US2269455A - Mold and sprue sleeve therefor - Google Patents

Description

' Jan. 13, 1942. F. HAGEMEYER MOLD AND SPRUE SLEEVE THEREFOR Filed Feb. 17', 1940- 2 SheetP-Sheet 1 INVENTOR v I v v I I 1942 H. F. HAGEMEYER 2,269,455v

MOLD AND SPRUE SLEEVE THEREFOR 4 Filed Feb. 17, 1940-, 2 Sheets-Sheet2 sprue aperture in the mold itself.

Patented Jan. 13, 1942 UNITED STATES PATENT OFFICE 2,269,455 MOLD AND SPRUE SLEEVE macros, Henry F. Hageme'yer, Chicago, 111., assignor to Castings Patent Corporation, Chicago, 111., a corporation of Illinois Application February 17,1940,, Serial No. 319,460-

6 Claims. (01. z t-134) This invention relates to molds for use as a casting matrix, and more specifically to an attachable sprue tube which may be aflixed to the mold, and through which molten metal or the equivalent may be poured into the mold cavity. This application is a continuation in part of my application Serial No; 213,164, filed June 11, 1938, now Patent No. 2,198,498, issued April 23, 1940, for Apparatus for forming mold sprue tube sockets. t a

In general foundry practice molten metal has heretofore been poured into a casting mold either merely through a. sprue aperture cut or' formed in the mold back, or through a sprue tube set on top of the mold in alignment with the Such sprue tubes have either been separately molded from the mold material employed for the mold or have been rigid metal tubes lined with some refractory material, such as fire clay, which have been held in place by weights The former type of sprue tube has been expensive to make because of the additional molding operation required,

whereas the latter have been expensive because. 'of' the materials used in their construction.

Furthermore, while the molded tubes are used only once, being'broken from about-the metal desired length, either by cutting the width of the sheet to be rolled to correspond to the finished tube length, or by cutting the tube to length after it has been rolled and the ends secured. The finished sprue tube is attached to the mold preferably by inserting one end into a socket formedin the back of the-mold and encircling material, sucli as asbestos paper, which may be against as it fills the tube.

, The use of, some type of sprue tube has definite advantages, especially where the mold is poured while inclined upwardly from the sprue aperture, enabling .a relatively large hydrostatic head of molten metal to be retained therein for.

exerting pressure on the metal in the mold cavity.

, The use of a sprue tube has often been ne lected, however, even where it should have been used, because of the drawbacks mentioned above, The economy and simplicity of 'useof my tube either with sand or plastic material molds makes it practical in many instances where a sprue tube would not have previously been used.-

My attachable sprue tube is formed of laminations of sheet, heat resistant material, such as asbestos paper. Thetube may be made by rolling an. asbestos strip spirally into a tube with a wall havingtwo or three layers of the asbestos paper. The iapping ends of the sheet extending lengthwise of the tube may be secured together in any desired manner to prevent the tube from unrolling. Such a tube may be made ofany the sprue aperture communicating with the mold cavity. .This socket has an end thrust seat It is a more ,specific object-to construct sucha sprue tube out of thin'and inexpensive ,sheet rolled spirally to form the tube. Although economical, such a tube will be self-sustaining in that it will have sufllcient lengthwise stiffness to be held in place solely by its socketed end during pouring of the metal, and sufiicient hoop tensile strength to withstand the stress which the poured metal exerts radially outward there- Another object is to attach a-sprue tube to a mold in a position encircling the sprue aperture easily, and yet sufllciently firmly so that the tube will be held upright solely by its engagement with the mold, and so that a tight joint,

preventing leakage of molten metal, will be formed between the base of the sprue tube and the mold. 'Such engagement will prevent the ,sprue tube from being dislodged from the mold socket by the inflowing metal and also will prevent the tube from being split lengthwise.

Still a further object is to provide a mold and sprue tube assembly in which the base of the sprue tube fits into a socket in the mold, and

is wedged thereinbyv material packed between a wall of the sprue-tube and a wall ofthe mold socket.

Another object is to provide an attachable thin walled sprue tube with a target to aid the operator in pouring the molten metal thereinto.

Additional objects will be observed in the following descrlption of the mold and sprue tube structure and the exemplary illustrations shown in the drawings, the novel features of which are defined in the appended claims.

