US1644543A - Machine for casting dental parts and the like - Google Patents

Description

4192 d 1644543 Od? 7 R.Y.mcHMoND MACHINE FOR CASTING DENTAL PARTS AND THEVLIKE Filed Aug. 14. 1925 Patented Oct. 4, 1927.

v 'MACHINE FOR CASTING DENTAL EARTSLANDTH-E y Application file d" Augn The usual practice in. casting such, small articles iste' torm fujst` a Wax pattern ot the article, it the articlevissuch that it can be moulded in Wax. This` Wax pattern is -embedded ina suitable investment material containedl in a casting cylinder or mould container Whichis open-ended, top and bot-` y tom. rl`he investment material, which is of a porous nature, is in a plastic condition so that itr ts or invests closely the Wax pattern.`

Other smalll articles ot little yintrinsic value1 and which cannot conveniently be moulded in Wax, tor example, insects, leaves material in the casting cylinder in the same manner as the Wax patternis invested. v The casting cylinder; containing the Wax pattern or other article and investment, is then placed in a suitable furnace, the heat of which dries vthe investment and melts the. Wax pattern which is absorbedbythe in vestment and then burnt. out, While in the case o-t articles other than Wax patterns `the heat ot the furnace burns the article to carloon and finally to gaseous vcarbon dioxide. The hot casting'- cylind'er, containing the dried investment having a cavity the shape ot the Wax pattern or other article, is then placed in a lcasting` machine. Into a recess, previously madein the uppersurtace of the investment and from. the bottom of. which a sprue hole or conduit, leads into the cavity, a piece ot metal or eth1-er.suitable material, in excess ofthe quantity required* to tormthe article, is placed. by means et a. bloW-pipe tothis pieceV ot material soas to melt same.` The casting cylinder is then closed by'means of a cover plate or lidand vpressure' iiuidis.applied to l the-molten material in therrecessso asto drive same through the sprue hole into the cav-ity in the investmentythe air or. vapour in the cavity passingv into4 or through the investment material.

for example,

andy ferns, are embedded in the investment Heat is applied, usually f After the material vin st 14, A1925, serial no. 50,334,V and in creat Britain/anys, 1 e 2{7 A the cavity has i cooled and solidfied; it'i's removed. f"

ROBERT YOUNG RICHMOND, or? PAISLEY; scofrzcnnn-.rv

In' such casting machines the' following@ features are desirable :-1- The casting cylinder' should be closedasi steadily andas quickly as ,possiblejfatter the: metal or other material I reachedthe desiredmolten condition. The torce applied to close th cylinder 01" mould should'be greater than the torce-ap@v plied i cavity, open by the casting torce.

The casting torce` should not be'.zappli'edi i Y molten material' maybe blown'out oftherei l l till' after the mould' is` clos`ed,otherwise l,tliel y cess` in .the upper surface of the investment;

and shouldl be applied mould is, closed' to avoid' cooling" ogtjthemolten material. bel-0W the correct casting temperature. t i i The casting :torcev'should befcapable of; regulation and control independently ofthe mould losing lclosingy pressure may remain constant at, 'about 30; pounds persquarel inch While'the' casting pressure in some cases may 2'poundsper square inch and inl thercases may beabout; 15' or inch. The pressure desired :tordriving the molten materiali intoA the? cavity ,varies with force, for example, the mould f 20 poundsper 'square a immediately after the. i

be about: n 'I the nature' ,ott-he material and if 1to0 great a i l d-angerfofthe t 'n the recesshas' e5 toy drive the molten-material into. the; f

otherwise lthe mould maybe torcedy rial vandthe internal surface ofthe' casting cylinder, Withthe'cylinders or moul-d'con trainers generally'in usethere is,-`whe'nthje investment is dried, usually a small space between the cylinder Walls andthel investi ment Vdue, tojunequal change inthe size of theinvestment and mouldY container under the act-ion of the heat; leakafe'e ot the casting pressure fluid.

a castinirmachine in which vall the abovede Thisspace resultsliny y The object ot this invention is to construct Vsirable.features are present, which 'Willhe simple and comparatively cheap in construe# tion,` which will be easily vand"A expeditiously operated and' Which-Will be eiiicientj and'eco! nomic'al.

