EP0127069B1 - Vorrichtung zum Verdichten von Giessereiformsand im Gasdruckverfahren - Google Patents

Vorrichtung zum Verdichten von Giessereiformsand im Gasdruckverfahren Download PDF

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Publication number
EP0127069B1
EP0127069B1 EP84105563A EP84105563A EP0127069B1 EP 0127069 B1 EP0127069 B1 EP 0127069B1 EP 84105563 A EP84105563 A EP 84105563A EP 84105563 A EP84105563 A EP 84105563A EP 0127069 B1 EP0127069 B1 EP 0127069B1
Authority
EP
European Patent Office
Prior art keywords
piston plate
gas
pressure
chamber
piston
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired
Application number
EP84105563A
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German (de)
English (en)
French (fr)
Other versions
EP0127069A2 (de
EP0127069A3 (en
Inventor
Norbert Ing. Grad. Damm
Alfons Ing. grad. Köbel
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BMD Badische Maschinenfabrik Durlach GmbH
Original Assignee
BMD Badische Maschinenfabrik Durlach GmbH
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by BMD Badische Maschinenfabrik Durlach GmbH filed Critical BMD Badische Maschinenfabrik Durlach GmbH
Publication of EP0127069A2 publication Critical patent/EP0127069A2/de
Publication of EP0127069A3 publication Critical patent/EP0127069A3/de
Application granted granted Critical
Publication of EP0127069B1 publication Critical patent/EP0127069B1/de
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B22—CASTING; POWDER METALLURGY
    • B22C—FOUNDRY MOULDING
    • B22C15/00—Moulding machines characterised by the compacting mechanism; Accessories therefor

