US68548A - James b - Google Patents

Description

JAMES B. BEAN, OF BALTIMORE, MARYLAND, ASSIGNOR TO l-IIMSELE AND l A. H. BALDEBSTON, OF THE SAME PLACE.

Letters Pate-nt Na 68,548, dated September 3, 1867.

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TO ALL WHOM IT MAY CONCERN:

Be it known that I, JAMES B. BEAN, of the city and county of Baltimore, and State of Maryland, have 'r invented a new and improved Method of Casting Aluminium in fine moulds; and I do hereby declare the following tobe a full, clear, and exact description of the same, suiiicient to enable one skilled in the art to which the invention appertains'to make and use the same, reference being had to the accompanying drawings, forming part of this specification, in which- Figure 1 is a sectional elevation through the line .c x, iig. 2.

Figure 2 is a plan or top view.

In this invention the metal is cast into fine moulds u nder pressure of a high column of the metal itself, contained in a conduitof soapstone, earthenware, or other similar substance, heated to about the melting point` of the metal cast. The moulds and conduit, at the moment of casting, are filled with hydrogen or other gas containing no oxygen.

In casting aluminium,'and several other metals possessing similar properties, the great diiiculty has hitherto been the impossibility of'producing a solid casting having all the details'of a fine mould faithfully represented. The source of this difficulty is mainly from the extreme lightness of the met'al'and the tough film which forms on the surface of the melted mass as soon as cast. These two properties combine to prevent the melted metal from owing into the more minute details and parts of the mould, and at the same time prevent the'closing up of faults and air-cellsin the body of the casting. Aluminium especially, Ain its pure state, is so verylight, vand the film formed is so tough, as to render it practically worthless for casting by the old methods.

Still another trouble in casting any metal, but particularly annoying in casting aluminium, arises from its great contractibility in cooling, by which holes and imperfections in the surface of the casting occur, rendering it indispensable to success that means should be devised for countcracting this eifect. i

In the invention hereafter to be described I propose to obviate all these diiliculties by a process which I 'have been testing and perfecting for years, and which, I am able at last to say, renders the casting of aluminium and other metals of kindred properties in fine moulds, forthe purposes of the dentist, the `jewcller, the artist,

i or any others who have to malte fine metallic castings, as easy and uniformlysuccessful as has been the casting of gold and silver heretofore.

In the drawings, A A represent a stand with a heavy base, having four. posts, a a a ct, projecting upward from it, two of the posts having set-screws a passing through them. This device is for the purpose of holding my flask, containing the mould, firmly in an upright position, and at the same time binding together the two halves of the mould. .B B represent. my flask, which I fix in the stand A, as shown in the drawings. The outside flask is composed of two similar parts, B and B', one having two or three projections, I: b la, fitting into corresponding recesses, or between pins b b b in the other, to-indicate the proper relative position of the parts 5 B and Bl to-each other. The two sides, BA2 and Bi, contain a number of holes, c c c e, for the purpose of giving vent to steam and gases that may accumulate in the interior of the mould. One of the sides, B3, is movable, for the purpose of llling in the last portions of the composition forming the mould. The projections di di, on either side of the gate d, are pierced for the reception of the vents C C.

The flask thus formed contains within it 'a mould or matrix of the article to be cast. I make this mould of a compoundof about two parts, by weight, of powdered pumice-stone, and one part of fine calcined plaster,l of Paris, mixed together with water to the consistency' of cream or thin batter, and poured over the model Jf -the article to be cast, in the manner usually practised in making such moulds in plaster of Paris.

Vent-s C C are placed on either side of the gate d, and communicate with the interior cavity of thc mould at two of its highest points. These permit the escape of the aeriform or gaseous contents of thc mould as the metal fills it. I fill the outer portion of these vents, in the manner shown in the drawing, with/Small metallic rods or wires e e e, between which the air will escape readily, and which will yet prevent they escape of the melte'd metal, by cooling it so rapidly as to congeal it by the time it has advanced half an infill 0l* more amOIlg ,f the rods.

