EP0319453B1 - Method for ramming moulding sand - Google Patents
Method for ramming moulding sand Download PDFInfo
- Publication number
- EP0319453B1 EP0319453B1 EP88710050A EP88710050A EP0319453B1 EP 0319453 B1 EP0319453 B1 EP 0319453B1 EP 88710050 A EP88710050 A EP 88710050A EP 88710050 A EP88710050 A EP 88710050A EP 0319453 B1 EP0319453 B1 EP 0319453B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- air
- sand
- passage
- model
- pressing operation
- 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 - Lifetime
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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
- B22C15/02—Compacting by pressing devices only
- B22C15/08—Compacting by pressing devices only involving pneumatic or hydraulic mechanisms
Definitions
- the invention relates to a method for compacting molding sand with a molding box, which is placed on a model plate provided with a model, which is provided with air passage recesses, the molding sand being briefly pressurized with compressed air after it has been poured into the molding box and then compressed using a press .
- the compression of the sand caused by the impulsive loading with compressed air is limited to certain areas of the sand and to a certain layer of sand thickness. This limitation depends on the type and grain of the sand as well as the design of the model. Since in the known method by the pulsed pressurization caused compression of the sand is not sufficient, then the sand is pressed using a press. It can prove disadvantageous, in particular in the case of complicated models, that the initial compression of the sand or increase in the packing density does not take place uniformly, but rather depends on the flow conditions of the compressed air as it flows through the sand. The flow conditions are influenced in particular by the shape of the model and by the arrangement and position of the air passage recesses in the model plate. Inhomogeneities of the sand also play a decisive role, by which the flow behavior is also influenced.
- the invention has for its object to provide a method for compacting molding sand of the type mentioned, which allows effective compression of the molding sand with a simple structure and reliable operation and in particular does not lead to excessive noise.
- the object is achieved in that air is passed through the sand during the pressing process.
- the inventive method is characterized by a number of significant advantages. Since the initial impulse-like pressurization of compressed air only leads to a partial compression and to a partial increase in the packing density of the sand, it proves to be necessary, in particular at critical locations of the sand mold, to additionally adequately compress the sand there. This used to be done by shaking the sand, but this was due to the required environmental compatibility due to the great noise development is hardly practical anymore. In a subsequent pressing of the impulse-like pre-compacted sand, it is hardly possible to adequately compact critical points, for example bevels of a model, which have a draft that tends towards zero, in the area of adjoining edges.
- Another advantage of the invention is that by rinsing with air, the fine particles of the molding sand are transported in the direction of the model plate and the models attached to it, which results in a very fine-grained, high packing density on the surface of the models or model plate Sand layer forms, which leads to a particularly high surface quality of the good.
- Another advantage of this movement of the very fine particles of the sand is that during the air rinsing in the sand areas above it, on the one hand the air permeability is increased and on the other hand the larger sand grains can be pressed into an even denser mutual system.
- Another advantage of the invention is that by flushing with air all the sand is fluidized, i.e. the sand shows a much more favorable flow behavior, which in turn advantageously improves the compression effect.
- a favorable further development of the method according to the invention can be given in that the air conduction takes place either in the form of an air purge or low air pressure or under high air pressure.
- a suitable air pressure for the air passage is selected depending on the type of sand and the type of model to be molded. Furthermore, it is possible according to the invention to adjust the air pressure to the type of sand compression, i.e. to adapt to the pressures and to the feed speeds of the stamps of the press.
- a further advantageous embodiment can be given in that the air is passed through either during the entire pressing process or only during part of the pressing process.
- the air may be sufficient to take advantage of the fluidization effects and the movement of the individual grains of sand only during the start of mechanical compression.
- it can also be effective to conduct air through the entire pressing process.
- a further advantageous embodiment of the method according to the invention is achieved in that a pressure-tight hood is placed on the filled molding box for the initial, brief pressurization. With such a hood, it is possible to evenly distribute the short-term, pulse-like pressurization onto the molding sand over the entire molding box thus to create flow conditions that are as uniform as possible.
- the sand can be compressed both by means of a multi-punch press and by means of a flat press plate.
- the selection of a suitable press tool depends crucially on the shape of the model and the desired degree of compression.
- Using a multi-ram press it is possible in a particularly simple manner to specifically compress certain areas of the molding sand, for example areas that adjoin model areas with an angle of the model bevel that goes towards zero.
- a particularly advantageous development of the method according to the invention is provided in that the air is passed through air passage openings arranged at shape-critical points of the model or the model plate.
- the air is passed through air passage openings arranged at shape-critical points of the model or the model plate.
- the air passage openings are designed in the form of stomata. It can prove to be particularly advantageous if the air passage openings have a clear width which is less than the diameter of the grains of the sand. The latter measure prevents sand from being flushed out of the molding box into the air paths.
- the first-mentioned measure makes it possible to produce the air passage openings particularly simply and inexpensively and to clean them after the respective molding process, since the cleaning of a large number of individual bores or recesses requires a very high level of maintenance.
- the invention is not limited to the passage of air described, rather it is also possible within the scope of the invention to pass a reactive gas through the molding sand instead of air, for example to carry out chemical reactions in the molding sand which lead to further solidification thereof . It is also possible to flush the molding sand first with air and then with a reactive gas during the pressing process.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Casting Devices For Molds (AREA)
- Disintegrating Or Milling (AREA)
Abstract
Description
Die Erfindung betrifft ein Verfahren zum Verdichten von Formsand mit einem Formkasten, welcher auf einer mit einem Modell versehenen Modellplatte aufgesetzt ist, die mit Luftdurchtrittsausnehmungen versehen ist, wobei der Formsand nach losem Einfüllen in den Formkasten kurzzeitig mit Druckluft beaufschlagt und anschließend mittels einer Presse verpreßt wird.The invention relates to a method for compacting molding sand with a molding box, which is placed on a model plate provided with a model, which is provided with air passage recesses, the molding sand being briefly pressurized with compressed air after it has been poured into the molding box and then compressed using a press .
