US2039872A - Stool to support molds for casting metal - Google Patents

Description

May 5, 1936. c. H. ALDRICH STOOL TO SUPPORT MOLDS FOR CASTING METAL Filed Jan. 2, 1955 5 Sheets-Sheet 1 INVENTOR dam/ BY JAM 271 .014 8 ATTORNEY May 5, 1936. y c. H. ALDRICH 2,039,872

' STOOL TO SUPPORT MOLDS FOR CASTING METAL Filed Jan. 2, 1955 3 Sheets-Sheet 2 Fay .5. I I 31 w I T L I 35 L1 r I l 1 I r 6; l l I l l I l l v l :U I i m I I I I 1 J. L L J L I L L J 3162/ d INVENTOR BY 59m 777 V W ATTORNEYS May 5, 1936. c. H. ALDRICH STOOL TO SUPPORT MOLDS FOR CASTING METAL Filed Jan. 2, 1955 5 Sheets-Sheet 5 INVENTOR a 2 lfTTORNEYQ Patented May 5, i936 UNITED STATES; PATENT j oF'FlcE 2,0s9,s1z-" Charles H. Aldrich, Elizabeth, N. 1., assignor, by

mesne assignments, to The" American Metal Company, Limited, New- York, N. Y., a corporation of New York.

, Application January 2, 1935, Serial No. s4

15 Claims. (01. 22-139) This invention relates to improvements in rate of such deterioration due to surface crackmetal stools adapted for use in casting metal, ing of'one-piece copper stools increases very rapand more particularly to improvements in stools idly as the horizontal dimensions of the stool I constructed of copper or suitable copper alloy are increased.

5 to be used as .a support for a mold to be em- It is an object of this invention to provide a 5 ployed in the casting of steel ingots. 1 stool which will be far more economical to con- It has been the practice in the past to cast struct, than the one-piece stools herein referred steel ingots in molds supported on cast-iron to, but which will provide for free local expanstools constructed in the form of a single unit. sion of portions of the stool immediately under- These stools were unsatisfactory because of imlying the molten metal poured into a mold sup- 10 perfections which developed-therein due to the portedon its surface, and thereby. reduce the relatively poor thermal conductivity of the metal tendency to distort and crack its surface and and the resulting strains in and distortions of render it unfit for service. I portions of the stool occasioned by local expan- The invention consists generally in the dision of parts in contact with or closely adviding of the stool, or atleast the surface porjacent the molten metal in the mold and also t on of the stool, into a number of o 's p to the fact that the surface of the stool isgradarated by crev s extending from its mold b ually eroded away bythe stream of molten steel, ing surface towards its base, the construction resulting in the early destruction of thestool. being such that the sections will either be As an improvement upon unitary stools made slightl'yi sepfl 'fl 'byfl Of an l precia le 20 of cast iron, resort was had tosingle massive t widtm with their surfaces out of contact, or stools of copper. Such stools were to'some exh t h ns .mflyqlfldlly a i tent more. satisfactory than the cast-iron stools themselves by movementfina in'view of the relatively greaterthermal con- (11 10215118 creviiies ductivity of the copper which dissipated the by increase of temperat re dur s'a il- 118. 9- '25 heat energy from parts immediately under the oration. v h I highly heated metal in the moldto underlying The feature of dividing the stool into a' g and surroundin portions of the stool, thus to berof sections with P n r 10681 some extent reducing the local distortion of por- D ion wou d constitute a very material in.- tions of its surface and resulting imperfections: provement in a y ,stool'whether constwcted 0130 ,Notwithstanding the advantages of the unicast iron, c pp 0 any other appropriate m tary massive copper stool, its life is greatly t t e best sul maybe ob ned by or shortened by the formation of surface cracks, p y this l im m coi P rticularly in cases of stools of large dimenperecopperalloy, or any J sions. The parts of the stool immediately'un r v ly Bh-th I'mRIOOnductIfltYQ dr the steel as itis poured intovth ingot mold I Importantfeaturesof th inventionno't 1 I are caused to rapidly expand while confined by More mentioned include means for rrovidins surrounding and underlying portions which are free air circulation about. the metal sections of i Y relatively cool. The expanded portion is caused the Stool to ra id 6 1 t; mall! w 40 t bulge upwardly sin e it is closely confined in by the secti ns may be readily asse b ed in. bold. all other directions. As the heat energy is con- 1 place, and removed from, a supporting and ducted from this expandedportion to the surc fl s ra e; means w y the tio rounding and underlying portions of the stool, may be yielding h in the frame with their they in turn expand, and at the same time the surfaces in snug contact, and the use of sections originally heated and distorted portion from of shapes such tha they may be lnterchansewhich heat is. being dissipated must contract. ably assembled in va us motions. thereby ma These violent opposing forces tend to tear the y increasing their effective" 1i1e.: surface portion of the stool apartand produce In he a p ny rflw sfl' mm the gaps and fissures which grow larger and larger preferred and various modified forms of the as the stool is successively used. These surface above-described invention,- r cracks orflssures soon become of a size suchas Fi ure 1 1 a P an V w f & Stool 1111 8 to permit molten steel poured into the ingot a plura ty of Sections ass m d in 1! 1 111! mold to enter and ilrmlyysecure the ingot being heldin-place by the use of wedges.