A ,castlng l machine construct-,edl `accordingv Y 1 tefthisv invention com pri'sesa piston adapted f to, operate Within a vertical:cylinderfandv H0 v a', `latfo on'which thecasting cylfind'erfis p aced, fitted horizontally atthe' up- V '..fper end Vfof the' piston rod.` A covery plateV for Alid incapable. ofjmofvement vin a verticaly vtwo-passages -nftheplug anda iplu-r n rality of 1ports, ,preferablysix ports, `in the fplugoasing or body, Oneof these ports is placed "in lcomuiuiiieation,'byl rine'ansl of a ipe,fyvith asource of lpressureflluid supply, v orjeigample, compressedair'or steain. An# I other of. thesebports is placedV iny communi- Yeatioin:by@lllsearlfS of` apipe, lwith the space .thev vertical ycylinder..below tlieprfpiston.

L bylflneans ofraf pipe '-an'd the passage` in the Y v vY.:glilgnl'lai`lxiiesmbei", yiwiththe und'ersurface.of j .thef' .cover ,platejor llid'against"which the fis` pipe: connection! and tubular 1uan@ierv gis... ,providedwwith :a sop coca Y a regulator *and va pressure gauge. port' is plaeed in communication, h imeansfof ap'ipe vvamil-'apassage in the- -atrfolfmrwith'thefupper surface yof the plat- 4forni onf..whi'ch the' casting'v cylinder rests.

`by mean'sgoff agfpipe, with. ava'cuum tank or` therssourceof suction.."siippl'y.v The reandthe twolpassages'in the plug larrengied `in' relationjto eachother that "thg-z--rstportion of the rotaryjmovenient fof y ,closes the exhaust` `port to.v the atxlnospherevzgandiadmitspressure fluid Ato the -.-Yer1eal foylignder.` bel'iw the4 piston Vsof as `to tliexzplatforin and close the upperfend nef; the .,Ca's'tiiigfcylinder; against the" under- ,-ldust portland@ the `pressure` fluid portato Y 1 thgkgnndersideiof the` pistonare so arranged fiirwrelation :to Veach iotherthat the exhaust movornentj of theplugo as.: to avoid 4any .""luddenpoj jerky vupwardr movement Vofi the pistonfand render thesaid upward movement steady, kand :more easily. controlled.

. .conixnunicationfybetweenthe vacuum source andthe uppergsurfacegot.y the platform so as-v '"felijmv,.airiancl.vapour` out of theV cavity :and 5ml-.1 rotary movement of. .the plus. ed* Apressure' fluid Vto the". `unde'rsuraoe ot vfthe Cover plate so AIVas'to drive theV inoltei'iyiua?l `feiliiiil;into.the: eavity y iii the *,investrnent from The opening oftlie'upperfsur 'of the platform to theisuet'ion from' the jvaciiiinifj'source Aisljslightlyprior to" the ad- IlisiiionV of`4 'pressure fluid' toi the` under vksur Another. portl `is l placedV in y communication,

npnijiendpf. the'fCastingl cylinder is made Vto fyApjnother 4Sport] is fplaced y in communication,

Y miaiaiertiethe exhaust Port .which is in 4 communication with thej atmosphere. Thesev open for ausliort durationjof diiringjgthe firstfportion yof Vthe' rotary Y y n duced pressure determined land indicated by` `1 the pressure gauge.. The casting pressure. therefore, can be Vreo'ulated and adjusted Further rotaryl movement `'of-the plug` opens (Dior through.' i the investment.` Further face of the coverplate so that air orv vapour does not. become lockedl in any narrow kor fine extremity Volf the cavity, while these two forces assist each other in performing` their' becoinescooled and solid. l*The rst portion of the return rotary movem'entvof the plug f closes the port admitting pressure fluid to *Y the under. surfaceof the cover plate and the portV leading to "the vaeuuin tank. Further rotary movement in this return directiony `closes* the portfleading to thek pressure fluid* supply and` opens the space below the piston in the vertical eylinder tothe exhaust. By rotating the plug'a little beyondgtli'e oil position the casting pressure `fluid may be used to open or unsealthe niould'so that the Y,

