US2006240A - Mold jacket - Google Patents

Description

2,006,240 l J. P KIPUES June 25, 19

MOLD JACKET Filed April ll, 1951 9v lo NVENTOR.

Ja W6 7 #[7166 Patented June 25, 17935 UNITED STkTESA l y 152,006,249' l A JAQKET l Y James: Fgli'nes, Iviakevvood,` Ohio Application April 11;. issrisnaifn;5293422.. s claims. (o1.l .2g-i122) k This'invention relates to mold jackets and a method of making the same and has among; its purposes thev production of a mold jacket which will be accurate under severe and. sustained usage,A of long life, light in. Weight, .economical to manufacture andv which will facilitate produc,- tion of perfect castings. These and other objects an'd results of theinvention will be. fully developed. in the following specification. which', with ther drawing appended. thereto, discloses a form in which I prefer to embody my invention, although it will be understood that otherforms of the jacket andother methods of making-it may b eused, all within the scope.v of the invention A In the accompanying drawing,y Fig. lis a v iew in perspective of the completed jacket; Fig. 2 is a detail of the corner construction; Fig, 3 is a vertical cross sectionv through either'l an end or side wall of the jacket; Fig. 4 is an enlarged detail:` showing the inside surface; Fig, 5. is an enlargedv detail showing the outsidesurface; Fig, 6 is ay'diagrammatic illustration of apparatusl and a method/of assembling thejacket; and Fig.. 7. is a plan view of the same apparatus.v

f Referring now particularly to.Fig. 1 itwilLbe seeny that the improved jacket comprises side members l vand 2 inclined inwardly toward the top;in' the usual manner of foundry. jackets,'with permanently secured corners; making, ineffect aunitarystructure. Y

It will of course be understood that jackets-:of other thanrectangular shape maybe made have ing the same surface characteristics as. here shown, or' that the jacket illustrated mightl be lmade* in a single casting, I find it most.v desire able,` however, to make the four sides" of th jacket separately and assemble them. f n

AmongV the most important. characteristics. of thejacket are the inner and-.outer'surface forniations. 1 1

The inner surface, best seen in Fig. 4,-is1 formed of, a large number of small projections with their tops smaller than their bottomsy and havingjthe topsy allnished olf in a common plane; The most convenient formation foundl inpracticefis ,that ofY a largenumber of truncatedl pyramids 3 with adjoining square bases. By this formation diagonal channels such as 5 and 6, intersecting atr'right angles, are formedv betweenk the 'various vrows of pyramids in either direction while the flat tops 'l formcollectively the eiectivehol'ding surfacef for the molding sand. The greater part of the inner face of the jacket isso formed,. but

this broken surfaceis conveniently/bounded. at top andi, bottom by narrow smooth ridges-8 nnislied. oiftolthe common effective plane ofthe elements- 1,. while beyond. theseridges there `are horizontal grooves 9 which drop volf quicklyxto about the. deptnof. the channels 5t and 6 but gradually slope: back to; the controlling inner level i 5 and merge into wider'strips whose inner surfaces In: curve intoitangency with the plane of theelements This arrangement of the, elementsyll, v 9v and |0f gives achannel formation which stiffer-1s the sides against outward bulging. Alsov the 1.0 grooves: slightly lighten thejacket. I Fonusing the jacket the mold is formed inv the usual' manner ina flask the-sides and inclination of whichagree precisely with that ofthe jacket. The jacketwillthus engage and support the mold l5 by meansof they surfaces 1,'8 and Hl'. The flasks in which the molds are made often have slight irregularities of their inner surfaceebecause they are generally castl without machining, forcthe reason-thatmachining would. cut ,offV the casting '20 scale. and vdiminishthe strength of the flask Such irregularitiesresult in correspondingirreg.- ularities in the outer surfaces of the mold. When lmy improvedjacket is puton the mold- `these irregularities are smoothed off bythe action of 25 the flat surfacesv 'l against the sand ofv the outer Vmold surfaces, these surfaces 'l all being at a commonicorrect plane. However, such smoothing. iswithout injurious effect to the mold for the reasYorr-that excess material shaved oiT'is de- 30 vposited inthe immediately adjacent grooves5 andf instead. of accumulating betweenqthe mold surface and thefinner'surface of thejacketand tending.- to.- crush: the mold cavity inward'. Thus whenthe. jacket. is forced down it makesfits own 35 perfect vt on, the. moldA without any 'injury thereto- Although the pressures within themold lin pouring may be very heavy, the numerous DOntsof-.v support. 1 are evenlydistributed andare separatedlbyvgrooves which: are small enoughvso 4'0 thai-,there is. a-.certain bridging effect ofthe wet packed sand over the grooves. It has beenfound in practcegwithA this jacket that. the Vformation described gives. as completeysupport as4 a: vsmooth solid surface.v The grooves 5A and 6 do not ll t5 rapidly, g althougl-iy some sand. adheres inethe baking,process.. `However, these grooves,l remain suiciently fopen tok allow. passage ofv :any lgas .which escapesrthrouglr. themold; so that 'no harm- 4 f-ulfgaspressures-V build up; In case the glQOVe's A'50 become toor much filled' with bakedl sand they can rreadily-be cleaned out with a'wire brush..

