US2808629A - Shell mold sprue construction - Google Patents

Description

Oct'. 8, 1957 J. J. wEGLARz SHELL MOLD SPRUE CONSTRUCTION Filed Aug- 9. 1955 0ct. 8, 1957 J. J. wEGLARz SHELL MOLD sPRuE ooNsTRucTroN 4 Sheets-Sheet 2 Filed Aug. 9. 1955 F/GQ ATTORNEY Oct. 8, 1957 J. J. wEGLARz SHELL MOLD SPRUE CONSTRUCTION 4 sheets-sheet s Filed Aug. 9, 1955 Oct. 8, 1957 J. J. wEGLARz SHELL -MoLD sPRUE CONSTRUCTION 4 Sheets-Sheet 4 Filed Aug. 9. 1955 ...H J-.-- l!" United States Patent' o y SHELL MOLD SPRUE CONSTRUCTION John JQWeglarz, Chicago, lll., assignor to International Harvester Company, a corporation of New Jersey Application August 9, 1955, Serial No. 527,210

8 Claims. (Cl. 22-134) This invention relates to the casting of molten metals or other liquid materials capable of solidication. More in particular this invention has to do with a sprue construction for conducting clean molten metal into a mold cavity with less turbulence and reduced amount of metal.

Metal castings made by pouring molten metal into molds without precaution generally .results in a poor grade of product. This generally is the result ofpermitting dross, oxides, slag and other insoluble impurities entering the mold cavity and become a part of the casting. Particularly in sand or shell molding a serious problem exists in preventing such impurities from entering the mold cavity. Turbulence or aspiration during the pouring of the molten metal into the mold tends to sweep in undesirable impurities into the mold cavity. It has been found that the quality of the product castings can to a surprisingly large extent be determined or enhanced by the construction of the sprue or gate means to the cavity of the mold. It is therefore a prime object of this invention to provide an improved casting device or sprue construction whereby the molten material is conducted uniformly to the mold cavity with minimum turbulence or aspiration. a i

A further object of the invention is to provide an improved sprue construction whereby substantially all insoluble impurities in the molten material will be trapped in the sprue, thus preventing the entry of said impurities into the mold cavity.

A still further object of the invention is to provide an improved sprue construction which, in addition to the preceding objects, requires a smaller quantity or volume of molten material thus reflecting a higher efficiency or yield in castings per lunit weight of said molten material.

Further objects and advantages of the invention will be apparent from the ensuing description, the appended claims and the annexed drawings wherein:

Figure 1 is a perspective view, quarter sectional, showing the assembly of the two parts comprising the invention, the'upper part being adapted for insertion in the cope portion of a mold and the lower part being adapted.

ingA only the lower part referred to in Figure 1.

Figure 3 is a perspective View, quarter sectional, showing only the'upper part referred to in Figure l.

Figure 4 is a side view, in section, of the upper part referred to in Figure 1 taken along the line 4 4 of Figure 3.

Figure 5 is a side view, in section, of the upper part referred to in Figure 1, taken along the line 5 5 of Figure 3.

Figure 6 is a side view, in section, referred to in Figure 1, taken along Figure 2.

Figure 7 is a side View, in section, of the lower part referred to in Figure 1 taken along the line 7 7 of Figure 2f 1 l Figure 8 is a side`viewtak'en in the direction along of the lower part the line 6 6 of a 2,808,629 Patented Oct. 8, 1957 the line 8 8 of Figure 1 showing the shape of the solidified material after pouring a mold using the sprue con` struction of this invention.

Figure 9 is an end view taken in the direction along the line 9 9 of Figure 1 showing the shape of the soliditied material after pouring a mold using the sprue construction of this invention.

Figure 10 is a perspective View, quarter sectional, showing the assembly of the two parts comprising a modilied form of the invention, the upper part being adapted for insertion in the cope portion of the mold and the lower part being adapted for insertion in the cheek or drag portion of the mold.

