US2029499A - Metal mold - Google Patents

Description

Feb. 4, 1936. A. "B. NORTON ET AL METAL MOLD Filed Jan. 3, 1930 2 Sheets-Sheet l INVENTOR .ALLe/v 5. N 0/ T BY /7,4,/z/.s 61/1 ATT RNEYS Feb. 4',v 1936. B. NORTON Er AL 2,029,499

METAL MOLD Filed Jan. 3, 1930 2 Sheets-Sheet 2 IINVENTORS B 12 ,4

LLE-N B. NoEfa/V ,l BY MAE/us 607077 A TORNEYS Patented Feb. 4, 1936 PATENT OFFICE METAL MOLD Allen B. Norton and Marius Guyot, Cleveland,

Ohio, assignors to Aluminum Company of America, Pittsburgh. Pa.,' a corporation of Pennsylvania Application January 3, 1930, Serial No. 418,362 14 Claims. (Cl. 22-436) This invention relates tothe casting of metal articles in permanent molds. More particularly it relates to a method of and an apparatus for casting thin walled, hollow articles-having upwardly converging walls. T

It has been diflicult'to cast in permanent molds, hollow articles having-upwardly converging thin walls composed of a light weight metal having a high crystallization shrinkage, such as aluminum or its alloys, and to obtain a casting which will completely fill out the mold cavity and which will be free from air. pockets. Another difficulty in casting such articleshas been in providing a gate which can be readily and rapidly removed from the casting itself and which will not leave unsightly gating marks thereon. In previously used constructions'lit has been necessary to utilizemolten metal which is heated'to an'extremely v high temperature in order to maintain the metal molten while filling the cavity.

It is an object of this invention to provide for the casting of an article of the class described whereby the casting is formed free from unsightly gating marks, the eradication of which is costly and annoying.

Other objects will be apparent from the specification and from the accompanying drawings in which latter Fig.1 is a top plan view of a. mold assembly embodying my invention;

Fig. 2 is a transverse sectional view taken along line 2-4 of Fig. 1; y

Fig. 3 is a detail view of the positioning means for one of the sections of the mold. a

Figure 4 is a fragmentary top plan view partly in section of the mold base and core.

Referring particularly to the drawings, one embodiment of this invention is shown as a device adapted to the formation of a washing machine agitator which has an upwardly extending substantially cylindrical hollow portion I closed atits upper end and outwardly flaring walls 2 at thebase thereof. which carry fins or flanges 3 in spacedrelation fin their upper surfaces. Preferablythe article is. composed of metal having low specific gravityas compared with iron and in-' eluding aluminum. magnesium, their alloys or.

other suitablelight metals and their alloys.

provide 'a mold for and method of casting hollow articles The mold for casting the article comprises the relatively movable mold sections 4, and 6 which are supported upon the base I and are adapted to cooperate with each other and with a sectional core A to form the casting cavity. 'The portion of the core A which is to aid in forming the por tion I of the article can be withdrawn from its operative position to facilitate removal of the cast article from the mold. Ejectors B operate to elevate the cast article from the remainder of the core when the mold sections 4, 5 and 6 are withdrawn therefrom.

The mold sections 4, 5 and 6 cooperate in the following manner: I

Each mold section is' provided with two straight working faces which meet atan' angle facesof adjacent sectors are in face to face engagement and flush with one another. Mold sections 4 and' 5 are pivotally mounted-upona pin Ill affixed to the base I. Mold section 5 carries a pivot pin II to which. mold section B is'pivoted for movement toward and from section 5. It will be seen that moldsections 4 and 5 can be swung to-' gether about their pivot points bringing work faces of the mold sections into contact with each other and that mold section 5 can be swung about its pivot point bringing its work faces into engagement with corresponding faces of mold sections 4 and 5. The mold faces are suitably recessed to form the casting cavities l2 in which the flanges 3 are to be formed. The adjacent mold sections are also recessed to form the common pouring sprue l'3a which communicates through three traps l3b with the three gates l3 which open into an annular runner cavity to be later described and to provide branch gates I4 which open into the upper portion of the casting cavity. Similarly the mold sections cooperate to form the riser I cavity [5 at the top of the casting cavity. The

mold sections 4, 5 and 6 are secured in operative position by means of a link I! secured to the mold section 4 and a cam lever I8 secured to link I! and adapted to bear behind a portion of the mold section 6. The upper portions of the mold sections are clamped together by means of clamping arms l9 and are locked in clamped position by means of the link and cam. lever 2 I. Auxiliary clamps'22 can be provided upon intermediate portions of adjoining mold sections. A pin is provided for holding mold section 5 in position with respect to the base 1."

forming a substantially wedge-shape. While the sectors of the mold are wedge-shape the meeting While mold section 6 5.v is being swung into or outofits assembled posia tion3l.

fion the pin is supported by brackets 28 and mold section I andis adapted to pass through an openinginmoldsectionlintoanopening 21inthe baa: I.

