US2420756A - Method of making patterns - Google Patents

Description

May 2o, 1947.

R. J. MILLER i METHOD 0F MAKING PATTERNS Filed Aug. 14, 1942 2 Sheets-Sheetl May 20, 1947.. R. J. MILLER y 2,420,756

METHOD oF MAKING PATTERNS l Filed Aug. 14, 1942 2 sheets-sheet 2 INVENToR.

EQ yMan/o J/V/L fe Patented May 20, 1947 PATENT 4crm METHOD' OF MAKIN Gr` PATTERNS "Raymond "J Miller, Detroit, `"lliiehi, assig'nor, by

direct and m'esneassignmentslto MillerfEni- Detroit,Micnyarcorpora- -neein'g "Corporation,

l tion of 'Michigan `Amilicauml.August 14, 1942,1sefia1rN0.'454;831

"'2'Clai'ms. (Cl. 22e-P195) `ll1is invention lrelates ltojthe art .of casting and more particularly `to the "making of gaccurately 'aligned vertically' spaced matched pattern segmentsof articles'havingsymmetrical or unsymmetrical contours, including :those where nosimple parting iineis available onthe article to be reproduced.

Heretofore in the 'formation of matched gpatterns great ldiiiculty vhas .been experienced in forming `and accurately aligning the vertically spaced segments of the1pat`tern with a'sum'cient degree of accuracy to producesatis'factory castings. 'Inthe makingof these matched pattern segments it has been `icustomaryto form each segmentseparately toiemboly the .contours of vertically spaced "sections of the article to be reproduced. `Aereat deal of"han"d andmachine Work 'has -thereforelbeennecessary to accurately icrmtlie'pattern ksections .,tofthe shape and contour of tl'ie'article to'be cast.

In the so`calle`d .Capaco process of casting, plasteris used La-sthe moldbody. The cope and dra'g sections "of .the` n1oldhavinef"A plaster therein are .brought 'into *contact with a die Vpattern formed rof combined pattern and 'flask elements.

The 'diepatte'rn maybe df any desired size and fis preferably subdivided into .arplurality of smaller segments :to 1,provide greater iiexibility in the casting operation. Asingle pattern may occupy oneormore oftliese smaller sections and f many diifererit pattern vforms may thus be used simultaneously in the diepattern.

"Each 4'pattern ,segment vvh'e'tlier it be Ya ,single segment of 'the 'die pattern ort-a 4,larger ,pattern extending Lover several df fthe ldie .pattern segmentsxnus'tlbe accurately machined-to veryclose tdleria'nces to t'witliin Itheflaskportion of the die patternto raccu'rat'e'li/ align the matched'patternsin Vt`1r'i1`^e`,e planes andtlo avoid thejformation betiveenthepattern blocks of cracks into W'hh the mold substance could 110W.

A great/'deal :of tirdand elToItQi's .thuslr'eqli'red in'the "formation ,di eac'liof the pattern segments because eacnpatteisn'block must be individually machined accurately to l.a gpredetermined size afterithepatte'rn liasbeen 'foizrriedtliereon Undesirable [expense and delay are .thusiinyolved in the formation of 'the ,pattern equipment.

In 'the "Capaco V'process rolds having plastei` andotfierdry elements to provide a 'desireddegres oi strength are mixed with somewhat afan excess of moisture and areibrou-ght into contact with-fthe dief'pa-ttern. The-#plaster mold A assumes tiie'pontour-df the pittern'and after a substantially `predetern-lined set 'has been feifected Xtlfie mold is `ren-ioved "from the -di-e fpattern rand is subjected to a drying or baking process whereby virtually l'all of themo'isture fin the Aplaster mold is Vfdissipated. "The re`sltin'g plaster imld has ya very smooth glass-like #surface accurately conforming to 'l the contour of the diefpattern.

EUuelto 'tliefeXcess `of 'moisture infthe formation of `-tlie plaster molds, the-'dried molds 4are qiiite porous v'permit the ready escape o'f entraiiied air Vanilla-ases fformed dilringthe casting operation. The molds are Avirtually lbone fdr-y -and therefore substantially no stearnisfforrne'd as the molten lalloy or 4metal 'is Vpoured 'into the 4assemtied-molos.

