US1758113A - Forming metal castings - Google Patents

Description

May 13, 1930.

A. KADow 1,758,113 1 FORMING METAL CASTINGS Filed March 15, 1926 .uyust Kalow.

@Eng @um Patented May 13, Y1930 unir-sn sfr AUGUSTSKADOW; or ffToLzsn'o,V- (inlogfissreuron'v oF toivisx-rrri-LF 4\fro.WILBEB.: oW'ENE AND' v FOKRMINGL METAL iensrmes applicateurnieaQMamhw, 1926. yserial No. 94,715;

This invention relates to"castin'g,`gandmore particularly to casting metal and foompre'ssa ingthe Inet-al in the Acastingwhile!still'liot;

rlhe principal obje'ctofhthe invention is to provideamethodandapparatus byrneans of, which a very dense oastingnijay be'made, and by which a selected sur-face portion may be Condensed and smoothed.' Minor objects Y of the inventionwill appear as'thedeserijgj'-V tion proceeds. c

.115 what-diagrammatic vertioallsection throughv onelf'rm" of apparatus suitablejfbr casting Y bushings; Figs. 2 'and" are sections on the saine plane as Fig,V 1,'showi`ng portions"v of the apparatus in successive vstagesloi;the* oper-z at1o1`i;,andF1g,V 41s an enlargedsectionon Vthe same plane, showing thesamefparts as in Figs. 2 "and`3, in a vposition which 'they asi sume duringthe final' stage off-theoperation.

In carryingoutmy invention, a'ladle 1, or

, 5 other suitable receptacle,is'provided'for mol! tenfnfietal2,"V A`mold3, of suitabledesign, is

brought into working `relation Withthe molten metal, andthe moldbavty is' evacuated through suitable `passages lleading to any :21a suitable vmeansfor exhausting air andiotherL cavity there is sleeve :8.V A spring19esur` a'bushing 7. i Y

Arounl' plunger dyand2 abovey thek lmold rounds the sleeve and presses upward against a shoulder or flange 10 on the sleeve',normally raising the sleeve until the upper: side of the flange-contaetsaoovercplate 11. i Y

The plunger has ahead ,12 anda iiXed collar 13 between whichthere is a ehannelor `groove 14; A plunger 15 of va suitable press is provided with clamping 'jaws ladapted to enter groove 14;-

Plunger 6 is ofasize torfitsnugly Within sleeve 8 and inlet opening; KThereis a reduced portion l8extending'from a shoulder '19, normally level with the bottom of sleeve- 8, to a sh0ulder20 at the lower end ofthei Plungerf The, amount oileduton otros" tion 18 is i. exaggerated in the drawingsor purpose of fillustration. Thev n'orma'lpo'si- .tion offplunger'6 is :with its ,shoulderxQO slightly above inletl openingV 5, so as to form anarrow inlet slot beneath the lower endrof thefplunger.' L

' Prei'erablythisfinlet 'slot is narr'owenongh Softlfat thefmoldand theysoureeof supplyofmetal may be separatedfimmediately after' the moldis illedwitliout the metal running back outofthe mold by gravity.l Ifidesired, plunge'r may beraised higher duringiillin'g, leaving-a wider'inletsl-ot, to eXpedite thielillL iiig'aetion.` In the'vpreferredviorm, where.

onlya' narrow inlet"V slot is used; plunger 65 may Vrest on sleeve 8;duringtheillinggopera- Ward movement of fbothsuiiicie's to completely Volose'the inlet, "as showninFigiZ Iflthie. operation yis such vthat ,someV of i ther molten metal solidifies. aroundf the 'walls offlinlet i5 and beneath theendof"pliinger,4 6, thisnfreta-l,A

commonly Called thev gate, is shea-red oil? f from the eastingfwhenplunger 6l is lowered;

In theconstruction illustrated,V lugs are providedon the sides of the'- vmold, lwhich are y rested upon abutments; to support the l Y d mold-when pressure is exerted by vphuigerf 15, gases. Thereupn'; the".metal1r1sesv through y inlet opening 5 andaround plunger 6to' formv andthek mold *is held; r'mly, by means-not shown, against the spreadingpressure offth'e- .Y metal in the Inold cavity.

