US1282963A - Metal-casting apparatus. - Google Patents

Description

F. SHRODER.

METAL CASTING APPARATUS.

APPLzICATlON HLED JULY 21.1912.

Patented 001;. 29, 1918.

" nearer-cherries AP]? l a s ecification or letters JPatent.

l at rf COMPANY, OF CHICAGQ, ILLINOIS, A CORPOEATIUN 015' ILLINQIQ.

TUS.

. Patented Get. $9, this.

Application filed July av, 1917. Serial no. nearer.

cage, in the county of Cook and State of 'lilmois, have invented new and useful Improvements in Metal-Casting para us, of which the following is a speci cat1on,'-reference being had to the accompanymg drawings, forming a part thereof.

The purpose of this invention is to provide an improved construction of metal casting devices, particularly for the purpose of die casting, and particularly relating to the melting pot or crucible for furnishing molten metal to the die or mold. It consists in the elements and features of construction shown and described, as indicated in the claims. a y

In the drawings:

Figure l is a to plan View of a crucible or melting pot an an adjacent portion of a die or mold which is supplied therefrom, equipped with this invention. 7

Fig. 2 is a section at the line, 2-2, on Fig. 1.

Fig. 3 is a section at the line, 3-3, on Fig 2.

ig. 4 is a section at the l1ne,44= on Fig. 2, as the same would appear straightened out flat.

In the drawings 1 represents a melting pot or crucible for holding metal and in wh1ch the metal may be melted b means of heating devices, not shown. his melting pot comprises a-well, 2, formed integrall with the pot and standing-up in the mi dle of the pot cavity, from WhlCh it is adapted to receive the molten metal through a port, 3, at the bottom of the pot, opening laterally into'the well near the bottom of the latter.

A discharge duct, 5, leads from the bottom of the well upward for discharge through the mouth, 6, at a point at least as high as the high llquid level of the well, that is, so that the liquid will not be discharged from the dischar e mouth of said duct by gravlty. The well to ehas a connection at the top for the admission and escape of air, it being de-- signed to force'the metalout of the well for discharge through the duct, 5, to the die, indicated at 7, by compressed air admitted through the pipe, 8, discharged into the t9p of the well through what is termed the compressed air head, 9, which is merely a hollow fitting into which the ipe, 8, is screwed, said fitting having its ischarge apertures,

9, opening back toward the top of the well; and the top of the well is dome-shaped, curved concavely downward, for the purpose of deflecting theair jetted through the ports, 9, in a manner to break up the jets and prevent them from causing a disturbance upon the surface of the liquid metal in the well. 12, is a three-way valve which is operated by means, not shown, for admitting compressed air supplied through a pipe,

13, leading from a source of compressed air,

not shown, into the well, and permitting its escape when the well is to be filled. The operation ofthis three-way valve is familiar and obvious and need not be further explained.

In the pipe line, 13, leading from a source of compressed air to the valve, there is interposed-a chamber, 14, in which what may be termed a reserve of compressed air is accumulated in the intervals of filling and discharging the well. The reserve chamber is situated proximate to the melting pot, the source of compressed air being usually at a very considerable distance, and the pipe connection from said reserve chamber to the well is relatively large and free, andafi'ording opportunity for the quick passage of air from said reserve chamber, as compared with the rate at which the air will reach said chamber through the smaller and relatively long pipe connection which leads from the source of compressed air to said reserve chamber. The employment of this reserve compressed air chamber greatly facilitates the operation of casting, because it makes the operation of discharging the metal from the well through the duct to the die or mold almost instantaneous.

In previous attempts to operate a casting apparatus of this character,that is, in which the molten metal is expelled from a chamber in which it is accumulated into the die, by compressed air operating upon the surface of the molten metal in such chamber, when the duct leading from the well to the die leads upward to a point at or above the level of the liquid in the melting pot, as is necessary that it should do in order to dispense with a valve at the discharge mouth, diificulty has been experienced in making solid castings, that is, castings without defects caused by air introduced with the metal into the molds,whenever the device is operated in such manner and to such extent as to completely evacuate the well and the disi with the well, and slide up along the duct and form bubbles of air in the metal discharged into the die or mold, and sometimes cutting oif a portion of the metal, which falls back and is trapped in the bottom of the well. This defect is overcome in the present structure by four features, each of which contribute somewhat to the desired result. In the first place, the .well is contracted or reduced in cross-section progressively at 1ts lower end beginning at a point a short distance above the intake mouth of the discharge duct; secondly. the discharge du ct itself is progressively contracted or 1nished in cross-section from its intake mouth upward toward and nearly to its dlscharge end; thirdly, this contraction or reduction in cross-section of the duct is made by narrowing horizontally rather than vertically, or rather, the duct is widened horizontally,- that is, increased in horizontal diameter,- from the portion at the discharge end where it is circular, back toward the intake mouth where it is quite flatly oval; and, fourth1y, and most important for the result desiredthe contracting of the well at the lower part, as mentioned, is effected by drawing in the wall of the well at the side at which the discharge duct leads oif, so that there is formed a tongue, 18, protruding in under the inner side,that is, the side toward the discharge duct.between the bottom of the well and said discharge duct. The total result of these features is that the action of the compressed air upon'the liquid metal in the well in lowering the level, causes the upper surface of the metal to remain horizontal until that upper surface is lowered to the point of contraction of the well at the bottom part; and as the level becomes lowered below this point and the velocity of the discharging metal increases as the cross-section of its path diminishes, the operation is as if the metal were caused to lag or be held back at the side at which the tongue, 18, protrudes in its path, while it continues to move without such lagging at the farther side where it is free from such obstruction, sult that the surface of the metal, instead of being horizontal, becomes slightly inclined downward away from the point at which the retardment occurs on said tongue, remaining substantially or approximately at with the re-,