or iii-st position; thev casting "pressure Huid platform Lmay be returnedeasily to the down nient' downward,y that! is,` vthe l maintenance'f of the casting' pressurer under the cover plate.V4

unseals tlieniould when the sealing pressure is removed. fWhen ,theeasting pressure is smelly' ior `4example, about v2` pounds Y perl square inch, it may not besuiiicie'nt to unseal the mould but this pressure rmay be -increased'for this purpose. by operating the pressure regulator up to. themaxiinuin preswo piston is "greater .than 'the cross-.sectionall i sure vin the'supply pipe. vThe area of. the

area oi the under surface of the' cover plate y withintheV upper end o1n` the casting cylinder so Athat Vthe mould closing;F force is always. fg'reater than the casting iforce, even should the castingpressure', in` pounds per square inelnbe the same as" the mould closing pres'- sure,` in pounds per square inch( The mould closingz pressure'v may' bethe same as the l pressure in theV main pressuref'luid supply pipeV and if this pressure `is toov great for a castingipre'ssure itVV is reduced by means of the pressure regulator and 'the Vdesired re-V with 4considerable Vdegree of. accuracy. Shouldtherebc any leakage of the casting i'iuid between theiiivestineut and the casting' eyliuder 'accurate casting. pressure will uur become inaccuratefivhenadmittedfunderthe cover plate. To avoid this source of inaccuraovi the vinterior surface. ofr therv castingr Y cylinder.'islprovided with a plurality ol" premiesv andvridges., forV exan'iple, for con# venie'nce fin manufacture `"the interior surface offthecastiiig cylinder'jniay *bel screw7 threaded;` 'The investment 'material` illing the rscre'wthreads or grooves makes the joint between the Y investmentV material and the der 1 provided means ,of which 'the machine'may be ses casting cylinder comparatively vand substantially tight. i formation of the interior of the casting cylinder assists in retaining .the dried investment in the cylinder. When there is aspace between the cylinder andthe investment there is a dangerot the investment Jtalling outo the cylinder when same is transported 'from the furnace, In order that othersskilled in the art to which this invention relates may properly understand the same I have hereunto appended one sheet ci' explanatory' drawings in which Figurel is a .sectional ,elevation of acastingmachine as constructed according to this invention, while' Figures 2, 3 and 4, are transverse sectional elevations of the vplug-cock showing same in three positions.

Referring to'these drawings In carrying this invention into effect, or practice a casting machine comprises a cylinwith a'soleor base plate 2 by cured to a benchQwork-table o r the like. `A

. by 'means loir' Ya n'ut p position occupi a spherical portion 16,. is

piston 3, secured on 'the endy oap-iston rod 4 whichpasses through theupper end plate 5 of the cylinder,. is adapted to reciprocate within the cylinder 1. The cylinder is provided. with an inlet 4vand exhaust port 6' at port or ports 7 at 7 ensures that the the piston is alits lower end andlwith a its upper end. This port space in the cylinder above. ways open. vent any back pressure or cushioning action in the cylidner when the pistony is raised. The'uppe'r end of the piston rod is provided with a platform or the like 8 having `a iange 9' all round its periphery so as to form a recess 1Q. Intothis recess as washer 11 of asbestos or other suitable heat resist-` ing j'ointing material is placed. In theA platfform' and leading from the bottom ofthe recess to the periphery a passage'or duit 12 is provided. An'upper,` cross-head orthe like 13 supported by pillars 14 is Var-V ranged a suitable distance above Vthe highest l.

