US2842817A - Method and means for the mechanical preparation of molds from compressed granular material - Google Patents

Method and means for the mechanical preparation of molds from compressed granular material Download PDF

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Publication number
US2842817A
US2842817A US385999A US38599953A US2842817A US 2842817 A US2842817 A US 2842817A US 385999 A US385999 A US 385999A US 38599953 A US38599953 A US 38599953A US 2842817 A US2842817 A US 2842817A
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Prior art keywords
sand
box
mold
granular
pattern
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US385999A
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English (en)
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Buhrer Erwin
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B30—PRESSES
    • B30B—PRESSES IN GENERAL
    • B30B11/00—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses
    • B30B11/02—Presses specially adapted for forming shaped articles from material in particulate or plastic state, e.g. briquetting presses, tabletting presses using a ram exerting pressure on the material in a moulding space
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/10—Compacting by jarring devices only
    • B22C15/12—Compacting by jarring devices only involving mechanical gearings
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor
    • B22C15/28—Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing
    • B22C15/30—Compacting by different means acting simultaneously or successively, e.g. preliminary blowing and finally pressing by both pressing and jarring devices

Definitions

  • This invention relates to methods of and means for producing molds from compressed, granular sand or like material.
  • the purpose of the method envisaged in the invention is to eliminate, at least to a very great extent, the various disadvantages above set forth in order thereby to improve the precision and the surface quality of the mold and to contribute substantially to meeting the requirements for an automatically operating molding machine.
  • the method according to the invention for the manufacture of molds from granular sand, wherein said sand is subjected to a preliminary and a final compression 70 process is characterized primarily by an amount of granular sand being poured over the pattern in excess of a predetermined amount necessary for the manufacture of the complete mold, this surplus being removed again between the preliminary and the final compression process. It is further characterized by the fact that the required amout of such granular sand surplus is supported by means which increase the height of the molding box in such a way that a surplus of granular sand can be poured over the Whole surface of the pattern.
  • the pouring in of the granular sand is advantageously effected by strewing or sieving.
  • the method yields, after the preliminary compression and the removal of the surplus granular sand, a pre-compressed mold in which the granular sand projects high enough above the top edge of the molding box to enable the final compression process to be carried out; that is to say, there is, in respect of weight, less granular sand over the heightened parts of the pattern, but, on the other hand, more granular sand over the other parts of the said pattern, than with the methods usual hitherto.
  • This improved horizontal distribution of the granular sand over the pattern before the final compression which has, at least in part, to be effected by squeezing, enables a compression operating transversely to the direction of the squeeze to be dispensed with.
  • the elevation of the top surface of the mold over the pattern therein is lowered, and the elevation is again lowered when the excess material is removed and lowered further when the final compression takes place.
  • the method according to the invention provides, in addition, for the preliminary compression to be effected by forces resulting from the inertia of the sand, said forces acting, preferably at right angles to the surface of the pattern, in the granular sand itself, and further, for said forces to be produced by jolting.
  • This increases the preliminary compression in the deep parts of the granular sand and decreases it in the parts above. Both these measures improve the pro-compressed mold as the starting material for final compression.
  • the method provides for the jolting blow to be elastically so strongly damped that in the preliminary compression process a deliberately more intense compression is produced in the lower part of the higher layers of thegranular sand filling than in the bottom part of the lower layers of the said sand.
  • the intensity of the preliminary compression is made so strong that-the full compression sought after is already achieved in the lowest part of the highest layers of the granular sand filling. In this way, as calculations andtests show, the uniformity of compression is still further improved.
  • a device for applying the method a device is used which is characterized by the fact that a filling frame which can be set up on the molding box and a means for removing the surplus granular sand are provided.