Definitions

  • the invention relates to a device for compacting foundry molding sand in the gas pressure process, consisting of a mold box closed at the bottom by a model plate with a model, with a filling frame and a space arranged above the filled molding sand, which is pressurized in the range of milliseconds in such a way that the molding sand at simultaneous gas pressure drop is compressed (DE-B-1 9661 234).
  • the basic requirement is to obtain the greatest possible pressure gradient, which reflects the ratio of the available pressure and the time of relaxation. Furthermore, a gas mass throughput that takes into account the free molding sand surface and the molding sand mass must be achieved. If the optimal process parameters are observed, the finished form shows the highest compression (hardness) in the area close to the model, which is due to the sudden deceleration of the accelerated sand particles on the model and the model plate. The compaction then generally decreases towards the back of the mold, the back of the mold itself usually not being compressed or only inadequately, so that the molding sand has to be scraped off to a certain depth there.
  • the invention has for its object to provide an embodiment that leads to consistent and reproducible compression results with little design effort.
  • This object is achieved in that a little above the surface of the molding sand filling at least at the beginning of the gas pressure separating the molding sand from the compressed gas space, while the pressure release in the direction of the sand filling freely movable piston plate is arranged, the outline of which about the free cross-section of the filling frame or Corresponds to the molding box and which can be returned to its initial position after the molding sand has been compacted.
  • the distance between the surface of the molding sand and the underside of the piston plate can be set in a defined manner, on the one hand to keep the dead space volume between them as small as possible, and on the other hand to ensure that there is sufficient gas or air in the dead space volume for gas pressure compression and not to obtain a pure compression by the piston plate. Sufficient gas or air is available in the dead space volume, even if it is small, in order to achieve the fluidization effect described.
  • the piston plate communicates its kinetic energy to the gas cushion in a uniform distribution over the cross section of the molding box, so that the irregularities to be found in the known method in the form of craters on the molding sand surface do not occur, in particular the back of the mold also has no more soft spots «.
  • the piston plate In its initial position, the piston plate is preferably in a position immediately above the upper edge of the filling frame, so that it does not hinder its movements together with the molding box. This also makes it possible to fill the molding box and filling frame with molding sand, be it that this unit is moved outside the device and filled there or the part of the device located above the filling frame is moved together with the piston plate for the filling process until filling frame and The molding box is exposed. Furthermore, the piston plate can be connected to a return mechanism, by means of which it is returned to its starting position after a compression process from the filling frame.
  • the piston plate is designed as a free-flying piston and is releasably locked in its initial position.
  • the locking can be released by a drive or by the gas pressure acting above the piston plate.
  • This embodiment is particularly suitable for the compressed gas process, in that the space above the piston plate is filled with gas, e.g. B. air, until the required pressure, which can be substantially below 20 bar, is filled and then the lock is released so that the piston plate is accelerated while releasing the gas pressure and at the same time the gas cushion located between it and the molding sand surface on the first Part of their movement is compressed to approximately the same pressure, this pressure being transferred to the molding sand filling and compressing the molding sand.
  • gas e.g. B. air
  • the course of the mold hardness can be favorably influenced and controlled in the device according to the invention in that dampers are assigned to the piston plate, which dampen them when a specific compression stroke is reached, the dampers being adjustable if necessary.
  • the mass of the piston plate can be decoupled from the molding sand after a certain stroke, so that its kinetic energy at the end of the compression stroke is not converted into compression energy by braking on the molding sand that has already been compacted, which may lead to excessive hardness on the back of the mold .
  • the piston plate has a downwardly drawn peripheral edge, so that an air cushion is always present on the underside of the plate and it is avoided that all the air in front of the piston plate can flow out laterally during the compression process.
  • the same effect can be achieved in that the underside of the piston plate is drawn towards the center.
  • the piston plate has overflow cross sections which are opened during the compression stroke.
  • the acceleration of the piston plate can be influenced in the sense of a reduction in that compressed gas can flow into the space in front of the piston plate.
  • the fluidization effect on the molding sand can also be influenced.
  • the overflow cross sections are provided between the piston plate and the inner wall of the filling frame and are closed by overlapping seals on the filling frame under the action of the compressed gas. Only at the moment when the locking device is released and the piston plate is released does this also come free of the seals, so that the overflow cross sections on the edge are also released.
