter than the diameter of the body of metal in the receptacle and reciprocable therein to force metal from the receptacle into the mold, and means for selectively moving the plunger to any of three positions relative to said cooperating receptacle, the intermediate position permitting filling of the receptacle.

in said receptacle, means for reciprocating the upper end of said plunger upwardly into the receptacle and downwardly below the receptacle, and means for stationarily positioning the upper end of said plunger near the bottom of the receptacle when filling the receptacle with molten metal.

6. A die casting machine, comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger substantially smaller in diameter than the diameter of the metal in the receptacle, means for positioning the upper end of said plunger near the bottom of the receptacle when filling the receptacle with molten metal, means to force the upper end of the plunger upwardly into the receptacle for dis.

placing the metal from the receptacle into the mold, and means for retracting the upper end of the plunger downwardly to a point a substantial distance below the bottom of the receptacle to facilitate ejection of the gate.

7. A die casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger substantially smaller in diameter than the diameter of the body of metal in the receptacle and reciprocable therein to force metal from the receptacle into the mold, a cylinder and hydraulically operated piston for moving the plunger between upward and downward positions, and means for stationarily positioning the piston and plunger at an intermediate position to permit filling of. the receptacle.

8. A die casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger reciprocable in said receptacle, a cylinder and hydraulically operated piston for moving the upper end of the plunger between an upward position for forcing metal from the receptacle into the mold and a downward position for retracting the upper end of the plunger from the receptacle preparatory to ejecting the solidified residue from the receptacle, and additional means for moving the piston and the upper end of the plunger from the lowermost position to an intermediate'position near the bottom of the receptacle preparatory to filling the receptacle with molten metal.

9. A die casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger smaller in diameter than the diameter of the receptacle, a cylinder and hydraulically operated piston for moving the plunger between an upward position for forcing metal from the receptacle into the mold and a downward position for retracting the plunger from the receptacle preparatory to ejecting the cup-shaped gate from the receptacle, an auxiliary cylinder and hydraulically operated piston located beneath the head of the aforesaid cylinder, and a stop operated thereby for moving the plunger from the lowermost position to an intermediate position slightly above the bottom of the receptacle preparatory to'filling the receptacle with molten metal.

10'. A die casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger smaller in diameter than the diameter of the receptacle, a

main cylinder and hydraulically operated. piston i.

for moving the plunger between an upward casting position and a downward position below the receptacle, a relatively small auxiliary cylinder and piston, a stop operateckthereby for moving the plunger from the downward position to an v 1,96l,94-2 intermediate filling position, a sourcelof com pressed fluid, means always connecting said source to the auxiliary cylinder, and valve means for selectively connecting either side of the main cylinder to' said source or to exhaust.

11. A die casting machine comprising relatively movable heads adapted to receive any of a number of dies having a mold impression and a cooperating receptacle for molten metal, a reciprocable plunger substantially smaller in diameter than the body of metal to be contained in the receptacle for displacing metal from said receptacle into the mold impression, mounting means adjustable to permit transverse movement of the plunger toward one side or the other of the die-carrying heads in order that the receptacle may be differently located in the several dies, as convenience may dictate, and means to operate the plunger.

12. A die casting machine comprising a lower fixedplate provided with supporting means for supporting a receptacle for molten metal in any of a plurality of locations on said plate, a die supported by said plate, a mold impression in said die, a receptacle for molten metal supported by said fixedplate and projecting upwardly into said die, an upwardly reciprocable plunger substantially smaller in diameter than the body of metal in the receptacle for displacing metal from said receptacle into the mold, means lo cated beneath said fixed plate for operating said plunger, and mounting means adjustable to permit movement of the receptacle, plunger, and operating means therefor toward one side or the other of the fixed plate in order that the plunger may be mated with the receptacle when the latter is located as desired.

18. A die casting machine comprising spaced fixed plates, pillars. therebetween determining the separation of the plates, a die portion mounted on one of said plates, a hydraulically operated piston and cylinder mounted onthe otherof said plates, a movable plate operated thereby, a die portion mounted on said movable plate for movement toward and from the aforesaid die portion, and adjustable means for limiting the opening movement of the piston and movable plate to a desired minimum value dependent upon the particular die used in the machine.