Figure 11 is a perspective view, quarter sectional, showing only the lower part referred to in Figure 10 Figure 12 is a perspective view, quarter sectional, showing only the upper part referred to in Figure 10.

Figure 13 is a side view, in section, of the upper part referred to in Figure 10 taken along the line 13 13 of Figure 12.

Figure 14 is a side view, in section, of the upper part referred to in Figure l0, taken along the line 14-14 of Figure 12.

Figure 15 is a side view, in section, of the lower part referred to in Figure 10, taken along the line 15-15 of Figure 11.

Figure 16 is a side view, in section, of the lower part referred to in Figure 10, taken along the line 16-16 of Figure 1l.

Figure 17 is a side view taken in the direction along the line 17-17 of Figure 10 showing the shape of the solidified material after pouring a mold using the sprue construction of the invention. p

Figure 18 is an end view taken in the direction along the line 18 18 of Figure 10 showing the shape of the solidified material after pouring a mold using the sprue construction of the invention.

This invention is particularly useful in the metal casting lield generally referred to by the foundry industry as shell molding. Briey, shell molds are generally constructed by packing molding sand, having about tive percent by weight of an uncured thermo-setting resin incorporated therein, on a base plate having the cope section of the pattern mounted thereon. The plate and pattern are usually made of heat resistant metal. After the sand and resin mixture is packed against the plate and pattern, heat is applied to the pattern which results in partly curing the resin binding the sand adjacent the pati tern and plate. The loose sand with uncured'resinis removed leaving a hard crust or shell of the partly cured resin in sand around the pattern and its associated plate. The sand shell, plate and pattern are then heated to cure the resin more completely after which the shell is stripped from the pattern and plate. The drag section of the shell mold is made in the same manner after which the two shells are positioned in cooperative relation and sealed together to form a mold having one or more cavities therewithin. The resin used for the binding of the sand may be conveniently of the phenol-formaldehyde condensation type which is well known. l

The sprue construction comprising this invention may conveniently be made as an integral part of the above described shell mold by incorporating as an adjunct to the` cavity pattern the necessary auxiliary pattern to form the.

sprue construction. Thus the complete shell mold may contain the sprue or gating means for introducing molten metal into the mold cavities as well as the cavities them-v sprue as used herein is meant to include that portion` of a mold which conducts liquid metal'into the mold cavities. The mold cavities form the useable cast product while the sprue construction forms the waste metal.

Referring to Figures l to 7.,'the@ numeral 2 0 generally indicates .the sprue vconstruction of this invention in 1as sembled form (Figure l) where-the onepantlorgcope member 21 (Figure 3=) is in cooperative relation with Jdie second part or drag :element 22 (Figure 2),. In Shell molding both parts 21 and `22 are constructed entirely of molding sand held together with a euredthermosetti-ng resin `andmay be made simultaneously and integrally connected with the cavity `containingportion (not shown) ofthe mold heretofore described. Of course, particularly in the case of liquids capable'of zsolidifying without involving very high temperatures, the sprue construction-'of this invention may be made of other material.

From Figures l and 3l it will .be noted that the wall ,26 of the cope member 21 forms a horn-shaped .opening 23. This opening 23 is a pouring basin adapted for receiving the liquid material or molten-metal poured from a suitable ladle (not shown). The upper portion of theopening 23 is generally referred to in the industry ,as 'the basin while the lower portion is generally referred to as the downsprue. However, for purposes herein, it will be most convenient to combine these two terms by referring to the entire opening from the upper lip 24 to the lower `oriiice 25 as the basin or pouring basin.

As stated previously the contour of .thebasin 23 as formed by the wall 26 is preferably horn-shaped. The basic reason for a horn-shaped contour of the basin Y23 is that it has the effect of reducing the turbulence of the liquid poured into the basin from a ladle because .the wall 26 is without creases or other obstruction yand the liquid is caused to flow downwardly and smoothly along the wall 26.

The bottom 29 of the basin -23 is dome-shaped and is formed by a wall 39 of the drag element 22 as best shown in Figures 1 and 2.

