US2084128A - Art of molding - Google Patents

Description

June 15, 1937. D. J. CAMPBELL ART OF MOLDING Filed Aug.. 17, 1955 4 Sheets-Sheet l /N VENTOR a/wu J @nM/2551.1.

A TTORNEY June 15, 1937. D. J. CAMPBELL ART OF MOLD ING 4 sheets-sheet Filed Aug. 17, 1935 A TTORNE YS.-

June 15,V 1937- D. J. CAMPBELL ART OF MOLDING' Filed Aug. 1'7, 1955 NVENTOR 'A TTORNE ys 4 Sheets-Sheet 4 D. J. CAMPBELL .ART OFIMOLDING :'Lled` Aug June l5, 1937.

u. RM 0 T V 6 WJ P m. M no? A TTORNEY Patented June 15, 19.37

Ulvlf'rfr-L-D STATES ART'OF MOLDING l y. Donald J. Campbell, Spring Lake` Township, (')t-A l,

tawaCounty, Mich., assignor to Campbell,` Wy-- ant & .Cannon Foundry Company, Muskegon, I Mich., a corporation of Michigan Application August 17, 1935, serial 10.136.679 44 claims. (ci. :ez-1729) mold. In the casting of cylinder blocks, elongated' baked sand cores are used, particularly in blocks for the so-called V-engines.

With articles of the nature mentioned, which are two examples onlyrof many different types l5 of elongated and more or less irregularly shaped articles cast' from cast'iron, when the molten iron from which theyare cast solidifles in the mold, there is a shrinkage of the iron which shows its greatesteiects in the direction of the greatest dimension of the casting made. 4This shrinkage in an elongated article like a crank shaft or in a long engine block, is in the length of the casting.

.Baked sand'molds or baked sand cores are re- 5 sistant against the movement of the casting which takes'place because of such shrinkage. While the iron burns the adjacent portions of the sand cores or molds where it strikes it to a slightvdegree,v the body of core does not yield readily and easily. l y l L v Therefore, in a great many cases when the casting shrinks and engages against the baked sand mold or core, with the resistance whichthe core has against the casting moving because of such shrinkage, thereare strains set up in the casting which frequently manifest themselves in thefinished castings in checks, cracks or other imperfections.

i vThe present invention is directed toa very sirn-` 40 ple, practical, economical and particularly effec-y tive mold or core improvement whereby all such detrimental effects ,which have previously occui-red because 'of 'the hard and more or less unyielding nature of the core sand used are entirely eliminated and the shrinkage of the casting maytake place freely and not be subjectedl to the resistance of the baked core sand material, as has been previously the case. There is an elimination of defects in the nished casting which have heretofore frequently occurred because of the resistance to shrinkage coming from the relatively unyielding nature of the bake core sands or molds. For an understanding of the invention, referv .ence may be had tothe following description,

taken in connection with the accompanying draw. ings, in which,l f

. i Fig. 1 is a horizontal section-through aL bakedv core sand mold for casting a crank shaft, the mold incorporating my invention therein. 1

Fig. 2 is a transverse section substantially on the plane of line 2-2 of Fig. 1. v

- Fig. 3 is yan elevationof the readily compressible member or plate, several fof which are'used in. the length ofthe mold-as shown in Figs. 1 and 2.

Figs. 4 and 5 are elevations of -two alternative.

' constructionsof collapsible or compressible platesf' such as are shown inelevation in -Fig.'3. Fig. 6 is a. transverse section'through an' in ternal combustion engine; casting with the elongated cores such Vasare-usedin casting the same, in place as they are used.' i I Y" Fig. 7 is a plan and sectiony of the structure shown'in Fig.6, the` section being'on the plane' of'broken line 1-1 of Fig. -6. i e v Fig. 8 is a central longitudinal vertical section through the engine block castingv and two large f longitudinal cores `which are used, and Figs. 9`and 10 are elevations,respectively, of the collapsible plates used inthe upper and lower longitudinal cores in casting the engine block, a plurality of such collapsible plates being-within the cores `v transversely thereof andin spaced apart relation to eachother. Like reference characters refer to like in the different figures of Athe drawings.

The engine blockcasting I, see Figs. 6 and 8, is of atype such as isused in providing a multiple cylinder internalY` combustion engine of the Y V-type. The crank shaft is of a conventional design, having a plurality of. cranks 3 with ad'- jacent integral flanks 4 connecting the same all as fully shown in Figs. 2. In the application of my invention tothe casting of a crank shaft, the

` mold drag and cope 5 (Figs. "1 and'2) are made from core sand and baked in an oven so as to have the rigidity of baked sand cores.- 'Ihe mold cavities are of a shape such that when filled with molten' iron the crank lshaft'is produced. There is in addition a cavity in the mold at one end of the crank shaft mold cavities and communieating therewith which fills with melted iron when the pouring takes place. This is shown at 6 in Fig. 1. The usual runner gates 1 and 8 for carrying the iron to the mold cavities are provided. The mold is filled with molten iron when in -a horizontal position and then turned upright to a substantially 'vertical position `so parts 2 -4 'i '7: a,os4,12s