Yllheingredients -dfthe yI'lasterInolds re;ieislcli as* tdl provide a fm'ld' having suiicient-streneth -to support" the molten alloy f or lmetal iwvl-ien lpoured but arenet-suiiicientlystrong tol resistthe'forces exerted vthereon' Aduring -`the :shrinkage -o'f the castings after solidific-ation, These moldstcle lapse or break up as the metal l-slirinlss whereby cooling stressesy are avoided in the castings;

fDue'to'ftne' 'smoothsurface of the plaster molds the articles i cast have exceptionally `vsrnootlr'surfaces land' can -generallyfbe usedfvvithout4 anymacliining Aoperations `because the 'castings follow the `shape and contours *ofthe vpatterns Withra high-degree-of accuracy.`

MyK coepending'application Serial "No. 42'1;1l5, ledllecember 1, 1'94'1* discloses a'process Wherebymatchedpatterns of 'articles having variously contouredvertically spaced sections kcan Vbe accnrately andeconomically reproduced'witha l'igh degree of"'accurac yl In `that developmentfernale impressions of "vertically 4spaced portions ofthe article to be reproduced are -formed in Aa substance possessing the `cl'raracteristics of accurately conforming to 'the contour vof Va 'nrodel o'f an article vto bereproduced "Without injury "to the surface of the modeL and male production patterns `are 'formed of :a moldable substance, from 'these female impressions. .The matched pattern segments maybe accurately located'witlo reference to eachother by suitable `loca'tors ior dowel pins positioned Linthe die block outside of the pattern contour. y In the use of these matched'patternsin"certain types of casting equipment such as 'the Capaeo process referred' t0 Labove, it lis necessary toa'ccuratelymachirietheexteriorpattern-carrying blocks to a 'predetermined size yand shape. Considerable time Aand effort is `required tio-preparelthe patterns `for use after they havebeen completely formed.v i l The instant invention `is fdirected more .par-

ticularly to a method of forming matched pattern segments on blocks of accurate predetermined size and shape in such a manner that the minimum time and effort will be required to prepare the patterns for use in various types of casting equipment after thev pattern segments have been formed.

An object of this invention is therefore to provide matched pattern segments formed in accurately dimensioned frames.

A further object of the invention is to provide pattern segments formed by a reproduction process in accurately dimensioned frames adapted to be accurately aligned vertically during the formation of the pattern segments to form accurate matched patterns.

Another object is to provide matched pattern equipment formed in accurately dimensioned frames adapted to be aligned vertically by means of a right angle to provide matched pattern segments in the frame members by a reproduction process.

Yet another object of the invention is to provide a production plate pattern by a reproduction method in a frame formed to accurate dimensions by superimposing a production pattern frame and a riser frame on a female impression frame and accurately aligning the frames vertically in a right angle, and thereafter limiting the vertical height of the pattern frame by removing the riser to accurately locate the bottom of the production pattern.

Another object is to form patterns by a reproduction method in accurately dimensioned frames whereby the pattern is accurately aligned in three planes with the model to be reproduced.

A further object is to provide an improved method of accurately controlling the over-all dimensions and vertical height of a pattern block for use in casting operations wherein multiple closely spaced patterns are employed.

Yet another object of this invention resides in the formation of production patterns on accurately finished blocks adapted to meet in surface contactl whereby a single mold impression may be formed from a plurality of patterns.

Another object is to provide pattern supporting frames cf accurate dimension having inter nal means to` locate and support the pattern at a desired height with reference to the frame.

Other objects and advantages of this invention will be apparent from the following detailed description considered in connection with the accompanying drawings, submitted for purposes of illustration only, and not intended to define the scope of the invention, reference being had for that purpose to the subjoined claims.

In the drawings wherein similar reference characters refer to similar parts throughout the several Views:

Fig. 1 is a side elevation of a master pattern o-r model of a typical article to be reproduced.

. Fig. 2 is a plan view of the pattern or model illustrated in Fig. l.

Fig. 3 is a view similar to Fig. 1 showing the pattern with parting material applied thereto to eliminate back draft.

Fig. 4 is a perspective view of a frame member adapted to be positioned on the parting material of Fig. 3 to surround the exposed portion ,of the pattern or model it is desired to produce.