14. A die casting machine comprising lower and upper fixed plates, replaceable pillars therebetween determining the separation of the fixed plates, a cover die and a. receptacle for molten metal-supported by the lower plate, an upward 1y reciprocable plunger substantially smaller in diameter than the body of metal in the receptacle and a hydraulically operated piston and cylinder connected thereto and located beneath the fixed plate for displacing metal from the receptacle, a hydraulically operated piston and cylinder mounted on the upper fixed plate, a movable plate operated thereby, an ejector die mounted on said movable plate for movement toward and from the cover die, and adjustable means for limiting the upward movement of the movable plate and upper piston to a desired minimum value dependent upon the particular die used in the machine. I

15. A die casting machine comprising a lower fixed plate, a' die and a receptacle for molten metal supported thereby, an upwardly recipro- 1 cable plunger for displacing metal from the 1'67 ceptacle, hydraulically operated piston and cylinthe receptacle into the mold, a downward position below the receptacle preparatory to ejecting the cup-shaped gate, and an intermediate position near the bottom of the receptacle preparatory to filling the receptacle with molten metal, an upper movable plate, a die supported thereby, hydraulically operated piston and cylinder mechanism for moving the movable plate in order vto open or close the die, a source of compressed fluid, and valve means so connecting said source with the said mechanism as to cause closing of the die prior to the casting movement of the plunger, and movement of the plunger to the intermediate position prior to closing of the die.

16. A die casting machine comprising a lower fixed plate, a cover die and a receptacle for molten metal supported thereby, an upwardly reci'procable plunger for displacing metal from f plate, a source of compressed fluid, and valve means so connecting said source with the said mechanism as to cause closing of the die prior to the casting movement of the plunger, retraction of the plunger prior to opening of the die, and movement of the plunger to the intermediate position prior to closing of the die.

1'7. A die casting machine comprising a fixed frame, a movable plate, an ejector die attached thereto, a core plate in said ejector die, a plurality of levers so interconnecting the fixed frame, the movable plate, and the core plate that the core plate is moved toward the parting face of the die when the die is closed and away from the parting face of the die when the die is opened, and means associated with said levers for adjusting the movement of the complete relative to the movement of the ejector die.

18. A die casting machine comprising a fixed frame, a movable plate, an ejector die attached thereto, a core plate in said ejector die, and a lever having one end pivoted on the fixed frame, the other end pivoted on the core plate, and an intermediate point pivoted on the movable plate, so that the core plate is moved toward the parting from the parting face of the die when the die is opened.

19. A die casting machine comprising a frame including fixed upperand lower plates and pillars separating the same, a movable plate therebetween, a cover, die and a receptacle for metal to be cast mounted on the lower fixed plate, an upwardly reciprocable plunger substantially smaller in diameter than the body of metal in the receptacle for displacing metal therefrom, an ejector die attached to the movable plate, a core plate in said ejector die, and a plurality of levers so interconnecting the fixed frame, the movable plate, and the-core plate that the core plate is moved toward the cover die when the die is closed and away from the cover die when the die is opened.

20. A die casting machine comprising a lower fixed plate, a die and a receptacle for molten metal supported thereby,\an upwardly reciprocableplunger for displacing metal from the receptacle, a cylinder and a hydraulically operated piston for moving the plunger upward for casting and downward below the receptacle preparatory to ejection, an auxiliary cylinder and piston, a stop operated thereby for moving the plunger to an intermediate position, a side pulled core in said die, a cylinder and piston attached to the fixed plate for operating said core, a source of compressed fluid, means connecting said source with the auxiliary cylinder and one side of the core pulling cylinder, a valve controlling the flow of fluid beneath the plunger piston, and a single valve controlling the flow of fluid above the plunger piston and to the other end of the core pulling cylinder.

