US319515A

US319515A - Metal mold for casting steel wheels

Info

Publication number: US319515A
Authority: US
Publication date: 1885-06-09
Anticipated expiration: 1902-06-09

Description

3 Sheets-Sheet 1.

(No Model.)

I W. SELLERS. METAL MOLD FOR CASTING STEEL WHEELS. No. 319,515.

Patented June 9, 1885.

J/z Caz eeZ.

Inventar.

N. PETERS, Phmxrulhcgmphur. Washinglnn, m;

(No Model.) 3 Sheets-Sheet 2. W. SELLERS. METAL MOLD FOR CASTING STEEL WHEELS.

Patented June 9, 1885.

Invento'r Wit es e oumg zmiw.

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3 SheetsSheet 3.

Patented June 9, 1885.

W. SELLERS.

METAL MOLD FOR CASTING STEEL WHEELS. No. 319,515;

(No Model.)

I Inv nt 01'. fifl/m 5 :3

N. PETERS. mmum m mr. wumn m n. cy

fitnesses WILLIAM SELLERS, OF PHILADELPHIA, PENNSYLVANIA.

METAL MOLD FOR CASTING STEEL WHEELS.

SPECIFICATION forming part of Letters Patent No. 319,515, dated June 9. 1885.

Application filed June 8, 1883. (No model.)

To aZZ whom it may concern.-

Be it known that I, WILLIAM SELLERS, of

the city and county of Philadelphia, in the State of Pennsylvania, have invented certain new and useful Improvementsin Metal Molds for Casting Steel Wheels; and I do hereby declare that the following is a full, clear, and exact description of my invention, which will enable others skilled in said art to make and use the same.

My improvements are adapted to the casting of all forms of wheels in which the rim is connected with the hub by arms or by a plate or web that is narrower than the rim; but as, perhaps, their most important application, I will describe them with reference to the manufacture of wheels for railways.

It is well known that the requirements of railway service demand a wheel with solid hub, arms, and rim, or with a continuous web or plate connecting the hub with the rim, and such'wheels have heretofore been made almost exclusively of cast-iron with a chilled tread. The higher speeds and heavier traffic of the present railway system exact requirements beyond the capabilities of cast-iron, and to meet also to impart sufficient rigidity to the mold.

to retain the fluid metal in the proper shape until by cooling this shape becomes fixed. The thickness and backing for the mold must be such that the pressure from the shrinkage of the cooling metal would crush the mold before it would distort the wheel; but it must be sufficiently stiff to retain the metal in the proper shape until so far cooled as to be per-- manent. The material of these molds is too porous to admit of pouring the molten metal directly upon the surface, so that it is requisite to wash the interior with plumbago or other refractory material to impart asmooth surface to the mold, so as'to produce a similar surface upon the casting, and as the earthy material of which the mold is composed, as well as the and gas when the molten metal came in contact with it, ample provision had to be made for the escape of these, as well as of the air contained in the mold. mold must be renewed, so that the operation is not only expensive, but tedious, and consequently it has been found impossible to make such wheels at a price that would compete with steel-tired wheels having built-up centers of other material.

In the development of the art of steel-casting it has been found that this metal, with a proper chemical composition, can. be cast perfectly solid, having a density, ultimate strength, and ductility almost identical with those of a steel-forgin g, and that these charac teristics can be more certainly attained when the casting is made in a metal mold. As the shrinkage of caststeel is more than double that of cast-iron, and as the fluid or semi-fluid steel has very little tenacity, a slight resistance from the mold would result in a rupture of the casting.

It is the object of my invention toobtain a metal mold which can be separated to permit a, shrinkage of the cast metal, and which when separated will evenly support the casting; and to this end my invention consists in a metal mold provided with a rim, a supporting-frame by which a hub portion of the mold is supported, and a movable relieving-annulus between the rim and the hub portion; and it further'consists in a metal mold provided with a rim and supportingframes, which maintain the hub portions of the mold at the proper distance from each other, and provided, further, with a movable annulus, which determines the position of its hub portion radially; and it further consists in a metal mold provided with supportingframes, a rim interposed between said supporting-frames, an-upper movable annulus, and a lower movable annulus, and devices for moving the upper and the lower annulus toward and from each other simultaneously; and it further consists in a metal mold provided with an upper and a lower movable annulus and devices through which one annulus is made to counterbalance the other; and it fur- For every casting this L wash upon its surface, would give off steam ther consists in a metal mold provided-with a space or spaces within the rim portion of the mold and above the true rim of the wheel to be cast therein, which space receives the cast metal to supply the shrinkage in the rim of the casting as its cools. 1 It is to be understood that by a solid hub I mean a hub not split or divided radially or otherwise, as I contemplate either casting the i hub solid and boring it, or casting it with a central core and then boring it.