cast to the stool, thus clearly indicating that the Fig. 2 1s a view. partly in side elevation and stool has become unfltior further service; The partly'inlongitudinal. section, of the form ottlie 66 time.

invention illustrated by Fig. 1, the plane of the section being represented by the line 2-2.

Fig. 3 is a plan view of a form of the invention in which springs, rather than wedges, are used as a means of yieldingly holding the sections of the stool in their assembled relation in a frame.

Fig. 4 is a large-scale view, partly in side elevation and partly in longitudinal section, of the form of the invention illustrated by Fig. 3,- the plane of the section being represented by the line 4-4.

Fig. 5 is a plan view of a form of the invention which differs from the form illustrated by Figs. 1 and 2 in that special means are provided for air circulation.

Fig. 6 is a view, partly in side elevation and partly in longitudinal section, of the form of the invention illustrated by Fig. 5, the plane of the section being indicated by the line 66.

Fig. 7 is a transverse sectional view of the stool illustrated by Figs. 5 and 6, the plane of the section being represented by the line of Fig. 5.

Fig. 8 is a plan view of a stool which differs from the one illustrated by Figs. 1 and 2 in that it is adapted to support two molds at the same Fig. 9 is a plan view of a stool the sections of which are in the form of cubes which may be interchangeably assembled in various positions.

Fig. 10 is a perspective view of one of the cubes of the stool represented by Fig. 9. i

Fig. 11 is a'fragmentary plan view of a circular 'stool having the invention embodied therein.

Fig. 12 is a cross-sectional view of the stool illustrated by Fig. 11. 3

The form of the invention illustrated by Fi l and 2 may comprise a plurality of metal sections 20 mounted in a metal frame 2! comprising side walls 22, end walls 23-and a base 24. The

frame may be of dimensions such as to accom modate the sections when assembled in a snug side-to-side relationship, and the sections may beheld in close contact with each other in the frame by any appropriate means, such, for example, as the wedges 25.

Although the invention is not intended tobe limited to the use of any particular metals, the

frame may preferably consist of cast iron and the sections 20 of copper or some suitable alloy of copper.

It is now possible to cast copper in vertical molds of relatively great height as compared with their cross-sectional dimensions, the resulting castings, which may be referred to as V. C. cakes, being of substantially uniform dimensions from end to end. Such cakes may now be cast with suflicient accuracy to be used as the sections .of stools constructed in accordance with this invention, by merely cropping their upper ends and placing them-on edge inthe frame, the width of the cake constituting the depth of the stool.

If desired, the cakes may be of slightly greater thickness at their centers than at their edges so as to provide crevices between the sections at the upper mold supporting surface of the stool, as indicated at 26, and by correspondingly flaring the opposite edges of each section. the section may be inverted after one of its working surfaces has been rendered unfit for service, thus increasing its period of usefulness.