Fig. 5 is a sectional view taken substantially on line 5-5 of Fig. 4, looking in the direction of the arrows.

Fig. 6 is a sectional view illustrating the frame of Fig. 4 positioned in assembled relation with the pattern or model of Fig. 3 and having a moldable substance applied therein to form a female impression of the exposed portion of the pattern or model of Fig. 3.

Fig. 7 is a sectional view similar to Fig. 6 showing the article in the inverted position with the parting material applied in the step of Fig. 3 removed and a moldable substance applied to the exposed portion of the model to form a female impression in a frame of the remainder of the pattern or model to be reproduced.

Fig. 8 is a sectional View of the female impression formed by the step illustrated in Fig. 6 with a pattern frame and a riser frame in position thereon preparatory to forming a male match pattern from the female impression.

Fig. 9 is an inverted sectional view of the male pattern formed by applying t0 the female impression of Fig. 3 a moldable substance possessing the characteristics of filling the space within the frames of Fig. 8 without fusing with the material of which the female impression is formed.

Fig. 10 is a View similar to Fig. 9 showing the riser removed and the pattern body section threaded preparatory to applying it to casting equipment.

Fig. 11 is a longitudinal sectional view of molding equipment showing a plurality of production pattern members in place.

Fig. 12 is a perspective view of a modified form of pattern frame member.

Fig. 13 is a sectional view taken substantially on the line i3-I3 of Fig. 12.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various Ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation.

Figs. 1 and 2 are illustrative of a master pattern or model lil of any article which it is desired to form by a casting process. The pattern or model Ill may be formed of any desired material such as wood, plaster, metal, alloy or a composition and may be symmetrical or unsymmetrical in form and need not have a straight parting line.

The pattern or model i0 may for example represent a hose tting having an internally threaded shank I2 communicating with a transversely extended bore by way of a hollow passageway extended through a neck I6. The fitting may have a hexagonal ywrench engaging portion VI8 and a boss 20 whereby it may be secured in place. Cores may be employed to form the hollow sections.

In the formation of matched patterns for reproducing the article, the master pattern or model I!) may be embedded in parting material 22 positioned on a plate 24 as illustrated in Fig. 3. The parting material 22 may be built up around the boss 26 as illustrated at 26 to eliminate back draft on the pattern or model I0 and to divide the article into vertically spaced segments adapted to be duplicated on the pattern equipment.

After the article to be reproduced has been embedded in the parting material as illustrated in Fig. 3, a generally rectangular shaped frame 30 having smooth external surfaces 32 and 34 zaza-rse preferably disposed .at frighteangrles-toifeach other and accurately machined rto1 desiredkpredeteremined dimension-sl is vpositionednon fthe'rpartingi material :22:13u: surround the pattern "or model; |81

as illustrated Fig. J6.

A moldabie substance v3t-fpossessi-mrg the char acteristics of 1 accurately conformfiing.` to `the fei:-

posed surfaces-of thelmaster pattern or'modeli la f Without iniuring tl-ref` surfaces thereof may: be introduced `into the :space within the', .framework Silto`V formwavfenzl'al'e` impression of the exposed portion of tfhe pattern or lmodel lila rThe subs-tance: 36 maybe `any suitable material t possessing the enumerated cliaracteris-tics,` suoi-lU for `example as: plaster; alloys-.- ineta-lsf, plalstieorA granular materials: Where-thepattern lBito-fbe'i reproduced is formed of Woodifsuchzfor example asmahogany or pine, the-rsubstancef; if an `alloy or metaL should possess't-he "characteristics o'f.Y

owirig under temperature conditionsV not induriousto thes-uiface of the Wood 'of Whichthepate tern or model YI is formed.

Illustrationsiof desirable alloyszffor this purpose.` are Cerrobend having a pouring temperature. `oi.

alloys `possess 1 the scharacteristics of ilowirrg andYV hardening un-dercsubstantialiy: constant 'volume condition-s.

