US2312796A

US2312796A - Casting metals

Info

Publication number: US2312796A
Application number: US416684A
Authority: US
Inventors: Donald J Campbell
Original assignee: Individual
Current assignee: Individual
Priority date: 1941-10-27
Filing date: 1941-10-27
Publication date: 1943-03-02
Anticipated expiration: 1960-03-02

Description

March 2, 1943. D. J. CAMPBELL CASTING METALS Filed Oct. 27', 1941 3 Sheets-Sheet 2 Enventor Darya/J c]. @arrzfiBo/l I M, 14/- Dal,

Cittorneg CASTING METALS Filed Oct. 27, 1941 3 Sheets-Sheet 3 JEA- 3maentor Donald J. (fang/11ml] M M Da/w attorney Patented Mar. 2, 1943 UNITED STATES PATENT OFFICE CASTING METALS Donald J. Campbell, spring Lake, Mich. Application October 27, 1941, Serial No. 416,684

' (o1. 22 7s) y Claims.

My present invention relates to improvements in casting metals and particularly to the casting of hollow metal bodies such as the bodies of projectiles employed in connection with warfare; and the objects of my improvement are; first, to provide a method by which hollow metal bodies can be cast free from internal defects; second, to provide a method whereby the molten metal is gaged to the amount approximating the amount required for each hollow body; third, to provide a method whereby surplus metal is reduced to a minimum; fourth, to provide a mold whereby it is possible to produce the above named objects, cheaply and rapidly.

I attain these named objects and such other ity. The member I 2 is provided with a central cavity l3 having valve seat It therein and an opening I5 extending from the said valve seat to the top of the member and, runner cavities objects as may appear from a perusal of the 7 description taken in connection with the accompanying drawings, in which- Figure l is a vertical sectional view of the mold in which I cast from metal the hollow bodies, the view being taken on a plane extending transversely of the mold on the axis of two ofthe mold cavities, as taken On line II of Figure 2.

Figure 2 is a cross-sectional view of the complete mold as taken on line V-V of Figure 1.

Figure 3 is a view illustrating a projectile body of which a portion is removed in order to show the explosive'charge cavity therein.

Figure 4 is an alternate structure of the mold illustrated in Figure 1, the view being in section similar to that shown in said Figure 1 and diflering from said view in that the molten metal gaging cavity extends down between the mold cavities; and the molten metal is partly fed to the moldcavities by gravity and partly by suction.

Throughout the several views of the accompanying drawings, similar numerals refer to similar parts or portions, and referring thereto:

Numeral 1, designates a metal mold structure comprising a plurality of mold sections 2 each having therein a mold cavity 3 in which to cast the body 4 of a projectile having an explosive charge carrying cavity 5 formed in the mold cavity by core 6 built of granular material and having voids reaching from the exterior of the core to the twine I wrapped around the perforated hollow core arbor 8 screwthreaded into hollow core supporting sleeve 9 having chamfer ID at its top and bore ll extending axially from its top to the top end of the core arbor. The core supporting sleeve 9 extends through granular slab like member l2 and is pasted or otherwise secured to the said member which positions the core in concentric relation to the wallof the mold cavity 3 and above the bottom of said cav- I3 extending from cavity l3 to above the mold cavities and in which is set core like slab I! having annular metal delivery gate l8 extending from each cavity Hi to each mold cavity and between the said slabs I1 is a granular core like slab l9 having opening 20 at its axis extending around which is clay like packing ring 2|. Each mold section 2 has a segmental like portion of pocket 22 having extending therein neck 23 of valve 24 having enlarged umbrella like top 25 engaging the seat; and held there against by fusible member 23 resting on pedestal 21 of valve supporting member 28 supported and positioned by pliable composition member 29. resting in the bottom of the pocket 22.

' At the top of the slab member I 2 is molten metal gaging or measuring reservoir 30 composed of a highly refractory material within cylindrical metal shell 3| and having a registry shoulder 32 whereby the amount oi molten metal in the reservoir is gaged; the cavity of the reservoir being in registration with the opening I 5 of the slab member l2.

Connected to the sleeve 8 and engaging the chamfer [0 thereof is suction head 33 having hole 34 registering with the bore ll of the said sleeve, and from which extends tube 35 for drawing suction on the heads 33 that are connected together by flexible metal hose 38. The heads 23 being supported by brackets 31 extending from the top of the mold and joined together by annular ring 38. Helical springs 39 interposed be--v tween the ring 38 of the brackets 31 maintain forced engagement of the head 33 with ,the chamfer III of said sleeve regardless of any discrepancies in assembly.

The mold comprises a plurality of mold sections 2 each having a V-cross-sectional form with flat adjoining faces, a semicircular exterior wall 2' and flanges 2" by which they are secured together by suitable bolts or screws.

Referring to the alternative structure of the mold shown in Figure 4; numerals from I to 38 inclusive refer to the same parts or portions referred to in Figures 1, 2 and 3 and referring to the additional numerals of said Figure 4; 40 designates a core like slab closing the upper end of the mold cavities 3, supporting the core 8, arbor 8 and having sleeve 9 extending through it with its beveled seat l0 and hole or bore II, at

the bottom of the mold is core like slab ll supported on bottom plate 42 and having therein chamber 43 with runner passages 44 extending therefrom to circular runner passage 41, the said plate 42 has at its axis, pocket 46 corresponding to pocket 22 of Figure l and in which are the valve 24, pedestalfl, fusible member 26, valve supporting member 21 and pliable composition member 29. Between the mold cavities 3 and the core like slab 4| is gate slab 48 having extending therethrough from the runner passage 41 to the mold cavity 3, gates 49 whereby molten metal passes from the runner passage 41 to the mold cavity 3.