In the making oiqthe drag and cope fory 5 casting crank shafts, apluraiityof transverse plates 9 are used so Vlocated as to lie between ank portions 4 as shown inFig. 1. Inasmuch as the Vcrank shaft shrinks from each end inwardly'toward the lcentral portion, there fwill be 10 more of these transverse plates' 9 toward the ends of the crank shaft than at the center. The plates 9 are notched, for example, at. Iland Il, so as not to enter the mold cavities or the gatev at- 1.5

It is evident from areierence to Figs. 1 and 2 that the plates 9shownare nearly. ofj anvarea i equal to the transverse sectionfottlie `and y the cope in which they are located, there beinghowever suflicient sand around theedges of the plates 9V that said plates are 4completely embedded and enclosed withinthe mold. f- ,i

When the iron vis poured into the mold 'and shrinkage takes placetheresistance which,` pre- -viouslyoccurred to such longitudinal movement of the end portions of the crank inwardly toward .the center is now removed, theplates 9 collaps- ,ing or crushing in the direction'of their'thickness, lthat is, lbetween Y their sides.:v Thesey plates 9, as shown in Figs. v4 and -,preierably consist of two spaced apart sides i2 of paper with a cor.-

rugated intermediate section i9 between the same, or'there maybe any *other suitablematerial between the two-.sheets-:IL such as that indicated at I4 in Fig.v5, which may be looseeasily kcompressible fiber.

In practice what hasrbeen'used has been well known corrugated/paper board.- The thickness of the plates 9,'if a single one is used, preferably is about one-quarterof;V an, inchibut two thicknessesof ordinary one-eighth oi'` Aan inch corru- 40 gated paper board may ,bev used satisfactorily.

The `pressure against the `sidesof the plates 9 crushes'and collapses the same without any fear of setting up a resisting `iorcefsufdcient to affect thecastng.r

.In connection with the casting. of,a VV-engine block,'such. aspshown in Figs. 6, 7Vand`8. there is an elongated core I6 which lies between the cylinder portions i5 and which, when the molten iron is poured, lies between thefends I1 of the casting made. The longitudinal partsoi the casting, indicated ,at I8 andZIIInFlgS. 7 and 8,.

shrink and tend to draw theends'of the casting toward each other. Ar second longitudinal core i9v is located infthe lower part and below the ends of the cylinder portions i5 yof thek casting and this likewise lies lengthwise between the yends o'f thev casting'made. "Therefore, thel longitudinal shrinking rtending to" draw theven'ds ofgthe casting toward each other necessitates ypressing against the endsof the cores/,I9 and i9, which being'of bakedsand resistsuch, pressure. The

n attempted movement oftheends ofthe casting inwardly toward each other hasresulted'in 'defects in the casting using solid cores. i f

With kfrny invention, a plurality' of transverse plates 9a in the upper core I 9, andv of 9b in the lower core I9, are'used in spaced apart relation to each other, the in woord-. ance with thetransverse section lof the cores. as shown in Figs.9 and 10,"and nearly as large as the cross sectional areal of the cores. The. same Y rcrushing ci.' these plates laand 9b. because o! 6 the end pressure on the cores at I9 and. I9. takes place, relieving strains in the casting and gr aiding in the productionoigoodcastings.

' c Tneinvenuonvdescnbed acne arg1-est pmu Y cai merit; It is very simple, it isrelatively in- 10i expensive insofar as additionalimold cost is concerned. The compressible collapsible ,plates serve to hold the mold or core in which used Asecurely to its desired shape. compressingand collapsing onlymunder the forces placed upon the l5 mold yor" core bythe shrinking'of the iron.

It is, of course-to be understood that this'trans verse embedding of a paper board. collapsible plate, or one ot an equivalent nature for the same purpose, may be used in any .core at any 20 place where the shrinkage oi the iron causes' the same to press against opposite'sides or ends oi the vcore where Vthe core resistsftheshrinkag'e which inevitablytakes place `when molten'irou solidies. `Likewise'inolds made .of core sand, 25 one of which has been describedwith respect to the casting of a crank` shaft, may utilize ths'lo eating of compressibleplatesvlike thosedescribsd Vmade of cormgatedpaper boardftranmrsly 011;

the `direction in which thepressure comes when so Lthe casting collapses so as tolyield under the pressure of the shrinkingcasting. s

The invention accordinglyis not to be limited to the particular disclosures made orto the particular articles illustratedwas, beingshown. but'is :is to be considered comprehensive oiallstructures coming within the scope of`l the claims appended'1 4.hereto which define theinvention. Y

VIclaim: Y. s 1. In a mold, an elongated mold element-oi' 40 baked core sand, `and apluralityoi' spaced spart i plates of corrugated paperboard located transversely o! the moldin spaced apart relation tol each other -and completely embedded mold member'and havingfdimensions approach- 45 ing` but somewhat lessy inail directions than the corresponding dimensionsof the mold-member j in which positioned. f Y

k2. An elongated baked core sand mold having a member of paper board of the general outline 50 of the mold but smaller in area than section oi' the mold disposed ,transversely of` and within the baked sandmold material.

3'. In the art oi' molding,. a mold member@ baked sand having a pluralityoi' spaced. apart 55 plates in said mold transversely thereof, each ot said plates comprising a compressible layerof corrugated paper board crushable under pressure conditions existingduring thek molding operation,` said plates being compressibie and collapsible in o the directionv of their thickness, as and ti'or the closely at the'end portions of the mold'member.- u

'e DONALD J.

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