Tine substance 35: .may ifA desired.` bei *a* i plastic, either of the thermoplastic or thermo'settingtype.,

and preferably` embodies` the characteristic "3f" negligible variation :of:` volume 4iupon'solidii'ca'tion: The substance-36mm also Abe 'a plaster For gypsum or any ne grained material possessihg'thecliaiaoteristicf of` accurately` following" the? cohtourof the master model 'iii'sucii val manmerthat the 'pate tern may be" removed to leave-a female impresision S-'If'of the illustratiyepattervfr or article W'. Suitable allowancey should' be ma'deainftlie forma`` stance 33.`

The substance' 36-5 may beranchored or.y secured Within the frame by means of an inward-1y direct-ed bead'or flangeA 38: fornmd` inth inside walls 32 and 34- of` the ramevmember 39.. After the substance y35:hasfbeen applied i to ztlie master pattern or model @win the'marmer"illirstratedxinA Eig. 6 they assembly maybeI invertedf and ti'eA posed tlieportion of the pattern I!) formerly covered by the parting material'Ziarldli.`

Another" frame member '40preferably of` the same external dmeinsionsasthelframe `v 30 .isnbwf superimposed on the: frame '3ilr as' illustrated The frames 3l) and 43 are accurately Fig, 7. aligned' with `each other` byfmeans cifra right angle 42Vpositioned: tov engage ktl're-l side Vandi eridwalls" ofV eachoi theframes all` and 'to'accuratey aiign` their vertcalfedges:

The. portion :of the patternor article HJ fore merly covered by the partinglmaterial222:and11 26 is-now exposedilab'ove theisubs'tanceS-'Witliin the frame 40. itl-substance` similar tosthesub stance 35 butnot fusibletherewith;` byreason of its physical characteristics-l or by reason of the addition'of apartir-1g-lrrateriaLv isrintroduced intoithe space Within thefralneto cfivexzthev exposed pbrtiowof the pattern: 10i toaforrn` 'aV-feiexposediportionzfof thepattern lil; The substance means-"ofi inwardly 'extended `ioeadfcr flange lliefor-Inedin tliie frame member `BIJ; y

The frames Si) and 4i! may now be separated:

and' time pattern' por modellil` removed to expose the;1 `"l-emai'e; impressions 31. and #46' iaith-'er 'substanees Pitti` 'and fil-ofthe: frames 30 :and 41| `respec tively; These" female impressions accurately con- 36': andiA 'Mg-aimed the frames: rarrdv .l0-f respecL tively.V

Male matched patterrii` segments accurately conforming to the sliape fandvcontour of thepat'f cally horizontally additional frames l 'of the" samef external: dimensions' as :the frames 30a and Y 40:"may be employed;` `For exar'nple;` the iframe 30 having tiiefemale'impressifon 3?! inthe' substanoewfi` lmay be again positioned in the right angle-:42 as illustrated inligr. 8: .lr-male pattern framewdfoi til-lez same longitudinal and: lateral dimensions asI the fra-me 3F issuper-imposed' on the fram-e @and isaccurately aligned therewith by means of the .right angie 42?.'u

Ariser `frame s52- having 'an iriysrardiyloisetpor-A1 tion 54 positioned tohli'e'insi'de` `oi' 'the inner. 'efdgev 56E-of the frame member '5% -Inaybesup'erimpoed on time pattern frame Eile The cuterV edgesn fof tli'erise :frame 52 'may beaii'gned with" the 'female'4 impression frame 3'@ fand the maiefpatt'ernf iframes'A The riser framev5121is preferably'iprovided'Witha tapered` inner wall 543 -towfaci'litateremova'l of the" riser frame` from 'thev 'substance of whichthe` male pattern 4segment' l is formed A substanceiicapable of illingitheiernale pression 31 and the space within the pattern-and risen frames 5U arrd'BZ respectively Withoutfusing; With-1 theosubstarlce" i which tide female impression is iormed'isvintroduced thereirto The substance 63 may p ossess'` generally silnilar 'chareacteristi'cs as thersubstancer S-"and may; if *desiredbe of the same materialg the-'physical proper-ties ortho substance or` suitableparting means being; provided to avoidfusing.

