US2612666A - Die casting apparatus - Google Patents

Description

2 sl-lEETS-fsHEET 1 J. J. MOGARIGAL DIE CASTING APPARATUS Oct.

Filed March 5, 194er INVENTOR. JH/V J. MCGAR/GAL VBY AT TURA/EVS Oct 7 1952 J.'J. MCGARIGAL. 2,62, 666

DIE CASTING APPARATUS Filed March 5, 194e 2 SHEETS-SHEET 2 IN1/Emma JOHN J. Mc GA R/GAL A r Tom/'EVS Patented Oct. 7, 1952 p JohnJ'. McGarigal, ,Batavia, N'. Y., Vassignor to Doehler-Jarvis C orporatiomNew York, 'N. Y., l

a corpprationof Michigan -`Application"March 5, 1946, Serial No.`6v52,1 0`5' This invention relates to' molding apparatus, and more particularly to die-casting apparatus for so-called cold-chamber molding.

Arr equally' important' advantage of cold-'chamber casting 4is that there .is far less contamination of the molten metal by iron, .because of the lower temperature of the metal. 1 In cold-chamber .casting, a single charge of `molten metal is` preliminarily poured inl a shot sleeve' communicating with the die cavity, whereupon'a plunger is `forced through the sleeve. i y "The primary object of the present invention is to generally improve molding apparatus, particularly cold-chamber casting apparatus.

.Much'fdie-casting apparatus is constructed withxhorizontally, opening dies, that is,:with the parting face ofthe die vertical. .This facilitates ejection-,fof thev finished piece. "Such, machines,

lhowever, require the use of a sideward or substantiallyy horizontal shotv sleeve. 1 It is` desirable to prevent the molten metal from flowing -into the die' cavity before the plunger is operated, for such fr metal will solidify prematurely, and cause linter.- nal fiaws-and surface'discolorations.

Heretofore such preliminary flow ofmolten metal ha'sbeen avoided by locating the shot sleeve lower than the die cavity, the shot sleeve passing through, the cover die and being connectedfto theflower edge of the cavity lby agate extending vertically 'on the parting face. j This wasl done even when-molding a thin circular articlesuch as a saucepan cover or a fry pan, whichshould more preferably be gated attthecenter for, equal-.dis-

ta-nce flow-of metal. Many pieces weredefective,

'and believe that the rejectswere caused largely by theedge gating. y

v'Oneobject of thepresentinvention islto make it'possible to gate-wherever desired inthe casting itself, even when using a horizontal shot sleeve. With a circular casting, the most desirable gate locationis usually at the center of the casting.

yStillfurther objects are to eliminate theneed for anove'rsized die .extending substantially belovvl thedie cavity in order to provide room for the vshot sleeve, and also 'to avoid the'fmachinework needed to cut through such a die. p /In accordance with the presentinvention, the shot sleeve is raised nearly to the, level ofthe center of the die cavity, and a substantially horizontal, taperedwgate much smaller inv diameter than the shotfsleeve passes throughthe die to the mold cavity. The cover die vand shot sleeve are made relatively movable, and when4 separated,

a slug-of solidified metal formed within the end of the sleeve remains withk the gate and cover die. Appropriate knock-'pff means is provided to break thisfslug away Vfrom the gate, after the die has been bodily separated from the shot sleeve, but before the die has been opened.

Another objectief the invention is to minimize the necessary length of shot sleeve, while preventing'p'remature flow of metal therefrom. For this purpose, the gate is located eccentrically of the sleeve, being raised substantially above the center line of the sleeve.

Still further objects are to prevent leakage of metal around the end of the sleeve during lthe casting operation, and to facilitate discharge of the `slug after. it is knocked off the gate. For this purpose, the end of the sleeveV is preferably enlarged and tapered," and the cover die is recessed with a matingI seat.l

.Other objects are to avoid the need for machiningV away a large volume .of metal from the backof4 the cover die; to facilitate changing from one die to another; and to conveniently mount the knock-offv means for movement with the die. With these objects in viewI provide an adapter plate on which the cover die isv detachably u mounted. The enlarged, tapered recess which receives'the end of the sleeve is formed in the adapter plate and the knock-ofi means are permanently mounted on the adapter plate. A tapered gate passes through the adapter plate and registers with a continuation gate passing -through the cover die tothe middle of the cavity. Thusthe operation is exactly the same as though -the -cover ,die were recessedv vand carried i. the

knock-off means, yet the adapterplate remains a partV of the molding machine when the cover die is removed or changed.