21. A die casting machine for producing sound castings of large or/and elongated configuration comprising a plurality of separable die casting machines each having a fixed plate, a receptacle for molten metal, a reciprocable plunger for displacing metal from the receptacle, hydraulically operated piston and cylinder mechanism for moving the plunger, a movable plate, hydraulically operated piston and cylinder mechanism for moving the same, means for rigidly locking said plurality of machines together, a single die mounted on the fixed plates, a single die mounted on the movable plates, a source of compressed fluid, and valve mechanism for connecting said source to similar elements of the hydraulically operated mechanism of the component machines in parallel, in order to cause simultaneous opera-.

tion of the machines as a unit. I

22. A die casting machine for producing sound castings of large or/and elongated configuration comprising a plurality of separable die casting machines each having lower and upper fixed plates with pillars therebetween determining the separation thereof, a receptacle for molten metal supported by the lower plate, an upwardly reciprocable plunger substantially smaller in diameter than the body of metal in the receptacle for displacing metal from the receptacle, hydraulically operated piston and cylinder mechanism formoving'the plunger, hydraulically operated piston and cylinder mechanism mounted on the upper fixed plate, and a movable plate operated thereby, means for rigidly locking said plurality of machines together, a single cover die mounted on the fixed lower plates, a single ejector die mounted on the movable plates, a source of compressed fluid, and valve mechanism for connecting said source to similar elements of the hydraulically operated mechanism of the component machines in parallel, in order to cause simultaneous operation of the machines as a unit.

23. A die casting machine comprising a receptacle for molten metal to be cast, a mold in communication therewith, a plunger substantially smaller in diameter than the diameter of the body of metal in the receptacle, means for positioning the upper end of said plunger slightly above the bottom of the receptacle when filling the receptacle with molten metal, and means to force the plunger upwardly into the receptacle for displacing the metal from the receptacle into the mold.

24. A die casting machine comprising a plate having an opening, a receptacle for molten metal received and supported in said opening with the upper portion of said receptacle projecting above the plate, a lower die portion supported by said fixed plate and fitting the upwardly projecting portion of the receptacle, an'upper die portion, and a reciprocable plunger for displacing metal from the receptacle into the mold portion of the die, whereby the plunger travels in a smooth continuous wall unbroken by transverse seams.

25. A die casting machine comprising a plate having a cylindrical opening, a generally cylindrical receptacle for molten metal received and supported in said opening with the upper portion of said receptacle projecting above the plate, a die supported by said fixed plate and having an opening for receiving the upwardly projecting portion of the receptacle, an upwardly reciprocable plunger substantially smaller in diameter than the diameter of the receptacle located subjacent the receptacle for displacing metal upwardly therefrom into the mold portion of the die, and means for operating said plunger.

26. A die casting machine comprising a lower fixed plate, a die supported thereby, a downwardly tapered receptacle for molten metal in said die, an upwardly reciprocable plunger substantially smaller in diameter than the metal in the receptacle for displacing metal from said receptacle, a hydraulically operated piston and cylinder located. beneath the fixed plate for opel'ating said plunger, a movable plate located above the fixed plate, a die mating with the aforesaid die mounted on said movable plate, a hydraulically operated piston and cylinder located above the movable plate for causing movement of the same in order to open or close the die, a source of fluid medium under pressure, a plurality of valves for controlling the fiow of said medium to the hydraulic mechanism, a cam shaft provided with a plurality of individually adjustably timed cams for operating said valves, and a motor for driving the cam shaft for a complete cycle of operation of the die casting machine.

27. A large die casting machine comprising a separable plurality of individual small die casting machines each having a lower fixed plate, a receptacle for molten metal, an upwardly reciprocable plunger located subjacent said receptacle for displacing metal from the receptacle, and a movable plate located above the fixed plate, a die comprising a single stationary portion mounted on all of the aforesaid lower fixed plates, and a single mating movable portion mounted on all of the aforesaid movable plates, means for causing simultaneous operation of said plungers, and means for causing simultaneous movement of said movable plates.

28. A large die casting machine comprising a separable plurality of individual small die casting machines each having a lower fixed plate, a downwardly tapered receptacle for molten metal, a reciprocable plunger substantially smaller in diameter than the body of metal in the receptacle for displacing metal from said receptacle, means to operate said plunger, a movable plate located above the fixed plate, and means for moving said movable plate, a die comprising a single lower stationary portion mounted on all of the aforesaid fixed plates, and a single mating movable portion mounted on all of said movable plates, and means for causing simultaneous operation of the plungers and simultaneous movement of the movable plates.

CHARLES PACK.