  • FIG. 1 is an upright section of the device along line 1-1 in Fig. 2,
  • Fig. 2 is a horizontal projection of the device as shown in Fig. 1.
  • Fig. 3 is a side projection of Fig. 1, partly along line II-II in Fig. 2, and
  • Fig. 4 is a View of the filling frame seen in the direction of arrow A in Fig. 3.
  • a molding machine comprising a machine or base column 1, a press piston 2 and a jolt piston 3, the latter being raised by a pressure medium in a manner already familiar, and, after this pressure medium is released, falling back by its own weight on to press piston 2 which rests on the bottom of column 1 during the ramming process. All the control members and pipe lines are, for reasons of clarity, omitted from the figures.
  • Jolt piston 3 carries a jolting table 3a on which lies a patern plate 4 with a pattern 5. On pattern plate 4 is supported the molding box 6 on the upper edge of which lies a filling frame 7.
  • Said frame has on its lower side a downwardly depending reinforced, circumferential edge 7a which on its inner sides exhibits surfaces 7b running obliquely downwards and outwards and which serve to shape the sand into a blunt or truncated pyramid, facilitate the lifting of the filling frame 7 from the molding box 6, and prevent the granular' sand from falling over the edge of the molding box in the final compression process.
  • the reinforced edge 7a On the reinforced edge 7a are arranged parallel walls 7c'lying opposite one another and connected to said edge. To another section of the edge a blade 8 is attached, and to the remaining section a flap 9. The two walls 7c are connected with one another by wall 7d and tube 7e. The sand container of the filling frame 7 is consequently bounded by the side walls 70, the blade 8 and the flap 9.
  • the blade 8 is arranged with the ends of its bottom edge 8a lying on the edge 7a and projecting inwards past the walls 70, while the opposite sides of the ends of its top edge 8b are connected by two endless chains 10. These chains run over sprocket wheels 12 and 13 which are arranged on shafts 14 and 15, journalled in the walls 7c.
  • the frame 7 is lowered onto the molding box by means of a pneumatic lifting and lowering device.
  • a pneumatic lifting and lowering device When the box hasbeen filled and the granular sand subjected to the preliminary compression process, the frame is lifted high enough from the molding box to enable the squeezer board 34) which is used for the final compression, to be swung over the mold.
  • the lifting and lowering device is arranged on a column 31, on which also the squeezer board 30 can be swivelled about axis 32.
  • the inner surface of lower rim 7a defines a space of truncated pyramidal configuration.
  • These eyes are provided with tapered bores into which the tapered centering pins 37 fixed to head 36 engage.
  • Head 36 is fixed to a piston rod 33 whose piston 39 is arranged in a cylinder 40, which is fixed to column 31.
  • the piston rod 38 which is kept from twisting or rotating by wedge or key 41, moves downwards until the tapered pins 37 emerge from the bores in said eyes, when 'the filling frame 7 lies on the molding box, so that the frame can follow without hindrance the jolting movements of the molding box 6 during the preliminary compression process.
  • a shaking or oscillating screen 42 arranged at the bottom end of a molding sand silo 43; the shaking movement of the said screen is produced by an electromagnet 44 and its oscillation period is controlled by a time switch (not shown).
  • the electromagnet can be switched on by hand or by means of a contact, not shown or described in detail, which is closed after the frame is resting on the molding box. This contact is advantageously actuated by the piston rod 38 moving still further downwards.
  • the device operates as follows: Let it be assumed that a finished mold, which has just undergone final compression by squeezing, as is shown in Fig. 3, is on the machine. Now, by the actuation of a control member, which is not illustrated, the pressure medium is released under the press piston 2, and said press piston and with it the jolting table 3a with the pattern 4 or 5 and the finished mold are lowered. The squeezer board 30 is moved into the swung-out or inoperative position, as is shown in Fig. 2, and the finished mold is lifted olf in a conventional manner.
  • the granular sand is now strewn onto the pattern 5 and the pattern plate 4, pouring down from the silo 43 in a continuous stream.
  • the electric current is automatically stopped by the said switch, the electromagnet 44 comes to a standstill and the sieving of the granular sand ceases.
  • the preliminary compression by jolting which now begins is carried out in a conventional manner by actuating the already mentioned control member. 7
  • the jolting as is well known, compacts the sand by making use of the inertia thereof.
  • the jolting blows may be elastically or resiliently damped, as by interposition of a suitable resilient or spring member 46 disposed between the jolting piston 3 and press piston 2, in order to reduce the magnitude of the effect of the jolting blows.
  • a pressure medium is supplied by actuating a further control member, which can also be combined with the one already mentioned, to the cylinder 19 via the opening 19a, while the pressure medium on the other side can escape via the opening 1%.