` To accomplish the foregoing objects,v and other more specific objects which will hereinafter, appear, my invention resides in the molding .machine elements and their relation one to another, as are hereinafterfmore particularly described in the specification 'and sought to be defined in the claims. :The specification `is accompanied by' drawings in which:

Fig. 1 is a schematic view in side `elevation of apparatus embodying features of my invention;

Fig; 2 is a'fragmentary view showing the invention in most elementary form; f Fig. 3 is a similar view showing a modification: Fig. 4 isa vertical section through a part of a machine having more of the features of my iny vention; and

Fig. 5 is a somewhat similar view through a jectingmaterial into the mold cavity, and then being separated from the die, as shown in theV drawing, in order to make it possible to knock the slug L from the gate by meansof suitable knock-01T means K. The slug L is, of course, formed by a residue of metal in the end of ther sleeve S during the molding operation. In Fig. 2 only a fragment of the ejector die E is shown. The knock-off means K functions beforethe' die itself is opened, and after the slug has been knocked from the gate, .theejector die E is separated .from the cover Ldie, Vtaking thel molded piece'and gate withit.-r 4 Conventional ejector pins, notv shown,.then stripI the molded piece from the ejector die. I

Fig. 3 shows a modification of the invention in Which .the dieD is `recessed at l2 to receive the ,endf Ill'A of the sleeve S. This helps prevent leakageof metaly and also', makes it possible to mount the knocl:-oii'-r'ody I6. in the die, so that it needv be moved vertically only a small amount, instead of being retracted to a position wholly above thel dieas shown in Fig. 2.

`Reference isnow made to Fig. 4. This differs from'Fig. 3- primarily in that the end of the sleeve isjenlar'ged and tapered.y This is preferably done bythe-:addition of Vva tapered ring I8r which-is -tted' tightly around the end of the sleeve. The v recess 29 in the cover. Adie;22 is enlarged and tapered to mate accurately with the ring I8. This has A'the advantages Aof, providing more room to knock the slug L from the gate G; of facilitating sliding uof the slug out of the recess; of provi'dingautom'atic alineinent of the parts; and of preventing lleakage around the end of the sleeve. .1. 'Y Y .5 ,In the arrangement shown in Fig. 4, the covel 'y die' 22 is made upof a cavity portion 24 permanently fitted intoan outer portion 26, the latter lbeing slidabl'y-mounted on the tie bars 28 ofthe machine.v It may beiremovably mounted on the 'tie bars by releas'ablejsupport means, but here the drawing hasfbeen simpliiied'as though the tie bars' p'assfthrough the die.' The knock-off rod 2lv is mechanically operated as the die moves 4away'fr'om thesleeve. A y

Only the top por'tionvof the ejector die 30 is shown, this being built up of y parts 32, 34 and 36 set'i'nt'o anl vouter portion 38. Concentric l pipes'flllland-l2` lead to a water-cooled core 44. The core isprovided to help pull the casting'with the Aejector die from the cover die. It helps form `a` hole needed in the saucepan cover to later receivea'handle. The core is made separate so that fit cani bie-replaced when eroded, it being at the hottest point in the die.

v Fig. 4, being to larger scale, more clearly shows tliepreferred location of` thevgate G lrelative to thesleeve' S. The gate isv preferably elevated substantially abovethe center line of the sleeve. Thishisyfurther indicated by the break-off point d8 .on theslug L. In this way a greater volume ofmetal may be poured into-*the sleeveA without danger of premature flow int-o the mold cavity. lWith small castingsthis would not be impor- -single-acting cylinders H2 and rods H4.

4 tant, but with larger castings, the sleeve and the plunger travel would have to be lengthened if the gate Were kept at the centerline of the sleeve.