In casting hollow metal bodies such as the bodies of projectiles, I provide a. mold substantially as described and disclosed having as its major portion, ferrous metal machined internally to close tolerances, and having provided the mold, I provide molten ferrous metal having a temperature approaching 2900 degrees Fahrenheit and deposit sufficient said molten metal in the reservoir 30, in which the amount is gaged by the shoulder 32 and which amount equals the amount required to fill the several mold cavities, the gates I8 or as in Figure 4 the chamber 43, passages 44 and 41 also gates 49 and the mold cavities 3. When the reservoir is filled up to the shoulder 32, heat from the molten metal is conducted by the valve 24 to the fusible metal member 25 thereby melting the fusible metal member whereupon the valve 24 is forced away from its seat and permitting the molten metal in the reservoir 30 to flow therefrom to the chamber l3, the runner passages l6 and through the gates It to the mold cavities, in which suction is drawn through the cores 6, and arbor 8 by suction applied to the tube 35 and flexible tubing 36; connecting the suction heads 34 with each other. The valve 34 when the fusible metal member is melted or weakened to an extent that it does not have sufficient strength to support the valve together with the weight of the molten metal in the reservoir 30, droops away from its seat with considerable force due to the weight of the molten metal in the reservoir and should it be allowed to strike the core like slab l8, would be liable to break the valve or core like slab and permit pieces of the valve or slab to be carried into the mold and thereby cause defects in the casting being produced; in order to prevent breakin of the valve or core like slab, the soft clay ring 2| is provided and which extends around the neck 23 of the valve and being soft, squashes when the valve strikes it when forced, or drooped from its seat, this clay ring besides preventing breakage of the valve or core like slab l8 forms a packing that seals the opening between the neck 23 of the within itself, by any mold coating formed by the molten metal disintegrating the moldcoating and by the core, from the mold thereby presenting all gas or air pockets forming within the casting and thus producing a metal casting that is homogeneous throughout and of substantially uniform density of structure, and by applyin the suction as described, during the warming of the mold, all moisture caused by condensation is removed and the mold brought to the required casting temperature hastened.

valve and the wall of the pocket 22, and thereby prevents molten metal entering the said pocket and clogging the opening of the valve fully which is essential in order to allow the molten metal to flow from the reservoir to the mold cavities freely. The molten metal is flowed partly by gravity from the reservoir 30 and partly by suction applied to the core forming the cavity of the casting, by applying suction to core 6, hollow core arbor 8, sleeve 5, suction head 34 and tube 35 connected to a suitable air pump by a suitable hose; the suction being equalized between the several mold cavities-by the flexible metal hose 38 connected to each suction head; the application of suction to the mold cavity through the core as disclosed by applicant, draws the molten metal up to the extreme top of themold cavities and all gases that are formed by the molten metal Having described my present invention, the rights to which I desire to secure are hereafter set forth in the claims.

I claim:

1. In casting metals, a metal mold comprising a plurality of elongated segmental portions having flat relatively inclined sides in engagement, each portion having a mold cavity therein and extending longitudinally thereof, an annular slab member extending over each mold cavity and having an annular gate opening extending therethrough, a core composition slab extending over all of the mold cavities and engaging the first named slab whereby an annular gate is formed for delivering molten metal to the mold cavities, the second named slab having a runner passage over each of the first named slabs and having connection with a chamber at the axis of the slab with a valve seat therein, a valve engaging the said valve seat and held in engagement therewith by a metal member having a melting point below 1000 degrees Fahrenheit, the valve having a hollow neck extending downward into a recess in the mold, a pedestal extending upward into the neck of the valve for supporting the said metal member having the low melting point and supporting the said valve and a compressible member supporting the said pedestal, a metal gaging reservoir above the core composition slab for gaging the molten metal to substantially the amount required to fill the mold cavities substantially as described.

2. In casting metals, ametal mold comprising a plurality of elongated segmental portions having flat relatively inclined sides' in engagement, each portion having a mold cavity therein and extending longitudinally thereof, an annular slab member extending over each mold cavity and having an annular gate opening extending therethrough, a core composition slab extending over all of the mold cavities and engaging the first named slab whereby an annular gate is formed for delivering molten metal to the mold acvities, the second named slab having a runner passage over each of the first named slabs and having connection with a chamber at the axis of the slab with a valve seat therein, a valve engaging the said valve seat and held in engagement therewith by a metal member having a melting .point below 1000 degrees Fahrenheit, the valve having a hollow neck extending downward into a recess in the mold, a pedestal extending upward into the neck of the valve for supporting the said metal mem forming core supported therein, a slab extending applying suction to the mold cavities through the said core substantially as described.

4. In casting metals, a metal mold comprising a plurality of segmental cross-section elongated portions having elongated cylindrical cavities with cores therein for forming cavities in the metal casting means for applying suction to the said cores and therethrough to the mold cavities,

a reservoir for gaging the amount of molten metal 20 required to fill the mold cavities, means comprising a valve and a fusible metal member for retaining the reservoir closed against flow of metal from the reservoir until after the required amount of molten'metal is in the reservoir, means for conveying sufiicient heat from the said molten metal to the fusible metal member to weaken the fusible metal member and thereby open the valve and allow molten metal to flow from the reservoir to the mold cavities through passages extending from adjacent the said valve to the mold cavities.

5. In casting metal, a mold having a plurality of mold cavities, including a reservoir therein for gaging molten metal in suflicient amount to fill the mold cavities and means interposed between the reservoir and the mold cavities with a valve for retaining the molten metal in the reservoir until the molten metal in the reservoir is gaged and a member having a melting point below the melting point of the molten metal in the reservoir for supporting the valve until the member is melted by temperature conveyed from the molten metal in the reservoir.

DONALD J. CAMPBELL.