US1988506A

US1988506A - Die-casting machine

Info

Publication number: US1988506A
Application number: US586857A
Authority: US
Inventors: Pack Charles
Original assignee: Individual
Current assignee: Individual
Priority date: 1932-01-15
Filing date: 1932-01-15
Publication date: 1935-01-22
Anticipated expiration: 1952-01-22

Description

Jan. 22, 1935. c. PACK. 1,988,506

l DIE CASTING MACHINE n File-d Jan. 1'5, 1932 ATTORNEYS.

f l0 i N Y INVENToR.

- 29' I @Haags E46/f -Patented 22, 1935 uNiraD .stares rettete liillEnCAS'lllNG MACME Charles Fach, Jackson Heights, N. Y.

I particularly to a novel form of diecasting-ma generally,

die.

v premature -ilow of molten metal into the chine.

The primary object lof the present invention,

is to provide animproved die-casting machine which will be relatively simple in construction, and which will operate efllciently over an exceptionally long period of useful life for the production of perfect die-castings. More particularly, some of the objects of the present invention are to permit the casting of an.; metal at any desired pressure, regardless of the melting point of the metal and o f the interisity of thecasting pressure desired; to permit the casting of the desired metal in a pure state, uncontaminatedby the 'gradual solution therein of. the metal of the'machine parts; to permit'the casting of a variety of metals and alloys; and to permitreadily changing over from one metal to4 another without dimculty during the operation of the machine. In a general way, l it may be stated that the` foregoing vobjects are fulfilled by utilizing in the die-casting machine a cupv or receptacle into which or out of which a pressureplunger maybe reciprocated in order to eject a single charge of. molten metal, previously ladled into the cup, from the cup to the Further and more particular objects oi the present. invention in connection with the general type of machine heretofore outlined are, first, to prevent ilow of molten metal into the die prior to the application'of pressure by means of the pressure plunger; and secondly, to' insure removal from the apparatus of waste metal.

In accordance with the present invention, die is prevented by means of a valve; and further olojects of the 4present inventionare to simplify the necessary valve mechanism; to use the gate post of the diefcasting machine as the valve mechanism; to retain the usual desir-able' functions of the gate post, such 'as -aiding in the uniform distribution .of metal flowing into the, die, andfsubsequently helping removal of solidified metal from the flow passage or gate: to simplify' controlling the necessary mechanical movements nism, to dispense with of the combined gate passage valve and gate post; and, in the case of hydraulically operated mechathe necessity o providing additional lor special valves for controlling vthe reciprocable gate post mechanism. i

To the accomplishment of the foregoing and suchother objects as may hereinafter appear,

my invention resides in the die-casting machine r1932, serial No. sedes? (ci. zz-ssi 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 speclilcation is accompanied by a drawing, in which: A

Fig. l is a partially sectioned side elevationoi one form of die-casting machine embodying features oi the present invention;- t A Fig. 2 isa-similar elevation oi a portion of the machine, illustrative of a different. stage in the l0 operation of the machin Fig.- 3 is an enlarged bottom view oi-the end oi the pressure plunger; and

Fig. 4 is illustrative ot the solidled 'residue obtained from the cup. l

Referring to the drawing, and more particularly to Fig. 1 thereonthe die-castingmachlne of the present invention comprises, generally, a cup or receptacle C, a reciprocable plunger P` adapted to be reciprocated into and out of the cup C', a die 20 D, a flow passage or gate G leading lfrom. the cup C into the die D. "a reciprocable gate post or rod R adapted to act both as a valve for the ilow passage or gate G and as a gate post, and knockout means K for knocking plunger P the solidied residue drawn from cup C.

In operation, brieny, a measured charge of molten metal snmcient for a single casting operation is poured or ladled irom a separate heating cruciale, not shown, into thecrp C. Plunger P descends and forces or ejecfts the molten metal from the cup C into the die D. Plunger P is then retracted, and the die D is opened in order to' separate the gate from the solidiiied residue oi metal remaining in. cup @and thereby to permit' removal oi the residue from the cup, as well -as removal of the nnislied casting from die D. The die is then closed, a new charge oi molten metal poured into the cup, and the casting operation repeated. 4 l