ItA will be understood,'ofcourse-, that a containerfholdling a comparatively; `large amount of meta-l may be -fu'sed insteadof the Y ladle showmzandthat the-pressing inajyY take plaoe'with'both containerl and mold iillingposition, o'rlthat either container or-Inoldor' bothrnay be moved vertically, laterally or both Vbetween the filling Yand pressinglopera` tion.y Where mold `and,Container" are'separat-V .ed between the lling' vandpressingsteps,E the mold may be supported) from beneath Preferably, vpressure is exertedy by plungerA 15 while atleast aplortion of-themetal iin' 'the eef moldeavity is 'liquidi and heavy pressure-is 1 usedQamounting to many ftons to the-l square inchiso that the-metalgin thegmold savtyhree' lOO maining liquid until pressure is applied is at once solidified by pressure raising the melting point, instead of being solidiedby cooling. The pressurevis maintaineduntil the metal is suiiiciently cool to remain solidl when the pressure is removed. VVherethe metal is fairly near the point of solidiiication before the pressure is applied, and the Vloss of heat is fairlyrapidit is p-ossibleto lower and raise the pressing plunger withno appreciable pause at Vits lowest point, but in cases where the metal is hotter when pressure is applied andzwhere loss of heat is compara-V tively slow, a dwell of the plungerat its lowest point, with Apressure applied, is requisite.

vImmediately after the mold is filled with metal, itis brought intov operative relation to lplunger 15,7if not previouslyin line there# Vwith.v

` casting.

When Vthe cast-ing has become solid, but whileit is still very l close toV themelting point,the action of plunger 15 is' reversed, and pluner 6 isY drawn upward out of the provided for. operating sleeve 8 and plunger 6, and the plunger might be provided with morethan one Vbreaching ring orshoulder,

ofsuccessively greaterdiameters. i If desired,

s suchbroaching rings vmight be provided. on v the. plunger abovethe mold cavity, and theV Vplunger might be drivenV down through the castingV to breach it; but ,-therarrangem'ent shown 4is simpler, and Yis preferable whereV it satisfactorily performsthe breachingv and Yburnishing operation.

i' It will be understood tliauwh'ere the na- Y Y f n y toceol after plunger g6iswithdr'awn, and

If the apparatus gf ture `of the finished article rendersthis-de sirablefa portion only ofthe interior of the'A article might be broached or burnishedy byA sliding the correspondingy portion of the plunger or 'moldcore therealong, and-a simiV lar burnishing action--couldbe exerted upon vrall lor.any"desire`d portion ofthe exterior'` of the castingby arranging'a slide to Iform that portionA ofthe mold` Vsurface.V and proe Y i viding mean-s for foreiblyfmoving the slidev se .within the mold.'

with respect to the Vcasting while itis still By-evacuating'the mold and introducing the metalipn thelmanner described therpmold is filled veryquickly andwith little entrappedair orgases.- iis advantageouslto ll the j leeve 8 vmoves with plunger` 6 until Y tioned above.

mold quickly, so that the entire casting may V.be of approximately the same temperature when pressure is applied, and absence of air or` gas reduces theopenings or pores in the metal. It is frequently desirable to coat some or all ofthe surfaces of themold cavity with a poor conductor of heat, to avoid too rapid chilling of the casting.

' The subjection of the metaltoheavy pres-k sure while setting prevents it from shrinking away from the moldl wallsgor plunger upon solidification, maintains intimate contact between 'the metal of the casting and the mold wall and so hastens transfer of heat and con-V sequent cooling of the casting, and tends toV prevent theformation of pores or openings in the metal and Vcloses those which do form, thus producing a very dense and uniform casting of the exact thickness determined by Y the spacing of the mold wall and plunger.