The core the annular section (see Fig.2) whichissupportedbyandisaflixedto the base I. Core section 30 carries rigidly a sec- An elongated'core section 32 is disposed in an opening in section 33 for longitudinal movement with respect thereto. Rotational movement between the two core sections is prevented by the key 33. Additional sections 34 and 35 are carried by core section 32. The core sections cooperate with the mold sections to form a casting cavity which is upwardly converging and of irregular contour. The core is provided with a runner recess 36 in its top surface which extends peripherally around and communicates with the casting cavity at a plurality of points. It serwes as an inlet for molten metal from the gates l3 to the underside of substantially all portions of the periphery of the bottom of the casting cavity.

As appears from Figures 2 and 4, the core sections 3| stop off or prevent communication for their full width between the annular rlmner 36 and the cavity for the casting proper. Core sections 3| ako carry slight ribs on their upper sides to form radial depressions or grooves on the underside of the casting below ribs 3. The runner 3 thus opens into the casting cavity at a plurality of places which, as shown, constitute a major portion of the entire circumferential length of runner recess or the periphery of the base portion of the casting proper.

The mold sections 4, i and 6 are brought into accurate relation near the top by a pilot member 6a. Below this pilot member the abutting inner faces of the mold sections are suitably re-' to receive and hold accurately in position a central upward rod or extension 320 of the core 32. The purpose of this extension 32a is to position the core at the top and prevent any lateral play or displacement of the upper part of theeore. Thislateralsupportinsures thatthe .small thin hollow upward extension of the casting will be of'the desired shape and dimensions.

Means are provided for withdrawing the core section 33 relative to the remainder of the core I A. Core section 32 is provided with an extension 31 which is guided inlongitudinal movement by abracketflaflixedtot'hebase 1. Member isprovidedwithrackteeth which are adapted to beengagedhythepinionflwhichisactuatedin mtarymnvunmtbythelever lilsoastoeflect dtudinal movement of core section 2.

AneiectorBforelevatingthecast metal frunthe core is supported by the bracket llsndthepinsflwhichareconnected withtheraflallandareadaptedtobeelevated shafts 45' is provided can be rotated and will eiector pins 43.

the device, with the mold sections In. and core in their assembled position the molten the casting cavity, rising therein to form the portions 3 and 3 of the article and then the portion i. As the metal rises in the casting cavity additional metal flows into the casting cavity through the bypasses I 4 to form the upper portion of the cast article i and to supply the casting cavity with molten metal to compensate for crystallization shrinkage of the metal during cooling. After solidification of the metal the mold is opened by releasing the clamps l9 and 22. Mold section 4 can now be swung about the pivot pin ill to open position and mold section 6 can be swung about.

pivot pin' II to a position clear of the casting. Positioning pin 25 is removed from engagement with the base 1 after which mold sections 5 and G are together swung about pivot pin it to a position laterally of the cast article.

The casting is now elevated from the core by actuating the lever 41 to raise the ejector pins 43 thereby forcing the casting into an elevated position. when the casting has been removed from the mold the gate metal can be readily broken oil, after which the runner metal can be sawed oif or cut off in a lathe and the riser metal similarly removed. This leaves the casting with clean smooth working surfaces that do not require any grinding and, for many uses, do not. require any polishing and hence the cost of production is lessened while an improved article is obtained.

While the invention has been described as applied to the formation of a washing machine agitator it is understood that it is applicable to form articles of irregular contour and of widely varying shapes.

While a specific embodiment of the invention has been shown and described it will be apparent 'that modifications can be made therein within the spirit and scope of the invention and such modifications are intended to be covered by the appended claims.

We claim:

1. A mold for making aluminum alloy castings which comprises a mold base, a core-associated therewith having. an upwardly projecting member, a plurality of pivoted mold sections carried upon the base, a supplementary mold section pivoted to one of the mold sections, and means to limit pivotal movement of the supplementary mold section with respect to another mold section, the mold sections being adapted to cooperate with the core to form a cavity for a thin walled hollow casting.

2. Av mold for casting an article having upwardly converging thin walls which comprises a mold base, a core reciprocably carried thereby and projecting thereabove, a slender upward extension constituting a part of said core, a plurality of mutually pivoted mold sections carried by said base and adapted to surround said core and form therewith a casting cavity, a conical positioning member carried by and in prolongation of said upward extension, inner faces on said mold sections forming a conical recess adapted to clamp said member, thereby holding said core extension in position in said casting cavity.

3. A mold comprising in combination, a base, a core carried by said base and having an annular runner recess in its upper surface, separable mold sections carried by the base and arranged to enclose said core to form a casting cavity therebetween, said mold sections being formed witha feeder extending therethrough and open- .ing into said runner recess and arcuate gates runner recess on each side of said feeder.

4. A mold comprising in combination, a base,

a core carried by said base and having an an nular runner recess therein, a plurality of sepa- -rab1e mold sections carried by said base and arranged to close about said core to form a casting cavity therebetween and to enclose said recess to form an annular runner, a plurality of feeders extending through said mold sections and opening into said runner, said core and mold sections ,co-operating to completely enclose said runners at the junctures therewith of said feeders, and gates opening from said runner into said casting cavity beginning at points spaced on each side of each of said feeders.