In order that my said improvements may be more fully understood, I will now describe the construction of my mold and the manner of operating the same, reference being had to the 1 accompanying drawings, which form a part of this specification, and in which Figure 1 is the plan of a railway-car wheel. having a solid hub and a continuousstraighti web or plate connecting the hub with the tread. Fig. 2 is a sectional elevationof the mold-- frame and mold in which such wheel is cast, and showing also asectionof the finished wheel l in position therein. Fig. 3 is a plan of the mold-frame and mold. Fig. 4 is a sectional elevation of the same, showing the matrix in which the metal is cast. Fig. :5 is a side elevation of the mold-frame and mold; and Fig. 6 is a plan of the lower half of the frame and a portion of the mold which is supported and.

- operated thereon, a part of this mold being broken away to show more clearly the mode of supporting and operating it from the moldframe. V In Fig. 2 the mold is shown opened, so as to relieve the casting from resistance during shrinkage after the metal is poured, and the wheel is shown as it"is after being bored,

turned, and finished, ready for placing upon its axle, to illustrate the clearance required; for shrinkage. In Fig. 4 the mold is shown: closed, ready to receive the molten metal. The space within the rim of the mold beyond that required to contain the finished wheel indicates the amount of surplus metal provided as a' sinking head for supplying the shrinkage in the rim of the wheel, so that after this sink ing head is-cut off the remainder of this rinr will be solid. A sinking head is necessaryat 5' this place, because the plate between the rim and the hub is so thin that it would chill solid before the rim had solidified. This chillingt between the rim and the hub would cut off any supply of metal from the sinking head atthe hub, and unless a supply from some other source is provided the rim, when cold, would be hollow, because it solidifies first upon the exterior, which defines the size, and the shri nkage in cooling must be supplied'from the fluid? metal in the interior until this is exhausted. 1 Such a cavity would of itself weaken the rim from the absence of metal; but the metal immediately surrounding the cavity would be weakened, owing to its irregular form and the l absence of pressure in cooling. The certainty that such a cavity existed would detract from the value of the wheel; but the uncertainty as to its extent would depreciate the market value still more.

The mold proper is composed of five principal parts. The rim A, Figs. 2,4, and 5, which is supported by the lower frame, B, and in turn supports the upper frame, 0, so that this rim is interposed between the upper and lower frame. They are all retained in position'laterally by the small flanges a a on the rim A, and they are clamped together vertically by the four hinged straps D D D D, which are attached, respectively, to the lower frame, B, by pin-joints. These straps swing over projections 00, cast upon the upper frame, so that as the straps are pushed on these projections the upper and lower frame and the rim A are wedged together. These projections also serve as handles by which the moldcan be stripped to remove the wheel after it is cast. The upper frame, 0, is provided with vertical bars a, by which the inner rim, E, is attached to the outer one, and this rim E is of such diam eter as to admit the upper hub portion of the mold, F, and allow free play laterally for the same. The hub Fis supported vertically only from the rim E by means of the ring-plate b b and the standing bolts d d. The lower hub portion of the mold, G, is supported upon the top of a similar rim, H, in the lower frame, and so as to have free play laterally. The flanges at the upper andlower ends of the hubs G and F are circular and beveled to admit the annular portions of the mold, J and K,

which, when closed, fill upthe space between the hub and the rim of the mold.

