US1675043A - Metal mold - Google Patents

Description

June 26, 1928.

\ A. B. NQRTON METAL MOLD Original Filed May 25, 1923 2 Sheets-Sheet l BY @0147, F

ATORNEYS' June 26, 1928. 1,675,043 A. B. NORTON I METAL MOLD Original Filed May 25, 1923 2 sheets $heet 2 I J \l I 1 1 ,5 1 3 4 F1 ATT RNEYIS.

Patented June 26, 1928.

- UNITED STATES ALLEN 3. non'ron, or CLEVELAND, OHIO, ASSIGNOR 'ro ALUMINUM comramr or PATENT OFFICE.

AMERICA, OF PITTSBURGH, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

METAL Mom).

Qriginal application filed May 25, 1923, Serial No. 641,359. Divided and this application filed March 16,

1925, Serial No. 15,796.

This invention relates to metal molds for casting light weight metals having a high crystallization shrinkage, as compared with iron. In particular-{it is concerned with a mold for casting thin walled articles composed of aluminum or its alloys v Heretofore it has been found difficult to cast successfully articles. composed of aluminum or aluminum alloys of the dimensions most desirable in articles such as cookingsuch articles is that when the articles are cast on theinsides or edges, their vertical dimensions are so great that the molten metal .must travel a conslderable vertical distance from the top of the mold to the bottom of the casting cavity, which distance, in many instances, is sufficient tocause agitation or breaking up of the molten metal as it enters the casting cavity and the formation of pores, pits and other imperfections'in the surface of the casting which renders attainment of a polishedsurface free from blemishes difficult or impossible. I

I have found however that articles of th classdescribed having smooth substantially unpitted surfaces maybe cast successfully of aluminum or aluminum alloys in permas' nent molds and with walls or wall portions much th nner than has previously been possible by suitably shaping and positioning a gate with respect to the casting cavity, so; that the entering molten'metal' need flow 40 only a minimum distance through the shalloW portions of the casting cavity in which the thin wall portions of. the article are cast. Furthermore I have found that by use of a new and improved form of gate, 1 can cast articles of the class described having relatively large vertical dimensions substantially without any of the present disadvantages which have been partially enumerated above.

One object .of my invention is to provide a new and improved gate for conducting molten. light weight metal, under the action of gravity. into a casting cavity from a convention.

- fied form of Renewed April 5, 1928.

siderable height in a. manner. to prevent leaping or splashing of the metal or other agitation thereof suliicient to result in entrapping air in the metal and tocause porosity or surface pitting of the casting; to avoid heating certain parts of the mold excessively; and to a separate light weight, floating impurities from the molten metal before-{the metal onters the casting cavity. Another object is to provide a new and improved gate for conducting molten, light alloy metal into a vertically elongated casting cavity from a point well above the upperextremity of the cavity substantiallywithout harmful agitation.

Another object is to provide a new and improved arrangement of gate and feeder cavities with'respect toa casting cavity for articles having thin wall sections whereby the entering molten metal is caused to flow'a minimum distance through the shallow portions of the casting cavity. i K Other objects will appear and be pointed out hereinafter. 'In the drawings attached hereto and forming a part of this specification:

Fig. l is a top plan view of one form of mold constructed in accordance with my in- Fig. 2 is an elevation partly in cross sec-- tion taken on line 33 of .Fig. l-showing a casting in the casting cavity.

Figs. 3, 4,5, 6 and 7 are fragmentary,

horizontal cross sections taken on lines 3-3,

L4, 55, 6-6 and 77 of Fig. 2 showing relative sizes of various parts of the gate and feeder cavities.

Fig. 8 shows in, perspective a casting as made in the improved mold, and

Fig. 9 is adiagrammative view of a modigate, feeder and coating cavities.

In the drawings in which I have illustratedone form of mold embodying my invention and adapted for casting a thin walled, shallow article such as a frying pan,

I'indicates a mold base comprising a flat top 2 and suitable supporting legs orflanges 3.

At the rear of base 1 a pivot pin 4 is secured to the base in an upright position.