If the sections are flared as indicated in Figs. 1 and 2, so as to provide open crevices extending downwardly a material distance from the mold supporting surface of the stool, the sections may be held in the. frame by relatively unyielding wedges which may be constructed of cast iron or steel, since the open crevices at the surface of the stool afford the desired free space for local expansion.

The width of the crevices as illustrated in Figs. 1 and 2 is somewhat exaggerated. Such width need be only great enough to provide for the increase in thickness of the surface portions of the sections of the stool when expanded during a casting operation, and, when so apportioned, it has been found that the crevices need not be of a width such as would permit the molten steel to enter during the pouring of a casting. If desired, however, the crevices may be closed by painting the surface of the stool with a thin coating of fire clay, or other suitable inert material, which wouldbe sufliciently soft to permit the sections to expand while acting as a seal against the entrance of molten steel.

In Figs. 1 and 2 the position of the bottom portion of an ingot mold supported by the stool is diagrammatically indicated in broken lines, the wall of the mold being indicated at 2'! and the casting cavity at 28.

It will be apparent that when molten metal is poured into the mold 21, the underlying surface portion of the stool will be rapidly heated, as a result of which the upper surface portions of the underlying sections 20 will be expanded and increased in thickness, but this expansion will merely tend to close the open crevices 26 until the local temperature has been reduced by conduction' of the heat energy to the underlying and surrounding parts of the stooland dissipated by radiation and convection. The depth of the stool should be such that it may dissipate the heat energy absorbed during a casting operation without being subjected to a dangerous temperature. A temperature of from 700 to 800 Fahrenheit is not regarded objectionable. In the casting of steel ingots of some considerable size it has been found that if the stool is made of copper sections a depth of twelve inches is quite satisfactory. For very large castings a somewhat greater depth of stool might, perhaps, be used to advantage.

As a precautionary measure which might tend to increase the life of the stool and prevent any possibility of trouble due to the cutting of its surface by the molten metal at the commencement of,the pouring of a casting before a ciently deep pool of metal has accumulated in the bottom of the mold to serve as a protection, a relatively thin steel plate 2! may be placed on the surface of the stool at the bottom of the mold cavity before the metal is poured. The plate need not extend over the entire area of the mold bottom but should cover so much of the surface of the stool as may be necessary to prevent the poured metal from impinging directly against the surface of the copper during the initial part of the pouring operation. The plate should be no thicker than required to serve its intended as having -their marginal portions flared so as to provide open crevice; along the surface of the stool. In this form of the invention, although. the crevices 26' between the sections are close-:1, provision for expansion is made by the use of springs 25, instead of wedges, as a means of holding the sections in their assembled relation in the frame. The springs 25" may be confined between a metal header 30 in contact with the end sections of the stool and spring seats 3| which may be held in their spring confining positions by means of threaded bolts 32 and nuts 33, the bolts being extended through openings in, and the nuts seated against, the end wall 2i! of the frame- The header 30 of the form of the invention illustrated by Figs. 3 and 4 may be provided with a shield or canopy 34 to overhang the springs and their associated elements and prevent molten metal, dust or other.foreign material from making its way around and between the parts of the spring mechanism and interfering with its usefulness.

Preferably the sections 20 may be slightly shorter than the internal width of the frame 2| so as to provide open air gaps 35 along the sides of the sections, and a series of openings 36 may be provided in the sides of the sections to permit air to enter and pass through the gaps 35 and dissipate heat energy imparted to the sections during a casting operation.

When metal is poured into the casting cavity 28 of a mold 21 supported on the stool illustrated by Figs. 3 and 4, the heat energy imparted to the sections 20 through the metal plate 29, if used, will cause the sections to expand, and since the crevices 26 are closed crevices, the walls of which are in contact with each other throughout the entire depth of the stool, the expansion will cause the sections to spread out-along the length of the frame 2 I and re-distribute themselves, such adjustment being permitted by the yielding of the springs 25. After the casting of the ingot, the heat in the stool .will be dissipated by radiation and convection, and, as the sections resume their normal dimensions, the springs 25 will cause them to be returned to their normal positions and held snugly against each other in readiness for another casting operation.