j The;-.numerous smallV elevations-.ron;.the inner face of the jacket also have the effect of increasu ing;,the-aexposedqarejaof metalv inthe wall- It 55 face.

shapes to form pockets therebetween asjwell ask Vto back up the inner surface;V The preferred'form 21 e being a known fact that in cast metal the surface has the greatest strength, thisfincrease of metallic surface, most of it being in the sides 3 Y of the pyramids which are not machined, adds greatly to the strength of the jacket so that the Vreduction in weight due to the grooves 5 and 6 is not accomplished by any dimunition in strength below that which would be present in a smooth surfaced`V side wall of corresponding thickness, b ut rather, gives .greater strength.-`

Referring now to theroutside :of ,the jacket, this consists over the :greater part of its area of a honeycomb formed by relatively deep ribs cast;` integral with the remainder of the jacketwall,

Vand thus strengthening the back of theinner These ribs may in any oneiofa Viiiety of comprises ribs in diagonal series I5 and I6 crossf ing each other at right angles, ,thusY forming a large Vnnumber of diagonally" disposed Ysquare Y pockets I1 on the outer face of thejacket.' Along V'the top and bottom-edges the? outer surface is strengthened by-a Lconcave vquarter round flange the outer edge of which consistsof the strip whose innersurface is indicated at I0 and the inner edge of which slightly overhangs the vribs I5,"I6 as shown at I 8.v A'tthe topfthis'fiange, outwardly overhangingv as itf does at I8, directs ffspilled metal away from the sides" of the V.jacket thus preventing burningof the jacket.`v The flange described also strengthens the sides against bending by reasonfofl its channel formation; In `using the-jacket the pockets I1 have the top and bottom flanges serve to A`sorneextent as hand holds, but the pockets are foundfuseful Vin that they collect and hold the damp-molding sand,

which sandprotects the metal of the jacket from linjury by spilled moltenmetal. Itis never necessary to clean the sandoutoftbe pockets of -the Vouter surfacer because the Ygreater-"the Vaccumulation of sand the-greater the insulating effect. -k

The corner construction illustratedherein is an improvement uponA thatl A'shown in' my earlier patents, No. 1,577,718, issuedMarchZS, 1926, and No.' 1,790,921, issued February 3, `1931. It comprises a deep Vgroove 20, Figs. 2 and 4, eaclrhaving its outer wall 2! terminating in an-outwardly di- `slightly spacedapart in the nishedfjacket, as

shown in Fig. 2. Posts 24* are disposedacross the groove 201 at intervals, but do not extend to Y the bottom ofthe groove 20.

f In making the jacket the sides and vendsV I and 2 are placed against a master die 30, Figs. A6 and 7,'01 very accurate construction, andthe exact size of the jacket is determined by therheight'of the elements on the tapered sides 3| of this master die,gauge marks 3 IAbeing placed thereon for convenience. The sides' 3I are inclined to the same angle as Ythe inner surfaces `I of the jacket sides and the corner edges, beveled of! as shown at SIB. The jacket members being held in position, molten metal;V preferably the same metal as Vu sed inthe jacket construction, usually aluminum,

is poured` into the grooves 20,fthus making yineffeet an integral joint. This cast binding metal is Vindicated at 32, Fig. 2. The interior cornersV of the jacket will consequently take a shape corresponding to the corners 3|B of the master die and as here shown will be at, as ,shown at 33, forming an angle of `135 withthe inner planes of the jacket. .This corner construction Vmay be concave, as shown in my above Vmentioned Patent No. 1,790,921. I have found, however, that the use of a. fiat face 33 is ordinarily preferablel because it allows a more accuratev fit of A the jacket over the mold. An advantage of a filled corner over a square corner, such as shown in my Patent No. 1,577,718, is that'when the jacket'is lifted off the mold `the corner catches and carries away some sand, and this sand has a tendency to bake and stay in the corner thus breaking the corners of new molds and sometimes seriously injuring the mold itself. The fiat corner face 33 has an advantage Vover the rounded corner face shown in fny Patent No. 17,790,921in'that the'obtuse angles of V"are as free from the evil 'of catching sand asare the rounded corners-while itis easier with the present` form to make a larger number of identical jackets on a series of master dies such as 30 on account of the readily apparent fact that it is easierto make a series of identical flat surfaces the corresponding dihedral angles vof which are absolutely equal than it is to make several roundedY surfaces of preciselyy the same curvature. This being the case it is cheaper, and there is greater assurance ofV accuracy in making a number of master dies, suchas 30, thanthe're would be in making corresponding dies with rounded upright corners such as would be necessary for making the jackets shown in my- Patent No. 1,790,921. VStill another advantageof the flat corner over the concave is that the flat corner has been found in practice to come off the mold without the `necessity of tapping the jacket. This result was unexpected but has been demonstrated in practice tobe reliably found in the use of the present fiat corner form as compared with theV earlier concave form.v f

