Machinable cast-in-place tube enclosure fittings

Abstract: The invention relates to an end fitting for closing at least one passageway having an external periphery and an internal periphery to be cast-in-place within a part comprising a fitting body having at least one elongated, blind-ended, aperture formed therein, said aperture defined at least in part by a first surface having a complimentary shape with respect to said external periphery of said cast-in-place passageway for receiving an end of said passageway disposed extending at least partially therein to close said passageway during casting of said part, said fitting body composed of material essentially identical to material used during casting of said part, said fitting body positionable within a casting mold for forming said part to be cast, such that machining said cast part removes said blind-end of said aperture within said fitting to open said passageway cast-in-place within said part.

Description: The invention relates to a method of making an article having a plurality of open-ended, internal, passageways, and in particular, to an end fitting for closing an end of the passageway, such as a tubular conduit, allowing the surface of the cast part to be machined in order to open the end of the passageway while eliminating bi-metallic machining complications. It is generally known in the manufacture of heat transferable castings, or castings having internal fluid passages for lubrication or the like to cast metal around a tube through which liquid or gas can be passed. The tube may be shaped to suit the form of the casting and situated where the maximum heat transference is required. The tube in this way forms a passage which will not leak irrespective of the soundness of the casting and may provide a conduit of a shape which could not be achieved through normal casting techniques using cores. In the past, various techniques have been employed to manufacture cast articles or parts, such as crankshaft for internal combustion engines or transmission housing components or the like, wherein the part includes a plurality of open-ended, internal passages for supplying fluid to desired locations. One typical approach involves casting the part in a suitable mold and then drilling the passages in the cast part. Passages formed by drilling are limited to linear configurations. Moreover, drilling produces metal chips and other debris that must be removed from the passages. It has also been known to form all passages within a part as a single serpentine tube with portions of the tube removed after casting the part in order to open the individual passageways through the part, or to form a bundle of tubular conduits to be cast in situ where an end portion of each conduit has a selvage portion that is crimped closed to preclude the metal used in the casting operation from intruding within the passageways. In either case, large amounts of scrap conduit are generated using these casting techniques, increasing the cost of production for these parts. In addition, if the parts require surface machining in the vicinity of the cast-in-place passageways, bi-metallic machining complications exist when using these known techniques of casting passageways in place. It is desirable in the present invention to provide a simpler, more precise, and less costly method of forming fluid passages in cast articles or parts. It is expected that the present invention can be adapted for use in castings using metal, ceramic, plastic or hybrid composition components. It is desirable in the present invention to reduce, or eliminate, the complications associated with bi-metallic machining of surfaces having cast-in-place passageways formed therein. The present invention provides an end fitting for closing at least one end of a passageway having an external periphery and an internal periphery to be cast-in-place within a part. A fitting body is provided having at least one elongated, blind-ended, aperture formed therein. The aperture is defined at least in part by a first surface having a complementary shape with respect to the external periphery of the cast-in-place passageway for receiving an end of the passageway disposed extending at least partially therein to close the passageway during casting of the part. The fitting body preferably is composed of a material essentially identical to the material used during casting of the part. The fitting body is positionable within a casting mold for forming the part to be cast, such that machining the cast part opens the blind-end of the fitting to open the passageway cast-in-place within the part. The aperture of the fitting comprises a second surface having a complimentary shape with respect to said internal periphery of said cast-in-place passageway and extending longitudinally and coaxially with said portion of said aperture defined by said first surface. The end closure fitting according to the present invention can be made of the same material as the casting. This eliminates bi-metallic machining complications. The fittings are designed to be opened during existing or common machining processes of the part, such as facing to eliminate special processes to open the tube to fluid flow. The end closure fitting can be used as a locator with a tit or projection on the end further enhancing processing of the fitting. The end of the fitting may also be concave, or convex in a cylindrical fashion, for a near net surface to the inside diameter or outside diameter of a cylinder or cylindrical shell. The fitting is bored from the back deep to near the face. The thin wall remaining keeps material out when casting the article and is the portion removed when the cast article is bored or machined to open the tube to fluid flow. A support may be used for supporting the span between ends of the tube to