The drag element 22 at the bottom portion 3d adjacent to the bottom 29 of the basin 23 is curved, downwardly to form a well 27 with a pair of vertically extending in spaced relation parallel disposed walls 2S, `one of which walls is shown in Figures l and 2. Thus the well 27 formed by the wall 31 and the lower portion of the parallel spaced walls 28 may be conveniently considered to eX- tend vertically to the orifice 25. It should be understood that the sprue construction of this invention may be cornprised of a plurality of such wells 27 disposed about the periphery of the bottom 29 of the basin 23 in like manner as illustrated in Figure l. For convenience two such wells 27 are illustrated in Figure 6.

Now directly above and contiguous to each well 27 there is disposed an opening or trap chamber 32. The trap chamber 32 is formed by the internal surface of walls 26 and 26 of the cope member 21 with the pair of vertically extending walls 2S of the drag element 22. The trap chamber 32 and its associated well 27 is cornmunicatively connected for fluid flow with the basin 23 adjacent the bottom of the basin by means of an outlet passage 33. Thus molten metal entering the basin 23 proceeds downwardly to the bottom 29 and thence outwardly through the passage 33 into the well 27 and rises to the upper portion of the trap chamber 32. It should be understood that where the sprue construction of this invention is provided with a plurality of wells 27 and associated trap chambers 32, the passage 33 may conveniently be extended circumferentially to provide outlet means for the molten metal from the basin 23 to each of the wells 27 and associated trap chambers 32.

.Leading from the upper portion of each well 27 there is provided one or more channels or runners 34. One end of each runner 34 extends to at least one cavity of the mold (not shown) and the other end merges with the upper portion of a well 27 thereby connecting communicatively for fluid tlow one or more mold cavities with the well 27 and provides means for conducting molten metal from the well to the cavities. The runners 34 are formed merely by interposing a channel formation 37 in the base wall 35 of the cope member 21 which cooperates with the base Wall 36 of the drag element 22 to form the runners 34 one of which is shown in Figure l.

The speed or velocity of movement of molten material should be retarded during the period `it passes from the outlet passage 33'through the well 27 to the runners 34.

By retarding the motion of the molten material in the'k well it allows suicient time for insoluble impurities of less density to float upwards into the trap chamber 32 where they are trapped in the upper portion thereof as shown at 38' in Figures 8 and 9. This may be accomplished by making the outlet passage 33 leading to each well 27 of a cross-sectional opening substantially equal to the combined cross-sectional areas of the runners leading to a given well 27. Thus the hydraulic head created in the basin causes the flow of molten material emanating from the passage 33 to divide, part to the lower portion of the well 27 and associated trap chamber 32 and the balance being directed through the runners 34. Further, the minimizing of turbulence of molten metal poured into the horn-shaped .basin 23 materially reduces the amount of air bubbles conducted through the passage 33. From this it may readily be understood by those skilled in the art that the liquid entering the runners 34 to the cavities will be substantiallyfree of insoluble impurities. Of course insoluble impurities of greater density than the liquid would settle to the bottom of the well 27 as shown at 39 of Figures 8 and 9.

Referring now to Figures 8 and 9 of the drawings there is illustrated the 4shape of the waste metal formed by the sprue construction of this invention after solidification of the molten metal and the sand shell removed therefrom. The trap chamber 32 forms the portion of metal designated 32 while the Vwell 27 forms the` portion of metal designated 27. The basin 23 forms the metal portion 23 and the passage 33 forms the metal portion 33'. Similarly the runners 34 leading to the mold cavities (not shown) forms the portion of metal 34.

The upper portions of the projections 32 indicated at 38' show the collection of insoluble materials of lower density trapped by the trap chamber 32 while the insoluble materials of high density are collected at the bottom of the well 27 and retained in the waste metal portion designated at 39. Y

It will be noted the thickness of the projection 32 is relatively lsmall as compared to ,that of 23. Thus but a relatively small amount of metal or other casting material is required to effectively trap insoluble impurities resulting in a much improved quality ofproduct castings.