It will immediately be noticed that because of the relation ci the cup C to the die D, the molten metal poured into tire cup C may tend io ow directly into th die D even before the pressure plunger P descends. This is highly undesirable because suchmetalwill tend to solidify in the die before it is placed under pressure, and will cause the nnished casting to be porous and non-uniform in texture. In accordance with one feature of the present invention, valve means is provided to pre' vent premature new of metal from 'the cup into the die. This valve means is here exemplitiedby the rod )R the tapered end oi which is reciproca: ble into the gate passage G and serves toretain the molten metal 4in the cup. When pressure from vthe endo! 5w plunger P descends, however, the rod R may be retracted to permit the desired ow of metal. Preferably, the valve is forced open by the pressure of the molten metal, for in this manner the metal is injected instantaneously and forcibly into the complete mold, so that all of the metal in' the casting is compressed and cooled under uniform conditions. In the present'case it is preferred to use the gate pon also as the valve means, so that the rod R further functions, even ln its retracted position as shown inFlg. 2, as a gate post and fulfils the usual desirable functions of such a post,

as, for example, to help uniformly distribute the.

injected metal around the mold, and to subsequently help removal of the solldiiied metal from the gate passage G with the casting when the eter, so that only a relatively die is opened.

Considering the machine in greater detail, the die D preferably consists of a stationary or cover portion 2, and a movable or ejector portion 4. The cover portion 2 is xed to a stationary platen 6, while the movable portion 4 is fixed to a movable platen 8. The latter may be reciprocated by suitable means, here exemplied by hydraulic piston 10, reciprocable in a cylinder 12. The cylinder may be mounted on a pedestal y14, only a portion 'of which is shown, and the reaction of the extreme force applied to piston 10, in order to keep die D closed during the casting operation, maybe taken by tension rods 16 extending between platen 6 and the cylinder 12. These rods may also be -used as guide rails for the reciprocable platen 8.

In order to simplify the valve mechanism needed to control pistonl 10, pipe 18, leading into one end of cylinder 12, may be continuously connected to a source of high pressure fluid, while pipe 20, connected to the head end of cylinder 12, may be alternatively connected to either the source of high pressure fluid or a low pressure exhaust tank through an intermediate control valve. The piston rod 2'2, connected betweenmovable platen 8 and piston 10, may be made very large' in diamsmall force will be exerted when opening the die, which force is directly opposed and overcome by the large force exerted when pressure fluid is admitted to pipe 20 in order to close the die.

The recipro'cablegate post R may be controlled` by mechanical means, but is here exemplied as being controlled by hydraulic piston 24 and cylinder 26. Cylinder 26 is mountedin end to end relation with cylinder l2, and is made of sutilcient length to permit the desired valve reciprocation of rod R in addition to its reciprocation with ejector die 4 while acting as a gate post.

. 'Ihe gate post rod R is connected to piston 24 by a piston rod 32, and this rod is preferably made coaxial with the main piston' and cylinder mechanism 10, 12 and extends completely therethrough, as is shown in the drawing, to the auxiliary piston and cylinder mechanism 24, 26.

In operation, it will be understood that when die D is closed, the gate post R is advanced or projected into the gate passage G, thereby sealing the cup C from die D when molten metal is poured into the cup C. During the casting operation, the

gate post may be retracted by appropriate valve mechanism controlling the flow of fluid to the auxiliary piston and cylinder mechanism. 'I'his valve mechanism may pe'rmit of further reciprocation of the gate post with the die when the die is opened. However, for the sake of simplicity vand in order to dispense with the necessity of separate control valves for the auxiliary piston and cylinder m the latter may be conof cylinder l2 or to pipe 20, while the other end of cylinder 26 may be connected by means of a pipe 30 to the corresponding end of cylinder 12 or to the pipe 18. Only a small force is needed for the retraction of gate post R with the die 4 when the die is opened, and accordingly piston 24 is made only slightly larger in diameter than the piston rod. Furthermore, only a relatively small force is needed to advance the gate post R into the gate passage G at the beginning of the casting operation, and this'force upon the head end of piston 24 need onlyy be alittle greater than the return force applied to the other side of piston 24. This ordinai-ily should be made possible by the use of a small diameter piston rod 32- between piston 24 and gate post R, together with a piston 24 which is only slightly larger in diameter than the piston rod 32. However, even if piston rod 32 is made of large diameter, the desired force may be obtained by usinga tail rod 34-extending from the head end of piston 24, as is shown inthe drawing, thereby reducing theeffective area of piston 24. Tail rod 34 will, of, course, be somewhat smaller in diameter than piston rod 3,2. Preferably the dimensioning of the parts should be lmade such as to dispense with the use of the tail rod 34, becausethis adds-considerably tothe over-all length of the machine. v v