5. A mold comprising in combination, a base, a core carried by said base and including a substantially circular portion and a relatively thin axially projecting portion, an annular recess disposed in said substantially circular, portion, a plurality of spaced blocks. arranged about the periphery of said circular portion and projecting a short distance into said recess, a plurality of separable mold sections arranged to close about said core to form a casting cavity therebetween and to enclose said annular recess, said mold sections engaging said projecting blocks to completely enclose said recess and at other points being spaced from said circular portion to form a gate opening from said recess into said casting cavity and feeders extending through said mold sections and opening into said annular recess.

6. In a mold, a base, a plurality of separable mold sections pivoted to said base and arranged to define a casting cavity, said mold sections having -a sprue therein and having three spaced feeders communicating with said sprue and each communicating with the casting cavity at substantially its lowest plane.

'7. In a mold, a base, a plurality of mold sections including a pair of sector shaped sections conjointly pivoted to each other and to" said base, and a third sector shaped section pivoted to one of said pair of sections, said mold sections being arranged to fit together to define a casting cavity, and means for clamping said mold sections together.

8. In a mold, a base, a core carried by said base, a pair of sector shaped mold sections conjointly pivoted to each other and to said base.

a third sector shaped mold section pivoted to one of said pair of sections, said three sections being arrangedto enclose said core to define a I casting cavity, and means for clamping said mold sections together.

9. In a mold, a base, a plurality of mold sections pivoted to each other and to said base and arranged to define a casting cavity, each of said mold sections having a relatively large portion adjacent said base and a relatively small upward extension, means for clamping said mold sections together adjacent the base, and a clamping ring arranged to surround the-upward extensions of said mold, sections andclamp the same together.

10. A mold for thin walled castings composed ity of mold sections co-operating with each other and the base and core to forms. vertical casting cavity having an enlarged base, and means for introducing molten light metal into the casting cavity including a common pouring sprue, a

of light metal comprising a base, a core, a plural- ,ing an annular runner recess formed therein sur 4 rounding the portion of said core defining the under surface of said flared base wall, a plurality of separable mold sections carried by said base and arranged to be closed about said core to define the outer surfaces of the casting cavity for said article, the abutting edges of I .djacent sections being provided with mating recesses forming feedersopening into said annular runner recess, and said mold sections being formed to abut said core to close the inner circumference of said annular runner recess at the points where said feeders open into the same, and being spaced from said core intermediate said feeders to provide narrow gates opening into the casting cavity.

12. A mold for casting an article having upwardly converging thin side walls, a flared thin base wall and thin upwardly projecting radial flanges which comprises a mold base, a core carried by the mold base and a plurality of separable mold sections carried by said mold base and arranged to be closed aboutsaid core to define the castingcavity, said mold sections and core being recessed to provide an annular runner surrounding the lowermost edge of the casting cavity, the abutting faces of said mold sections being recessed to define the casting cavity for said radial flanges and being separately recessed to define gate passages opening into said annular runner, said mold sections being formed to abut said core to close the inner circumference of said annular runner at the abutting faces of said mold sections, and being spaced from said core intermediate said abutting faces to provide narrow gates opening into the casting cavity, whereby the metal entering the about the lower-most periphery of the casting cavity, and the abutting edges of said mold sections being recessed to form a pluralityof gate passages opening into said annular runner recess and converging upwardly and joining together above the top of said casting cavity and core, and said mold sections being recessed to form a single pouring spru'e above'and communicating with the juncture of said gate passages, whereby molten metal may be supplied from the single pouring sprue at the top of the mold to said annular runner recess at the bottom of the casting cavity simultaneously at a plurality of spaced points.

14. A mold for casting an article having upwardly converging thin side walls rising from an annular flared base wall and terminating at their upper ends in an integral boss havinga relatively small diameter and a relatively thick section intelowermost periphery of the casting cavity, themeeting faces of said mold sections being recessed to form gates leading downward between each pair of meeting faces to said annular runner recess, the meeting faces of said mold sections being further recessed to form a feeding riser extending upwardly from and opening into the casting cavity for saidlthick section boss and said meeting faces being further recessed to form by-passes opening from said gates and extending inwardly and upwardly therefrom and leading into the casting cavity above the portion oi. the cavity forming said thin side walls, said gates and annular runner being arranged to feed molten metal into the lowermost periphery of the casting cavity so that the metal rises upwardly through the casting cavity and fills the same and said by-passes being arranged to flll'the casting cavity for said thick section boss and said riser with metal at a higher temperature than the metal which has risen through the casting cavity, whereby the metal forming said thin upwardly extending walls will solidify before the metal in said thick section boss and the metal in said boss will solidify before the metal in said riser.

' ALLEN B. NORTON. MARIUS GUYOT.

Images