US1906676A - Method of forming composite molds for casting metals - Google Patents

Description

May 2 1933.

METHOD OF A. WALCHER 1,906,676

FORMING COMPOSITE MOLDS FOR CASTING METALS Filed Aug. 11. 1952 :5 Sheets-Sheet 1 May 2, 1933.

A. WALCHER METHOD OF FORMING COMPOSITE MOLDS FOR CASTING METALS 3 Sheets-Sheet 2 Filed Aug.

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' ME\THOD 0F FORMING COMPOSITE MOLDS FOR CASTING METALS Filed Aug. 11. 1952 3 Sheets-Sheet 5 16 L. if P6 H ZOI 13 MINIMU WW M IMT 15 Z'Qi/O. 13 +6 H' iLl ll lHllllhllll' a Patented May I i ALFRED .WALCHEIQY or f CHICAGO, ILLINOIS. Assmnon To G NERAL- s'rnm. 'cns'rmes CORPORATION, f or IDLEY 'rownsm DELAWARE iwE'rKoi) or romaine courosrrr.Momsrommis'r NGMmA s :I

Application filed Augmn; 193 2 ;.Seria1 no. 28,329.

This invention relates to improvements in a 1 theart of molding andfparticularly to very perfect part in novel method of forming molds of thetype composed of the plurality of independent sections adapted to'be' fitted together to form the comp mold- Molds used for casting large castings are difiicult to formas an integral, unitary construction and in such instances, :1 individual mold sections may be made from cor of the casting pattern,

responding parts whereby upon assembling the Ysections'ther'emold results.

for large castingsmade upjof three sections.

Molds of. this type are particularly useful for'casting "large frames,

stance'ytrdck frames for railway cars, locomotives andlikecastingsl Whereas q molds of the type illustrated by -Weaver have been used with a high degreeiofsuccess, ithas' been found in practice that certain difiiculties are met with sult between the composing sections.

I Itis obviousth'at a crack is left between adjacent sections into which aportion of the molten metal may undesirable finishkand a more or'lessjimthose portions of'thes'and adjacent the joint are more subjecttodamage andfrequently break or wash away during the pouring operatlon, resulting in an 1mperfect casting.

Itis the object ofgthisi'nvention to utilize the advantages afforded by a sectional mold, yet provide a new and improved joint and process of producing same whereby' the. above mentioned difficulties are avoided. Theprocess' of this invention utilizes the principle of forming each composite section of the mold from corresponding sections of the pattern but forming each section of slightly less length than for forming the complete mold uponlbringing the. sections into abutting relationship. Each section is formed in a section 'ofthe flask of proper leng hfor end toend attach-- suchfas for indue to the joints that reflow forming a flange' operation,

which must be removed andresulting-in an the casting. Furthermore,

the dummypattern's would be required ment, to the adjacent section butduri ng the 1 ,l PENNSYLVANIAp A. CORPORATION or operationof tamping the sand around the patternthe end of'the mold section adapted for abutting attachment 'withthe next. ad-

jacent mold,i's providedwith a temporar section.

" In: practice, itresultsthat tlie flask sections maybe attached endto end, but when 's0 arranged, the metal receiving cavities formed ,iinaccordance with the pattern sec tions are of insufficient length to come into- Accordingly, when assembled,'there, is left 5 abutting relationship. the mold sections are in the sand portions thereof, a space which may I conveniently be from 4 to 12 inches in ordinary practice at the location ofthe joints between-adj acentv sections.

7 -dummy'patterns are used which are formed as; short sections of shape correspondng to that portion of the casting formed at the location of the joints. These dummy patterns are of length sufficient to I safely bridge the space, referred to andafter being placed the space referred to to complete the mold [which thereby" provides a metal receiving.

formation" free from cavity of continuous joints, cracks or other" imperfections which would otherwise be" present. Thereafter, may be withdrawn, and a suitable closing'or top section placed over the mold soformedg 'The mold, so completed,is the ready for the pouring'opera- In order to illustrate this invention one preferred form is hereinafter described in.

connection with the accompanying drawings in which: a I V I Figure 1 is'a perspective view of the lower, half "of a mold section with thete'mporary wall in place'prepared for tamping the sand around the corresponding pattern section;

and

Figure '2 is a perspective view of a com ple'ted Jlower half of a mold, in" this in- 7 At this pointin the mold forming operae' tion,

tobe

in position, enable the completionof the mold by a further sand tamping V Sufiicinet sandv is tamped into,

looking in the direction noted that constitutes a sectionof the .sections.

stance composed of two sections showing the molded sand forming the metalreceiving cavity and with the dummy patterns in place. This figure also illustrates the condition of the mold while applying sand in the space allowed at the location of the joint; and r Figure 3 is a plan view, partly in cross section of the mold formed "as illustrated in Figure 2 Figure 4 is a side elevational View ure 3 and I Figure 5 is anelevational 'view-inc-ross section taken on the line 5-5 of Figure 3 and looking in thedirection of the arrows- Figure ,6 is an elevational View of the mold section illustrated in Figure 1, showing the end to which the temporary wall-is applied; f V j Figure 7 is a fragmentary elevational view taken on the line 7-'7 of Figure 6, and

lookin'gin the direction of the arrows;

Figure 8 is a side elevational view in cross section at the location of the joint beof the mold. This 8-8 of Figure 9, of the arrows.

cross sectional View taken tween; adjacent sections figure is taken on line Figure 9 is a ,on line 99' of Figure 8, and looking in the direction of the arrows and Figure 10 is a side elevational View of a mod fied form of this invention, illustratmg a mold composed of three sections.