With the arrangement shown, it will be understood that when pressure fluid is admitted to pipe 20, die D is closed and at the same time the gate post R is advanced not only along with the ejector die 4, but is further projected -into the gate passage G in order to seal the passage. When pressure plunger P descends, an. extremely high pressure is applied to the molten metal in cup C, and

this pressure forcibly pushes gate post R back until a stop collarv 36 on the gate post bears against a stationary part of platen 8, as is best shown in Fig. 2. After the cast-ing shot has been taken, pipe 20 is connected to exhaust, whereupon the pressure applied through pipe 18 causes the ejector portion 4 of die D to open, and at the same time causes the gate post R to move back with the die. Ejector mechanism in the ejector portion 4, which mechanism may be conventional and is not shown, then serves to eject the finished casting from the die. This arrangement dispenses with the use of lspecial valves for controlling the auxiliary piston and cylinder mechanism, and at the same time has the advantage of securing a sudden and instantaneous injection of the complete charge of molten metal into the die, for the gate post R is not forced rearwardly out of gate passage F until considerable pressure is developed within receptacle C.

The pressure plunger P may be operated by any preferred means, here exemplied by hydraulic piston and cylinder mechanism generally indicated at 40. The cylinder 40 is mounted on a frame 42 which extends downwardly to the foundation of the machine and intermediately includes the stationary head 6 previously referred to. The ends of cylinder 40 may be connected for. uid ow by pipes 44 and 46; and here again; in order to simplify the valve mechanism, the area of the lower side of the piston may be made relatively small, and pipe 46may be constantly connected to the source of high pressure fluid. Pipe 4 4 may then be. connected to either the escasos source of high pressure fluid or' an exhaust tank through an appropriate valve. The valve in pipe 44 is'properLv related to the valve in pipe '20 to insure closing ofthe dieD prior to the pressure stroke of tlleplunger sequently explained, to insureelevation of the plunger P prior to opening of the dieD.

The solidied `end oi the casting operation is preferably forced upwardly before die D is opened, in order to shear the said residue 'from the gate G at the point of minimum diameter. In some cases, particularly with a very mail gate opening at the cup, it may be possible to first open the die D and separate the metal in gate G from the residue in cup C by a direct pull in tension. This, however, is a relatively undesirable sequence of operation, iirst, because it requires undue hold by ejector die e on the casting therein; and second, because there is vno perfect assurance that the point of separatiouwill take place flush with the wall of the cup'.

In order to simplify the' machine and to dispense with' special mechanism for ejecting the solidified residue from cup C, the plunger P of the present machine is preierably provided with appropriate recesses, undercuts, or slots suitably shaped tocause the residue of metal in the cup to .be retracted along with the plunger. In' the particular embodiment here shown, this means consists simply of the transverse dovetail-shaped slot 50 at the bottom of the plunger. This slot, incidentally, is located near the gate opening,

and therefore provides ashearing force at the point where it is most needed. Asis most clearly shown in Fig. 3, the slot 5t, while made dovetailed in cross section throughout its length, is tapered in its longitudinal direction, that is, from the end 52 to the end 54, in order to facilitate subn sequently knocmng the solidided residue from the end of the plunger. This residue, as is best shown in Fig. d. is generally in the form of a disc, pancake, or biscuit 5d surrnounted by a dovetailed member 58 complementary tothe slot 5o. It is obvious that by hitting this residue in the direction from the point 54 to the pointiiz in Fig. 3, itmay readily be separated from the end of the plunger. The pancak -shapedlresidue of metal may be rnade relatively thin in order to economize in the use of material and fuel, and irl-such case the end 5d of slot 5u provides additional thickness ci residue metal which may be struck when knocking the residue from the plunger.-

in order to moet: the residue from the end' oi the plunger, knockout means is preferably provided, consisting' of hammer-like element 132 carrying a knockout bar 13e. These elements are reciprocable and pr the residue on the 'end of the plunger when the plunger is in retracted position. The desired movement may most simply be obtained by suspending the elements 132 and 134 on an arm 136 pivoted at i3d on brackets le@ mounted on the machine frame. This knockout mechanism may be' operated manually after each stroke of the plunger, or, if preferred, may be operated autornatically, and means for automatic operation is schematically shown in Fig.- -l of the drawing. iuris means consists simply of a projecting bell and. crank arm M2 rigidly secured to the arm 136 and interposed in the path of a collar las mounted on plunger P. The position oi collar its is adjustable, as also are the positions of element i351 and the miockout bar 13e. These va rious members are so relatively positioned that- P, and, for reasons sub-` the die D.

