US2839801A

US2839801A - Pressure casting apparatus

Info

Publication number: US2839801A
Application number: US566207A
Authority: US
Inventors: Ellis J Zickefoose
Original assignee: Griffin Wheel Co Inc
Current assignee: Griffin Wheel Co Inc
Priority date: 1956-02-17
Filing date: 1956-02-17
Publication date: 1958-06-24
Anticipated expiration: 1975-06-24

Description

I 2,839,801 v Y PRESSURE ycAsTiNG APPARATUSV Ellis J. `Zickefoose, Chicago Heightsplll., assiguor to Grilin Wheel Company, Chicago, Ill., a corporation Aoli Delaware Y v Application February 17, 1956Serial o. 566,207

6 Claims. (Cl. 22-69) y Y I This invention relates to apparatus for the pressure l() i composite construction. A wedge `shaped ring 24y which y 2,839,801 Patented June24,u 1958 molten metal 10, `such as steel, `which is forced upwardly through al tubular pouring spout 12 into the cavity of a mold generally designated 14responsive to an increase ein, pressure within the housing. The mold 14 is prefer-v ably formed of a porous material such -as graphite.

The pouring tube 12 is held by refractory cement 1 6 within a retainer cylinder 18. At the top of the pouring tube 12 aretainer ring20V secured by screws 22 extend. ing into retainer `cylinder/18 forms an abutment for the refractory cement and lgives additional strength to the enables the mold 14 to assume a tilted 'position is secured by Allen head screws 26 to the cover 2. A shoulder pouring ofy castings and particularly to apparatus com- :i:

prising a permanent mold with a removable-gate.

- -In the pressure casting of molten metal in a permanent mold, the metal is delivered under pressure `from a ladle up through a pouring tube and thence through "a gate into the casting cavity of the mold. After the casting cavity is filled with molten metal a plunger'is activated to engage a seat adjacent to the inlet opening of the casting cavity and terminate further flow of the metal into the mold. Upon closure of such inlet opening, it is desirable thatthe molten metal drain from the pouring tube andreturn to the ladle. In order to lassure the occurrence ofzreturn flow, provision should be made for the passage of gas into the interior of the pouring tube.

An object of the invention, therefore, is to permit the passage of gas into the interior of the pouring tube upon i termination of the-pressurized ow of molten`metal Vint the casting cavity .ofa permanent mold.V Another object ofthe invention is to provide a porous gatemember in a permanent mold that will permit the passage of gas through the walls thereof to'the interior rof the gate after' closure of such gateto terminate metal ow therethrough.

Still another object of the invention is to provide a porous gasket between' the mold and the pouring tube adjacent tothe molten metal inlet of the mold, such gasket permitting the passage of gas therethrough to the interior .of the tube after closure of the inlet by a stopperV and thus'breaking the vacuum lock existing in the pouring 'tube after termination of molten metal ilow into the castingcavity.

Another object of the invention is to' provide ya gasket between the mold andthe pouring tube to cushion and v absorb the shock forces resulting from positioning a mold upon and vinconta'ct with thev'end of the pouring tube. A Y s Another object of the .invention is to provide a gate `member in a mold, such member being renewable in situ by machining, and when excessivelyworn so that further renewal thereof is not practical, being. readily removable and replaceable by a new gate member.

The invention embodies other novel features, details ofrconstruction and arrangement-of parts which areherevafter set forth in the specifications and claims and illustrated in the accompanying drawing, wherein:

Figure l is a central vertical sectional view of the apparatus according to the invention, and

Figure 2 is an enlarged view of a portion of the apparatus illustrated in Figure 1.

Referring now to the drawing for a better understanding of the invention, the pressure pouring apparatus is illustrated as comprising a cover 2 adapted to be detachably secured to a housing 4 to form therewith a sealed chamber 6, the housing being provided With an air conduit 7 leading to a suitable source of air under pressure. The housing is adapted to enclose a ladle 8 filled with 28 is provided on the retainer cylinder 18, such shoulder being in mating engagement with a shoulder 30 formed on a `male frustroconical ring 32 which ispositioned to be adjacent to vor engageable with a similar frustroconical member 34 of female construction. The member 34 has a shoulder 36 .which receives and holds a'plate 38; A recessed portion is formed on the inner periphery of the plate 38 and constitutes a leg 40 which is engageable with -a similar leg 42 formed by recessing the outer periphery ofa retainer ring 44. The two legs 40 and 42 are secured to eachother by meansof screws 46.- As shown inthe drawing, a gasket 48 is provided on top of the pouring tube 12. This gasketisin -abuttingrelation with'a y' removablegate member 50 when the mold is in A.position vfora pour. f The gate member 50 is removablyreceived ina moldA opening in themold provided for that-purpose `and has, a friction iit therein. It will be noted that the gate member 50 is provided with a peripheral ring 5.4 nearthe bottom thereof. VThe retainer-ring 44 embraces or surrounds the gate member 50 and the peripheral ring 54prevents the gate member from dropping out of the mold in the event that a tight friction t between the jmember'50Y and the-mold is not obtained. Usually, however, a tight friction lit will be had due to contact of the member 50 withy the mold at the upper and lower friction surfaces 51 and 5S of the member 50. The length yof friction surfaces 55 and 57, which are separated by a relieved section 56, can be varied to suit, depending on the degree of friction required balanced against the ease of removability desired.l f

f At its upper end member 50 is'provided with a seat 58 which is engageable with a mating seat 62 on a stopper which is movable to close the open endV of the member 50 by downward actuation of astem v64.attached tothe stopper 6 0. v i Y The removable gate member 50 is particularly adapted for use with a permanentmold formed of graphite blocks y or other material, ywhich mold can be renewed by machining -when the castingcavity hasbeen worn oreroded to an appreciable-degree. It will be noted that the upper portionY of the member 50 adjacent to the seat 58 has a longer friction surface 57 than that-of lower friction surmixture, such as a clay-graphite composition. kOf` course, if the drag and cope blocks of the mold and the gate member are of Ia similar porous material, then sufficient passage of gas will be permitted through the mold blocks and through the gate member to break anyV vacuum lock existing in the pouring tube after the stopper has been moved into closed position, thus permitting the molten metal in tube 12 to return to the ladle. However, if the mold blocks should be made of a refractory material which is not porous such as copper, for example, then an air channel should be provided extending through on'e of the blocks of material and establishing Communication' between the gate member and the atmosphere:

On the other hand, if it isdesired to retain the advantages of areplaceable ,gate member but for one reason orV another it 'is notA desiredto fortnsarne of" a' porous material, then -the necessarygas' Ieakagexean. be 'obtained solely fromtheus'e'ofi a porousrgasket 48.; Such gasket" may be of asbestos material which has su'nicientv porosity for theindicated purposewhileV at the same time otter'- ing a cushioning et'ectwhich Vwill absorb some of the shock forcesV exerted upon the enjd tof the' pouring tube when a mold is positioned in place upon; the'itop of same; I't'will thus be appreciated that'eithe'r or both a porous gate member and a porous `gasketcan beused tobreak the'v vacuum' lock existing in the pouringtube' after terminationof tlow of metal into' thejca'stingv cavity'of the mold.

The gate member yStr is of'V one piece construction without' verticaly or horizontal lines` of juncture andv in1 this fashion Cracking or' chipping at lines ofi Contact areeliminate'dl to assure a relativelyy longer-'usable life ofthe gate rnembersrY Figure2 shows a space between the-male' and female frustroccmi'cal V` members 32 and 34 that is'greatly exz'igg'er'ated.4 I-n use, these membersrwould be' very close to c'ontaet withV each other.' If the members actually do establishcontactit may be necessary to'provide grooves said annular: member in one -or both ofthe contacting'surfaces to permit air passage tothe porous gasket in the event that a non-V the molten metal in a 'housing is forced through a" gate kintol the casting cavity of' a permanent rnoId' formedof porous materia1 in response to 4an increase ofl fluid pressure Vin thev housing,V a housing-cover having a pouring tube aperture, a pouring tube extending downwardly through said aperture forthe upward passage of molten metal from the ladle tothe mold cavity, a downwardly movable plunger having a seat engageable with-a complementary seaty on the gate, said gate beingf'formed of porous material to permit 'the leakage of air through the mold vand gate into' the interior of the gate to break any vacuum existing in the gate and pouring tube and permit the metal in the pouring tube to return to `the ladle after the plunger moves into sealing engagement with the gte. Y

2; "In a pressure casting apparatus ofthe type in which molten metal in acovered housing is forced through a pouring tube and thence through agate into the casting cavity of a permanent 'mold in response toan increase of ilu'id pressure in the housing, the combination of an annular cushioning member positioned between the gate and 'the pouring tube, said member being formed of a porous material which will readily permit the passage' of'air between the tube and gate into the interior of the gate.

3. In a pressure casting apparatus of a type in which molten meta-l in a housing is forced through a gate into the casting cavity of a permanent mold in response to an increase of fluid pressure inthe housing, a housing cover having a pouring tube aperture, means to support the mold on the housing, a pouring ltube extending downwardly through said aperture for the upward passage of molten metal from the ladle to the mold cavity, a movable plunger having a seat engageable with a complementary seat on the gate, a porous annular member positioned' between the lowerend of they gate and the upper end of the pouring tube, said annular member permitting the leakage of air into the interior of the pouring tube to break'any vacuum existing therein and permit the metal in the pouring tube to `return to the ladle after the plunger has moved into closure position, said supporting means including an opening to permit the passage of air from the atmosphere through the supporting means to 4.- Ina-pressure casting apparatus ot the type in which molten'm'e'tal: in a covered housing is forced through a pouring' tube and thenceA throughv a moldV opening into the casting cavity of a permanent mold formed of porous materialvinvresponse to an increase of iiuid pressure in the housingf,the'cornbination of a removable tubular gate memberformed of porous-material and havingI a frictional tit in said moldropeninga movablerplunger having a seat engageable with a complementary seat on the gate mem'- ber, a porous annular member positioned between the gate member andthe pouring tube, said gate and annular members both permitting the leakage of air into the'interior of. the. pouring tube to break any vacuum existing therein and permitting Vvthe metal in the pouring tube to drainr back to the ladle after the plunger hasvmoved into a closure position.,`

5. -A:unitary; readily'removable gate member for a permanent mold haviuganexterior mold cavity, comprising a generally cylindricalisleeve having a closure engaging seat at. one Yend thereof adjacent said cavity, a peripheral frictional surface adjacent. to saidseat, a relieved peripheral portion'adjacentto said friction surface, facilitating removal of said gate from said mold, a second friction surface adjacent to saidrelievedportion, a peripheral projecti'on, adjacent .to said secondfriction surface and a terminal portion engageable with a pouring tube.

6. A removable gate member according to claim 5, wherein theV first peripheral friction surface is of greater lengthV axially of the gate member than the length of the second friction'surface tolpermit a surface of the mold cavity to be renewed by machining without removal .of the gate from the mold.

- References Cited in the file of this patent UNITED STATES PATENTS Great Britain Nov. 17,A 1954