Fig. 5 illustrates a preferred formof the invention, in which an adapter `plate is provided, on which the cover die 52 is removably bolted. The adapter plate is slidable on the tie rodsl filofjthelmachina'andca'rriesfa double-actinghydrauliccylinder 56 for-the knock-off rod 58. The tapered recess 60 for the enlarged end 62 of shot sleeve S is formed in the adapter plate 50, rather than in the mold itself. A tapered gate opening Gil passes through the adapter plate and registers with-ran extension 66 cut through the die. In preferred form, a special gate bushing 68 is ttedinto the adapter plate. This bushing may, if desired, be provided with water passages 'l0 for cooling. Registration of the gates 64 and 66 is important, in order not to oppose withdrawal of the casting l2 from the cover die. The bushingv may accordingly bevprovided with a shallow projectionv'ld Which ismatingly received in a shallow recess inthe .cover die. When the ejector'dieis retracted, single-acting hydraulic cylinders V'lli-*move the adapter plate 50 'awayrom the stationary-head 'I8 :for a lim-Y ited distance, by ymeans ofrods 80. The casting 12 has. alreadybeen'withdrawn `from the cove die. Theejectordie is not shown.

The. arrangement of Fig'. 5 `using lan y'adapter plate as described, has the advantagethat the samel adapter-plate may be used withY a series of different dies. It avoids theneed for athick, bulky cover die, and the further needforexten` sive machining of the cover die to cut inthe tapered recess and to receive the knock-oil' rod. It has the additional convenience of remainingon the tie'rods 54, andA remaining with the operating mechanism 56 for the knock-off rod, and re'maining connected to the single-acting cylinders'l Which keepthe die closed during its initialmovement. Referringfnow to Fig.' 1, the apparatiiscomprises stationary front and back plates 82 and 84 connected bytie rods 86. The cover'die 88 is mounted lon an adapter plate slidable on Vtie rods 86. The ejector die 92, includingdie ibase 93, is mounted on. a movable plate 94 slidable on rods 86.' The die'base 93 has the usual ejector mechanism, not shown, for operating the ejector rods. The ejector die ris moved by a double-actingv hydraulic cylinder 96. 'A togglev` mechanism may be used between the cylinder and the movable plategll, but has been omitted here in order to simplify' the drawing. f

The shot lsleeve S is secured to front plate 82 and isprovided with an enlarged tapered end 98. The plunger l 90 is movedlby a double-acting hydraulicrcylinder v|02. It will be understoodthat the plunger, whenin retracted position, is to the right of the Yopening 104,' so that molten metal may be poured through the openingv into the sleeve, y y," y, i

Thef hydraulic cylinder 95 is controlled by a valve ,H36 Which is` operated by air cylinders |88 controlled by manual means H0. The cover die 88 Vand adapter plate 90 are initially moved to the leftv with the ejector die 92, bymeans of The cylinders l l2 are connected by pipingschematically shown at l I6, to the pipe H8 leading to the returncsideof cylinder 96. In this way, pressure and isrelieved When the dieis closed.

vinglinto said sleeve through the other end, said sleeve having a diameter at vleast as great as thatof the plunger all the wayto the open end Yof the sleeve, an adapter plate movable toward or away from the end of the sleeve in the of said sleevexbeing enlarged and tapered, the adapter plate having a tapered recessed seat matving 'with the enlarged tapered end of the sleeve,

a die having aV cover die portion carried on the opposite side of the adapter plate, and having an ejector die portion, said die having avmold 'cavityiand an-enclosed gate through the cover die, said adapter plate having a gate passage forming a continuation of the gate in the cover fasi-'2,666

direction.' ofthe axis ofthe sleeve, the end Y die, and knock-off -means mounted on the adapter *platev for movement therewith, said knock-off means being slidable tranversely of the axis of the sleeveinto'or outof said recessed seat.

4." Casting apparatus comprising a horizontal stationary shot' sleeve having an open end, said sleeve having an fopening to receive poured molding material inzliquid state, a plunger movable in saidsleevepast said opening, said sleeve `having a diameter atleast as great as that of y the plunger lallfthe way to the open end of the sleeve, an 'adapter' plate movable toward or away from the end of the sleeve in the direction .of the axis'of` the-sleeve, the end of said sleeve being enlargedand tapered, the adapter plate having a' taperedl recessed seat mating with the enlarged tapered end of the sleeve, a die having Ia`-cover die portion carried on the opposite side of the-adapterd plate," and having an ejector die portion, said die havingy a moldcavity and an enclosed horizontal lgate through the cover die portion, said adapter plate having a gate passage vforming a continuation of the gate in-the cover die, said gate beingvlocated above the ybottom of rtheV sleeve a distance suiilcient to prevent any 'of the-desiredcharge of liquid molding material from flowing into the gate and cavity before the plunger is operated, and knock-01T means movable transversely of the axisvof the sleeve into'or out of said recessed seat, said seatserving to lfacilitate dischargeba solidified slug of. rexcess molding material as well as alignment andflt of the mating parts. .5. .A casting machine for rapidly repeated casting cycles, said machine comprising a horizontal stationary shot sleeve'having an v.Open end, said sleeve having an opening to receive poured molding material in liquid state, a. plunger movable in said sleeve past said opening, said sleeve having, a diameter at least as great as that of the plunger all the way to the open end of the sleeve, anadapter plate movable toward or away/from theend of the sleeve in the direction of the axis ofthe' sleeve, a die having a cover die portion carried on the opposite side of the adapter plate, and having an ejector die portion, said die having a mold cavity and an enclosed horizontal gate through thecover die portion, said adapter plate "having, a gate formingga continuation of the gate in the cover die, said gate being located above the bottom of the sleeve a distance suffi- .cient to prevent any of the desired charge of .liquid molding material from flowingL into` the gate and cavity before the plunger is operated,