Fig. l is a vertical section through a mold and an attached sprue tube; I

Fig. 2 is a plan view of a mold showing the attached sprue tube in section as seen on line 2--2 of Fig. 1;

Fig. 3 is a vertical section through a mold and an attached sprue tube showing a modified form of tube receiving socket;

Fig. 4 is a. horizontal section through an attachable sprue tube showing one form of securing means for preventing unwrapping of the sheet;

Fig. 5 is a longitudinal section through a part of the sprue tube showing another type of securing means;

Fig. 6 is a transverse section showing still another type of fastening;

Fig. 7 is a fragmentary perspective view of a mold and an attached sprue tube showing a split reinforcing and securing sleeve encircling such tube;

Fig. 8 is a plan view of an asbestos sheet from which the sprue tube shown in Fig. 1 is formed;

Fig. 9 is a side elevation of a partially completed sprue tube; and

Fig. 10 is a plan View of the sprue tube shown in Fig, 1, illustrating the appearance of the target as seen by the operator.

While I have illustrated my invention as applied to a two part mold consisting of a cope section and a drag section, it is to be understood that it is equally applicable to a one part mold or to a mold having three or more parts. The mold M is provided with the usual sprue aperture A extending through the back into communication with the mold cavity by the runner R. About the sprue aperture is formed a sprue tube socket l consisting of a substantially cylindrical wall and a planar thrust seat III at the base thereof, disposed substantially perpendicular to and encircling the sprue .aperture A. In the form shown in Fig. 1, the thrust seat is separated from the sprue aperture by a flange, while in the form of Fig. 3 merely a shoulder-12 is provided between the sprue aperture and the sprue tube end thrust seat.

I have devised a .way of eliminating the separate molding operation previously required to make the sprue tube by fabricating it from heat resistant sheet material, preferably asbestos paper. Sheet stock from ,4 to %4 of an inch in thickness has been nse'd satisfactorily. Such a sheet is rolled into a tube having two or three layers or laminations ordinarily, although if the sheet is thick enough a single layer only may be used if a suflicient lap is provided at the joint and the ends are held securely against unwrapping. Usually it is unnecessary to use more than three layers, and to avoid use of more, it maybe desirable to employ heavier sheet material. A total wall thickness of something less than I; of an inch is adequate for general purposes where the sprue tube has about a two inch diameter or less and metals of medium melting point, such as bronze and aluminum, are being poured. For pouring metals having low melting In making the tube, a sheet is preferably cut 1, 2 and 3, the tube having two laminations 20. At the joint theouter end 2| preferably laps over the inner end 22 approximately a quarter of a turn, so that if the infiowing metal tends to turn back the edge 22 to a slight extent the joint will still have at least as many layers as the rest of the tube.

Preferably the exterior end or flap 2| only is fastened to the tube body in order to allow pressure of the metal to unroll slightly the inner end 22 of the tube, thus to press the laminations tightly together to further stiffen and strengthen. the tube. For-this purpose any satisfactory heat resistant adhesive may be employed, water glass or sodium silicate being suitable for use on asbestos. Instead of gluing the sheet end in place, any of various mechanical fasteners may be used. In Fig. 4 a staple 23 pierces the tube wall at the joint and its inner ends are bent over -Any suitable type of metal stitching may be used for this purpose. Figs. 6 and 7 show still a dinerent type of.mechanical means for holding the tube rolled. In Fig. 6 a wire 28 is wrapped about the tube 2 and the ends are twisted together at 21 to bind it upon the tube. If the tube is not too long a single wire will be s'uflicient, although if its length is more than five or six inches 2. second wire may be required. In the form shown in Fig. 7, the asbestos roll is held by a resilient, sheet metal sleeve 28 having a lengthwise split to make it expansible. The longitudinal ends 29 are separated only very slightly. With this arrangement, the sheet stock from which the tube is rolled may be thinner than that used with the other embodiments, since the metal sleeve lends considerable support to the asbestos tube.

