US 2561266 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
July 17, 1951 H. w. DIETERT METHOD AND APPARATUS FOR FORMING TEST SPEGIMENS OF MOLDING SAND AND THE LIKE Filed May 1, 1950 2 Sheets-Sheet 1 INVENTOR.
HAR RY W. DIETERT M) /WM ATTO RNEYS July 17, 1951 H. w. DIETERT METHOD AND APPARATUS FOR FORMING TEST SPEGIMENS OF MOLDING SAND AND THE LIKE 2 Sheets-Sheet 2 Filed May 1, 1950 Patented July 17, 1951 UNITED STATES RA'RENT o F iF'lCE METHOD AND -APPARATIIS or: FORMING TESTsSPECIMENSDF MOEDING SAND A-ND ,THE: LIKE "1 .=The-invention relates to theforming of compacted .--specimens of "molding sand -'or other similar materials -.to".be 'use'd "for.various tests determining characteristics "thereof. "Among the testslto which such. specimens are subjected are green, Idryandhotstrength, permeability and air-set strength, etc. "It has been" the practice in the past to formsaid specimens by ramming the material withaconstant impact energy, but thisdoes not-produce the same effect in different materials .varying in bonding substances and other additives ina particular sand. Good foundry practice requires that molds in .the foundry should be rammed to as nearly as practical a specific mold hardness,.the optimum or desirable mold I hardness being obtained by choosing the one that produces the better castings. However, the various"tests performed on the specimens will difier'in results with different degrees of hardness of the specimen, andsit'is therefore important that the'hardness of the specimen should correspond to the hardness of the mold which is to be'iormed of the 'materials tested.
It is the object of the invention to obtain test specimens whichhave a predetermined Shardness substantially corresponding to the hardness of the mold'to be'formed of the material tested.
It is a' fu'r'ther object of the invention toform specimens of measured hardness wh'ich isjindependent of the "impact 'energy'for forming the same. The invention .therefore consistsffirst, in "the method employed for attaining such results and, second; in the apparatus .by which said method may becarried out.
.In the drawings:
"Fig.1 is .a..side.elevation of the apparatus;
'Figfz is a top plan view thereof;
Fig.3 isa .vertical central section partly in elevation of .the compacting and indicating means and Fig.- 4 is an end-elevation ofa portion of the structure.
As above stated it has been the .practice in the past to form specimens by a constant impact energy such, for instance, asis obtained by-"a plurality of'droppings of a. ram of predetermined weight. Withmy improved process'the hardness of the specimen is measured during'the acompacti-ng-=operationsoathat the impact may '.-be governed to-obtain the *particular hardness pglesired. .Molding sand and other-flowable mat te rlials formed oi. separate partic1es behave Fin some respects/similar :to. a hydraulic -fluidiin that pressureaprilid'. inoneidirection will be transmitted throughlthe materials. in other directions also. However, .such materials differ mm hydraulic fluidslin that the transmitted pressures are not the samefl'in. all directions per 'unit of area. "It is ther.e'f.ore...apparent thatlthe .reaction of. materialstoiimpact. compressivev energy is not always the same and that the hardness or.resistance' to displacement will .also vary.
"To obtain .a predetermined ldegree .o f har'dness the reaction of the -.mate'rial "to Lthe impact energ ismeasured-andindicated, and by progressivlyincrea'sing' thislimpact energy any desired degree of findicated har'dness. may be 6btained.
l lvly improved imetho'd .may' be carried 'oiit'in different forms Lofapparatuafbl'it as illustrated in the drawings, Titis of .the following construction. YA isa' frame including a base po'i'tion B, a commie rising therefrom and having at'it's upper .eridaLlaterally extending portion D also .above 'the base anditerminating I in 'abifurcat'ed portion E. The furcations of'theiportioriEezitend upward. above lthe,.'.porti'on' -D .and are .bored in axial alignmentwi'th each other-to receiVeshaftS F ijourn'aled Lin: antiefri'ction bearings Ih'e shafts'TF. are respectively secured to a pair or lever arms'l-l which extend substantiallfhorb zontally and have. adjustably mounted 'on'thei'r .outer .end. portions. a weight-10f" predetermined mass. There=is a1so.a stop or restiorlthes'elever rarmsi formedibya'shafti J, which projects'la'terally onoppos itelsides o'fa 'lug'C' -on the upper endoflthe .c'olurnn -"C to extend beneathjsaiii .arms. ll'Ihus'the normal. position of thelever arms vvilll-lbe inelind slightly in a "downward Idirection towards their outer ends. "Supported on .the; portion-of the base-TB which .is' beneath the vertical ,plane .of the I fulcrum is a .,post ..or
.column. K- which isexchangeableand which may :be :eitherround, square or anyothensha'pelin cross sectional :contour. L..isa tube or. casing :ior holding the material of which the. specimen is formedsaid tube being cm shape .to vtelescopeovertheiposthK. -Inititll-ythis tube ILQis :supportedon. the -postlbyclips. M beneath tithe flowerend of the=tube.and-. engaging aperipheral groove. in the-. post. ."However, .afterthe. inaterial is .eompacted within-lthel tube 1'. L, the ,f clips M.may, be. removed andithe tube. telescoped lover thepost to remove fit. from 'thecompact'd specimen. The compacting meansisacplunger-N'having at its lower end a head Nflfittmgwithinltm .tube-.L,--and. at. its upper ven'dengagingmea'ns 3 for pressing it downward. As specifically illustrated downward pressure is produced by a threaded nut having radially extending actuating arms 0 and engaging a correspondingly threaded upper end portion N of the plunger N, said nut reacting against hearings on the lever arms H. More in detail the lever arms H have mounted thereon rollers H having their axes in alignment with each other and ofiset from the axis of the fulcrum shafts F. These rollers project inward from the lever arms and are adapted to engage an annular groove 0 in the nut 0. Thus if the nut is turned in a direction to move the plunger downward it will react against the rollers H, which will initially be held stationary by the weight I, forcing said arms to rest upon the stop shaft ..J. Thisstationary position will be maintained until the reactive force against the lever arms exceeds the downward thrust thereon produced by the weight I,but if a higher pressure is developed the arms H'will be lifted. Thus the construction is such as to limit the maximum force which can be applied by the plunger against-the material to be compacted to that determined by the weight on the lever and which may be varied by shifting the weight to different positions.