The upper annulus of the mold, J, is supported from the upper frame, 0, at four points by thestrapsc c c c, which extend over cams formed in theshafts L L in the frame 0, as shown by dotted lines in Figs. 2 and 4. The bottoms of the openings in which these cams work areat such adistance below the centers of the shafts "that the circular andouter portion of the cams will press on these bottoms when the annulus J is resting upon the rim A, so as to force theannulus against the rim, and when the shafts are turned so that the straps c a 0 0 are resting upon the circular portion-of the cards the annulus J willibe raised,as shown in Fig. 2. The strapslc 0 0 a and the blocks with projecting arms M M, upon which they are supported, are securely attached to the annulus J by the standing bolts 6 6 ea. The arms from these blocks project through slots in the rim of the-frameO, forthe purpose hereinafter explained.

lnrorder that the shafts L *L 'may be rotated simultaneously and conveniently, a crank-arm, f, .is keyed upon the-endof one and a handlever iupon the-other, and these two are connected by the illllk g g.

The lower annulus of the mold, K, is supported from the lower frame, B, at four points by the levers N N, the fulcrums of which are pins fixed in the frame. One end of each le Ila ver operates in a groove or slot in a projec' tion cast for the purpose on the under side of the annulus, and the outer end of each lever is provided with a swinging strut, m, which fits under the projecting arms from the blocks M M, so that the weight of the lower annulus, K, through the intervention of the levers N N, serves as a counter-balance to the upper annulus, J, and the two will open and close simultaneously as the opening and closing devices (in this instance the shafts L L and their cams) are rotated back and forth.

The annular portions of the mold, J and K, are provided with projecting flanges h h, overhanging the hub and rim of the mold, respectively, which act as squaring-pieces, to insure the accurate final closing of the mold.

It is evident that when. a wheel is to be cast with the plate, which connects the hub with the rim, entirely on one side of the rim, the hub portion of the mold on-that side may be a part of the frame, and the mold would re quire only one rclieving-annulus. My improvements are equally applicable in such cases, the only modification requisite being that the single annulus must then be counterbalanced, if any counterbalaneing is required, by a weight substituted for the omitted annulus.

In the center of the lower hub portion of the mold, G, I provide a block of metal, 0, Fig.4, of suitable thickness to carry off the heat from the cast metal so rapidly that the metal will chill before it has time to soften or to penetrate the side of the hub. The vertical position of this block in the mold determines the length of the lower hub of the wheelcasting, and this block is supported at the proper height by sand packed in between it and the floor on which the mold rests. The upper hub portion of the mold is made of sufficient depth to contain the length of the hub required on the wheel-casting, and a suitable length in addition for a sinking head.

The process of casting a wheel with the above-described mold is as follows: The frame is to be placed substantially level, with the block 0 supported at the proper height. The upper and lower frames must be clamped upon the rim of the mold by the four hinged straps D D, and the four swinging struts on the end of the levers N N must be placed in position under the projecting arms from the blocks M M. The annular portions of the mold must then be closed against the rim and hub portions by rotating the cam-shafts in the upper frame, which will adjust the hub portions of the mold radially-that is to say, to a position concentric with the rim. The mold and frame thus closed and clamped is moderately heated before the cast is made, with a view to avoid a too sudden heating from the molten metal, and, when arranged as described,

the metal is poured rapidly at the hub until the mold is full. The fit between the annular portion of the mold and the rim will ordinarily not be so close as to prevent the escape of the air above the plate of the wheel; but to insure this escape with ease a few small grooves should be filed across these surfaces. After this cast has been made the mold is allowed to stand about one and a half minute, or until a skin of the casting has set, when the leverhandle must be moved so as to open the annular portions of the mold and allow the necessary room for shrinkage of the wheel. When these portions of the mold have been removed, the metal in the casting will still be so supported by the lower hub and by the bottom flange on the rim that the weight of the casting cannot distort it. The length of time during which the annular portions of the mold must remain closed after the cast has been made will vary somewhat with the proportions of the wheel. It is only requisite to keep those portions of the mold closed until a skin is formed strong enough to prevent the fluid metal in the interior of the casting from bursting it when they are opened, and it is requisite that they should be opened before they can present any appreciable resistance to the shrinkage of the metal. As soon as the metal has solidified sufficiently to permit the removal of the casting without distorting it, the swinging clamps and struts are thrown off,

and the upper rim,with the portions of the mold attached to it, are lifted off, and the casting can be lifted out of its place by the hub. The mold may then be reelosedas before, and the operation may be repeated as often as required. After the wheel has been removed from the mold I prefer to pass it directly to the annealing-furnace, and after it is annealed the sinking heads of the hub and rim are out off and the wheel is bored and turned.