keep the tube from warping due to differential heating during the casting process. The present invention can be modified for different sizes and shapes of passages to be cast in place. Other objects, advantages and applications of the present invention will become apparent to those skilled in the art when the following description of the best mode contemplated for practicing the invention is read in conjunction with the accompanying drawings. The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein: Figure 1 is a cross-sectional view of a machinable cast-in-place tube end closure fitting according to the present invention; Figure 2 is a cross-sectional view of an end closure fitting according to the present invention having a hollow locator protruding outwardly therefrom; Figure 3 is a plan view of an end closure fitting according to the present invention; Figure 4 is a side elevational view of the end closure fitting illustrated in Figure 3; Figure 5 is an end elevational view of the end closure fitting shown in Figure 3; Figure 6 is a side elevational view of the end closure fitting shown in Figure 3 with a concave surface formed thereon; Figure 7 is an end elevational view of the end closuring fitting shown in Figure 3 with a convex edge of the concave surface illustrated in Figure 6; Figure 8 is a side elevational view of the end closure fitting shown in Figure 3 with a locator pin formed on a surface thereof; Figure 9 is an end elevational view of the end closure fitting illustrated in Figure 3 with the locator pin formed thereon; Figure 10 is a plan view of a support for a cast-in-place passageway according to the present invention; Figure 11 is a side elevational view of the support shown in Figure 10; and Figure 12 is an end elevational view of the support shown in Figure 10. The present invention relates to an end closure fitting 10 for closing at least one end of a passageway 12 having an external periphery 14 and an internal periphery 16 to be cast-in-place within a part 18. Referring now to Figure 1, a cross-section of the cast part 18 is illustrated with a first surface 20 corresponding to a surface formed by an appropriate mold (not shown) for forming the part 18 during the casting process. Openings communicating with the cast-in-place passageway 12 are initially closed by the end closure-fitting 10 during the casting process, and can be opened when the cast part 18 is machined, or the like, during subsequent processing to the level of finish surface 22 shown in phantom. Machining first surface 20 by suitable machine operations to finish surface 22 removes a portion of the end closure fitting 10 opening the cast-in-place passageway 12 to fluid flow. Referring now to Figures 3-5, an end closure fitting 10 according to the present invention is illustrated for a straight flow through passageway. The end closure fitting 10 includes an elongated, blind-ended, aperture 32 defined at least in part by a first surface 34. The blind end wall 36 is removed by subsequent machining operations as previously described with respect to Figure 1. In order to provide sufficient spacing from the finish surface 22 of the part, it is desirable to provide a longitudinally extending second surface 50, preferably formed having a complementary shape to the internal periphery 16 of the passageway 12, or at the very least acting as a longitudinally extending projection from the blind end 36 in order to engage the blunt end of the passageway 12 so that sufficient distance is provided between the blind end 36 and the blunt end of the level of finish surface 22 to open the passageway 12 after casting. The second surface 50 can be formed as one or more longitudinally extending projections.from the blind end 36 forming a shoulder 52 for engagement with the blunt end of the passageway 12. If more than one projection is provided, preferably the projections are equally angularly spaced about the longitudinal axis of the first aperture 32. Alternatively, the second surface 50 can be formed as a longitudinally and circumferentially extending surface complementary in size and shape to the internal periphery 16 of the passageway. The end closure fitting 10 can be formed with a flat, generally planar surface 42 for engagement with a wall of the mold (not shown) for forming the part 18 for casting. As illustrated in Figures 6 and 7, the end closure fitting 10 can be formed with a concave, or convex, surface 46 formed in a cylindrical fashion for a closer fit with respect to an inner diameter or outer diameter of a cylinder or cylindrical shell portion of the mold or part to be formed during casting. As illustrated in Figures 8 and 9, the end closure fitting 10 according to the present invention can include a solid or hollow locator pin 44 for engagement with a wall of the mold (not shown) for forming the part 18 during casting. The locator pin 44 assists in accurately positioning the passageway 12 to be cast-in-place, during the casting of part 18 within the mold. Referring now to Figures 10-12, a support 54 according to the present invention is disclosed for supporting a span of the passageway 12 between the ends 24 to keep the passageway 12 from warping due to differential heating during the casting process. The support 54 includes a longitudinally extending, open ended, aperture 56 allowing passage of the passageway 12 therethrough. Preferably, one surface 58 of the support 54 is formed for engagement with other supporting structure within the mold, such as a wall of the mold for forming the part 18 during casting. Preferably, the support 54 is formed of essentially the same material as the material being used to cast the part 18. As previously described, using the same material, or material having essentially the same machining characteristics, reduces or eliminates the