US1564274A - Method of and means for casting articles - Google Patents

Description

Dec. 8 1925- 1,564,274 c. c. RAND METHOD OF AND MEANS FOR CASTING ARTICLES Filed Oct. B, 1923 Qy Aff? Patented Dec. 8, 1.925.

UNITED STATES PATENT oFF-ICE.

CHARLES CLAFLIN RAND, OF LOMBARD, ILLINOIS, lASSIGN OR T WESTERN ELECTRIC COMPANY, INCORPORATED, OF NEW YORK, N. Y., .A CORPORATION OF NEW YORK.

Application ile-d October 8, 1923..: vSerial No. 667,109.

` To all whom t may concern:

Be it known that I,.CHARLES CLAFmN RAND, a citizen ofthe United States, residing at Lombard, in the county of Du Page and State kof Illinois-have invented certain new and useful Improvements in Methods of and Means forl Casting Articles, of which the following is a full, clear, concise, and

Y exact description.l

This invention relates to methods of and means for-casting articles, and more particularly to methods of and means for casting refractory articles. 1

In making articles'by the introduction of la a casting slip into a mold composed of water absorbing material, it is desirable to insure a uniform and perfect product and that the slip shall reach all` parts of the' mold approximately simultaneously and under sub. stantially the same unit pressure.

t In some cast refractoryA articles, for instance, a tube serving to support resistance lmaterial for forming a heating element in an electric soldering iron, it is desirable that l5 it have a predetermined uniform outside diameter and wall thickness. This is due to the restricted space in which a heating eleplastic clayso as to properly regulate the ment may be placed in a soldering iron.

An object vof this invention is to insure 80 the simultaneous introduction of a casting slip into Aa plurality of portions of a mold under a substantial uniform-unit pressure.

. Anotherobject is to produce a cast article having a predetermined 'and uniform wall 85 thickness. l Y

oaterial into a mold through a core mem- A still further object is to improve and 4D Vsimplify methods of and means for manufacturing refractory articles.v

In accordance with one embodiment there'- of, the invention may comprise a separable.

mold of plaster of Paris or similar material adapted to surround and to center therebetween a perforated vertical conduit, which not only serves as a core for the article to be cast, but also to direct the casting material or slip through the perforations thereof into l0 all parts of the surrounding lmold cavity, thus producing an article having a wall of predetermined and uniform thickness. The

silicon carbide (220 mesh); 12 parts da clay; 121/2 parts English China clay; 1/8

' to al Fig. 3 is a fragmentary view, partially in section, showingl the method of producing separable molds used in cast-ing, and

Fig.- 4 is an elevation lof a tube produced inl accordance with the invention.

In order to successfull cast articles including silicon carbide, 1t is necessary to employ it in a very finely 'divided condition, preferably of the character known as 220 mesh. As is sometimes the practice in connection with casting refractories, it is often' desirable to employ as a binde-r a combination of differentv clays possessing somewhat different characteristics. For instance, a plastic clay. is often combined with a less lshrinkage due to the firing of the cast article In order to maintain the various ingredients of the casting slip in suspension, suitable defiocculating agents are also usually employed, such agents also serving to reduce the. quantity of water required in the slip. A further obIect 1s to introduce casting vA casting slip which has been found to be very satlsfactory in the casting of silicon carbide is composed of the. following ingredients in the proportions noted: 50 1 parts loripart solid sodium carbonate; 3/8 part liquid sodium silicate ;40 parts water.

The various ingredients are wet ground ether in a pebble mill of the type usuy employed in mixingceramic com osi- -tions After they are thoroughly mixe the slip should have a Specific gravity of approximately 2.25.

An apparatus shown in Figs. 1, 2 and 3 of the rawings may be used to advantage in casting articles in accordance lwith the be formed by using suitable molding flasks 12 and 13 and a separable pattern composedl of lportions 14 and 15,l preferably of' brass, the openings in the flasks around the portions 14 'and 15 being filled with plaster of Paris or other similar material. After this plaster of Paris has hardened sufficiently, the iiasks 12 and 13 are separated in the usual manner, and the pattern port-ions 14 and 15, and the plaster of Paris portions 10 and 11 are removed from the flask. The

pattern portions 14 and 15 are provided with semi-circular extensions 16 at either end (see Fig. 3 which provide the mold portions 10 an 11 (see Fig. 2) with alined re- 'duced semi-.circular depressions 17 at either end. These mold portions l0 and 11 are then placed on end onseparated supports 18 and 19 with suitable retaining bands 20, which may be of rubber or'oth'er material, a conduit or tube 22 being placed between the portions 10 and 11', and projecting from the top and bottom ofthe assembled mold. The depressions 17 form an openin at either end of the mold for centering t e conduit 22 within the cavity formed y the mold portions 10 and 11. The depressions 17 serve to engage the tube 22-and to effectively seal the openings at either end of the mold. collar 24 attached to the conduit 22 serves to position itvertically within the mold. The conduit 22 is provided with a plurality of openings 25 occurring within the mold cavity, and is also provided with a plug 26 suitably screwed into the bottom of the conduit.