To determine the hardness of the material compacted within the tube L by the plunger N, I have provided means for measuring the reaction of the material while subjected to compressive stress, which is indicative of hardness. This means is mounted within the plunger N and has an indicator which is at all times visible to the operator. As shown it comprises a small head P which is within a central recess'in the plunger N to'form a portion of the surface bearing against the material within the tube L. The plunger N has a lower hollow portion N and a tubular portion N of larger diameter secured to the portion N by a head N The upper threaded portion N of the plunger is connected by a head N to the upper end of the tubular portion N 'Within'the tubular portion N is a gauge P of any suitable construction, which is operated from the head P through the medium of a plunger rod P The gauge is visible through a window in the tube and is calibrated in units of hardness.
Consequently, when downward pressure is ap- I plied by the head N to the material within the tube L, the portion of said material beneath 'the head P will react to relatively raise said head and, through the plunger P and mech- "anism operated thereby, will turn the index hand P to indicate the hardness. If the specimen being compacted is to be used for determining qualities of the molding material when used in a mold of predetermined hardness, then the compression of such material may be continued until the gauge indicates the same degree of hardness. However, when this is once determined then the apparatus may be adjusted to automatically limit the pressure that can be applied through the plunger N to a corresponding amount. This is effected by adjusting the weight I on the lever arms H so that when the desired exactly horizontal.
' After the specimen has been-compacted down- 4 ward pressure of the plunger N is relieved, after which the tube L may be moved downward telescoping the same over the post K and leaving the specimen free on the top of said post from which it may be removed.
What I claim is my invention is:
1. The method of forming from'loose material compressed specimens of predetermined hardness, comprising applying to the material a progressively increasing compressive force and simultaneously measuring the reaction of said material independent of said compressive force which is indicative of the hardness thereof, and continuing the progressive increase of said compressive force until the desired hardness is indicated.
2. The method of forming from loose material compressed specimens of predetermined hardness, comprising applying to the material a progressively increasing compressive force and simultaneously measuring the reaction of said material independent of said compressive force which is indicative of the hardness thereof, continuing the progressive increase of said compressive force until the desired hardness is indicated, and limiting the compressive force to that amount.
3. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a plunger for compacting the material in said container, and means for measuring and indicating the reaction of the material during the compacting thereof independent of said compressive force which is indicative of hardness thereby permitting the con tinued compression until the desired degree of hardness is attained.
4. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a plunger fitting within said container for compacting the material therein, said plunger having an aperture therein, a smaller plunger filling said aperture, means for actuating said first plunger, and means mounted on said first mentioned plunger and actuated by said smaller plunger for measuring and indicating the reaction of the material indicative of hardness during the compacting thereof.
5. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a hollow plunger fitting within said container for compacting the material therein, a smaller plunger within said hollow plunger completing the enclosure of said con- ,tainer, means. for actuating said first mentioned plunger, means mounted on said. hollow plunger and actuated by said smaller plunger for measuring and indicating the reaction of the material indicative of hardness during the compacting thereof. i v
6. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a plunger fitting within said container for compacting the material in said container, means for measuring and indicating the reaction of the material during the compacting thereof indicative of hardness, actuating means for said plunger, and a yielding member for absorbing the reaction of said actuating means limiting the maximum compressive force -of said plunger.
7. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a plunger fitting within-said container for compacting-the material in said container, means for measuring and indicating the reaction of the material during the compacting thereof indicative of hardness, actuating means for said plunger, a yielding member for absorbing the reaction of said actuating means limiting the maximum compressive force of said plunger, and means for adjusting said limit.
8. Apparatus for forming test specimens of compacted material, comprising a container for the loose material, a plunger fitting within said container for compacting the material in said container, means for measuring and indicating the reaction of the material during the compacting thereof indicative of hardness, actuating means for said plunger, a lever for absorbing the reaction of said actuating means and limiting the compressive force of said plunger, and an adjustable weight on said lever for changing the limit.
9. Apparatus for forming test specimens of compacted molding material, comprising a base, a column and an adjacent standard rising from said base, a mold telescopically engaging said column, means for temporarily supporting said mold on said column to extend above the upper end of the latter to receive and hold the loose molding material, a plunger engaging said mold above the material therein and having an upwardly extending threaded portion, a nut enga ing said threaded portion, a bifurcated lever fulcrumed on said standard and embracing said nut, being adapted to bear downward thereupon at diametrically opposite points adjacent to said fulcrum, a weight adjustable on said lever, means for rotating said nut to move downward said plunger with a force limited by the resistance to upward movement of said weighted lever, and a gauge mounted on said plunger in operative con tact with the material being compacted within said mold for indicating the hardness thereof during the compacting operation.
HARRY W. DIETERT.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 306,660 Stewart Oct. 14, 1884 423,756 Girdler Mar. 18, 1890 1,661,718 Davis Mar. 6, 1928 1,941,780 Angeli Jan. 2, 1934 2,421,449 Zaber June 3, 1947