The form of the invention illustrated by Figs. 5 to 7 inclusive, differs from those heretofore described in that the frame 21 within which the sections are mounted. has a base in the form of spaced bars 24 upon which the sections 20 may be supported, and section confining elements or walls 22", 23 separated slightly from the outer surfaces of the sections so as to provide intervening gaps 35 for the circulation of air, the lower margins of the walls 22 23 being spaced above the level of the under surfaces of the supporting bars 24* so that the walls will be separated from the surface of any support on which the' frame may be placed and thereby permit air to enter and pass upwardly through the gaps 35 and cool the sections of the stool during and after a casting operation. K

In the form of the inventionillustrated by Figs.. 5 to 7, inclusive, as distinguished from the form illustrated by Figs. 1 and 2, the. mold supporting sections 20* are held in the frame by takeup means in the form of wedges 25 of wood or otherappropriate material between both of the end sections of the stool and the adjacent walls 23 of the frame, so that air gaps may be provided between the sections and both end walls between the outer surfaces of any of the mold supporting sections and adjacent surface portions of the frame is not dependent upon the I character or location of the springs, wedges or other take-up devices used to hold the sections in close association.

It will be apparent that when using any one of I the three forms 'of stool thus far described, any section or sectionsthe surfaces of which become unfit for further service may be readily removed and inverted or interchanged with one at the end of the frame or replaced by a new section, by merely removing the wedges if the stool is one of the form illustrated by Figs. 1 and 2 or Figs.

5, 6 and 7, or by unscrewing the bolts 32 sufficiently to render the holding springsfli ineffective if the stool is one of the form illustrated by Figs. 3 and 4. The stool is, therefore, not only capable of being manufactured at relatively small expense, but the maintenancecost is also relatively small for the reason that each section of tiple stool, if the material of the mold supporting sections is relatively expensive as compared with that of the frame, it is not necessary that the entire frame be filled with such relatively expensive sections. The mold supporting sections may be confined to the parts of the stool on which the molds are intended to rest, and the intervening space or spaces may be filled in with some less expensive material. In Fig. 8,

'for example, two sets of sections 20 are assemble'd in a frame 2| in positions such as to-be adapted to support two casting molds 21. These sections, which might be constructed of copper or copper alloy, might be separated by a single intervening section 31, and this intervening section and the frame in which it and the copper sections are assembled might be of cast iron. The entire series of sections, including the copper sections and the intervening cast-iron section, might be kept in close contact with each other and with one end of the frame by any appropriate take-up means such, for example, as the wedges 25 driven into spaces between the wall at the opposite end of the frame' and the adjacent surfaces of the sections. Such a multiple stool might conform as to details of construction of its parts with other forms of stool heretofore described.

In Figs. 9 and 10 is illustrated a form of the invention which diflers from that illustrated by Figs. 1 and 2, for example, in that the sections 20 may be in the form of cubes which may be held in an assembled relation in a frame 2| by means of wedges or other appropriate holding means 25 which may be insertedat the ends of the transversely disposed series'o'f sections as well as at the ends of the longitudinally disposed series. As best indicated by Fig. 10, the, four marginal portions-of each of the six faces of each cube may, if desired, be slightly inclined so that, when the cubesare assembled in the frame, the faces which form t e mold supporting surface of the stool will be separated by two series of open crevices intersecting each other at right angles, and, since the cubes are symmetrical asto all three of their axes, they may not only be readily shifted from one part of the frame to another, but may also be used with each of their six similar faces uppermost until all six surfaces have been rendered unfit for further use ' is not essentialthat the relative sizes of the various faces of the sections conform with any tire width of the supporting frame as illustrated by Fig. 5, or even half way across the frame as illustrated by Figs. 1, 3 and 8. They should be of a depth suflicient to avoid overheating and their other dimensions should bear such a rela- 5. tion to the joints by which they are separated from each other as to avoid undue distortion of their upper surface portions when heated during a casting operation.

