US783675A - Material for making cores. - Google Patents

Description

WE Srrrs Patented February 393, 1905.

arr iiir i ricia WWUFEIFHNIL WWW llillfltl tlNGi GUl lllEFM SPECIFICATION forming part of Letters Patent No. 783,675, dated February 28, 1905.

Application filed August 3, 1904. Serial No. 219,407.

To all whom it may concern:

Be it known that LGuonen W. Bmoosn citizen of the United States of America, residing at (lhicopee Falls, in the county of I-lampden and State of Massachusetts, have invented new and useful lnuin'ovel'nents in Material For Making Cores, of which the Following is a specilication.

This invention relates to cores used in metah founding, the object thereof being to provide a compound which when mixed with sand may be formed into cores, the nature oi the compound being such that when the core is subjected to the intense heat of the molten metal in the casting process it will become brittle enough to be easily broken up when it is desired to remove the same from theiinished casting, one particular object of the invention being to provide means whereby the core may be rendered more or less brittle when subjected to the action of the molten metal,

whereby large cores may be made stronger than smaller ones.

The invention consists in a compound con taining the ingredients about in the proportion described in the following specification, and pointed out in the claims pertaining thereto.

in carrying out my invention 1 first make a compound consistingof linseed-oi1,about one and one-third gallons, either boiled or raw, but preferably the former, soft soap, three gallons, to which ingredients two and one half pounds of starch is added, all being thoroughly mixed together, preterabl y in the pres ence of heat, and sand is then added thereto and thoroughly incorporatr-zd with the compound, the quantity of the sand being suiiicient to produce a mass containing the requisite amount of moisture to insure the easy molding of the cores, which are then baked in the usual manner.

When the cores have been used in the making of a casting and subjected to the intense heat of the molten metal, those properties which make the compound a good and serviceable binder for the sand particles are changed and the binder becomesbrittle and is easily crumbled into line particles. whereby the elements constituting the core may be readily removed from the interior of the casting.

If it is desired to make a core which may be more readily pulverized than when made as above described, particularly for use in making small cores where there can be but a small aperture through which the core elements may be removed, there is added to the a1awe-described compouml one gallon oi 1nolasses, which is thorrmghly stirred up with the other ingredients prior to the incorporation of the compound with the sand. The mass of core material containing this addi tional element is treated in precisely the same manner as above described when the compound is used without it; but the ellect of this additional ingredient is to render the core more brittle after it has been subiectedto the intense heat 01'' the molten metal than is the case when the compound consists only 01 the three elements lirst above recited.

To enable others to practice the invention, it should be stated that the best method oi mixing the compound is, lirst, to dissolve the starch with water, using only enough of the latter to produce a mass that can be poured; second, add the soap to the starch and mix thoroughly; third, when molasses to be used mix it with the oil and work them thoroughl y together until they become thoroughly incor 'iorated', amhiourth, mix the oil and molasses with the soap and starch, working them together thoroughly. The compound is then ready to use. Vhere the molasses is not used, the soap and starch are [irst mixed and the oil then added.

The etlect of the oil in the compound is to hold the sand together, producing a hard rocklike substance a'lter baking. l urthermore, it renders the core impervious to moisture, and thus prevents blowing or sputtering oi the iron in the mold when poured.

The effect of the soap is to hold the sand together while the core is green, and it also renders the core porous after baking, thus providing for the tree escape of any gases which may be generated by the contactot the hot metal with the core. The ellect ol' the starch in the compound is fourfold: First, it

shortens the time for baking the core, as the latter will bakeina lower temperature than it would without it; second, it assists in holding the sand together while the core is green; third, it assists in making the core porous, having the same effect in these last two particulars as the soap; fourth, it prevents the sand from adhering to the core-box while the core is being molded, and thus make a core having a smoother surface than could otherwise be obtained. w

The effect of the soap and starch in the core after the metal has been poured around it is to cause it to disintegrate readily and free itself from the metal, thus requiring less labor When removing it from the casting.

It has been demonstrated in practice that cores made from this compound will not generate any perceptible amount of gas when subjected to the intense heat of the molten metal, thus rendering it especially valuable in the manufacture of chamber-castin gs, where only small apertures are permissible. Furthermore, the compound is free from offensive odors when hot, and what little smoke escapes from the core when the metal is poured has no irritating effect on the eyes or nose, which is a serious objection to all of the flour or meal mixtures now known to me. It is also to be noted that the cores made according to this invention are strong enough to hold together without taking especial care in wiring them and that cores made from this compound do not require spraying or sprinkling previous to baking and are therefore left with a much smoother surface than are the cores which must be sprayed before baking to make them hard. Furthermore, cores made from this compound do not give off any oily substance, which will in a short time destroy the adhesive qualities of the GEORGE W. BRIGGS.

Witnesses:

VVM. H. GHAPIN, K. I. ULEMoNs.