  • the overflow cross sections in the piston plate and to cover them at least in their initial position by means of closures so that in the initial position the full pressure on the piston plate comes into effect.
  • the closures can either be stationary, so that the piston plate lifts off from them after their acceleration and the further compression stroke takes place essentially only on the basis of their kinetic energy.
  • the piston plate can be provided with a guide piston which extends into the gas pressure chamber, this guide piston preferably being hollow, e.g. B. is designed as a guide cylinder and itself forms part of the gas pressure chamber.
  • the guide cylinder can either be the cross-sectional shape of the piston plate and thus of the filling frame, or it can also be circular-cylindrical, in which case it is expediently provided with overflow cross sections which, after the start of the compression stroke, provide a connection between the interior of the guide cylinder and that outside of it and above the piston plate Make free space to apply the pressure to the entire piston plate.
  • the piston plate can be exchanged in such a way that its mass and / or its shape can be adapted to different models and / or mold box cross sections.
  • the piston plate can be arranged in a separate insert, which at the same time may have detents and is replaced by an insert with a different piston plate when the model or mold box is changed.
  • the uniformity and reproducibility of the compression in an explosion process depends above all on the quality of the mixture of the fuel gases, which for safety reasons only takes place in the area of the device.
  • a fan is arranged for this purpose in the explosion chamber, which should ensure an intensive mixing.
  • the intensity and quality of the mixture depends not only on the design of the fan, but also on the geometry of the explosion chamber, the type of gases used, etc.
  • the invention makes it possible to generate and also ignite the explosive mixture immediately above the piston plate, without any negative phenomena occurring when the molding sand is compacted.
  • a mixing process has proven to be particularly efficient and cost-effective, in which the gas components are injected into the space above the piston plate in a swirling flow and mixed by free-turbulent flow.
  • This mixing method known per se (DE-A-1 557 215) has the advantage that it does not require moving mixing tools with a minimum of energy consumption by the kinetic energy required for the mixture is drawn exclusively from an externally generated pressure gradient of the fuel gases, which are under a slight excess pressure.
  • a free turbulence mixer is arranged in the space above the piston plate, which is formed from a tube which is open at the bottom, widens conically downwards and is drawn in in the area of the opening and is expanded in a ring shape in its upper closed area the inlet opening for at least one gas component opens tangentially into the annular space.
  • the other gas component can be blown in either axially from below or tangentially in the upper annular region of the mixing tube, and advantageously against the direction of the other gas component.
  • a model plate 1 with model 2 and a molding box 3 placed on the model plate 1 and a filling frame 4 placed thereon are shown in a schematic representation.
  • the model plate 1 sits on a lifting table, not shown, by means of which the molding box 3 and the filling frame 4 can be moved tightly against the actual compression unit 6 after pouring molding sand onto the model 2.
  • the surface of the molding sand filling is designated 5 in FIG. 1.
  • the compression unit 6 consists of a pressure-resistant container 7, on the bottom 8 of which a frame 9 is flanged, against which the filling frame 4 is approached in the compression position.
  • a piston plate 10 is arranged within the frame 9 and has a downwardly drawn edge 11 on its underside 12.
  • An edge 13 also extends upwards on the upper side of the piston plate 10. The outline of the piston plate 10 or its edge 13 corresponds approximately to the free cross section of the filling frame 4 and the molding box 3.
  • the piston plate 10 is locked in its initial position shown in FIG. 1.
  • the lock can, for example (right half of the illustration) consist of a roller 14 or a ball which engages under the action of a spring or by means of a pneumatic cylinder 15 in a corresponding recess on the peripheral edge 13 of the piston plate 10.
  • the gap between the peripheral edge 13 of the piston plate 10 and the frame 9 is closed by a sealing strip 16 which is fixed between the frame 9 and the bottom 8 of the pressure vessel 7 and rests on the upper end face of the peripheral edge 13.
  • FIG. 1 Another embodiment of the locking and sealing is shown in the left half of the illustration according to FIG. 1.
  • This is an elastic bead 17 which is attached to the frame 9 and closes a pressure chamber 18.
  • the elastic bead 17 is pressed into a corresponding recess on the peripheral edge 13 of the piston plate 10 and at the same time seals the gap.
  • a return mechanism 19 which has a pressure medium cylinder 20, the piston rod of which is extended before the compression stroke and carries a plate 21 with shock absorbers 22 at its end.
  • a plurality of rods 23 are fastened, which in turn are connected by a frame 24 at their upper end.
  • stop profiles 25 which cooperate with the dampers 22 on the plate 21.
  • the embodiment shown in Fig. 1 is primarily used for compression by means of a compressed gas, ie the pressure vessel 7 is in the initial position shown in Fig. 1 of the piston plate 10 with a compressed gas, for. B. compressed air, up to a maximum of 20 bar, preferably less than 8 bar (operating pressure of a compressed air network) filled.