In castin the article the tube 22 is completely filled with a casting slip produced as o-utlined above, and due to the openings 25 which'are uniformly located throughout the extent of the moldcavity, the slip flows therefrom into all portions ofthe cavity simultaneously and with substantially the same pressure. This arrangement insures the uniform and complete filling of the cavity around the conduit 22, thereby pro ducing an article with a predeterminedand uniform wall thickness. Some of themoisture in the slip within the" cavityis withdrawn by the moisture absorbing walls of plaster of Paris which serve to retain the material firmly in contact vwith the cavity walls. The mold is allowed to remain in this condition for a period extending from one to two minutes and the plug 26 is then removed from the conduit 22, permitting the excess slip to flow out of the conduit. The conduit 22 is then removed by a rotation through a small 'arc' and an upward pull, which serves to break the small projections of casting material extendin into the openings 25 and to form a perfect y smooth inner wall for the cast tube. The mold is then laid on its side and maintained in this position for a period of from one to two minutes, and the bands 20 are then removed and the mold portions 10 and 11 separated. The

`cast tube 30 is removed from the lower por- `is allowed to cool for from eight to ten hours, whereupon the cast and fired tube 30 is ready for service. l

llll/'hat is claimed is:

.1. The method of casting an article, which consists in directing a slip against the wall of a mold cavity `from a position within the cavity. l

2. The method of casting an article, which consists in introducing a quantity of slip into the interior of `a mold cavity, directing a portion thereof against `the wall of the cavity, and removing the remainder of the quantity introduced.

3. The method of casting a walled article which consists in introducing a stream of slip into the interior of a mold cavity, divide ing said stream into smaller streams, and directing the smaller streams against the wall of the` cavity in ,such manner that they unite and form a lwall 'of the article.

4. The method of casting an article, which consists in introducing a slip into a mold cavity at a plurality of levels by the action of gravity.

5. The method of casting a walled article which consists in centering a column of slip within a mold cavity, directing portions ofthe slip at different levels against the wall of the cavity to form the wall of the article, preventing the return to the column of such portions, and removing the slip remaining in the column.

6. The method ofcasting a walled artid-16;.. which consists in introducm a slip against the wall of a 'mold cavity rom a position within the cavity, maintaining the directed sli against the wall of the cavity, and partia ly drying the maintained slip.

7. The method of casting a. walled article,v

which consists in introducing a chamber-into a mold cavity, introducing a slip into the chamber and therefrom into the mold cavity surrounding the chamber, releasing the surplus slip from the chamber, partially drying the slip remaining within the cavity, causin a relative rotation between the chamber an the slip surrounding it, and contemporaneously therewith withdrawing' the chamber from the mold to produce a smooth surface on the .interiorT of the Wall of the cast article.

8. The method of. casting a walled article, which consists in directing a slip against the wall of a mold cavity from a position within the cavity, partially drying the slip within the cavity, removing the cast article from the cavity, drying the cast article at room temperature conditions, and thenA hardening it by increased temperatures.

9. In a casting apparatus, a mold having -a cavity for forming casting material into an article, and common means for simultaneously directing casting materialy into a plurality of portions vof the cavity and for forming an opening in the cast arti-cle.v

10. In a casting apparatus, a mold having a cavity for forming casting material into an article, andf common means for introducing casting material into the cavity and for 'forming an opening in the cast article.

11. In a casting apparatus, separable mold portions of water absorbing material having cooperating cavities therein, a hollow perforated member surrounded by the cavities for introducing casting material 'into the cavities, and means for retaining an xcess amount of material within the mem- 12. In a casting apparatus, a mold having' a cavity for forming castin `for centering it transversely of the mold and for sealing the mold cavity.

In witness whereof, I hereunto subscribe my name this 21 day of Sept. A. D., 1923.

`CHARLES CLAFLIN RAND.

material intoy an` article, and a hollow per orated member

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