Uponsolidication ofV the substance Si) Athe riser framev-5f2 may be removed-and theipattern frame 5U with the i substance* 66 secured :therein separated fromtlie frameiand-the substance 36" Vpression 31 sthus formedinvthe subs-tance 6l! and issecuredi-tothe iframe :50- by'` means ofan" inwardly extendedbead 64 of the patternirame A` .riser portion $6 of the: substance 6 9 `forniedt Within-the riser-frame 53 may bere'rnovedtopere mit thermale pattern E21` tolrest onthe bottom-'0f` the `frame fieras illustrated in Eig; 10.r Thein- Wardly-ofset portion 540i tlfreriserfran-1e152-pro vides a ange portion 68 in'theisubstance Sil-ace 4 curatelyf alignedl with a bottom edge 'mf of `tlie freinet-Sli.A Infren'ioving' thefriser portion' 655 all that'is `ne'ct-:ssaryg i'sftliatthe `substance -60 f be reL moved doWnr to :a point beyondf the flange f 681 as If@ desiredaa portion ofthe substace 16?); adjacent the bottom-of the pat r illustrated 1 in `Figi 10;:

tern carrying block may be removed to reduce the weight of the pattern equipment. The substance 60 carrying the male pattern 62 may be provided with attaching means such for example as threaded holes 12 to permit attaching the pattern members to a flask plate 14 as illustrated in Fig. 11.

A substance known as moulage may be advantageously used in the making of this pattern equipment. Moulage is a substance having a, wax or paraflin base and negative moulage may be applied to the male impression of the pattern or model by the application of heat and moisture to form a female impression of the article to be reproduced. The negative moulage is preferably prepared for application by the application of heat in a double boiler, a little Water or other liquid being added to bring the negative moulage to the desired consistency. The negative moulage possesses considerable elasticity and may advantageously reproduce contours where there is a considerable back draft, After the female impression has been formed in the negative moulage and it has been permitted to set, male impressions may be formed by applying moulage to the female impression of the negative moulage.

The frames which carry the male patterns may be of considerably less height than the frames in which the female impressions are formed because the frames for the female impressions must be deep enough to accommodate the portion of the pattern or model being reproduced, and this condition does not exist with respect to the frames for the male patterns.

Where the male patterns 62 and supporting member therefor are made of the Cerro alloys, a relatively high riser portion 66 is desirable because these alloys require a relatively high head to form with a desired degree of density. Where the male patterns are formed of other alloys or substances the high riser frame is unnecessary and in many instances may be dispensed with entirely. Risers may also be employed where the female impressions are formed of the Cerro alloys.

In View of the fact that the male pattern 62 is formed by a reproduction process directly from the female impression of a portion of the pattern or model Il), the male pattern follows the shape and contour of the master pattern or model with a high degree of accuracy.

No dowels or locators are needed to align the matched production patterns because each of the production patterns is accurately aligned in three planes with reference to its associated carryingframe in the process of forming the patterns. This result is achieved by reason of the fact that the female impressions of vertically spaced portions of the master pattern or article l are accurately aligned with reference to each other by the use of the frames 30 and 40 accurately superimposed on each other by means of the right an- `ele 42. The matched male patterns being formed by a reproduction process in frames accurately aligned in two horizontal planes by means of the right angle 42 and vertically by the mating edges of the frames with reference to the frames 30 and 40 are thus accurately located horizontally and vertically with reference to each other.

The male pattern 62, frame 50 and iiask 14 (Fig. 11) form what may be called a die pattern. This die pattern may be divided into any desired number of equally or unequally spaced sections. An individual pattern may occupy one or more of these equally spaced sections. The frames. 50

8 carrying the matched pattern segments are accurately aligned with each other to locate the various male patterns positioned in the flask 14 in proper alignment and to avoid the formation of cracks between the pattern block members into which the mold material might flow.

In the Capaco process referred to above, die patterns 12 x 18" dimensions have heretofore been employed. 'Ihese die blocks are divided into twenty sections, each section being approximately 1%" X 5% x -i-" high. Each of these pattern carrying unit sections in the Capaco process must be accurately machined to a tolerance of approximately plus .0000 minus .00025, after the production pattern has been formed thereon. Time consuming and expensive operations are thus involved.