The final withdrawal of the plunger, with the'broaching and burnishing action of shoullder 20, while the metalis lstill'close to the'. Vmolding point, insures that, when the cast- Y ingis completed, its bore will be uniformly of the exact sizedetermined by said shoulder, land that the surface of the bore will be exceedingly dense and smooth, a result particularly `desirable vin bushings Most metalsV contract VVupon' solidifying.

The contraction is especially marked in lead 1 and ink alloys containing 'a considerable percentage of lead,but it .occursrinvother metals.,V Where a liquidcontracts upon solidilication,

`the .melting point is raisedby pressure. *For that reason, when metal in a mold. is liquid near the solidifyin liquid and. partially solid, heavy pressure raises the melting point andsolidiiies, or completes s'olidificationv of, thepmetah'as men- When ftheV solidiiication takes a Jtemperature, or partially,

place because ofpressurefsucient to raiseV the melting point above the temperature of the previously liquid `metal,iit is obviousthat the ,mold cavity? is completely filled.v upon solidiicationffand thereforeV contraction 'of the-casting.away'y fromfthe mold walls due V i tor shrinkageV in.. solidification V:is eliminated.-

` 0f course,the solidified casting Dcontinues shrinks Vwhile cooling. Y manipulated so that plunger 6 is withdrawn atsuch times as to4 leave thecastings at a sub-1 j I l When metal-:issolidified byfcooling, it tends to shrinkiineverydirectiomrand so `opens'up y i or Yenlarges poresthroughout its structure.

When metalis solidified by .pressure,thereis V a tendency. to reduce the@ size ,of any vpores e caused bygas, and Yto preventtheseparation pores. Y

-fof'occluded gasto form bubbles and openlup 'I urinaire very hot, the metal int-the casting yields to pressure,- so' that 'heavy- :pressure-'bronght"to bear lupon themaSting-the moldiimmedi- 4atelj7 :after setting :fills outthe-'rnioldcavity and reduces the size of pores infthezmetal.

Thus, someof the fben'eits ofmy process imay be realized when the 'metalisallowedY tofsolid- `'But there isla tendency forocoludedgases to.- separate` and-:form :bubbles aslthe metal cools,

lt'vhether or not itisunder Ipressure;and Vthere -isatendencyor impi'irities iii-.metals and in gredients insal'loys to segregate to someextent and destroy fthe 'uniformityfof the casting when lit cools andv-solidifiesgradually. 'For the best resi`1`l'ts,' therefore, its'lbestto .apply to the 'stiill inolten :metal v aj: pressure high enough tosolidiffy it.- Y

generally withmit materially clisplacing` the surface. `Afsirn.ilar,` ibut more-l etectual, action results :when the metal is .hotand the'rubbing ldisplaces the rsurfaoeaand condenses an' app reci able ilayerras Wellcas v:smo othifng the sur `faceskin. 1

The. sha-pe ofthe .-mold,' thevsha'peA size"l and :methodY of moving" :pressing plungers :and

iburnishiing slides; the .fmaterfial ietf-.Which vvarious portions .ot the ahold-are :madef,.the thickaness vof 'the' moldstalls,-A coatings of desired vflrindson portionsio t'hemold cavityft'heltemsure, and. Var-ions other-detailsmay be Varied in accordance iwithxtlie metal which .is-being u castr.- and `the size,-t.shape other desire qualities fof Vthe 'objectibeing termed.

llclaim:

l; "The'process AWlrr-iclr consists ina-withdraws.

fing air from one endr of: a" mold Jchamber, introducing Amolten metal into the iotherfend of in the first said end. .and wards thesecond said gend.

` i2. YThe process which consists infeiiacuating aimo-ldtcavityaand' lliing -it with frnoltenimetal, closing the'mo'ld and, 1Wlirilev portion of the imetal inthe `mold'. -is still '.molten, moving a portionv of :the moldiiigisnrfface of` thecavity 4inrxrard totpresssaid'metal.