Figures 10 to 18 illustrate a modified form of the invention. Brieiy the cope member is modified to terminate the wall 26 (Figure 3) at the lip 24 thereby .elimi-` nating the wall 26 from the lip 24 to the orifice 2S. The drag element (Figure 2) is modied to bring the walls 26 in a closer spaced relation. Thus the assembly of the cope member with the drag element results in that the outlet passage 33 of Figure 1 extends to the lip 24 at the top of the basin 23.

Having the above in mind we new describe the particular construction of the sprue comprising a modified form of this invention.

Referring to Figures 10 to 18 the numeral 120 gener ally indicates the modied construction of this invention in assembled form where the one part or cope member 121 is in cooperative relation with the second part or drag element 122 (Figure 11). Similarly as described in the preceding embodiment both parts are constructed of molding sand held together with a cured thermo-setting resm.

From Figures 10 and l1 it will be noted `that the wall 126 of the drag element 122 forms a horn-shapedopenng 123. The opening 123 is a pouring basin adapted for receiving the liquid material or molten metal poured from a suitable ladle (not shown), The basin 123 extends downwardly from the lip 124 to the bottom wall 130. The bottom 120 of the basin 123 formed by the wall 130 is dome-shaped as will be noted from Figure` 11.

As Will be noted from Figures 10, 11 and 15 the bottom portion 130 of the drag element is curved downwardly to form a Well 127 with a pair of vertically eX- tending in spaced relation parallel disposed walls 128, one of which walls is shown in Figures 10 and 1l and 15. Thus the well 127 formed by the wall 131 and the lower portion of the parallel spaced walls 128 may be conveniently considered toextend vertically tothe horizontal plane formed by the, base or wall 136 of the drag element 122. As before it should again be understood that modited form of sprue construction of this invention may be comprised of a plurality of such wells 127 disposed about the periphery of the bottom 129 of thejbasin 123 in like manner as illustrated in Figure' 10. For convenience two such wells 127 are illustrated in FigurelS.

Similar to the first embodiment previously described, directly above each ,well 127 there is disposed an opening r trap 132. However, the trap, 132 is not a chamber as the opening is contiguous to the basin 123 from the lip 124 down to the bottom of the basin 123. The trap 132 is therefore an opening formed by the parallel walls 128, the Well 127 of the drag element 122 and the wall 126 (Figures and 12) of the cope member 121. From this it can be seen that the trap 132 Vand its associated well 127 is cormnunicativelyV connected for fluid ow with the basin 123 by means of an outlet passage 133, which passage extends from the lip 124 downward to the bottom 129. Thus molten metal entering the basin 123 passes into the trap 132 and associated well 127 through the passage 133. It can berfurther seen that where the modied sprue construction of this invention is provided with a plurality of wells 127 and associated traps 132, a separate passage 133 connects each respective trap and Well with the basin 123.

As in the previously described embodiment, leading from the upperportio'n of each Well 127 there is provided one or more channels .orrunners'134. One end of each runner 134 extends to at least one cavity of the mold (not shown) and the other end merges with the upper portion of a well 127 thereby connecting communicating for uid ow one or more mold cavities with the well 127 and providing means for conducting molten metal from the well to the cavities. The runners 134 are formed merely by interposing a channel formation 137 in the base wall 135 of the cope member 121 which cooperates with the base wall 136 of the drag element 122 to form the runners 134, one of which runners is shown in Figure l0.

. Nowit can be appreciated that ow of molten metal from the basin 123 into the trap 132 to the runners 134 will be governed by the cross-sectional area of the elongated passage 133. Since the cross-sectional area of the passage 133 is in turn governed by the spaced relation between the walls 128 it follows that the spacing between the parallel disposed walls must be adjusted to attain a cross-sectional area of the passage 133 substantially equal to the combined cross-sectional area of the runners 134 leading to the Well 127.