  • the blade 8 is thus pushed by the movement of the piston 18a via the piston rod 18, gear wheel 17, sprocket wheels 12 and chains from the position illustrated in Fig. 1 into that illustrated in Fig. 4, while at the same time the flap 9 is raised by the pins 24 into the position illustrated in Fig. 4. Thereby, the surplus granular sand above the molding box 6 is scraped.
  • cylinder 19 is supplied with a pressure medium via the opening 1%, while the pressure medium at the opposite end can escape via the opening 19a, whereby inversely to the already mentioned process the blade 8 is withdrawn into the position illus trated in Fig. 1 and the flap 9 is lowered into the position illustrated in Fig. 1.
  • cylinder 40 is supplied with pressure to raise piston 39 and piston rod 38, and therewith head 36 with the centering pins 37 engaged in it.
  • a pressure medium is supplied below the press piston 2 by actuating a control member, whereupon said press piston and with it the jolting table 3a, the pattern plate 4, the pattern 5 and the molding box 6 are raised, and the pre-compressed mold is pressed against the squeezer board 30 in such a way that the granular sand, which in the pre-compressed state projects above the molding box like a blunted or truncated pyramid, is compressed as far as the top edge of the molding box. After the final compression the series of operations begins anew.
  • the above-described method of preparing a complete mold of predetermined volume and configuration having at the termination of the mold preparation an upper face located at a predetermined elevation above a pattern in the mold includes the steps of placing over the suface of the pattern a total quantity of granular material equal to a predetermined quantity of the granular material required by the complete mold and in addition thereto an excess quantity of the granular material, while laterally confining the total quantity of material to provide the same with a top surface at a first elevation above the pattern greater than the above predetermined elevation.
  • the total quantity of material occupies-a lower space equal to the predetermined volume of the complete mold, an intermediate space of the configuration of a truncated pyramid form ing a continuation of the lower space and having a base coincident with the top of the lower space, and an upper space directly above the intermediate space.
  • This total quantity of granular material which is laterally confined in the above fashion is preliminarily compressed until the top surface of the total quantity of material is lowered to a second elevation between the above-mentioned first and predetermined elevations above the pattern to thereby attain a preliminary compressed material, and
  • this preliminary compressed material fills the lower and intermediate spaces and part of the upper space.
  • the predetermined quantity of material required for the complete mold exactly fills the lower and intermediate spaces, and the excess quantity of material remaining in the upper space is removed to leave the predetermined quantity of granular material with an upper face coincident with the top of the intermediate, truncated pyramidal space which is at a third elevation between the above-mentioned second and predetermined elevations above the pattern.
  • the granular material is now finally compressed so that the predetermined quantity of material is compacted out of the intermediate space into the lower space of predetermined volume to form the complete mold, and it will be noted that during this step the upper face of the granular material is lowered from the above-mentioned third elevation until this upper face has the above-mentioned predetermined elevation above the pattern.
  • the principle of the invention is not limited to the device described, nor exclusively to the operational sequence described.
  • the preliminary compression by jolting for instance, can be introduced even while the granular sand is being poured in.
  • the method is restricted neither to the form of silo illustrated nor to the system of strewing.
  • the method can be applied to all types of molding machines, both to flask-lift-type molding machines and to turn-over-table molding machines; the method is merely committed to the presence of suitable means for the preliminary and final compression processes.
  • the surface of this section can also be produced unevenly in two or three dimensions.
  • the latter can be designed in several sections, so that the means for the removal of the surplus sand may be arranged independently and separately.