ed by `the platform 8'." A tubular member 15, having arranged vertically above and in alignment withthe' piston rod V4. This tubularmember l'passes through the Vcrosshead 13 A'and is retained in position centrai stem or spaces 18 are yprovided between the member and the nut 17 vand between the member 15 vand the crosshead 13. From this 'construction it is obvious that aswivel connecandthe K be later described. A cover plate orglid 19 is iitted, preferably byl scre'rvingnvonf to the lower end othe tubular member tie-crosshead '13 andl is providedl lwith a V'flange 2O round its periphery Vforming a` re- 'cess into `'which a wa'sher'QQ o asbestos Further this construction or to the atmosphere so as to pre- Y conor the like 1'? Clearance r 15 below or thelike is inserted. The passage V23 in@` ing an 'operating' handle or' knob '2? is fitted iny a. suitable4 position, preferably tothe side of thecylinder 1.l lThis plugtv cock isprovidedwith twoy passages 28 and 'as shown l15 above the erossf` head 13. A plug'rock vvor the like .26"liav-I and a plurality of ports,k preferably six I ports, y 30, 31, 32, connected toa main'source of pressure fluid 33, 34 and 35. `Port 30 is .Q15 y supply,jsuch;as anfair compressor' orcomef. pressed air tank or to-"a 'boiler orfother l source of steam simply. by means Lota pipe' 36. Port 31 isfconnected,by means-cfa pipe?.V to the inlet and vthe cylinder 1. Port 32kisc'onnecteddl by means lof apipe 38, to the passage'y Qin the tubular member 15.'v This pipe f3 8 is provided `with a pressure regulator 39, while the passage 23' isprovidedwith va pressure" gauge 40.

Vof a pipe 41, to the .passa-ge `12 in vthe plat-v form 8. Port 34 is connected-hfbyA means 'of ya pipe 42',v withk a vacuum tankfor the like,

while portA 35 Opensto the-atmosphereby' means of a'pipe 43.

The casting cylinder or mould containerv exhaustport i 6 of Port-"3 3 vis connected, bym'eans rons'ists Otan open-ended cylinder ,44h-ailing its interior surface formed with ridges'an'd grooves orl screw threadsf so that when the cylinder is illed'with the'investmenft'-material the latterwill'seepwithin thesegrooves or ridges toestablish' a vclosed jointurebei' vtween the internal-surface of :the cylinder "and the investment material whereby 'the fluid under pressure.,Willbecaused topass through vthe investment` v the walls of the y cylinder.v

` 4material andA pre-A vented from passing between the( same and. 1

shown .placed upon: the platforin 48=which is' in itslowest position'iready to be raised' to.

close the mould. yVJhen the cylinder israised its upper end willbeclosed byfmeans' ci` the cover 20 and owing to the swivel Vconnection between `the member 15 which support the cover and the'crossheadthe ccver will automatically adjust itseltupon-tlie' cylinder.

The cylinder .44' contains @the investment i material" 46 having a" cavity'. 47 k'-i'ormed by Vthe wax pattern or'otherarticle' which hasV been' melted, .bin'ntifandjabsorbedV bythe inyfestmen,t1. 46.4 piece-got."

in the upper! surface .of ythe investment-and metal orf" other '.materialf'48 has been place'dinthe recess49 fir i 17,644,545,

V1 1 VVVlineltedl-ready"to be forced through the s'prue and the` plug-cock 26f returned togits first Y @hole 50 into the cavity`;47.f .f v Y f i f1.' Thismachine may he operated to cast by cylinder 44 tobe placed in position as shown @differenti methods, forfexample, Vthe m olten Vby'Figure l. v

the-'cavity ,47 by pressure lnidacti'ng onthe theplugecock 26 from/the position shown'A fsalnef--l ThisY pressure'fluid; may Vbe by Figure 12 tothe position shown by'ilgure compressed air or. steam conducted tothe 3. [This raisesfthevplatform and closes the f 'Inachil'iefroma source ofsnpply `outside the Y mould vas described above 'in 4 reference to the,`

generated by the frnxfl'ohine.",.fnstead'ofpres-y plug-cock 26 admits thefcastingf ,pressure sliegluid acting` upon the top `surfacesofthe fluid above' the molten material '48 l.and j-inolt-en material 'so as vto drive sanne into the drives same intoA the Cavity 47. VPrior to the` tinnfmechod; i