Two similarly formed complementary mold bodies 5 are pivoted to'pin 4 by outstanding lugs 6, the mold bodies5 being slidably seat, ed on the base and being adapted to swing about pin 4. 7 indicates another mold member removably secured to base 1 on the top surface thereof and in a position .to engage and cooperate with one end of 'each of mold bodies 5 in certain positions of the latter. Suitable securing means for mold body 7 are indicated at 8, where bolts are shown passing through a flange portion 9 of body 7 but if desired bolt 8 may be omitted and the mold body left free to be moved on base'1. Suitable pilot or positioning meansfor determining the proper positions of the several mold bodies may take various forms but I have shown dowel'pin's 1 mounted in the top of base 1 and engaging in recesses in the meeting faces ofthe mold bodies which have been found satisfactory. i v

In the meeting faces of mold bodies 5, recesses are suitably formed to constitute gate, feeder, casting and riser cavities when the bodies are in engagement with each other. These cavities are designated respectively b numerals 10, 11, 12 and 13 on Fig. 2. Pre erably the inner face of mold body 7, or the surface thereof which is adjacent one end of "mold bodies 5, is substantially vertical, al-

though if it is desired to form acasting in a position other than substantiallyvertical as' is here shown, this surface may be correspondinglyinclined. The inner face 14 of mold body 7 forms the edge or end walls of the casting cavity 12, the remaining outer sides of the casting cavity being formed by the walls of the mold bodies 5.. Mold body 7 carries a movable core 15slidably mount ed therein in a substantial horizontal position. This core is substantially circular in cross section, and is of sufficient length so that its inner end projects beyondthe inner surface-14 of mold body 7 and into casting cavity 12 where the inner 'e'nd'and exposed side-walls of the core constitute walls for forming the interior of the castingcavity.

Core 15 is preferably hollow with its walls suitably proportioned in thickness to the size and nature of the casting desired. To facilitate movementof core 15 in mold body 7, as is ,desired for ready removal of the p casting from the casting cavity,-bracket 16 is secured-to the mold body 7 by suitable means indicated generally at 17, This bracket isperforated, as I at 18, to receive a screw threaded rod 19' engaging in a threaded hole 20 in cross bar 21 secured to core 15. Collars 19* pinned to rod 19 on either side of bracket 16" prevent longitudinal movement of the rod through the bracket and when the rodis revolved, as by hand wheel 19, the rod serves to move, core '15 relative to mold body]. -It will be obvious that other means may be usedfor actuating core 15 in mold body 7, but such means. are considered mechanical equivalents of ,the form -herein.

7 may present a continuous surface 14 to mold bodies 5 instead of being cut away for a" core as hereshown.

22 designates a core pin adapted to seat on the top of the mold bodies 5 and 7 and to pass through an opening in the meeting faces thereofand projected into the casting cavity for the purpose of forming a cored out opening in a handle lug 28 on the casting.

' It will 'be understood that other forms,

of core pins may be used when-occasion demands, and thatthe' nature of the casting be'ingmade will to some extent determine the location of the pin with respect to the mold bodies. All such ins are however, considered to be the equivalent of the one herein shown.

Main core 15 has a substantially'circular side surface adjacent the inner end thereof to form a substantially circular inner wall for the casting."

The new and improved form and arrangement of the casting and riser cavities contribute to the'casting of articles requiring" sound, non-porous smooth surfaced articles of the class described,,wi th' a minimum of grinding and other finishlngoperations be-j ing required. By reason of the gateand feeder cavitycommunicating with the casting cavity along the rear side thereof which corresponds to-the bottom of the casting, it will be evident that the only finishing operation required will be a severing of the gate metal and the bottom of the casting and riser 'metal from the handle lug. .The cost of thevcastings is thus greatly reduced.

For articlesof the class shown where the article is cast in an upright position and the molten metal is led under the action of gravity through a considerable vertical distance, the improved form of gate and feeder cavities illustrated are preferable.

.The gate indicated as an entirety at 10 comprises a downwardly extending inletpassage 10 inclined slightly to the vertical which communicates at its lower end with a restricted pasage 10 which turns abruptly about'point 20 and extends upward and rearward or away from the casting cavity-to a point 21 above point 20, the passage thus serving asia means of retarding and more or less controlling the speed of flow of the entering molten metal as well as forming a liquid seal which tends to trap out light impurities and prevent their entry into the casting cavity; From point21passage 10" curves downwardly and forwardly, or

toward the casting cavity, at a progres-,

sively increasing angle to the vertical and flares out adjacentto the feeder cavity in a other parts of the gate and an uprightdhmenslon approximately equal to the height of the feeder cavity 11.