By referring to Figures 17 and 18 illustrating the shape of the waste metal formed by the modified sprue construction of this invention after solidiication of the molten metal and sand removed therefrom and comparing sarne with Figures 8 and 9 of the previously described embodiment, it will be seen that the trap portion 132 of Figures 17 and 18 is much thinner than the corresponding trap portion 32 of Figures 8 and 9. Thus less waste metal together with less quantity of sand and resin mixture are the advantageous results of the modified form of the invention as compared with the rst described embodiment. It will also be noted that the waste metal portion 132 is integrally connected throughout the vertical length of 6 the waste metal basinvportion 123f whereas in the previously described embodiment the` portion 32 is connected to the basin only at the lower end. n

In the modified sprue construction when the molten metal is poured into the basin 123, forming the waste metal portion123 (Figures 17 and 18), it tiows through the elongated passage 133 into the trap 132 and well 127 forming the portions 132 and 127' respectively. Since the velocity of the molten material is retarded in the well and trap insoluble impurities of lesser density oat to the top as indicated at 138 While the, higher density insoluble impurities settle at the bottom lof the well as indicated at 139 thus permitting a much purer form of molten metal to enter the mold cavities through the runners 134 formingthe waste metal 134 of Figures 17 and 18.

Having described this invention in its preferred embodiments it should be Vunderstood that further modication may be made therein .without departing from the spirit of the inventionorrthe scope of the appended claims.

What is claimed is: v Y

1. In combinationwith aV mold having at least one cavity adapted for casting of a liquid capable of solidiiication, an improved sprue construction comprising a cope member and a drag element in cooperative relation forming avertically extending pouring basin having at least one outlet passage adjacentthe bottom thereof, a well disposed adjacent to and extending'below said basin, a vertically extending liquid trap disposed above said well, at least one runner disposed in substantially the same plane as said passage andcommunicatively connecting for tluid flow each cavity with said well and trap, said passage being adapted to connect communicatively for fluid flow said basin With said well, said passage having a cross-sectional area substantially equal to the combined cross-sectional area of said runners to each cavity of said mold for hydraulically minimizing the flow velocity and turbulence of liquidin said well thereby facilitating the flotation of insoluble impurities of said liquid into said trap. Y v

2. In combination with a mold having at least one cavity adapted Ifor casting of aV liquid capable of solidification, an improved sprue construction comprising a pouring basin having at least oneA outletpassage adjacent the bottom thereof, a well disposed adjacent to and extending below said basin, a vertically extending liquid trap disposed above said well, at least one runner disposed in substantially the sameplane as said passage and communicatively connecting for fluid ow each cavity with said Wall and trap, said passage being adapted to connect communicatively for uid ow said basin with said Well, said passage having ,a cross-sectional area substantially equal to the combined cross-sectional area of said runners to each cavity of said mold for hydraulically minimizing the ow velocity and turbulence of liquid in said Well thereby facilitating the ilotation of insoluble impurities of said liquid into said trap.

3. In combination with a mold having at least one cavity adapted for casting of a liquid capable of solidification, an improved sprue construction comprising a cope member and a drag element in cooperative relation forming a vertically extending pouring basin having at least one outlet passage adjacent the bottom thereof, a well disposed adjacent to and extending below said basin, a vertically extending liquid trap chamber disposed above said well, at least one runner disposed in substantially the same plane as said passage and communicatively connecting for fluid ow each cavity with said well and trap chamber, said passage being adapted to connect communicatively for iiuid ow said basin with said well, said passage having a cross-sectional area substantially equal to the combined cross-sectional area of said runner to each cavity of said mold for hydraulically minimizing the flow velocity and vturbulence of liquid in said well thereby facilitating the ilotation of insoluble impurities of said liquid into said trap chamber.