j setfthemachine:tocasgt at .the. desired presassist each* other in drawingv the molten-' Sure-:and-this lis done by closing 4the'ustop-V ymaterial into-'fthe cavity 47.4 `lhen it is g l*the passagefQS in thetubular memdrive the molten material into the cavity 475 ,5.1

ti-1lport 30,-pa`ssage29;1port 132,* pe. 38, 25 closed. The castingcylinder;V hot it'ron'u pressure'regulator3 9andvpressure @redirige/,40 ,the furnace, WhenplaC-ed against the Wet ,onlyfare'in y,communication withl each other *Washer 22V generates' suiiicientsteain toV per- *f ldwiththe'pressuregud:Simply pip. form this operation.y This-methody 'of castli' l at 1gg theypressure regulator 39 the itis desired to y draw by suction the molten desired;pressurejisindicated by-the gauge 'material-48mm the cavity y47 yWithout-fthefr 1lifgproyideditxmlyh-bG-leftopen the closed. and when Sit is desired to :dispense machine 'set-by. plaoingadummy cylinderlon lwith the suction and touse the 4pressure duid @the 'platfonnjrS 'and nrovingthe plug-cockv only on the'top ofv themolten material the .'flffi'l'rlfthe position shownpby Figure 2 tothe pip-e 'connections Vto the Vacuum sourceV isv positiorflshownlby `3j I ,I'L'Fgure 2 disconnected. Y the-compressed airginlet port- 30 andtheport 4 I,.c1ai1n v maehineffgWhen rotary movement 'to the1 mounted 'upon said support,y acasting;- cylin-l f 11min-uid?Sdmtd thllQughi-:port 30,'1 PaS-1' 'means for;v moving'sai'd.platform Whereb)7 i n ilindf `1 b elOW i. theff'PStOD f 3 i and i laiedf v 'mould-'closing position, means Vfor supplying Same-Uutheglppel 6nd Ofi'he'dummv 0311111- 'a castingorce into said cylinder and meansV mentoftheplng-cock 26 ytothe position; by'saidrcylinder will VAbe,"caused jlto assume "n fpassageZf andtheiundersidge V( )fthe Washerwinn afcastinggforce.into,saidfcylinderand a `"surefluid supplyiport and rotatable Pivalve mounted upon said support y Y 28' 'the lPIVGSSUIE ffQffjvWhlCh --lS for jointly-andindependently controlling" ndicated is regg-greatwasting fit" is; reduced aIldT-regulated by 'v the :qregul atoreV 39. I. After-f the castinv gbinationa support, .a platform, ay fluid actu` l position the' machine isready for the casting 'fxnafterialiin the recess49 m'ayibedriveninto e The Vfirst operation inca`st ing g` islto operateI 70 'f fneohine' jfThis pressureuid-maybe steam dummy..f c 'ylinderl.` 'Further rotation of the 75.

oavity=47 the molten jm'ateria148 may-. be admission of the vca stingr-ipressurefluid suc-Q ,v .f drafwngintothe ca-Vity47 bysuctionactlng" VVtion fromV the ,dport 34fandvac'uu1n source 80 Y "The fi St rprelimrinviy opeitionis to The casting pressure Huid and the suction 8 5 benl .The-pliug-cock 126 is f thenturned the' washer 22 iswetted vand the 'stopfcock 90 i( The,de`sir-ad` pressure. is obtainedby loperf ing is known asthefwet method. When 95;@V

.-.\ 40 Whenfstopicock '251g Qnot providedil or aid "offpressure Huid the stop-cock25 is O il A i fftd thelyacuuxn Vsourceare y'closed so that 1; A castingmachine comprisingn corn- 105Vv ;there1sj-no"pressure fluidnor suction in thefbination support, ya platform mo'ilably i 1 position `.horWr'lLb- Figure YB,takes.place pres- Yder oarriedby's'aid platform, fluid actuated, V Y Y l:di?,, the2passage28T ,':Furtlierrotaryfmovei-V djmemsgfomoving Said platform Whe e 1 2o -shwnlbyFigu'efOpens POI'VSQ'PGfSJ'@.niouldflsin positiilme'ans for" Suppy- 'i i Y 125 bythe pressure gauge lf-thesaid fluid actuated `'means and said Vcasting,"v i