The :processi which rconsists `ina a mold with .molten nnetalywhli'lethe metalisiat -least'partia'llyamolten subjecting it to'pressure i ent to fr a'ise; itsnelting point tand zconipl-ete its asolidicationnaid maintaining fthe pressure .until the .casting y.is-cooled Vbelow yfits normal melting point.v

- 4.' The process ofproducing castings -in mold Ahaving relatively movable sections,

Vwhich consists in evacuatingiA air from @the mold through a j oint between its sections, illing the mold' cavity 'with molten ,metal i and.Y

thereafter .pressing the vmetal 'in the cavity by :moving one of said sections inward along said4 j oint'and 4reducing thesizefof the cavity.

:e 5. i The process which .consists in evacuating y.arnold chamber and filling thechambenwith molten metal, While the metalisat-least par- .tiallymolten subjecting uit Eto pressure suflicient to raise its Y melting pointand complete uts'solidilication, and maintaining the pressure until the casting is-cooledbelow it'snormalimeltingnpo-nt.' l g: I

Q6. The' process 'which consists infcasting;

v`metalrfin a lmoldy and burnishing. a :portion :of

the surface of the castin-gfbymovement :of a

.portion :of- `itl-1e Amoldwall with respect tothe i casting. C v

- The process Which-consists iin-casting :fmetal and burnishing :by rubbing pressure@ portionoif the-surface .foj the castinggatter lit has,.solidified'fand while-it `is'stilfl-near its l Vit isfuold tofburnish .metal'iby rubbingfit, f

snel-ting' point.

8. A The.process-Which'fconsistsin evacuatingv9. The process WhichA `lconsists` finlilling/ Ymold chamber' With molten meta-l,- compressing themetal line-the chamber, andl after .the

f'metal has solidlilied'into-acasting, but while it is still hot,burnishing a portion ofthe sur- :face-thereof. perature atMhi-clithe fmetaleis: 'drawn into E Vl0. `iTlie process rWhichcensists in, evacuati- ,eingi a moldf-chainberandfirlling itvwithmo'lten- `fcolnp iesslo nl burnishingafportion lolli-'the surface; ci t f e metal'iwhile it issti'll het.

`21711". Theaprocessioiiorming a.busliing.,l wlnohfoonsists :ml-linganannular space'irifa imold `Witliizmolten-^1netalandsubjecting the' i12. vThe ilprocess 'O' :forming: a :bushing- .r Y

. Which consists' :in illirrg:` an annularfsp acefina #moldWrthmoltensnetalfrsnbjecting the metal,

:heitere iit-has completely solidifedgto rpmssfure sufficient' :to-1 raise its mlti-ngpoifnt i and vcon v rplete its-fsoflidiflication, and airain-,taining .fthe pressurefunt-il lremetalihas'cooled sufficiently to;` vretain- ;its solid :state @whenv the .f pressure Ais removed. i Y y i 13.? A :process *in ,accordance :withclafim'V 7,

inWhihh-thepressure is applied flongiitudinalilfylof; theeaKis-,rof thefbush-in'g. A

' c `lasllhe Ytprocess :of forming a cri whichconsists in casting a bushing,and compressingthe metal in the casting longitudiitis still hot, burnishing its interior surface.

l5. The process Vof `forming a bushing` which consists in casting a bushing and, while it is still hot, broaching andburnishing its interior surface.

16. The process of forming Va bushing tudinally and `breaching and burnishing its interior :surface while it is still hot.

17. The process which consistsin castingga bushing about a plunger having an enlarged end and, while the bushing isstill het, broaching and burnishing it byforcing the enlarged end of the'plunger therethrough.

18. Thepijocess Whi'clirconsists in casting a bushing about a plunger having an enlarged end, compressing the Casting about the plunger, and thereafter broaching and burnishing the casting by forcing saidienlarged end of the plunger therethrough.