  • a compressed gas for. B. compressed air
  • the locking device 14, 15 or 17, 18 is released and the piston plate 10 is suddenly accelerated while simultaneously relieving pressure in the pressure vessel 7. It compresses the air between its underside 12 and the molding sand surface 5 to the same pressure level. This in turn leads to the compression of the molding sand.
  • the Verdichtun g of the piston plate shub 10 is limited by the damper 22, against which the stop profiles 25 of the frame start 24th Subsequently, the piston plate 10 is raised and locked in its initial position by lifting the plate 21 by means of the pressure medium cylinder 20
  • the embodiment according to FIG. 2 differs from that according to FIG. 1 only in that the overflow cross sections 26 are designed in a different way.
  • the piston plate 10 has a recess 27 in its central region, into which a perforated plate 28 is inserted.
  • the perforated plate 28 is covered in the starting position shown in Fig. 2 by the plate 21 of the return mechanism 19, so that at the moment of release of the locking means 14, 15 and 17, first the full pressure of the gas in the pressure vessel 7 acts on the piston plate.
  • a variant of the piston plate 10 can first be seen in the left half of the illustration, in that its underside 12 is drawn in from the outside toward the center. For the rest, in this A l is Insertform the seals 16 are also on the underside of the piston plate 10.
  • a locking device 14, 15 is reproduced analogously to that in FIGS. 1 and 2, while the return mechanism 19 only consists of a pressure medium cylinder 29, e.g. B. there is a pneumatic cylinder. This either engages directly on the piston plate 10 (left half of the illustration) or has a magnetic head 30 on its piston rod, which lies against the top of the piston plate 10.
  • the piston plate 10 has a hollow cylinder 31 with a circular cross section as the guide cylinder, which is guided in the circular cylindrical pressure container 7, at least in the lower region.
  • the interior of the guide cylinder 31 thus also forms part of the compressed gas space.
  • the guide cylinder 31 is provided with a recess 32 which acts as an overflow cross section as soon as it reaches the lower edge of the pressure container 7.
  • the magnet 30 is de-energized after the pressure vessel 7 has been filled, so that the piston plate 10 is accelerated.
  • the piston rod of the pressure medium cylinder 29 is retracted until the excited magnet 30 holds the piston plate 10 and this can be brought back again.
  • the lock 14, 15 (as in FIGS. 1 and 2) is released after the pressure container 7 has been filled.
  • the pressure medium cylinder 29 can also be used as a damper in that a pressure cushion that brakes the piston plate 10 builds up therein with an increasing compression stroke. To return the piston plate 10, the pressure medium cylinder 29 is acted on in the opposite direction.
  • the piston plate 10 in turn has a guide cylinder 31, the interior of which forms parts of the explosion chamber 33 enclosed by the pressure container 7.
  • the explosion chamber 333 also has a blow-off opening 34 and an ignition device 35.
  • a smaller storage container 36 is placed on the pressure container, into which the quantities of the gas components necessary for a compression stroke are introduced separately under slight overpressure via the connections 37, 38.
  • a turbulence mixer 39 is arranged in the explosion chamber 33 and essentially consists of an initially conically widening mixing tube 40 of large diameter. The mixing tube 40 is drawn inwards in the region of the lower opening 41 on a short section 42.
  • the mixing tube 40 widens to form a cylindrical ring 43, in which one or more lines 44 are tangential and possibly. flow in opposite directions. These lines 44 are connected to the memory 36 via a ring line and a collecting line 45 and are closed off from this by a valve 46. After opening the valve 46, the premixed gas flows from the reservoir 36 and the lines 44 in a swirl flow into the upper region 43 of the turbulence mixer 39. A downward spiral flow forms along the wall of the mixing tube 40, while at the same time a part of the gas flows back in the center of the opening 41. A certain proportion of the gas emerges from the opening 41 into the explosion chamber 33. After reaching the Pressure equalization between the accumulator 36 and the explosion chamber 33, the mixture is ignited and the piston plate 10 accelerated.
  • FIG. 5 A variant of the turbulence mixer 39 is shown in FIG. 5.
  • the turbulence mixer 39 is accommodated in a pressure container 47 arranged next to the actual molding space.
  • the gases can be supplied in a manner similar to that in FIG. 4.
  • the connections 37, 38 are provided for this. Instead, however, the combustion air can also be supplied via the connection 37 and the explosive fuel gas via the line 48. Both variants can also be combined with one another.
  • the ignition 49 is located in the lower part of the pressure container 47.
  • the explosion pressure wave propagates via a line 50 of large cross section into the space above the piston plate (not shown) and accelerates it in the manner described above.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Casting Devices For Molds (AREA)
EP84105563A 1983-05-26 1984-05-16 Vorrichtung zum Verdichten von Giessereiformsand im Gasdruckverfahren Expired EP0127069B1 (de)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE3319030 1983-05-26
DE19833319030 DE3319030A1 (de) 1983-05-26 1983-05-26 Vorrichtung zum verdichten von giessereiformsand im gasdruckverfahren