I have shown and described the rim of the mold, the supporting-frame, and the hub portions as separate and distinct from each other, because when so constructed avariety of sizes of both rims and hub portions maybe used in the same supportingframcs. The several parts will then be free to expand with the heat of ICC the casting without one being restrained by the other, and those parts directly exposed to the molten metal can be rcplaced,when injured,with the least expense. But it is evident that in many cases the hub portion and the supporting-frame for each half of the mold may be in one piece, the supporting-frame in this case being simply arms projecting from the hub portion to permit free expansion as the mold becomes heated, their outer ends beveled to receive and center the rim, as shown in the drawings, of the outer edge of the supportingframes. In such case the inner circumference of the annulus and the corresponding part of the hub portion must be cylindrical in place of conical, as the annulus can only be then placed in position when the mold is open. The cylindrical joint between the annulus and the hub portion may be quite free without affording any outlet for the fluid metal, because it chills so rapidly that escape through a narrow aperture is impossible.

It is also evident that with such sizes or proportions of wheels that would not impart sufficient heat to the mold to make its expansion a serious element of destruction, the rim, hub portion, and supporting-frame for each half of the mold may be in one piece; or the whole rim and the supporting-frame and hub portion for one half of the mold may be in one piece, and the supporting-frame and the hub struction; but in all such cases the removable piece could be taken completely away from the mold, leaving the mold as a whole connected' and self-supporting; but in casting a.

wheel in which the rim is connected with the hub by arms or by a plate or web that is narrower than the rim to which my improvements are adapted it is requisite to remove an annular portion of the mold between the rim and the hub to permit unobstructed shrinkage of the casting, and this must necessarily cut off the rim from the hub portion. With a mold having its central part entirely separated from and unsupported by the outer portions provision must be made for maintaining the several parts in proper relation to each other, so that when closed the matrix shall be perfect and continuous, to prevent the escape of the fluid metal when poured into it, and this I accomplish by the mold-frame, in which the devices for opening and closing the annular portions are placed, as hereinbefore described 5 and whether this mold-frame is in one piece with the hub portion or with the rim and the hub portions, or in separate pieces, as shown and described, the annular movable portions must of necessity remain within the mold or its supporting-frame. In all molds heretofore employed for relieving strains in castings portions of the upper half alone have been removable, and the cast metal has been supported over its whole under surface by the mold after the removal of the relieving portions. No mold has heretofore been employed in which any portion of the under or lower side of the cast metal could be left entirely without support immediately af-' ter casting; no mold has heretofore been employed in which any portion of both the upper and lower halves were removable, so as to leave the cast metal unsupported on. both sides when the relieving portions of the mold have withdrawn their support before the cast metal has contracted appreciably; no mold has heretofore been employed in which a movable relieving portion of it must of necessity remain within the mold or its supporting- .frame, and no mold has heretofore been employed in which two or more relieving portions counterbalance each other. All of these features are necessary to successfully cast such wheels as I propose to make, and all of these features are prominent in my mold, and these characteristics clearly distinguish it from all other relieving and supporting molds.

Having thus described the natureand object of my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. In a metal mold for casting steel wheels, a rim, a supporting-frame by which a hub portion of the mold. is supported, and a movable relieving-annulus between the rim and the hub portion, substantially as and for the purposes set forth.

2. In a metal mold for casting steel wheels, a rim and supporting-frames which maintain the hub portions of the mold at the proper distance from each other, in combination with a movable annulus which determines the position of its hub portion radially, substantially as described.

3. In a metal mold for casting steel wheels, an upper movable annulus and a lower movable annulus between the rim and the hub portions of the mold, substantially asand for the purposes set forth.

4. In a metal mold for casting steel wheels,

an upper and a lower movable annulus, in combination with devices through which one annulus is made to counterbalance the other, substantially as described.

5. A metal mold for casting steel wheels, provided with space for a sinking head within the rim portion of the mold and above the true rim of the finished wheel, substantially as described.

WM. SELLERS. Witnesses:

CHAS. M. MILLER, DAVID L. LUKENS.