` Y19. The process which consists `in filling molten metal into an annular space about a plunger having an enlarged end," exerting pressure upon the metal before it! isfullyl solidified, compressing it about said plunger Vand raising its `meltingV point to complete fmold, about a plungerV having an enlarged through said slit, and thereafter moving said enlarged end to close the'slitV andfshear oiV i thegggate.VV l T40 bis I lar space-and introducing' molten metal through saidslitto fill-said space, thereafter Ymoving said enlargedfendto close.said`-slit end, so that an inlet-slit is left between s aid enlarged end and the-*mold wall, evacuating p the-mold and iilling itwith molten metal 21'. The process of rormi'rng` a bushing,

a plunger havinganenlarged end, so that'V a Y slit is left between one'end of said moldspace and said enlarged end, evacuating said annu- .with` claimY 22,` al' sleeve surrounding the Vplunger-,a spring exerting'outward pressure on 'the sleeve, ay stopptolimitV the-outward'. rmovement of' thesleeve, and a collar on the 'plunger adapted to ,limitYV the*v inward movement of the plunger withY respect to the sleeve.' Y.

and-.compressing the metalfin'said spiace longitudinally, and thereafter, while the said 1' lmetal is still close-to, the melting point,

'f V'broaching and` burnishing the opening therein by passing saidenlarged end therethrough.

22. .In casting` apparatus, :a `mold having *i a casting space therein, a yplunger extending Vthrough the Asaidl space, aY collar surrounding the plunger, rand means" tof move said collar to compress the metalin said: space.

Y Yci IVwhich gas may be evacuatedffrom said space, a plunger extending through'the said space,

l23.5In casting apparatus, ajmold having a casting space thereinV andpassages through a collar surrounding the plunger, and means to move said 'collarv to compress the metal in said'spaee. ,i

24. In castin apparatus, a mold havinga casting space t erein, a plunger having an enlarged head, and means to move said plunger and reciprocate fits head completely through said space. A Y

25.- In casting apparatus, a mold having a casting space and aninlet opening, a plungerv adapted to extend through said space, a sleeve surrounding said plunger, the end of the sleeve forming a portion of the wall of said space, yielding means normally holding vthe sleeve in a predetermined position, connections lbetween. the sleeve and plunger adapted to hold the plunger Vwith its end adjacent the inletv opening when the sleeve is in said position, and means for forcing the v plunger andsleeve Vtowards said inlet.

26. lncastingapparatus, a mold havinga central b ore shouldered at one endto form va reduced-inlet opening, a sleeve in the other endl of tliebore having an opening the saine size aslsaid inlet, and a plunger extending throughsaid sleeve to'said inlet.

'27.' In .casting apparatus, a mold having a bore therethrough,a plunger working in said bore, and an annular casting space surrounding the plunger, theplunger being slightly reduced in cioss section where it is normally in register with the casting space.

28.* In apparatus in accordance with claim 20,- a'sleeve filling a space between the plunger and walls of the'mold bore at an end of said bore, the inner end ofthe sleeve forming one end of the casting space. l .29. Incasting apparatus, a mold havinga vcentral bore therethroughA and` evacuating opening, aplunger entering the'other end of said bore, and .meansv normally holdingthe which consists in positioning a permanent end of the-plunger spacedslightly from the mold,`having anannular casting space', about Vinlet opening 'leaving a narrow slot between the end of the plunger and the shoulder where"k 30.' In Vcasting apparatus in accordance' passages. leadinggfrom Vsaid bore, the bore Y being reduced at one end to form anV inlet iio` vertical bore reduced at its lower end to form an?inletcopening,evacuating passages' leading into said bore, a stop plate onthe upperV end of the mold, a sleeverin the Vupper end of the b0re,,a spring adapted normally to raise slightb7 less above said lower end up to ven Withrthe normal position of the bottom of the sleeve, and means for reciprocating saidV plunger. Y v

In testimony whereof, I have hereunto signed my name to this specification.

AUGUST KADoW.

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