  • Means for preparing a mold from granular material comprising a mold box including pattern means, base means supporting said box and including means adapted to transmit preliminary compressive forces to said material to preliminarily compress said material when placed in said box, a filling frame attachable to and removable from said box, whereby said material may be supplied to said box when said filling frame is attached to said box, means operatively connected to said frame for selectively moving the latter to and from said box, means movably connected to said frame for removing excess of said material from said box, pressure exerting means on said base means operable to finally compress said material in said box to complete said mold on said pattern means, and a pneumatic system comprising a piston and a cylinder, said piston being provided with means disengageable from said frame to lower the latter onto said mold box when said piston moves in one direction and engageable with said frame to raise said frame from said box when said piston moves in another direction, said disengageable and engageable means on said piston comprising tapered pins, said frame being provided with tapered holes into which said pin
  • Means for preparing a mold from granular material comprising a mold box including pattern means, base means supporting said box and including means adapted to transmit preliminary compressive forces to said material to preliminarily compress said material when placed insaid box, a filling frame attachable to and removable from said box, whereby said material may be supplied to said box when said filling frame is attached to said box; means operatively connected to said frame for selectively moving the latter to and from said box, means movably connected to said frame for removing excess of said material from said box, pressure exerting means on said base means operable to finally compress said material in said box to complete said mold on said pattern means, a pneumatic system comprising a piston and a cylindensaid piston being provided with means disengageable from said frame to lower the latter onto said mold box when said piston moves in one direction and engageable with said frame to raise said frame from said box when said piston moves in another direction, and stops on the lower edges of said filling frame, whereby said filling frame in the lowered position rests on said
  • a machine for producing a mold made of molding sand comprising a pattern plate with a pattern thereon, a molding box on said pattern plate, a filling frame on said molding box and separable therefrom, means extending above said filling frame, said molding box, said filling frame and said extending means being adapted to enclose together a total quantity of molding sand composed of a predetermined excess quantity of molding sand and the quantity of molding sand required for the finished mold, means located below said pattern plate for imparting a jolting action to said total quantity of molding sand, said extending means including a plurality of operable means arranged for movement relative to each other for removing said excess quantity of sand from above said molding box, and pressure exerting means arranged for movement above said molding box to apply final compaction to the quantity of molding sand required for the finished mold after said filling frame and said extending means with said operable means have been separated from said molding box.
  • said operable means being mounted on said extending-means and including at least one blade having a cutting edge for removing said excess quantity of sand from above said molding box.
  • said filling frame being provided with a downwardly and outwardly projecting circumferential edge having an inner surface which is substantially in the form of a pyramid.
  • a machine wherein a blade having a cutting edge for removing said excess quantity of sand is movably arranged on said inclined inner surface and adapted to remove sand extending above said box and beyond said edge.
  • a machine according to claim 8 including means providing with a compressed air cylinder and a piston for movement of said blade along said edge, said blade forming an acute angle with respect to the top surface of said filling frame, said filling frame being provided with guide surfaces for said blade.
  • Means for preparing a mold from granular material comprising a mold box including pattern means, base means supporting said box and including means adapted to transmit preliminary compressive forces to said material to preliminarily compress said material when placed in said box, a filling frame attachable to and removable from said box, whereby said material may be supplied to said box when said filling frame is attached to said box, means movably connected to said frame for removing excess of said material from said box, saidmovably connected means including two elements forming in one position closure means for said filling frame and in another position at least one of said elements being movable across said filling frame to remove said excess of said material, while the other element is adapted to release said excess material from said filling frame, pressure exerting means on said base means operable to finally compress said material in said box to complete said mold on said pattern means, and actuating means connected to said base means and provided with means disengageable from said frame when the latter has been lowered onto said mold box and engageable with said frame to raise said frame from said box, respectively.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)
US385999A 1952-10-22 1953-10-14 Method and means for the mechanical preparation of molds from compressed granular material Expired - Lifetime US2842817A (en)