' the casting cavity 12. Where projections "from the main casting are to be cast above The feeder cavity preferably extends upwardly to a point above the main portion of the main casting cavity, as handle stud 28 (Fig. 8), a riser cavity 13-1nay be provided to insure proper filling of the stud'cavity,

12 by a short narrow passage 11 which may be formed conveniently by projecting ribs or ridges on the faces of themold halves, as

shown in Figs. 1 and 2.

when. cast in' a mold of the foregoing description. 21 indicates the casting proper which is a thin walled, shallowor pan-like article having a flat bottom 25, sides 26 provided at diametrically opposite points without-turnedlips 27, and a short handle 28. 29 indicates a'quantity of metalforming a riser in communicationwith handle 28. "30 indicates a quantityof metal formed in feeder cavity 11 and connected to articleQA by a 'thin neck 31. A portion of the gate metal formed in gate 10 is indicated at 32.

In the operation of the mold illustrated,

the mold bodies 5 are swung into assembled. relation with mold'bodies 7, did main core 15 and core pin 22; are brought to their proper positions with respect to the mold bodies and casting cavity after the parts forming the cavities have been coated with a suitable mold coating composition. The mold bodies, and chiefly those in which the gate and feeder cavities are formed, having first been brought to the desired operating temperature, as by applying a heating flame thereto or by other suitable means, a molten metal which may consist of aluminum or its alloys or other light weight metals having relatively high crystallization shrinkage "as compared with ironds poured into the inlet passage 10. 1 It immediately fills the pocket or passage 10 at the bottom of passage 10,

thus effectually sealing the control passage 10 and. preventing light impurities on the surface of the molter'rmetal from entering passage 10. The metal with. its velocity materially decreased flows npwardlythrough passage 10 and-passes downwardly and forwardly into the discharge passage 10 at a velocity materially less than if-it had fallen from the-top of the .mold bodies without in- I terruption, and thence flows into feeder and casting .cavitysmoo-thly and without leaping or suiii'cient velocity to cause harmful agitation, breaking up or splashing of the metal which'may result in the entrapping of air therein and the consequent production of porous or pitted castings. *As the pouring proceeds, the molten metalenters the bottom v ofthe casting cavity and rises in the casting and feeder cavities with'the entering metal tion with the metal in the casting cavity Feeder cavity 11 is joined to cast ng'cavity until it has solidified to compensate for voids free from crystallization shrinkage defects; F g. 8 shows,inperspcctivc, an article with gate and riser attached ass-1t appears.

1 The first entering metal will presumably impinge against the part of the core directly opposite the opening 11 but due in part to i the configuration of the gate subsequently entering metal will flow onto the top of the molten metal already in the casting cavity,

.and successively strike against higher parts of the core thus avoiding theexcessive heatmg of certain portions of the mold or core.

However, I have provided a boss 23 on the core adjacent the point of first contact of the. molten metal therewith for the double purpose of rapidly dissipating heat from the face of the core in contact with the first entering molten metal and for providing a padto which an insert could be attached should the outer face of the core become worn or corroded. In practicethis boss ha not been, found necessary however.

Although the particular type .of gate and feeder herein shown is particularly applicable to the type of casting illustrated, (it' may be utilized to advantage with other ofbeing transversely positioned as shown heiiein'. With such arrangement of cavities, it is often possible to use'only two movable mold bodies instead of three'as here shown, and asan illustration of suchmolds reference is made to Patent 1,296,588 granted March 14,1919, to J.- H. Bamberg.

, Thearrangement of the gate and feeder cavities atsubstantially right angles to th medial'part of the casting cavity is of especial importance where the casting has a thin section, since it is accord with the ;prinstantially the entire length of the casting ciple of causing the molten metal to flow a minimum distance thru narrow or shallow casting cavities. With the illustrated arrangement of cavities the molten metal flows each way laterally from the feeder cavitythus traveling the .minimum' distance thru the narrow cavity to reach all parts of the casting cavity. Somewhat similar results could be obtained by feeding metal into opposite edgesof the casting cavity thus causmg the metal to "flow from opposite sides toward the medial portion of the casting cavity. j I

If 'desired the oppositely located feeder cavities maybe supplied by a single gate outside the casting cavity as is indicated diagrammatically in Fig. 9 where 33 indicates a casting cavity, 34-the opposite feeder cavities, 35 the gate and a passage connecting the two feeder cavities.

I do not wish to be understood'as limitlng my invention to the particular article shown plates and similar articles.

but on the contrary contemplate the casting of many different sizes of types of articles, for culmary'and other uses and including pans of various depths, griddles, covers,

This application is a division of my copending application, Serial No. 641,359, filed on or about-May 25, 1923.