By referring to the drawings it will be each section is made of framelike construction having side walls preferably of metal and properly reinforcec which may if desirable, be formed of'inde- I pendent wall sections bolted, rivet-ed or otherwise secured together. As shown in Figure 1, each section of :the mold here illustrated is composed of wall 10, which side wall of the completed mold, wall 11 forming an end wall of the mold, and a wall 12 which extends only part way of the vertical height of the mold section. cThe remaining portion of the wall is supplied by a temporary wall 13, removably its inner wall surface surface of wall 12. It

that each section is more than two sections are employed in composing thefinlshed mold the intermediate sections will have two opposite walls provided with temporary wall portions.

It should be noted that the inner surface of walls 12 and 13 are inwardly to some extent from the outer abutting edges. of the mold sections so that the pressed sand portionof the mold will be of less length than the jointure between the walls of adjacent "lnforming'the moldin practice, a base plate 14 is provided, to which is attached a section of the pattern 15. The base plate is preferably securely, fastened after which the mold section with the temporary wall 13 in place, is positioned thereover as shown in Figure 1, with the temporary wall downwardly and in abutment with the end surface 16 of the pattern section. The mold section in-th is position is inverted as compared to the pouring position. That is to say, after tamping, it will be turned over in accordance with usual mold-forming practies. The mold is positioned and fixed with rcsp ct to the pattern by means of pins 15, which fit into properly located openings in the base plate 14. With the mold section so positioned the usual tamping operation is-carried out whereby a properly formed sand cavity results.

After the pattern is covered, t is met erable to provide a reinforcement of suitable construction, such as, for instance, the grate work l6,which in this illustration, is provided with extending ends received in openings 17 and held by wedges. After location of the reinforcement, the sand .tamping operation is continued until the mold section is filled.

By similar process, all sectlons of the mold are completed, and thereafter each is lifted from the base plate 14, free of the sand forming pattern. Each section is then acent portion of the tamped sand and the end of the. metal receiving cavity exposed.

In assembled relationship adjacent wall I sections 12 fit in cooperating relationship as shown in Figure 8. It is then preferable to place a metallic strip 20 over the crack located between the edges of the wall section 12 so as to assist in forming a crack free joint in the sand. Strip 20 is clearly shown in Figures 8 and 9. With the mold section so assembled, dummy patterns 21 are placed in'position at the location of the jointso as to safely bridge the space 22 left at the joint. The mold is then completed by continuing the tamping operation to fill the cavities 22 with sand, which is tightly packed to form a complete unitary mold. Thereafter the dummy patterns are with drawn.

The mold so formed is then ready for receiving the top closing be of any suitable form. For instance, it may comprise a plurality of sections somewhat similar to the lower half of the mold but perhaps of less height and with or without sand reinforcing means similar to the grate improvement 16. If desired, the mold maybe closed by suitable, baked sand i the mold.

blocksor plates provided with adequate pouring openings and clamped in place by 3 metal braces attached to the lower half of i molds, are eliminated.

It is to be understood that individual mold sections may be-made of any suitable or convenient form and may, if desired,

con-

in the above described manner of insuflicient length to complete the mold when in assema bled relation, assembling said mold sections for completing the mold and completing said mold by a second tamping operation with the employment of dummy patterns;

thesteps of forming individual seotionsfrom corresponding 'sectlons of the pattern, each of insuflicient length to complete the mold when assembled, assembling said sections in the'proper relationship whereby a space is provided at the joint, placing dummy'patterns across said joints and completing said mold by a second tamping operation.

Signed at Chicago, Illinois, this 30th day of June,1932. ALFRED WALCHER.

comprise a plurality of individual walls I bolted, riveted or otherwise secured together. In the present illustration, the pattern shown represents a four wheel truck frame for railwaycars, and here, like in many other instances, the two mold sections are duplicates. I

In cases where symmetrical castings are formed, certain mold sections may be dupli-. cates and therefore 'fewer pattern sections are required; As in such cases,the end 'sections and intermediate sections are frequently duplicates respectively, one of the other. I p

The invention is not to be-limited by the particular illustration herein given. as it is obvious that this invention covers broadly the process of producing a mold involving the novel steps herein described for providing a smooth and continuousjoint.

Iclaim: p

1. The improvement in the art of casting which includes providinga mold in sections, each section of which is formed from a corresponding portion of the pattern, but being of such length as to provide space between adjacent sections when assembled in rem; tionship to form thepfinished mold,assemblingthe sections in proper-relationship to complete the mold, placing dummy patterns in proper relationship across the space so provided and completing saidmold by tamp ing operations in the manner'to eliminate cracks at the joints. o

2. The improvement in the art of casting which comprises forming a sectional mold by providing individual mold sections adapted for joining, one, to the other to form the completed mold, each provided with a. tem-, porary wall, at the sideor sides to be joined, employing corresponding pattern sections for each mold section, and tamping sand impressions from said pattern, sections with the joining ends thereof in abutment with said temporary walls, forming said mold sections 3. In the art of makingcomposite molds I for large castings from individual sections,

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