,andl knock-011 means -mounted ron the adapter f! 'pl'ate, for movement therewith, said-knock-off meansifheing movable transversely of ythe axis 'of the sleeve to break fromvthe gate a solidified zontal stationary shot sleeve having an open end,

said sleevehaving an opening at the top to receive-poured metal in liquid state, a plunger movable in said sleeve past said opening, said sleeve having a diameter at least as great as that ofthe plunger all the Way to the open end of the sleeve, an adapterplatemovable toward'or away from the endvof .the sleeve in the direction `of the-axis'of the sleeve, the end of said sleeve being enlarged and tapered,l the adapter plate having a tapered recessed seatA mating with the enlarged tapered'end of the sleeve, a die having a cover die portion carried on 4the opposite side of the adapter plate and having an ejector die portion, said die having a mold cavity and an enclosed horizontal gate through the cover kdie portion, said adapter plate having a gate passage formingv a continuation of the gate in the cover die, said gate being located above the bottom y of the sleeve a distance sufcient to prevent any the axisof the sleeve into the aforesaid tapered recessed seat in order tof break from the gate a solidified slug of excess metal formed by the end ofy the sleeve. Y v

'7. A die casting machine for rapidly repeated casting of metaLsaid machine comprising a horizontal stationary shot' sleeve having an open end, said sleevehaving an opening atthe top to receive poured metalin kliquid state, a plunger movable vin said sleeve past said opening, said sleeve-havinga diameter at least as great as that of the plunger all the way to the open end of the sleeve, anl adapterA plate movable toward or away from ythe end of the sleeve in the direction of the axis of the sleeve, the end of said sleeve being enlarged and tapered, the adapter plate having a tapered recessed seat mating' with the enlarged tapered end of the sleeve, a die having a cover die portion carried on the opposite side of the adapter plate and having an ejector die portion,

said die having a mold cavity andan enclosed horizontal kgate through the cover die portion, said adapter plate havin'g'a gate forming a continuation of the gate inthe cover die, said gate being located above the bottom of the sleeve a distance suflicient to prevent any of the desired kcharge of molten metal from flowing into the moving the adapter plate away from the shot sleeve, and means connecting said single-acting cylinders to the return side of the double-acting cylinder.

JOHN J. MCGARIGAL.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED STATES PATENTS Number Name Date 70,038 Smith Oct. 22, 1867 1,533,617 Soss et a1 Apr. 14, 1925 1,717,254 Polak June 11, 1929 1,898,671 Lester Feb. 21, 1933 1,900,863 Lester Mar. 7, 1933 1,909,253 Claus May 16, 1933 1,922,937 Eckert Aug. 15, 1933 Number Name Date 2,011,378 Sherman Aug. 13, 1935 2,060,224 Lannert Nov. 10, 1936 2,174,847 Stacy et al Oct, 3, 1939 2,244,816 Von Lynn June 10, 1941 2,259,781 Shaw et al Oct. 21, 1941 2,366,475 Bartholomew Jan.r2, 1945 2,372,177 Conner -'Mar. 27, 1945 2,411,999 Lester Dec. 3, 1946 FOREIGN PATENTS Number Country Date 536,111 Great Britain May 2, 1941 OTHER REFERENCES Modern Plastics, June 1944, page 105. Die Casting for Engineers, pub1ished41942 by the New Jersey Zinc Co., pages 12 and 13.

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