memes right angles to the axis of the body of liquid metal below or in front of it, so that by the time the surface of the metal has been pushed around the bend of What may be called the trap at the foot of the well and at the enthrough the discharge duct as perfectly as it operated as such iston in forcing the metal down in the we I; and in this process the air obtains no opportunity for bubbling around the bend or acute angle at the junction of the well and discharge duct and so sliding up on the upper side of the metal in the discharge duct, as it would but for the protruding tongue, 18. This result is further assisted, or rather the escape of the air around the bend and on the top of the metal is prevented, by the steady reduction of the cross section of the passage both at the lower end of the well and in the discharge duct, the reduction being more than suiiicient to compensate for any gain in velocity of the liquid which in a duct continuously uniform cross section would result in the opening of space in the duct around the llquid movlng therein into which the air will pass.

It is of course essential that a snug junction should be made between the discharge mouth of the duct and the die which is to be filled. This has usually been a matter of considerable difficulty, whether the meltmg pot is moved up to the die or the die moved up to the melting pot for making this unct on, because wherever there are moving parts, very slight wear or play at the bearlngs upon which they move tends to defeat the perfect accuracy of position of the meeting faces of the 'twomembers which must meet accurately and seat perfectly upon one another to eifect the desired junction to prevent metal being discharged through the seam at such meeting faces. This difliculty is overcome in the present construction by means of the junction member, 20, which is a tubular member,that is, has an axial duct, 20, through which the metal is conducted from the discharge mouth, 6, of the ot, into the ingate, 21, of the die shown at 4, the receiving end of the unction piece having a spheroidal boss 20*,

with respect to which the duct, 20 is axial, and the discharge mouth 6, of theduct, 5, being circular so that the spheroidal boss will seat accurately in it, notwithstanding considerable variation in respect to the direction of axis of the junction member. Said un ct1on member has an annular flange, 22, forming a shoulder, 22 which faces outward with respect to the discharge mouth ofmesses member in the discharge mouth. The outer end of the junction member, 20, is plain or flat, adapted to seat against the correspondingly fiat face of the die; and from the construction described it will be seen that if the two planes,that is the'flat end of the junction member and the flat end of the die,are not perfectly parallel when the die is advanced against the junction member,- or the junction member advanced against the die in cases Where it is the pot that is movable,the continued approach of the two members after the face of the die and the end of the junction member come in contact at one edge or the other, will square them up to each other, efi'ectin a perfect junction of their two flat faces, t e spheroidal boss at the opposite end of the junction member permitting the accommodation of the junction member at that end to the discharge mouth of the duct, 5, while continuing to be perfectly seated thereat.

I claim 1. In combination with a melting pot or a crucible, a junction member for connecting the discharge mouth of the crucible to the ingate of a die or mold, the junction memher having a flange forming a shoulder facing outward with respect to the discharge mouth of the melting pot and a clampfor holding said junction member seated at the said discharge mouth, comprisinga forked end embracing said junction member and having its fork-prongs curved convexly toward and seating on said flange.

2. In a structure such as set out in the last claim foregoing, said clamp being pivoted intermediate its ends upon the melting pot, and a screw set through the end remote from the fork prongs, and impinging against the melting pot for clamping the forked prongs against the flange.

3. In a fluid metal casting apparatus, a pot for containing the molten metal; a well therein arranged to be supplied with molten metal from the pot, having a discharge duct from its lower part, a source. of fluid pressure and a discharge nipple protruding into the top of the well connected with said source of fluid pressure, and having its discharge apertures directed back toward the v top of the well.

4. In a structure such as defined in the last foregoing claim, the top of the well being interiorly dome-shaped. p

5. In a metal casting apparatus, in combination with a melting pot and a well therein adapted to be filled by gravity to the level of metal in the melting pot, and a discharge duct leading from the bottom of the well upward for discharge at a point above the liquid level of the pot, whereby such discharge may be valveless; means for forcing the metal out of the well for discharge through said duct, consisting of a conduit from a source of compressed air leading into the top of the well, whereby the metal is forced from the well by a fluid pressure acting upon the surface of the liquid metal in the well, the well being reduced in crosssection taperingly at thelower part, leading to the duct intake mouth, the duct being progressively reduced in cross section from its intake mouth on upward toward the discharge end. 7

6. In a structure such as set out in the last claim foregoing, the taper or reduction in cross-section of the well at the lower part being effected by drawing in the wall of said well at the side at which the duct extends up, whereby there is produced a tongue protruding into the well cavity at that side and "at the bottom, and between the well and the initial portion of the duct.

7. In a metal casting apparatus, in combination with a melting pot and a well therein ada ted to be filled by gravity to the level of metal in the melting pot, and a discharge duct leading from the bottom of the well up ward for discharge at a point above the liquid level of the pot, whereby such discharge may be valveless; means for forcing the metal out of -the well for discharge through said duct, consisting of a conduit from a source of compressed air leading into the top of the well, whereby the metal is forced from the well by a fluid pressure acting upon the surface of the liquid metal in the well, the wall of the well at the side at which the duct leads up therefrom being deflected inward with respect to the well 01111.- ing a tongue protruding under the upper part of the Well cavity and forming a partial bottom for the well at the side toward and immediately above the inlet mouth of the duct.

In testimony whereof I have hereunto set my hand at Chicago, Illinois, this th day of July, 1917.

' FRED SI-IBODER.

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