The form of the invention illustrated by Figs.

1 and 2 has been disclosed as one involving stool sectionshaving slightly flared upper edges so as to provide crevices along the upper surface of the stool, and the sections are disclosed as being held in close contact with each other by metal wedges 25 driven into spaces between the end sections and an adjacent wall of the supporting frame. The form of the invention illustrated by Figs. 3 and 4 has been disclosed as one comprising copper sections having parallel side faces so as to fit quite closely together and be separated by closed joints, the sections being held in contact with each other by springs inserted between the end sections and an adjacent wall of the supporting frame. In the form of the in- 5 vention illustrated by Figs. 5 to '1, inclusive, the

device is disclosed as one having copper sections with closed joints held in close association with each other by wedges which may be of wood or,

other appropriate material. The form of the invention illustrated by Figs. 9 and 10 is disclosed as one having sections with slightly flared surface portions. to produce open joints at the surface of the stool, the' sections being held in close association by appropriate fastening means which mightbe springs or wedges of metal or wood. In

making these various disclosures it has been indicated that when relatively unyielding fasten-- ing means, such as metal wedges, are used, it might be preferable to use copper sections having flared surfaces such as to produce open joints at the surface of the stool, and that when sections having parallel plane side surfaces are used, such as to produce substantially closed joints at the surface of the stool, it would be preferable to use springs or wedges of yielding material,

face expansion due to slight irregularities in the joints even though they have previously been wedged together tightly enough to prevent steel from entering the joints. If, therefore, the dimensions of the metal sections. are properly pro portioned with respect to the joints, metal wedges, wooden wedges and spring-holding means may be interchangeably used as means for keeping the sections in close association irrespective of whether or not-the lateral surfaces of the sections are flared to produce open crevices at the surface of the stool.

In Figs. 11 and 12 is illustrated a form of the invention which might be so expensive to construct as to be impractical. It serves, however, 5 'as an illustration of one oiE'v the many forms in which the generic principle of the invention may be applied.- It consists of a circular stool comprising a frame 2| having a base 22 consisting of a series of annular section seats 38 and a 10 circular central seat 39 at different levels and a plm'ality of sections 20 supported on said seats, comprising a central cylindrical section surrounded by concentric annular sections. The sections may be of dimensions such that they will fit 15 and the working clearances allowedbetween the 25 rings and the.shoulders surrounding the seats, as well as the clearances between the rings to allow for expansion, may be such that the rings might be cast and used without machining, or the metal may be drawn or extruded into cyl- .30

inders of considerable length and cut to sizes required in making the stool. The gradation in the depth of the rings is such as to provide the greatest depth of metal at the center of the stool where the need for absorbing and dissipat- 35 ing heat is greatest.

. It will be apparent from the foregoing description and the accompanying drawings that the word crevice" is used throughout this applica- 'tion' in its broad sense such as would include 40 either an open crevice having its walls out of contact or what might be called a closed crevice amounting to nothing more than a dividing zone between two parts having complemental surfaces in contact with each other. 45 It will also be apparent that the widths (if the crevices between the sections of the forms of the invention illustrated by Figs. 1, 2, 9, 11 and 12 are grossly exaggerated. They need be no greater than is necwsary to provide for expansion due to 50 heating during a casting operation, and by making the sections of the stool sufllciently narrow the crevices may be of widths such that the metal poured in an overlying mold will not enter.

If desired, the support for the copper mold sections may be provided with mold centering lugs and pads for properly positioning the stool upon a' truck, suchas are commonly applied to cast-iron stools. Such pads and lugs might be applied to the supporting frame of any of the 69 Y forms of stool herein disclosed. As illustrated for example in Figs. 1 and 2, the frame may be provided at the four corners of its upper surface with centering lugs 4| so located as to properly -in the surfaces of the trucks serve as a means of definitely positioning one with respect to the 5 other. The possibility of applying such centering lugsandpadstoanyofthestoollfillclosedin The invention is not intended to be limited to the specific forms which have been selected for purposes of illustratiombut shouldbe regarded as including'modifications and variations thereof within the scope-of the appended claims.