Publications (3)

Publication Number Publication Date
EP0127069A2 EP0127069A2 (de) 1984-12-05
EP0127069A3 EP0127069A3 (en) 1986-04-30
EP0127069B1 true EP0127069B1 (de) 1988-08-10

Family

ID=6199875

Family Applications (1)

Application Number Title Priority Date Filing Date
EP84105563A Expired EP0127069B1 (de) 1983-05-26 1984-05-16 Vorrichtung zum Verdichten von Giessereiformsand im Gasdruckverfahren

Country Status (5)

Country Link
US (1) US4588017A (enrdf_load_stackoverflow)
EP (1) EP0127069B1 (enrdf_load_stackoverflow)
JP (1) JPS606246A (enrdf_load_stackoverflow)
DD (1) DD218848A5 (enrdf_load_stackoverflow)
DE (2) DE3319030A1 (enrdf_load_stackoverflow)

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3740185A1 (de) * 1987-06-13 1989-06-08 Badische Maschf Gmbh Verfahren und vorrichtung zum verdichten von formstoff in giesserei-formmaschinen
ES2011685A6 (es) * 1988-10-21 1990-02-01 Lopez Foronda Fernandez Vicent Mejoras introducidas en maquinas de moldeo por impacto de aire.
DE3914160C1 (enrdf_load_stackoverflow) * 1989-04-28 1990-05-17 Kuenkel-Wagner Gmbh & Co Kg, 3220 Alfeld, De
DE4126962C2 (de) * 1991-08-14 1997-02-27 Kuenkel Wagner Serv & Vertrieb Verfahren zum Verdichten von Formmassen
CZ238894A3 (en) * 1993-10-29 1995-08-16 Fischer Georg Giessereianlagen Device for compacting grained moulding materials
JP3164271B2 (ja) * 1994-12-09 2001-05-08 新東工業株式会社 鋳型造型装置
EP0849017B1 (en) * 1996-12-17 2001-10-04 Loramendi, S.A. Improved sand mould air impact or blast compacting machine
ES2148020B1 (es) * 1996-12-17 2001-04-16 Loramendi Sa Maquina mejorada para compactacion de moldes de arena por impacto de aire u onda expansiva.
US6823929B2 (en) * 2000-04-21 2004-11-30 Sintokogio, Ltd. Die molding machine and pattern carrier

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3041685A (en) * 1961-07-14 1962-07-03 Taccone Corp Diaphragm molding machine
US3170202A (en) * 1962-08-22 1965-02-23 Sr William J Huston Foundry process
DE1415661A1 (de) * 1962-09-28 1968-10-10 Carborundum Co Halbleiter
DE1961234C3 (de) * 1969-12-05 1975-02-06 Kramatorskij Nautschno-Issledowatel' Skij I Projektno-Technologitscheskij Institut Maschinostrojenija, Kramatorsk (Sowjetunion) Verfahren und Vorrichtung zum Verdichten von GieBereiformmassen
SU521993A1 (ru) * 1974-04-02 1976-07-25 Краматорский Научно-Исследовательский И Проектно-Технологический Институт Машиностроения Импульсна головка
DE2844464C2 (de) * 1978-10-12 1983-03-24 Bühler, Eugen, Dipl.-Ing., 8871 Burtenbach Verfahren und Vorrichtung zum Verdichten von Gießformen
AT381877B (de) * 1978-12-15 1986-12-10 Fischer Ag Georg Verfahren und vorrichtung zum verdichten von koernigen stoffen, insbesondere giessereiformstoff
CH642288A5 (de) * 1980-02-18 1984-04-13 Fischer Ag Georg Verfahren und einrichtung zum verdichten von formstoff, insbesondere fuer giessformen.
CH650175A5 (de) * 1981-01-23 1985-07-15 Fischer Ag Georg Verfahren und einrichtung zum dosieren von brennstoffen bei der herstellung von giessereisandformen.
DE3202395A1 (de) * 1981-01-28 1982-08-26 BMD Badische Maschinenfabrik Durlach GmbH, 7500 Karlsruhe Verfahren und vorrichtung zum pneumatischen verdichten von formsand

Also Published As

Publication number Publication date
DE3473238D1 (en) 1988-09-15
EP0127069A2 (de) 1984-12-05
DD218848A5 (de) 1985-02-20
EP0127069A3 (en) 1986-04-30
JPH0417744B2 (enrdf_load_stackoverflow) 1992-03-26
JPS606246A (ja) 1985-01-12
US4588017A (en) 1986-05-13
DE3319030A1 (de) 1984-11-29
DE3319030C2 (enrdf_load_stackoverflow) 1989-06-08

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