Having thus described the "invention in I some sufficient detail to permit those skilled in the art to practice the same, what is desired to be secured by Letters Patent is. defined by what is claimed. i

What is claimed is;

1. mold for casting articles of the class described provided with a casting cavity, an

upright feeder cavity adjacent to the casting cavity, a short, narrow passage joining the said casting and feeder cavities throughout substantially the entire length of the casting' cavity, and a gate for conducting molten metal intojthe said feeder cavity, the said gate comprising an inlet passage extending downwardly from the topof the mold, an

upwardly and rearwardly'and t-hen downcavity and a gate for conducting molten metal into the feeder cavity, the said gate comprising an inlet passage extending downwardly, an upwardly and rearwardly extendingseal pass age which turns downward- IV and forwardly and a narrow, vertically, elongated discharge passage communicating with the said feeder cavity. a

3. .A mold for casting articles of the class described, provided with a casting cavity, an upright feeder cavity adjacent to the said castin cavity, and communicating therewith t rough a short, narrow passage, and a gate for conducting molten metal into the said feeder cavity, the said gate comprising a downwardly extending inlet passage a control pasiage, of restricted cross. sectional .area turning abruptly and laterally at the lower end away from the casting cavity and extending downwardly and forwardl and terminating in a discharge passage aring widely in a vertical plane and communicating with the said feeder cavity.

4. A mold for casting articles of the class described provided with a vertically elongated casting cavity, an upright feeder cavity adjacent to the casting cavity, a short, narrow passage joining the said casting and feeder cavitiesthroughout substantially the entire vertical length of the ca:ting cavity, the said feeder cavity having larger cross sectional dimensions than either the short, narrow passa e or the casting cavity, and a gate for con ucting molten metal from the topof the mold into the said feeder cavity,

the said gate'comprising a downwardly extending inlet passage, an upwardly and rearwardly extending passage leading from the lower end thereof and constitutin a liquid seal when molten metal is poured into the inlet passage, and a passageextending downwardly from the said upwardly extending passage and opening into the said feeder cavity throughout a relatively lar e portion .of the vertical length of the said feeder cavity.

5. In a moldfor casting metallic articles, the combination of a mold base and a plurality of mold bodies mounted thereon, the meeting faces of the said mold bodies being recessed to form gate, feeder and casting cavities, the said gate cavity being adapted to conduct molten metal under the force of gravity in a substantially unbroken mass to the feeder and casting cavities, comprisin a downwardly eXtending aJsage of sli ht 1nclination to the vertical, an abruptly and rearwardly curved passage of constricted area, turning downwardly and forwardly and with increasing inclination to the vertical and a discharge passage enlarged in a vertical plane adjacent to and opening into the feeder cavity.

6. In a mold for casting metals having a high crystallization shrinkage as compared with iron into articles having a relatively thin wall portion, the combination of cooperating mold bodies having a casting cavity formed in the meeting faces thereof, a certain portion of the said casting cavity being relatively shallow for forming a thin wall portion of a casting, a vertical feeder cavity communicatin with the casting cavity throughout a ma or portion of the vertieal height of the casting cavity, and'a gate passage formed in the mold bodies to conduct molten metal to the feeder cavity, the said gate passage being flared vertically adjacent to the feeder cavity and communicating therewith throughout the major part of the vertical height of the feeder cavity, thesaid feeder cavity being so arranged with respect to the casting cavity that molten metal delivered thereby to the casting cavity flows a minimum distance through the shallow portion of the casting cavity with molten metal progressively entering the casting cavity on top of metal previously delivered to the casting cavity.

7. In a mold for casting aluminum or aluminum alloy articles having a thin wall portion the combination of cooperating mold bodies having their meeting faces'recessed to form communicating gate, feeder and casting cavities, the said casting cavity having a shallow portion for forming a thin wall portion of a casting, the feeder cavity communieating with the casting cavity throughout a major portion of the vertical height of the latter and so disposed with respect to the shallow portion of the casting cavity that molten metal in filling the casting cavity flows a minimum distance from the feeder cavity through the said shallow portions of the casting cavity, the said gate cavity communicating with the feeder cavity throughout a major portion of. the vertical dimension of the latter and adapted to deliver heated metal progressively from the bottom to the top of the feeder cavity.

In testimony whereof I hereunto affix my signature this 12th day of March, 1925.

ALLEN B. NORTON.

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