ferably adjusted to strike.

v3 knockout bar 13d is moved against the residue at the end of the plunger at or near the end of the upward stroke of the plunger. It'will be understood, of course, that the knockout means here shown is merely by Way of exemplication, and that more complex mechanical movements may be used for thesame purpose. residue of metal in cup C at the The `operation of the machine may now be briefly summarized. A measured charge of molten metal is transferred `from a crucible or melting furnace to the cup C, Plunger P then descends, and after developing a certain amount of pressure, overcomes the resistance of valve R and forces the same rearwardly until its -movement is arrested by collar 361. At the same time, the charge of molten metal is forcibly ejected into Plunger P is then-retracted, causing the resi'- due of solidied metal from the metal in gate G, and at the same time retracting the residue of metal with the plunger. During the upward movement of plunger P, the die D may be opened, the movable portion 4 of the die carrying with it the casting and the conical core of metal from gateG. 'Gate post R also moves back with the ejector'portion 4 of the die, and during this movement helps to withdraw the solidified metal from gate G. At:

or near the end of the upward stroke of plunger P, the solidiiled residue of metal on the end of I the same is knocked free from the plunger, after which it may be remelted and again used. Near the end of the opening in the-cup to shear free movement of the die, the,

casting and gate are ejected therefrom and removed. The die is then closed; gate post R is-advancedinto gate G, after which the cup or receptacle C is again ready to receive a fresh charge and making it possible to cast with pure rather than contaminated metal. The machine makes it possible to cast anyv metal at any desired pressure-the metal being heated in a separate-and preferably refractory Crucible. The metal being used for casting purposes may be changed in an instant by simply beginning to ladle metal from a diderent crucible. No rnetal is permitted to ow .into the die until the entire body of'metal is forcibly elected from the cup into the die, and this prevents aws, porosity, and other defects. This desirable result is accomplished by the use of valve means of a simple type, and the valve means mayitself be or be used as the gate post oi the die. This post.-in addition to its valve functions, retains all of the usual advantages and functions of a gate post.` The necessary movements of the combined valve and gatel post are obtained without necessitating'addtionajl valves for controlling the over-all operation of the machine. The solidied residue manner, and withoutthe'provisfion o f special mechanicul means with attendant complication, although-.such special ejector meansmay, if desired be used. 'lhe residue is preferably removed with the plunger, and when so removed, is readily knocked from the plunger either manually or automatically. Y

of metal in the cup is removed therefrom in a simple and eflcientl It vlbe apparent that while I have shown and described my invention in preferred form, many changes and modications may be made in the structure disclosed, without departing from the spirit of the invention, dened in the following claims: l A

I claim:

1. In a die-casting machine, a die. a gate or ilow passage leading into said die, said passage being substantially larger in crosssection at its discharge end than at its-inlet end, a reciprocable gate post in said die, said gate post being substantally smaller in crosssection than the discharge end of the passage, in order to freely permit flow of metal through the passage around the gate post and into the die cavities, when the gate post is in normal position, and means for reciprocatingsaid gate post between projected and retracted positions, the projected position advancing tlie gate post into the small inlet end of the gate passage in order to act as a valve to prevent` premature flow of metal into the die, and the retracted .position being the normal gate post position. l

2. A die-casting machine comprising a vertical cylindrical pressure cup for receiving a charge of molten metal sufilcient for a single casting operation, a vertically reciprocable plunger arranged to reciprocate into and out of said cup, a horizontally separable die located alongside of said cup, a gate or ilow passage interconnecting the lower portion of the cup and the die, said passage being substantially larger in cross-section at its discharge end than at its inlet end, a horizontally reciprocable gate post in said die, said gate post being substantially smaller in cross-section than the discharge end of the passage, in order to freely permit ilow of metal through the passage around the gate post and into the die cavities, when the gate post is in normal position, and means for projecting said gate post into the small inlet end of the gate passage in order to act as a valve to prevent premature flow of metal from the cup into the die.