Where a tube of asbestos paper held only by glue or by small staples as shown in Figs. 4 and 5 is employed, it is not necessary to remove it from the metal sprue after the sprue has been separated from the casting. Instead the covered sprue may be put into the melting pot and the asbestos tube will separate from the metal as slag. This operation saves time, but if desired the asbestos may readily be stripped from the metal sprue before it is put into the melting pot. Where the wire 26 is used, it should be removed by breaking the twisted joint in order to prevent contamination of the sprue metal when it is remelted. The sleeve 28, after solidification of the sprue, may be sprung toseparate farther the edges 29, so that the sleeve may be slipped end.- wise off the sprue. The asbestos paper may then be unwrapped, for with the wire 25 of Fig. 6 or the sleeve 28 of Fig. '7 it is unnecessary to have additional means for holding the sheet rolled.

Assuming that a mold sprue tube socket of the type shown in Fig. 1 has been formed, the sprue tube may be made of a diameter to just slip within the outer wall of the socket, as shown in .points, such as zinc, a thinner wall may be used.

to a width which corresponds to the desired length of the finished tube, and of a length'sufficient to make the required number of wraps in the production of a tube of the desired diameter. A representative finished tube 2 is shown in Figs.

that figure, and to be moved endwise into engagement with the end thrust seat Ill. It is desirable to have a groove of a depth several times its width so that the sprue tube will be held in place solely by insertion of its lower end into the seating groove. Since the groove outside the flange I I is preferably of a width slightly greater than the thickness of the sprue tube, there will be a space left between the inner periphery of the tube and the outer periphery of such flange. As the metal is poured into the mold through the sprue tube 2, it fills that portion of the groove between the sprue tube and the flange and serves to wedge the end of the sprue tube in place to give it still greater support. As the bulk of the metal flows on into the sprue aperture A there will be relatively little outward pressure on .the inserted end of the sprue tube, and since it is in contiguous engagement with the outer periphery of the groove, it cannot be spilt by the pressure of the metal thereon.

As an alternative, a wall of the sprue aperture may be flared so that as the cylindrical sprue tube 2 is pressed into place a wedging action will occur. Thus, with a sprue tub socket such as shown in Fig. 1, a sprue tube having a smaller diameter than that shown may be used, just great enough so that it will be spread to some extent by the inner flared periphery of the socket groove as it is pressed downward, yet insufficiently to prevent the end seating firmly on the seat l0. If the groove is substantially wider than the tube thickness, this will leave the outer part of the seat groove unfilled, and it may be packed with anysuitable material to wedge the tube end in place, although ordinarily this should not be necessary. With the inserted, end of the tube fitting closely about the inner wall of the groove, no appreciable amount of metal will flow between the flange and tube. There is therefore no outward pressure of the inflowing metal against the critical portion of the tube, namely, its inserted end.

In order to wedge in place the inserted end of the sprue tube when a socket such as shown in Fig. 3 is employed, the outer socket wallmay be flared upwardly. As the tub is slid downward its periphery is slightly contracted, and outward pressure of the molten metal against the inside of the tube merely tends to expand it to its original diameter, and it therefore cannot be split. Under ordinary conditions it may not be necessary to make even this type of socket tapered if the tube is constructed fairly accurately, for the sheet material is somewhat yielding and its en-- gagement with the socket wall will prevent suflicient expansion to rupture it. Moreover the lower end of the tube need not be fastened, so

'that outward pressure of the metal may tend to unroll the tube slightly and thereby cause the tube to engage the socket wall firmly. If a taper is used, as described, it need be only very slight, since any considerable taper would tend to collapse the inserted end of the sprue tube. In fact, the illustration of the taper in Fig. 3 is exaggerated in order to make it visible in the drawing. In this form also the end thrust seat positively prevents endwise downward movement of the tube under the influence of the inflowing metal. It will .be noted that the end thrust seat is spaced a considerable distance laterally from the sprue aperture A by the ledge l2 so that there will be no danger of the corner of such aperture being caved in. Any scraping of the tube along or held by a binding member, such as the wire 26 or the split sleeve 28, the securing means need not extend clear to the bottom of the tube to allow it to be expanded enough by pressure of the molten metal to be pressed into firm engagement with the sprue tube seat. Especially if the sheet of asbestos or other material has a rough surface, the surface of the tube will tend to become embedded in the wall of the mold socket, which is preferably of plaster of Paris, although it may be of molding sand. I