These operations are entirely unnecessary when my improved process is employed because a number of pattern frames may be accurately formed to a desired dimension and may be used over and over again whenever the patterns are changed, the substance 6D of which the production pattern is formed being removed when it is desired to change the die pattern. If Cerrobend is used to make the male patterns, it may be readily removed by placing the frame with the pattern in place in water and boiling it because the Cerrobend has a pouring temperature of 160 F. and this temperature is not suiciently high to spring or warp the frame.

In forming castings from the die pattern illustrated in Fig. 11, the mold forming substance may be applied to the die pattern to form the vertically spaced cope and drag sections of the mold. Any desired substance may be employed as the mold material such for example as plaster, cement, sand, any granular substance possessing the desired characteristics, etc., and the castings poured after the molding substance has been properly treated.

It will be understood that the patterns formed in this manner embody suitable dimensions to compensate for shrinkage of the casting. If the female impressions or the male patterns are formed 0f substances which do not possess the characteristic of substantially constant volume upon solidication, suitable allowance should be made to compensate for the expansion or contraction of the material of which the pattern 1s formed.

Figs. 12 and 13 illustrate a modied form a the invention wherein a frame member may be formed of sheet metal, stamped or rolled to form an inwardly extended ridge or bead 82 to retain the material of which the pattern segments are formed. The frame member 80 may be welded together as at 84 and the outer surfaces may be machined or ground to bring the frame to the desired dimensions. If desired, cast frames having roughened internal surfaces and smooth external surfaces may also be employed.

Segmental patterns formed of a plurality of individual blocks may be formed in segmental frames of keystone, triangular, circular or any other configuration to form circular, annular or other shaped articles such for example as iiywheels, pistons, etc.

The patterns formed as disclosed herein may be used for casting any alloys or metals, and are not limited to use where a die pattern having a plurality of pattern blocks are employed.

Cores may be employed with this pattern method by merely locating suitable core prints on this pattern as is well known in the art. Impressions of these core prints are transferred by the foregoing process to the female impression so they are reproduced in this nal pattern equipment for the placement of the cores upon closing the mold.

It will be understood that this frame method of forming patterns may be used to form a base for stripper plates of the types disclosed in my co-pending application Serial No. 421,115, filed December 1, 1941.

I claim:

l. The method of making production patterns on bases of predetermined accurate external dimensions which comprises forming an accurately dimensioned frame to carry the pattern thereby assuring accuracy as to length and Width and providing an indication as to the desired height, forming a frame having similar length and width dimensions to carry a mold having an impression of the pattern to be formed, superimposing the Apattern carrying frame on thev mold carrying frame, and superimposing on the pattern carrying frame a third frame having similar external length and Width dimensions adapted to overlie the inner wall of the pattern carrying frame to establish a point for dimension change of a pattern forming substance cast into the pattern carrying frame and the mold impression of the pattern to be formed to serve as an indication of the amount of material to be removed to cause the pattern base to conform to the desired height dimension.

2. The method of making production patterns on bases of accurate external dimensions in three planes which comprises forming prefabricated pattern carrying frames having accurate length width and height, forming pre- 10 fabricated mold carrying and riser frames having accurate length and Width dimensions corresponding with the length and Width dimensions of the prefabrcated pattern carrying frames; forming a mold impression oi a master pattern in the mold carrying frame, removing the master pattern from the mold impression, superimposing the pattern carrying and riser frames on the mold carrying frame, aligning. the edges of said frames, introducing a pattern forming substance to ll the mold impression, pattern carrying frame and extend into the riser forming frame, removing the pattern carrying frame and pattern from the molding carrying and riser forming frames, and removing the riser.

`lEtAYl\/iGl\lD J. MBLLLER.

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

UNITED STATES PATENTS Number Name Date 1,303,097 Ivi'enfee May 6, 1919 984,461 Bayer Feb. 14, 1911 914,263 Bonvillain Mar. 6, 1906 373,634 Wachalac Feb. 28, 1888 985,154 Forster Feb. 28, 1911 2,070,945 Jones Feb. 16, 193'? 2,070,564 Damberg et al Feb. 16, 1937 2,206,934 Hagemeyer July 2, 1940 928,714 rThompson July 29, 1909 1,335,509 Kralund Mar. 30, 1920 2,348,086 Miller May 2, 194:4

FOREIGN PATENTS Number Country Date 176,300 GreatBritain Oct. 25, 1920

Images