4. In combination with a mold having at least one cavity adapted for casting of a liquid capable of solidiiication, an improved sprue construction comprising a pouring basin having at least one outlet passage adjacent the bottom thereof, a well disposed adjacent to and extending below said basin, a vertically extending liquid trap chamber disposed above said Well, at least one runner disposed in substantially the same plane as said passage and communicatively connecting for fluid flow each cavity with said well and trap chamber, said passage being adapted to connect communicatively for fluid ovv said basin with said well, said passage having a cross-sectional area substantially equal to the combined cross-sectional area of said runners to each cavity of said mold for hydraulically minimizing the ow velocity and turbulence of liquid in said Well thereby facilitating the flotation `of insoluble impurities of said liquid into said trap chamber.

5. In combination with a mold having at least one cavity adapted for casting of a liquid capable of solidiication, an improved sprue construction comprising a pouring basin having at least one outlet passage adjacent the bottom thereof, a well disposed adjacent to said basin, a vertically extending liquid trap chamber disposed above said well, at least one runner disposed in substantially the same plane as said passage and communicatively connecting for iiuid flow each cavity with said well and trap chamber, said passage being adapted to connect communicatively for uid ow said basin with said well, said passage having a cross-sectional area substantially equal to the combined cross-sectional area of said runnersto each cavity of said mold for hydraulically minimizing the flow velocity andV turbulence kof liquid in said well thereby facilitating the flotation of insoluble impurities of said liquid into said trap chamber.

6. In combination with a rnold having at least one cavity adapted for casting of a liquid capable of solidication, an improved sprue construction lcomprising a cope member and a drag element in cooperative relation forming a vertically extending pouring basin having at least one outlet passage, a Well disposed ,adjacent to and extending below said basin, a vertically extending liquid trap disposed abover said Well, 4said trap being contiguously connected to and substantially o o-extensive with said basin and said passage, atleast one runner disposed in substantiallythe s ame plane as said passage and comwell, said passage having a cross-sectionallarea substantially equal-to nthe combined cross-sectional area of said runners to 'each ,cavity of said kmold for hydraulically minimizing the :flow velocity and turbulence of liquid in said well therebyfacilitating the 4flotation of insoluble impurities of 'said liquidinto said trap. Y 7. In, combination with a mold having at .least one cavity -adaptedfor casting of a liquid capable of soliditication, an improved sprueV construction comprising a pouring basin having at least one outlet passage, a well disposed adjacent to and extending below said basin, a vertically extending liquid ytrap disposed above said well, said trap being contiguously connected to and substantially co-extensive with said basin and said passage, at least one runnerdisposed in substantially the same plane as said passage and communicatively connecting for fluid flow each cavity with said well .and trap, said passage being adapted to connect communicatively for `fluid flow said basin with said well, said passage having a crosssectional area substantially equal to the .combined crosssectional area ofsaid runners to each cavity of said mold for hydraulically minimizing the flow velocity and turbulence of liquid in said well thereby facilitating the Yiiotation of insoluble impurities of said liquid into said trap.

8. In combination `with a Vmold having at lleast one n cavity adapted for casting of a liquid capable of soliditication, an improved sprue construction comprising a pouring basin having at least one outlet passage, a well disposed adjacent to said basin, a vertically extending liquid trap disposed above said well, said trap being contiguously v4connected to and substantially co-extensive with said basin and said passage, at least one runner disposed in substantially the same plane as said passage and communicativeljy connecting for fluid ow each cavity with said well and trap, said passage being adapted to connect commu-nicatively for fluid flow saidbasin with said well, said passage having a cross-sectional area substantially equal to the combined cross-sectional area of said runners to each cavity of said mold for hydraulically minimizing the ow velocity and turbulence vof liquid in said well thereby facilitating the notation of insoluble impurities of said liquid into said trap.

References Cited in the le of this patent UNITED STATES PATENTS 1,030,066 Erlandson .Tune 18, 1912 1,100,831 Kline lune 23, 1914 1,410,775 Thomes Mar. 28, 1922 V1,992,677 Sorensen Feb. 26, 1935 2,691,196 Banister Oct. 12, 1954 FOREIGN PATENTS 620,670 vGreat Britain Mar. 29, 1949

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