It may be herenoted that the corners of molds are generally the most troublesome parts for .the y reason that the mold maker in tamping or peen-V ingdown'thesand with the handle of' hisshovel, as usually practiced in foundries, cannot .reach well back into the corner. Speed being a very important feature inV mold making, it vis not feasible touse afspecial .tool for Jtamping the comers. Y Y

Y An advantage of a cast corner over one made by riveting, bolting or other similar means, isthat the cast corner` always remains absolutely accurate and any derangement whichY will impair vaccuracy will 'be serious enough to give a plain warning thatthe jacket is unfit for use, such as a break or crack.

A further advantage of a cast corner, especially when made on a master die,` is that it stands fre-heating without strain because 'originally made with hot meta.1;` Thedegree of accuracy-is Vthe same as though the entire jacket were cast in one piece, but by castingeach side separately and afterwards putting them together,"casting strains inthe entire structure are prevented. "'In making the jacket by the method of fitting to a master'die andpouringv the'corners as described, it will be noted that the method is almost one ofdie casting. On account of the taper of "the master die a high degree of accuracy as `to dirension is obtainable by setting the side and the endmembersup or down on Vthe die 6. .It

will also be observed that the position on the die instead of the exact meeting of the flanges 22 is' depended on for the nal accuracy. For this reason the anges 22 need not have their abutting faces machined off unless it is necessary to get some of the metal out of the way to permit a smaller size jacket to be made from the same piece. Usually in the finished jacket there will be some slight clearance between the flanges 22 but this will be filled by the cast metal 32.

It will be seen from the foregoing that I have constructed-a jacket which is light, strong, accurate, and which cannot in any way injure molds on which it is placed, but rather rids them of any slight irregularities of side and end surface and gives perfect support to the sand, which jacket includes means for allowing escape of leaking gas during the pouring. This jacket is also convenient to handle either with gloves orA with tools for the reason that the exterior surface gives a greater number of holds. Furthermore, the jack- Y et when new is well protected against spilled molten metal by reason of the outwardly directed top ledges I8, and in use very quickly acquires additional'protection by the sand which catches in the spaces I1. Furthermore, on account of the cellular reenforcement an occasional hole accidently burned through the thin part of the side will weaken only a very small area and will not ordinarily be sufliciently serious to destroy the usefulness of the jacket. Nor will cracks work out from such a hole beyond the next reenforcing rib I5. My method of making the jacket provides means for quick and accurate work and allows a number of exact sizes of jackets within a given range to be made from end and side pieces of given sizes, although close accuracy to any desired size within the range is obtainable by the gauge marks 3|A on the master die.

In situations where weight is of no particular consideration this jacket can be made of cast iron, although for most purposes aluminum is advantageous. Where cast iron is the material used,

times warp, particularly if they are shaken out too quick, and it is therefore frequently necessary to grind the faces 'I to an even plane, whereas when the sides are cast of aluminum such grinding is rarely required. Even when made of iron and ground, my inner surface construction has an advantage in manufacturing for the reason that the channels 6 allow air cooling of the iron during the grinding operation so that the grinding can be carried on quickly without danger of the heat of abrasion vinducing further warping.r

'I'he foregoing description and accompanying drawing are to be vtaken in an illustrative and not in a limiting sense. The scope of the invention is to be determined from the following claims. p

What I claim is: f s

1. A mold jacket having its outer surface formed with a plurality of intersecting ribs reenforcing a side plate element, and edges of approximately the depth of said ribs and of outwardly concave arcuate cross section extending along the top and bottom .of said side plate element, the inner extremity of said arcuate edge intersecting said ribs, and the' outer extremity of said arcuate edge being approximately tangent to f the inner surface of the jacket.

2. A mold jacket having an outer surface comprising a plurality of intersecting reenforcing ribs forming pockets therebetween and horizontal grooves along the top and bottom edges, said grooves being of approximately cross section, outwardly concave, and lying approximately tangent to the plane of the inner surface of said jacket and approximately tangent to a perpendicular to said plane, said last-named tangent por-

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