What is claimed is:

1. A metal st00l f0r an open-bottomed ingot mold adapted for use in casting metal, said stool .comprising a composite, mold-supporting structure consisting of numerous, relatively small sections separated by crevices extending from its upper surface to its base and means for holding said sections assembled with their adjacent surfaces in, close association.

2. A stool, as defined by claim 1, of which the component sections are constructed of copper.

3. A stool, as defined by claim 1, of which the component sections are constructed of an alloy 25 crevices between the'sections are vertical and mutually parallel. I v r c 5. A stool, as defined by claim 1, of which the crevices between the sections, when cool, are open at and for a considerable distance below the mold supporting surface to an extent such as to allow for free expansion. of the heated parts of the stool during a castingoperation.

r 6. A stool, as defined by claim 1, of which the crevices between the sections are vertical and mutually parallel, and of which the means for holding the sections in an assembled relation in clude means for forcing the end'sections towards each other and foranaintaining the forcing means.

efiective whereby each section of the series, intermediate the end sections, is compressed and snugly held} between a pair.of adjacent sections. 7. A stool, as defined by. claim 1, of which the opposed side surfaces of the sections are fiared slightly along their opposite edge portions so as to produce narrow open gaps between the sections extending along the opposite surfaces of the stool when the sections are held in close contact with each other along the zones of their opposed surfaces intermediate their fiared portions.

8. A stool, asdefined by claim 1, of which the means for holding the sections in an assembled relation comprises a rigid, open-topped frame of a size such as to accommodate the assembled sections and wedging means to set up mutually opposed forces between the sections and adjacent parts of the frame, whereby the sections may be held compressed in close contact with each other and with the section confining portions of the section holding means. 1

9. A stool, as defined by-claim 1, of whichthe means for holding the sections in an assembled relation comprises a rigid, open-topped frame of a size such as te accommodate the sections and expansive resilient means to set up mutually opposed forces between the sections and adjacent parts of the frame, whereby the sections may be yieldingly held compresseddn close contact with each other and with the section confining portions of the section holding means.

10. A stool, as defined by claim 1, of which the means for holding the sections in an assembled relation comprises a rigid, open-topped frame of a size such as to accommodate the sections, ex-

pansive resilient means to set up mutually opposed forces between the sections and adjacent parts of the frame, whereby the sections may be yieldingly held compressed in close contact with each other and with the section confining portions of the section holding means, and means, for adjusting the tension of the resilient means.

11. A stool, as defined by claim 1, of which the sections are in the form of cubes separated by two series of vertical crevices, the crevices of one series being perpendicular to those of the other.

12. A stool, as. defined by claim 1, of which the sections are in the form of cubes separated by two series of vertical crevices, the crevices of one series being perpendicular to those of the other, and each of the cubes being slightly flared along each of the four marginal portions of each of its six faces, so that the cubes maybe interchangeably used with any of their faces up and invariably cooperate to produce a chequered mold supporting surface having portions which are equally expansible in all directi'ons.

13. A stool, as defined by claim 1, of which the means for holding the sections in an assembled relation include an open-topped frame of dimen-- sions such as to accommodate the assembled sections and leave gaps between outer surface portions of the sections and adjacent walls of the frame, the walls of the frame which extend along the gaps being slotted to provide for GIfiICUJE-m tion of air to cool the sections during a casting,

operation.

14. A stool, as defined by claim 1, of which the means for holding the sections in an assembled relation includes an open-topped frame having spaced base members to support the sections and side section confining members in spaced relation with outer surface portions of the sections so as to provide passages for air circulation, thelower margins of the confining members being above Y the lower level of the base members so as to vening spacing material which need not be of the same character as that of the sections of the supports- CHARLES H. AIDRICH-

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