3.- Acasting machine comprising in com- I y Y f fluid actuated means to a closed position, means for supplying ay casting force into said cylinder,

-means for supplyingy a casting force to said cylinder, means for creating a suction within said cylinder and means for jointly controlling said mould closing forces and said means for creating a suction within the cylinder.

5. A casting machine comprising in comnination a vertically movable mould cylinder, for moving said cylinder a single valve for controlling said fluid actuated and force supplying means and a pressure regulating means arranged within said casting force supply means adapted to lloe actuatedV independently of said valve. i

6. A casting machine comprising a casting Vcylinder adapted to contain investment material, a mould cover plate forsaid cylinder,

Y a movable platform for supporting said cylinder, lmeans whereby pressure fluids may be admitted below said cover plate into Vsaid cylinder, and means whereby leakage ofsaid pressure fluid between said investment material, contained within saidcylinder, andthe inner walls of said cylinder is prevented.

7 A casting machine comprising a mould cylinder adapted to contain investment material, means for supplying a casting force to one end of said cylinder, means kfor causing 'a suction at the opposite end of said cylinder and a plurality of projections arranged upon the inner wall of said lcylinder whereby leakage between the investment material and the inner walls of said cylinder is prevented.

movably mounted and casting 8. A casting machine of the character described comprising a support, a movable platform mounted upon said support, acasting cylinder carried by said platform, ai mould cover plate suspended from andre-A tained against vertical ymovement by said support, and means whereby said covery plate j will adjust itself automatically to the upper endof said casting cylinder when the latter contacts therewith substantially as and for. j

" co 9. A casting machine of the character de-v f the purpose specified'.

scribed comprising a support, 4a platform upon said ing cylinder carried by saidl platform, va cross head carried by said support, a cover plate pivotally connected to saidrcross head whereby the same will automatically adjust support, a cast-` itself to the upper end of said casting cylinder, and means whereby a casting force maybe supplied through said cover plate into said casting cylinder substantially. as and for the purpose specified. j y f 10. A casting machine of the character described comprising a support, a platform movably mounted upon said support, a casting cylinder carried by said platform, i a cross head carried by said support, a .tubular stem, lar stem and crosshead, and a cover .plate carried by the lower end of said stem.V`

11.. Acasting vmachine of the character described comprising a base, a vertical cyll inder formed with said base, a piston.

a swivel connection between s aidvtubumounted forreciprocation within said cyly inder, a platform carried by said cylinder, a casting cylinder carried by saidplatform, pillars carried by the vertical cylinder, a cross head supported by said pillars, a cover plate secured to said cross head, means forv supplying a casting force through said cover plate into said casting cylinder, said' platform having a Vsuction passage way vtherein I communicating with the casting cylinder, f i

and a single control whereby fluid pressure f ksubsequently 'a lcasting force and suctionv may first enter said vertical cylinderv and created within' said casting cylinder.

ROBERT YOUNG RICHMOND.,y

CER'HTECATE @E GRREGTWN.

Patent No. 1,644,543. Granted ctober 4, 1927, to

RBER'E YUNG RICEMND.

It is hereby certified that error appears in the printed specification of the above numbered patent requiring corr-sation as ioiiows: Page l, in the heading to the printed speoiiioatiori, iiiie, date oi iiiiag application in Great Britain, for "July 9, i927" reati ",iaiy 9, @25% and that the said Letters Patent should be reati with this correction tiieraiii that the same may conform to the record oi the oase in the Patent iiice.

Signed and sealed. this 24th day oi January, Pi. D. i928.

M. J. Moore,

Seal. Acting Commissioner' of Patents.

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