US1733513A - Means for producing articles from granular or plastic substances - Google Patents

Description

Oct 29, 1929. K. a. w. PETTERSSON j 1,733,513

MEANS FOR PRODUCING ARTICLES FROM GRANULAR OR PLASTIU SUBSTANCES Filed Dec.,29, 1927 Patented Oct. 29, 1929 rona rron o a a ;A rgunorFlC I KNUT GUNNAR wnntmtrm rngrrnnsson, or i vas riines, SWEDEN,-ASSIG1\TOR To" l AKTIEBOLAGET 'LINDHOLMENMOTALA,

orfivro'rnna vnRKsrAn sWnnEN, A 003- MEANS ron 'rnomrcrne lmrrcnns men chariot-Anon rLAsmoI-snnsmnces .appnoationmea sam a 2a, 1927, semi No. a4s,412, ana n1 Sweden May 29, 1926.

In making-casting molds from sand or other granular material, it is hitherto a common praxis to subject the casting box or flask to a strongshaki-ng movement in a verticaldi rection. This has generally been performed in such a manner that the downward movement has been suddenly interrupted, and especially at the shocksth ereby caused the grains have been'packed together in the desired manner. The total movement j has neecssarily been rather large, in order to pro-' duce a suflioiently "strong shock, and during the majorpart of this movement no real pack ing of the grains has taken place. A close examination of this process therefore shows it to be of rather smallefliciency.

According to the present invention, the moldor casting box together wi'ththe granular material, such as sand contained therein, is subjected to rapid vibrations for packing the said material together. It appears at the first thought that such vibrations which involve alternating, practically equal forces acting on the grains in opposite directions, would not cause an efficient packing of the grains. The experience, however, proves that a much greater force is necessary for loosening the grains after they have once been squeezed in between each other by wedge action, than for the said squeezing in, and the result will be that practically every change in the direction of movement will increase the packing effect, if the vibration process is used, whereas in the old shaking process a packing takes place only when the direction of movement is reversed from downward to upward. Theoretically, if the maximum retardation is the same and other circumstances equivalent in both cases, the proportion between the working speeds of the two processes would therefore be about twice the proportion between the frequencies. In practice it has also been found that a very considerable savin of time is obtained. Further it is possi le with this process to manufacture much smaller cores, molds and the like than by the shaking process. I It is advisable to subject the sand or other materal to alight pressure during the vibra-' tion. For smaller objects, the said pressure can be exerted by hand; for larger objects,

a pressv plate or the like may be employed, 1 i

serving as a counter support against the vibratory motlon.

The frequency of the vibrations employed I may vary within rather widelimits. As a lower limit, ten complete cycles per second may be chosen, this being at any rate considerably more than has been used in the shaking process, that is, about five cycles per" second as a maximum. Generally it is,"however, advisable to employ between 30 and I 100 cycles per second, The vibrations may be either single, reciprocating in a certain direction, or complex, alternately 1n various directions forming angles with each other.

They may also, ifdesired, be ofa moreirregu l-ar character. The introduction of thesand or other material may take place either before the beginning of the vibrations or gradually during the said vibrationsand in either case bemade by any kind of filling means.

The invention is applicable also in making I I keramicand cementatory objects, such as p1pes,bricks and the like to be produced in a mold,-said, mold and the cement, clay or other suitable material contained therein be- I ingsubjected tovibrations in the manner set f a i J r The inventionalso relates to means for exe outing the process, comprising a movable table or other support for the flask or castingboxcarried by one or more mechanically or electrically driven vibrators adapted to set the support with the objects carried thereby in vibrations. lf desired, the vibrators may instead be carried by the table] I I i I In the accompanying drawing, two embodiments of a machine for'carrying'the process into elfect are illustrated] Fig- 1 shows a molding machine in elevation, partlyin section and Fig. 2' shows a detailof a modified form ofthe upper portion of the machine shown inFig, in elevation and partial section. a

s 1 {Referring to Fig. '1, ram 1, which my tiltablein a stand 2m aknown; manner, a

is provided at its lower part with-guiding grooves Sin whicha vibratorcylinder'i containing a iston 12 ismovableup. and down.

The cylin er carries, at its top a tablet for the, casting box 6. Placed on the latter is a separate filling hopper or frame 7 which may be partially or totally filled with sand or corresponding material during the operation.

The table '5 is carried by the cylinder 4 by means of bolts 8 secured to the'former and traversing guide holes in projections 9 on the cylinder.v The bolts are surrounded by springs 10 which normallypress the table 5 downwards into its lowest position. By

7 means of set screws 11, the bolts 8 may be lockedto the guiding projections 9 so that the table is held firml to the cylinder. The resilient connection with loose set screws) is used for big objects, the rigid connection for small ones, for which'the deformation of the material provides for sufiicient vibrations.

For accelerating the compression of the material to be molded, especially in the upper layers, a press plate 13 may be used, which for instance may be lifted by means of a hand wheel 14, and which according to Fig. 1 is presumed to be so heavy that its own weight is suflicient for the compression, so that no readjustm'entis necessary for packing the sand.

For molding small objects, the said press plate may not be necessary, as a pressure by hand maybe suflicient. For such cases, the upper portion of the frame 1 may be swung to the side on'a hinge 15. Withthe machine illustrated, two or more objects placed on one another mav be molded, for instance the two halves of a divided casting mold or c0re.

' The cylinder 4 is, asalready stated, some what movable in the frame in a vertical disupport carried by said vibrator, and means for compressing said granular substances.

4. A machine for making molds from granular substances, comprising a frame, a vibrator resiliently carried by said frame, a mold support carried by said vibrator, and means for exerting vibratory pressure on objects carried by said support.

5. A machine for making-goods from granular or plastic substances, comprising a frame, a vibrator resiliently carried by said frame, and a mold support connected to said vibrator.

6. In a machine for making molds from granular materials, a frame, a mold support on said frame, a. castingbox on said support for receiving granular material, resiliently mounted means for applying vibratory movement-to said mold support and; means for simultaneously applying pressure to the granular material in said casting box.

' rection and resiliently supported in the same I by means of springs 16 surrounding bolts 17 This movement can be'arrested by means of latches 18 which is especially desirable when the, frame shall be tilted for extracting the mold or core. i

In the modified embodiment of the machine 7 shown in Fig. 2, the plate 13 is carried by means of bolts 19and springs 20 by a vibrator i cylinder 21, which in its turn is carried by the piston-rod 22 of a cylinder 23 mounted on the frameand serving to exert pressure during the molding and to lift the plate. (to which the molded object or part thereof may be fixed) after the said operation.

r p Whilll'I claim is:-

1. .A machine for making molds from granular substances, comprising a frame, a

vibrator resiliently carried by said frame,- and V f a moldjsupportcarried by said vibrator.

2. A machine for making molds from gran- 7 i ular substances, comprising a frame, a vibra tor resiliently carried by sa1d frame, 'a'de'vlce for" locking 'said"v ibrator rigidly to. said support I carried by said frame, and a mold vibratonf 3. Amachine for making molds from granular substances, comprising a frame, a vibrajtor resiliently carried by said franie,a mold

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