complications associated with bi-metal machining operations. The present invention provides a passageway that is completely formed and cast-in-place without the necessity of drilling straight, angled, cross, or intersecting apertures. The passageways 12 are opened during normal machining operations required after the casting process. Eliminating the need for drilling consequently eliminates broken drills and down time for drill and tool changes. The bore within the tube is smooth, even and consistent. The direction of flow is controlled in a position to the point of best application and is not a compromise of available drilling angles and intersecting lines. The casting can be made lighter by eliminating excess materials supplied only for the purpose of providing space to drill apertures. The process is also adaptable to existing casting processes with minimal effect to the existing casting process. Care must be exercised to reduce the amount of time that metal washes over the passageway 12 or the end closure fitting 10 during the pour of the casting process, and tight radius curves in the passageway 12 should be reduced during the design phase. It should be understood that the article or part 18 can be cast in a mold by any conventional process. One or more tubes can be suspended in a mold, so that a cast member forms around the tubes. In effect, the tubes are encapsulated in the part 18 and form one or more passageways through the cast component. The tubes are never removed from the casting. The present invention eliminates the length of tube that previously would extend beyond the cast component that required additional machining operations to cut off the length of the tube, or to otherwise remove the exposed length of tube, and also presented difficulties in machining the finish surface of the part 18 due to the bi-metal surface be machined where the tube extended through the finish surface of the cast part. By using end closure fittings 10 of essentially the same material, or at the very least of material having comparable machining characteristics, the complications due to bi-metal surface compositions are dramatically reduced or eliminated. It is expected that the present invention can be adapted for use with plastic, ceramic, metallic,.or hybrid composite combinations of tubing materials to be cast within any castable, i.e. molten, fluid or flowable, material. The tubes or passageways 18 can also be secured together by welding, or any other suitable method, prior to placement in the mold to retain the passageways 12 in any desired positional relationship with respect to one another. In addition, a single end closure fitting 10 may include a plurality of apertures 32 for receiving the ends 24 of a plurality of passageways 12 to be cast-in-place during a single pouring process. While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiments but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as is permitted under the law.

Claims: An end fitting (10) for closing at least one passageway (12) having an external periphery (14) and an internal periphery (16) to be cast-in-place within a part (18) comprising: a fitting body having at least: one elongated, blind-ended, aperture (32) formed therein, said aperture (32) defined at least in part by a first surface (34) having a complementary shape with respect to said external periphery (14) of said cast-in-place passageway (12) for receiving an end (24) of said passageway (12) disposed extending at least partially therein to close said passageway (12) during casting of said part (18), said fitting body composed of material essentially identical to material used during casting of said part (18), said fitting body positionable within a casting mold for forming said part (18) to be cast, such that machining said cast part (18) removes said blind-end (36) of said aperture (32) within said fitting (10) to open said passageway (12) cast-in-place within said part (18), the aperture (32) of the fitting (10) having a second surface (50) having a complementary shape with respect to said internal periphery (16) of said cast-in-place passageway (12) and extending longitudinally and coaxially with said portion of said aperture (32) defined by said first surface (34). Fitting (10) according to claim 1 wherein a transitional shoulder (52) disposed between said first and second surfaces (34, 50) of said aperture, such that said cast-in-place passageway (12) abuts against said shoulder (52) when inserted within said fitting (10). Fitting (10) according to one of the preceding claims wherein a second aperture (38) in said fitting (10) having a complementary shape with respect to said external periphery (14) of said cast-in-place passageway (12) and being coaxial with said portion of said aperture (32) defined by said first surface (34). Fitting (10) according to one of the preceding claims wherein a locator pin (44) formed on said fitting (10) for cooperative engagement with a mold for forming said part (18) during casting. Fitting (10) according to claim 4 wherein said locator pin (44) having a hollow interior defined at least in part by a blind end wall (36) communicating with said aperture (32), such that machining of said part (18) after casting removes at least said blind end wall (36) of said locator pin (44) and opens said passageway (12) cast-in-place within said part. Fitting (10) according to one of the preceding claims wherein said fitting body having a generally flat, planar or a concave or a convex surface (42) operably engageable with a mold for forming said part (18) during casting. Fitting (10) according to one of the preceding claims wherein a stand (54) for supporting an intermediate portion of said cast-in-place passageway (12), said stand having at least one aperture (56) extending therethrough of a shape