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BE (1) BE523431A (ja)
DE (1) DE1058702B (ja)
GB (1) GB757602A (ja)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4077459A (en) * 1974-12-10 1978-03-07 Erwin Buhrer Method and apparatus for the production of foundry molds
CN105252809A (zh) * 2015-11-10 2016-01-20 北京京城环保股份有限公司 一种散料固化成型模具及散料固化成型方法

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4593739A (en) * 1983-12-30 1986-06-10 Outboard Marine Corporation Method of and apparatus for packing sand around a mold pattern by vibration
CN118060498B (zh) * 2024-02-28 2024-08-27 河北青峰车体模具有限公司 一种铸造造型用振实压实装置

Citations (13)

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Publication number Priority date Publication date Assignee Title
DE106821C (ja) *
US33291A (en) * 1861-09-17 Heney a
US177395A (en) * 1876-05-16 Improvement in molder s flasks
US329814A (en) * 1885-11-03 Machine for molding wheels
US386951A (en) * 1888-07-31 Art of preparing sand molds
US704952A (en) * 1894-05-11 1902-07-15 Marcellin C Adams Method of forming sand molds.
US1756776A (en) * 1926-06-02 1930-04-29 New Process Multi Castings Com Molding machine
US1806042A (en) * 1929-10-31 1931-05-19 Lionel A Carter Machine for filling molding flasks
US1962734A (en) * 1931-04-10 1934-06-12 Western Electric Co Vibrating screen for molding
US2209792A (en) * 1938-02-14 1940-07-30 S P O Inc Molding machine
US2420392A (en) * 1942-12-21 1947-05-13 Herbert S Simpson Foundry sand reclaiming system and method
US2533959A (en) * 1948-12-09 1950-12-12 Fischer Ag Georg Shockless jolting device for molding machines
US2614303A (en) * 1949-09-21 1952-10-21 Duncan Foundry And Machine Wor Molding process

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
AT57020B (de) * 1911-12-18 1912-12-27 Bernhard Keller Verfahren und Maschine zum Verdichten des Formsandes durch Rütteln.
US1554402A (en) * 1921-08-27 1925-09-22 Frederich W Burgdorfer Molding apparatus
GB394667A (en) * 1931-12-28 1933-06-28 Carborundum Co Improvements in or relating to bonded articles such as abrasive wheels, and methods of making them
DE741383C (de) * 1933-12-08 1943-11-10 Zimmermann Gustav Ruettelformmaschine
DE833243C (de) * 1946-01-28 1952-03-06 Fischer Ag Georg Formmaschine mit Ruettelkolben

Patent Citations (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE106821C (ja) *
US33291A (en) * 1861-09-17 Heney a
US177395A (en) * 1876-05-16 Improvement in molder s flasks
US329814A (en) * 1885-11-03 Machine for molding wheels
US386951A (en) * 1888-07-31 Art of preparing sand molds
US704952A (en) * 1894-05-11 1902-07-15 Marcellin C Adams Method of forming sand molds.
US1756776A (en) * 1926-06-02 1930-04-29 New Process Multi Castings Com Molding machine
US1806042A (en) * 1929-10-31 1931-05-19 Lionel A Carter Machine for filling molding flasks
US1962734A (en) * 1931-04-10 1934-06-12 Western Electric Co Vibrating screen for molding
US2209792A (en) * 1938-02-14 1940-07-30 S P O Inc Molding machine
US2420392A (en) * 1942-12-21 1947-05-13 Herbert S Simpson Foundry sand reclaiming system and method
US2533959A (en) * 1948-12-09 1950-12-12 Fischer Ag Georg Shockless jolting device for molding machines
US2614303A (en) * 1949-09-21 1952-10-21 Duncan Foundry And Machine Wor Molding process

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4077459A (en) * 1974-12-10 1978-03-07 Erwin Buhrer Method and apparatus for the production of foundry molds
CN105252809A (zh) * 2015-11-10 2016-01-20 北京京城环保股份有限公司 一种散料固化成型模具及散料固化成型方法

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GB757602A (en) 1956-09-19
DE1058702B (de) 1959-06-04
BE523431A (ja)

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