The melted metal is introduced to the mould through the high conduit D, composed off SOPBOHC earthen* Ware, or other substance equally capable of enduring the necessary heat, and not liable to contaminate the metal with impurities. The conduit D is made in two parts: the lower, d, is fastened into the flasks D B1, as shown in the drawings, and the upper, cZ, which should be at least ten inches in length for aluminium, is made detachable for the purpose of being heated separately, and also for the purpose of emptying it of the melted metal contained in it after that in the mould has become solid. The two parts are fitted together by the ground-joint d.

The whole apparatus being thus constructed, it remains to show my method of operating it. In the first place, I. expose the mould or matrix, together with the flask B B1, to a gentle heat, until it is completely dried andis heated to about 300D or 400 Fahrenheit, and thev point of the gate d is heated to redness. At the same time, the upper portion rl of the conduit D is uniformly heated to a point at or above the melting point of the u metal to be used, and the metal itself, in sufficient quantity to till the mould and conduit, is heated to a degree somewhat above its melting point. Before closing the mould, its interior surface is quickly heated to redness by the blow-pipe Haine.

The liask, containing the mould in its heated state, is now placed in the stand or holder A, as shown in fig. 1, and the-set-screws tightened to a proper degree. The vents C C, containing their bundles of little rodse e, are now put, while cold, into their places on each side of the gate CZ, and the. upper portion of the conduit, heated as above described, is put in place and attached by means of the ground-joint al. v

I next ll the whole apparatus with common illuminating gas, hydrogen, or other gas entirely free from oxygen, by means of a pipe leading from .the source of supply of the gas and passing through a small plate or disk of mica placed on the open end of the conduit, and the gas forced into the mould, issuing at the vents until all is completely filled. The gas pipe and plate of mica are new quickly removed, and the molten metal poured in without delay, quickly filling up the mould and conduit to the top.

As soon as the metal has become solid in the mould,` and before it has congealed in the conduit D, I detach the upper part d and let the nieltedmetal run out, for if allowed to become solid in the conduit, this portion of the apparatus might be destroyed in removing it therefrom, or in subsequent manipulations of the iiask.

In this manner a solid and perfect casting can be made, not only from aluminium, butfrom light and easily oxidized metals. The air being unable tovcome in contact with'the metal in the mould, no oxide is formed on its surface, and under pressure of the high. column of fluid metal, it flows rapidly and easily intoall the finest parts of a delicate mould, and brings out all the details of the design.

As the metal cools and contracts in the mould, by the pressure of the superposed molten metal in the conduit, it flows in and supplies the deficiency until the casting is complete, .thus absolutely remcdying all the evils of its great expansibility by heat. l

The pressure of the column of metal may be regulated at pleasure by making the conduit of a height proportionate to the specific gravity of the metal to be cast. Even silver and gold,and other heavy metals, are castby means of this apparatus with much greater perfection than by the old methods.

The apparatus is simple, and easily worked, and, if the process above described be followed, is uniformly.

successful in producing most perfect castings, however delicate may be the moulds.

Having thusdescribed my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The iiask B D1, in combination with the frame or holder A, having the posts a e a aand the set-screws a" a', constructed as and for thc purpose specified. 4 v

2. The flask B D1, having the vents C C and the gate cl, all constructed and arranged substantially as described.

3. Stopping the vents C C with the small rods ye e e, as and for the purpose set forth.

4. The conduit D, composed of soapstone or other similar material, in combination with the gate d, as described.

5. I claim supplying fluid metal to compensate for the contraction of the metal in the mould, as well as to secure a denser casting, by meansA of the detachable' reservoir D, heated previous to pouring the metal, substantially as described.

G. Expelling the atmospheric air from the mould by meansof, and substituting therefor, a gas which is destitute of oriygen, in the manner and for the purpose set forth.

7. The iaslc B Bl, constructed, gated, and vented substantially as described, in combination with an interior lining-composed of pumice-stone and plaster of Paris, in proportions substantially as set forth. Y

' JAS. B. BEAN, D. D. S.

i Witnesses:

JAMES H. GRIDLEY, SoLoN C. Kanon.

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