and size complementary to said external periphery (14) of said passageway (12). A process for casting a part (18) having at least one passageway (12) with an external periphery (14) and an internal periphery (16) to be cast-in-place within the part (18) comprising the steps of: providing an end fitting (10) having a fitting body with at least one elongated, blind-ended, aperture (32) formed therein, said aperture (32) defined at least in part by a first surface (34) having a complimentary shape with respect to said external periphery (14) of said cast-in-place passageway (12), said fitting body composed of material essentially identical to material to be used during casting of said part (18); receiving an end of said passageway (12) disposed within said blind-ended aperture (32) and extending at least partially within said fitting body; closing said passageway (12) with said blind-end of said aperture (32) in said fitting body; positioning said fitting body and attached passageway (12) within a casting mold for forming said part (18) to a wall of said casting mold; casting said part (18) with said fitting body and attached passageway (12) embedded therein; and machining said cast part (18) to remove said blind-end of said aperture (32) in said fitting body to open said passageway (12) cast-in-place within said part (18). A part cast by the method of claim 8 comprising: at least one passageway (12) with an external periphery (14) and an internal periphery (16) cast-in-place within the part (18); at least one fitting body disposed adjacent a surface of said cast part (18), said fitting body having at least one elongated, blind-ended, aperture (32) formed therein, said aperture (32) defined at least in part by a first surface having a complementary shape with respect to said external periphery (14) of said cast-in-place passageway (12) for receiving an end of said passageway (12) disposed extending at least partially therein to close said passageway (12) during casting of said part (18), said fitting body composed of material essentially identical to material used during casting of said part (18), said fitting body positionable within a casting mold for forming said part (18) to be cast, such that machining said cast part (18) removes said blind-end of said aperture (32) in said fitting body to open said passageway (12) cast-in-place within said part (18). A cast part (18) having at least one passageway (12) with an external periphery (14) and an internal periphery (16) to be cast-in-place within said part (18) comprising: an end fitting (10) disposed adjacent a surface of said cast part (18), said end fitting (10) having a fitting body with at least one elongated, blind-ended, aperture (32) formed therein, said aperture (32) defined at least in part by a first surface having a complementary shape with respect to said external (14) periphery of said cast-in-place passageway (12) for receiving an end of said passageway (12) disposed extending at least-partially therein to close said passageway (12) during casting of said part (18), said fitting body composed of material essentially identical to material used during casting of said part (18), said fitting body positionable within a casting mold for forming said part (18) to be cast, such that machining said cast part removes said blind-end of said aperture (32) within said fitting to open said passageway (12) cast-in-place within said part (18). The cast part (18) of claim 10 formed by the method comprising the steps of: providing an end fitting (10) having a fitting body with at least one elongated, blind-ended, aperture (32) formed therein, said aperture defined at least in part by a first surface (34) having a complementary shape with respect to said external periphery (14) of said cast-in-place passageway (12), said fitting body composed of material essentially identical to material to be used during casting of said part (18); receiving an end of said passageway (12) disposed within said blind-ended aperture (32) and extending at least partially within said fitting body; closing said passageway (12) with said blind-end of said aperture (32) in said fitting body; positioning said fitting body and attached passageway (12) within a casting mold for forming said part (18) to be cast with said blind-ended aperture (32) disposed adjacent a wall of said casting mold; casting said part (18) with said fitting body and attached passageway (12) embedded therein; and machining said cast part (18) to remove said blind-end of said aperture (32) in said fitting body to open said passageway (12) cast-in-place within said part (18). A cast part (18) having at least one passageway (12) with an external periphery (14) and an internal periphery (16) to be cast-in-place within said part (18) comprising: a fitting body having at least one elongated, blind-ended, aperture (32) formed therein, said aperture (32) defined at least in part by a first surface having a complementary shape with respect to said external periphery (14) of said cast-in-place passageway (12) for receiving an end of said passageway (12) disposed extending at least partially therein to close said passageway (12) during casting of said part (18), said fitting body composed of material essentially identical to material used during casting of said part (18), said fitting body positionable within a casting mold for forming said part (18) to be cast, such that machining said cast part (18) removes said blind-end of said aperture (32) within said fitting to open said passageway (12) cast-in-place within said part (18).

Inventors: HAGA DAVID, MCDANIEL JAMES D, NAGEL ROGER B, HAGA, DAVID, MCDANIEL, JAMES D., NAGEL, ROGER B.
Applicants: ITT MFG ENTERPRISES INC, ITT MANUFACTURING ENTERPRISES, INC.
Application year: 1996
Main classification: B22D19
IPC codes: B22D19