3. A die-casting machine comprising a pressure cup for receiving a charge of molten metal, a reciprocable plunger arranged to reciprocate into and out of said cup, a die located near said cup, a gate or flow passage interconnecting the lower portion of the cup and the die, said passage being substantially larger in crosssection at its discharge end than at its inlet end, a reciprocable gate post in said die. said gate post being substantially smaller in crosssection than the discharge end of the passage, in order to freely permit ow of metal through the passage around the gate post and into the die cavities, when the gate post is in normal position, means for controlling the reciprocation of said gate post in order to project the same into the small inlet end of the gate passage prior to the casting operation and to permit withdrawal of the same from the gate passage during the casting operation, and means to remove the solidified residue of metal from the cup including undercut recesses at the end of the plunger and knockout means for knocking the residuelfrom the end of the plunger after the plunger has been retracted from the cup.

4. A die-casting machine comprising a pressure cup for receiving a charge of molten metal, a plunger arranged to reciprocate into and out of. said cup, a separable die located near said cup, a main hydraulic piston and cylinder mechanism for opening and closing said die. a gate or flow passage interconnecting the lower portion o1' the gate and the die, said passage being substantially larger in cross-section at its discharge end than at its inlet end, a combined reciprocable gate passage valve and gate post located in said die, -said gate post being substantially smaller in cross-section than the discharge end of the passage, in order to freely permit ilow of metal through the passage around the gate post and into the die cavities, when the gate post is in normal position, auxiliary hydraulic piston land cylinder mechanism connected to said reciprocable gate post for projecting the same into the small inlet end of the passage to close the same, and means controlling the sequence of operation of said main and auxiliary piston and cylinder mechanisms to prevent premature ow of metal from the cup to the die.

5. A die-casting machine comprising a pressure cup for receiving a charge of molten metal, a plunger arranged to reciprocate into, and out of said cup, a separable die located near said cup,

a main hydraulic piston and cylinder mechanism for opening and closing said die, a gate or flow passage interconnecting the lowyer portion of the gate and the die, said passage being substantially larger in crosssection at its discharge end than at its inlet end, a combined reciprocable gate passage valve and gate post located in said die and extending axially through the aforesaid hydraulic piston and cylinder mechanism, the

end of said gate post being substantially smaller in cross-section than the discharge end of the passage, in order to freely permit flow of metal through the passage laround the gate post and into the die cavities, when the gate post is in normal position, auxiliary hydraulic piston and cylinder mechanism connected to said reciprocable gate post for projecting the same into the small inlet end of the passage to close the same, and means suitably interconnecting said main and auxiliary piston and cylinder mechanisms.

6. A die-casting machine comprising a cylindrical pressure cup for receiving a charge of molten metal sumcient for a single casting operation, a vertically reciprocable plunger arranged to reciprocate into and out of said cup, a horizontally separable dielocated alongside of said cup, a main hydraulic piston and cylinder mechanism for opening and closing said die, a horizontal gate or ow passage interconnecting the lower portion of the gate and the die, said passage being substantially larger in crosssection at its discharge end than at'its inlet end, a reciprocable gate po'st located in said die and extending axially through the aforesaid hydraulic piston and cylinder mechanism, the end of said gate post being `substantially smaller in crosssection than the discharge end of the passage, in order to freely permit flow of metal through the passage around the gate post and into the die cavities, vwhen the gate post is in normal position; auxiliary hydraulic piston and cylinder mechanism connected to said reciprocable gate post, means connecting the said main and auxiliary hydraulic piston and cylinder mechanisms in parallel whereby the gate post is reciprocated'into the small inlet end of the gate passage when the die is closed and is retracted when the die is opened, the area of the auxiliary piston being relatively slight in order to ypermit an initial retraction of the gate post under casting pressure, and-means to -limit the aforesaid initial retraction. Y r

7. A die-casting machine comprising a pressure cup i'orreceiving a charge of molten metal sumnsl cient for a single casting operation, a vertically lel whereby the valve post is reciprocated into the reciprocable plunger arranged to reciprocate ine when the die is closed in order to prevent to and out of saidv cup, a se ble die located premature flow o! molten metal from the cup innear the cup,'a main-hydraulic p ton and cyiinto the'die, the area of the auxiliary piston being der mechanism for opening and closing said die, relatively slight in'order to permit the valve post a flow passage interconnecting the lower portion to be readily forced back under casting pressure i a of the cup and the die, a reciprocable valve post to open the passage, means to limit the opening the aforesaid piston andcyiinder mechanism, move the solidified residue from the cup and to auxiliary hydraulic piston and cylinder mecha- Isimultaneously separate the said residue from 10 l nism connected to said reciprocable valve post, the additional solidiiied residue of metal in the means connecting the said main and auxiliary hys z e at the end oi the casting operation. draulic piston and cylinder in parai- CHARLES PA