US1396341A - Casting and mold therefor - Google Patents

Description

A. RAUTENBACH. CASTING AND MOLD THEREFOR.

APPLICATION FILED JULY 27,1920.

UNITED STATES PATENT OFFICE.

ARTHUR RAUTENBACH, OF SOLINGEN, GERMLNY.

CASTING AND MOLD THEREFOR.

pplicaton led July 27, 1920. Serial No. 399,342.

To all lwim/1u z'zmay conce-m Be it known that I, ARTHUR RAUTENBAUH, a citizen of the German Republic, and resident at Solingen, Germany, have invented certain new and useful VImprovements in Castings and Molds Therefor, (for which I have filed application in Germany Dec. 3, 1917; Jan. :24, 1919; Austria. June Q8, 1918; Hungary, July 9. 1913; Czechoslovakia, Jan. 20, 1919,) of which the following is a specification, reference being had therein to the accompanying drawing.

This invention relates to casting and iron molds therefor.

As is well known, aluminum pistons for internal combustion engines are subjected to severe service with consequent quick wear. I

It isthe object of this invention to so cast the pistons as to avoidair holes or cracks and to insure greaterlrigidity and density, smoother surfaces,` and complete uniformity o`t` the separate castings.

Figure 1 is a vertical section through the mold.

Fig. 2 is a top plan with a portion broken away.

Fig. 3 is a vertical section of a modified form. I

Fig. 1 of the vdrawing shows a construction of a mold ready for casting in substantially Vcentral vertical section. and Fig. Q shows the same in plan. In these drawings, a indicates the outer mold of iron. 7) the core of Sande, the pouring holes. (l and f the risers. f andy/ the projet-tions ot' the core which forni the openings tor the eyelets of the piston bolts.yv 7i indicates the hollow space by the filling of which with molten metal the article to be cast is produced.

lf it be desired to apply specially resistant material at particularly severely strained parts of the aluminium casting. tor instance such as bearings of steel. then these can be fixed in the sand core. so that on the casting of the article they are firmly embedded in the aluminium; tor instance. the boxes i and may be inserted in the projet-tions f and g.

From this description the operation of the invention will be readily understood without much further explanation.

` very poor conductor of heat, the'metal loses but very little heat in its passage through the sand core, and it experiences no serious cooling up to the moment in which it reaches the hollow space h, in which space it must solidify. In consequence ot' the slight losses of heat on the way from the ladle t0 the space h, the metal in the furnace need not be overheated. which was always necessary when it had. before entering into the mold, to pass through a pouring hole or funnel of iron, because in this manner even when the funnel was previously heated much heat was lost. The overheating ot the metal, 1s is well known, is a frequent cause of bad cast ings. Moreover. overheated metal tends to eat into the iron mold and reduce its service in a quite extraordinary manner.

The central position of the pouring hole enables the fluid metal to cover the bottom of the mold quite uniformly and, rising slowly, fill the mold. In consequence of the uniform rise of the metal there is attained a quite uniform cooling and'etting of the same, whereas formerly. through the introduction of the fluid metal sidewise to the bottom or to one side surface of the mold, this part was very strongly heated at the pouring place. By reason of this one-sided heating, there occurred, on cooling. strains which frequently led to cracks in the casting and also inrthe mold. By pouring through the centrally located pouring hole. the metal fills the mold from below, rising without resistance and driving the air in front of it, which air escapes at d and e. ln the previously side casting system, the metal flowed against the core and frequently took up 'air bubbles from it, which the cooling metal could no longer liberate, and which then formed flaws in the finished casting. On cooling, the closes aroundthe yielding sand core, whereas the formerly employed rigid iron core, if it could not immediately, and before the cooling and contraction began, be removed from the mold, was firmly inclosed by the casting or even burst the same.

The above described arrangement renders possible the use of a mold in onejpiece, whereas previously, in view of the 'pouring device. a division of the mold was necessary. The present invention may be usefully employed not only for aluminium and alumi nium alloys, but also forall metal castings of low vmelting point, especially also for magnesium and magnesium alloys.

solidified metal shell to have the depends on havingth'e' Ijournals at both' sides situated exactlyyoncne and the same axis, and further that this anis' may rest eX- actly perpendicular tot-he pistona'xis, care must be taken, on the shaping of the core and the setting thereof in p ositionlin the journals in the correct position. This operation however presents vdifficulties'inasmuch as the sandvcore.- during the ldrving, 'warps and ,twists inan unvrcertainr an( indeterminable manner, so `that spaceof the mold. These preferably placed, in slightly tapering, bor-A `ings of .the shell wall and can obvimisly be attached witlicomplete exactness so that their axes coincide. The journals then rest the axes of the inserted journals become displaced with regard -to one another. The

drawbacks of this conditionare then dis-- covered during the'` further operations, because'a uniform rboring of `the journals 1s lnot possible. This moreover 'further influj ences thene'cessary balance of the weight of the pistonin ythe case of multiple cylindered engines.

1 order to ton are placed upon projections which l'are insert'edvfrom the outsidethrough openings in the walls of the shell into the casting yupon the innerlimbs of these projections exactly at the right` place. lIn order, however.

y:still morefto increase, the exactitude, there 5 are formed. in, ,the

sand core yannular disks, the boringsof. which (preferably slightly tapering) `4serve as inner supports for the projections inserted fromtlie outside. In

thismanner the exact positionvof the jour-.. nalsiis doubly assured, and, moreoiv'er, there arts of the castingy projecting inward irte t\ e cylinder,

is attained .theresult that the oliviate these drawbacks, the present improvement is devised whereby the bearings or journals to vbe cast intothe pis! projections are,

and surrounding the journals, have as uniform thickness as possible and do not become eccentric to the journals.

The supporting projections of the journals inserted from the outside are removedimmedia-telyafter the setting of the casting and while the casting is still as hot as possible, in which condition they are easily drawn out of the box.

The drawing illustrates in Fig. 3 the casting mold of this kind in section.

a consequently indicates the shell mold, I) the sand core, c the pouring holes, It the hollow space for pouring the metal, z' and le the journals to be cast in the mold con- Structedoffstronger material. At two opposed points there yare provided in the mold. 0n one and the same axis, Wall perforations of slightly tapering form which serve for the insertion of the bolts These are provided at their inner ends with cylindrical projections n, for the reception of the journals Iand lc. At the ends of these projections therev are' provided alsoshort conical pieces o, which fit in corresponding recesses vof the annular disk p connected with the sand core.

'lVhat I claim is: y 1. In a'mold for the purpose described, a shell provided with coaxial borings for the insertion ofllolts, and bolts therein having at ltheir inner'ends cylindrical projections adapted.' to bear upon the inner. projections of thev journals which are to be incorporated in the casting. i 2, In a mold for v the purpose described, a shell provided with coaxial borings for the insertionof bolts, bolts therein having at their inner ends cylindrical projections adapted tol bear upon the` inner projections of the journals which 'are to be incorporated in the casting and at the bearing points of the axle boxes annular rings for the reception of short coni"- cal pieces.l i

Inl testimony whereof .l ailix my signa; ture inl the presence of two'witnesses.

ARTHUR.- RAUTENBACH. i, Witnesses-v: i i i WILH. Einenns,l i AUG.v RAMEB,

conical pieces at the vrends' vof sald projections, and a sand core having

Images