' In the form of Fig. 7 the split, spring sheet metal sleeve is shown as stopping short of the mold so that the asbestos tube seats either in a socket suchas shown in Fig. 1 or that shown in Fig. 3 as previously described. As an alternative, however, the metal sleeve 28 may be made of a diameter such that its lower end will fit within the sprue tube socket. In such case fewer layers of the heat resistant sheet material will afford the same strength. Moreover, while all the tubes illustrated are of constant diameter'throughcut their lengths they may be flared upwardly from the surface of the mold, or the upper end only of the tube may be flared upwardly, in order to facilitate pouring .of the metal into the tube. Tubes of this shape are not preferred, however, because sheets of special shape must be used in their construction instead of merely rectangular sheets being employed. It would, of course, also be possible to make a flared tube which would have fewer layers at the top than at the bottom,

this being permissible because the pressure of the metal at the bottom of the tube is greater than its pressure against the top. It has been found, however, that for ordinary purposes the straight, cylindrical tube illustrated having a constant wall thickness throughout its length is perfectly satisfactory and is easiest to make and most economical.

Since the sprue tube is thin walled, it is sometimes diffi-cult to see it from the top during the pouring operation. I, therefore, prefer'that the side of the sheet that is to form the upper portion of the tube be cut inwardly a short distance in several places to form upstanding members 30 as shown in Fig. 8.- The tube is then rolled from this sheet and the end of the sheet secured in place in any of the alternative manners previously mentioned. At this point the tube appears as shown in Fig. 9. The upstanding members 30 are then bent outwardly into a rough cone as shown in Figs. 1 and 10, thus providing a jagged light grey target of substantial size, surrounding the sprue opening, which appears as a dark hole.-

Having described my invention, what I claim as new and useful and desire to secure by Letters Patent of the United States is: I

1. In combination, a mold having a sprue tube socket depressed below the back thereof and encircling a sprue aperture communicating with the wall would break off particles of mold mametal against the tube will have sometendency to unroll it if it is not secured against such movement. Thus whether the tube be glued, stapled,

the mold cavity, such socket having a planar sprue tube end thrust seat encircling and spaced a considerable distance laterally from such sprue aperture, and a sprue tube of substantially uniform wall thickness throughout its length having an end inserted in such sprue tube socket with such end seated against said end thrust seat, and with that portion of the sprue tube wall adjacent to such end in contiguous engagement with a side wall of the sprue tube socket disposed substantially perpendicular to the end thrust seat, said sprue tube comprising a thin walledself-sustaining tube of heat resistant material.

2. In combination, a mold having a circular sprue tube socket depressed below the back thereof and encircling a sprue aperture communicating with the mold cavity, a wall of such socket extending inward from the-mold back being slightly flared, and a cylindrical sprue tube having one end inserted in such sprue tube socketwith its wall pressed into contiguous, wedging engagement with such flared socket wall, said sprue tube comprising a thin walled self-sustaining tube of heat resistant material.

3. In combination, a mold having a sprue aperture in the back thereof communicating with the mold cavity and encircled by an annular groove, and having a flange separating the groove from said aperture, and a sprue tube having a wall thickness slightly less than the width of said annular groove, having its lower end seated in such groove, and adapted to be clamped therein by molten metal flowing into such groove between the sprue tube and said flange and solidifying therein, said sprue tube comprising a thin walled self-sustaining tube of heat resistant material.

4. An attachable mold sprue tube comprising a spirally rolled sheet of heat resistant material, means to secure said sheet against unwrapping, the top portion of said tube being split longitudinally to form members partially separated from said tube, and said members being bent outwardly to form a target surrounding the opening at the top of said sprue tube.

5. An attachable mold sprue tube comprising thin walled, self-sustaining tube of heat resistant material, said tube being split longitudinally to form a target provided at the top thereof to aid the operator during the pouring operation.

6. A combined mold and sprue tube comprising a mold having a sprue aperture extending vertically thereinto to provide a passage for fused metal, a. thin walled self-sustaining tube formed of rolled heat resistant sheet material, and means to attach the lower end of the sprue tube to the mold so that the tube communicates with the aperture and is supported by the mold, said attachment means comprising a formation on said mold which, in co-operation with the annular wall of said tube, produces a wedging action between the mold and the tube when the tube is pressed endwise against the said attachment means, whereby said mold and said rolled tube can be formed separately and assembled by pressing said tube endwise against said attachment means.

HENRY F. HAGEMEYER.

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