Bei einem bekannten Verfahren zum Verdichten von Formsand (Zeitschrift Gießerei 74 (1987) 4, $. 92 bis 94) erfolgt nach dem losen Einfüllen des Formsandes in den Formkasten eine kurzzeitige, impulsartige Beaufschlagung mit Druckluft. Durch den auf diese Weise hervorgerufenen Luftstrom wird auf jedes einzelne Sandkorn eine nach unten gerichtete Druckbelastung aufgebracht, welche zu einer Bewegung der jeweiligen Sandkörner führt. Auf diese Weise wird die Packungsdichte des Sandes in Strömungsrichtung dadurch erhöht, daß sich die Sandkörner gegeneinander anlegen. Da durch eine steigende Packungsdichte die Gasdurchlässigkeit des Sandes verringert wird, ist die durch die impulsartige Beaufschlagung mit Druckluft hervorgerufene Verdichtung des Sandes auf bestimmte Bereiche des Sandes und auf eine bestimmte Sanddickenschicht begrenzt. Diese Begrenzung hängt von der Art und Körnung des Sandes sowie von der Gestaltung des Modells ab. Da bei dem bekannten Verfahren die durch die impulsartige Druckbeaufschlagung hervorgerufene Verdichtung des Sandes allein nicht ausreichend ist, erfolgt anschließend ein Verpressen des Sandes mittels einer Presse. Dabei kann es sich insbesondere bei kompliziert gestalteten Modellen als nachteilig erweisen, daß die anfängliche Verdichtung des Sandes bzw. Erhöhung der Packungsdichte nicht gleichmäßig erfolgt, sondern von den Strömungsverhältnissen der Druckluft beim Durchströmen des Sandes abhängt. Die Strömungsverhältnisse werden insbesondere von der Form des Modelles sowie von der Anordnung und Lage der Luftdurchtrittsausnehmungen in der Modellplatte beeinflußt. Weiterhin spielen Inhomogenitäten des Sandes eine entscheidende Rolle, durch welche das Strömungsverhalten ebenfalls beeinflußt wird.In a known method for compacting molding sand (Zeitschrift Gießerei 74 (1987) 4, $. 92 to 94), after the molding sand has been poured into the molding box loosely, a brief, impulse-like application of compressed air takes place. Due to the air flow caused in this way, a downward pressure load is applied to each individual grain of sand, which leads to a movement of the respective grains of sand. In this way, the packing density of the sand in the flow direction is increased by the fact that the grains of sand lie against each other. Since the gas permeability of the sand is reduced by an increasing packing density, the compression of the sand caused by the impulsive loading with compressed air is limited to certain areas of the sand and to a certain layer of sand thickness. This limitation depends on the type and grain of the sand as well as the design of the model. Since in the known method by the pulsed pressurization caused compression of the sand is not sufficient, then the sand is pressed using a press. It can prove disadvantageous, in particular in the case of complicated models, that the initial compression of the sand or increase in the packing density does not take place uniformly, but rather depends on the flow conditions of the compressed air as it flows through the sand. The flow conditions are influenced in particular by the shape of the model and by the arrangement and position of the air passage recesses in the model plate. Inhomogeneities of the sand also play a decisive role, by which the flow behavior is also influenced.
Der Erfindung liegt die Aufgabe zugrunde, ein Verfahren zum Verdichten von Formsand der eingangs genannten Art zu schaffen, welches bei einfachem Aufbau und betriebssicherer Wirkungsweise eine wirksame Verdichtung des Formsandes ermöglicht und insbesondere zu keiner übermäßigen Geräuschentwicklung führt.The invention has for its object to provide a method for compacting molding sand of the type mentioned, which allows effective compression of the molding sand with a simple structure and reliable operation and in particular does not lead to excessive noise.
Erfindungsgemäß wird die Aufgabe dadurch gelöst, daß während des Preßvorganges Luft durch den Sand geleitet wird.According to the invention the object is achieved in that air is passed through the sand during the pressing process.
Das erfindungsgemäße Verfahren zeichnet sich durch eine Reihe erheblicher Vorteile aus. Da die anfängliche, impulsartige Druckluftbeaufschlagung nur zu einer Teilverdichtung und zu einer teilweisen Erhöhung der Packungsdichte des Sandes führt, erweist es sich insbesondere an formkritischen Stellen der Sandform als notwendig, dort zusätzlich eine ausreichende Verdichtung des Sandes vorzunehmen. Dies erfolgte früher durch Rütteln des Sandes, was jedoch hinsichtlich der geforderten Umweltverträglichkeit wegen der großen Lärmentwicklung kaum noch praktikabel ist. Bei einer nachfolgenden Verpressung des impulsartig vorverdichteten Sandes ist es kaum möglich, formkritische Stellen, beispielsweise Schrägen eines Modells, welche eine gegen Null gehende Formschräge aufweisen, im Bereich von daran anschließenden Kanten ausreichend zu verdichten. Die Ursache dafür liegt darin, daß sich unter dem Preßstempel eine durch die Vorverdichtung und durch die vorgegebene Geometrie bestimmte Form der Druckverteilung einstellt. Demgegenüber ist es mittels des vorliegenden Verfahrens möglich, durch alle Bereiche des Formsandes Luft durchzuleiten, um auf diese Weise einen Druck auf die jeweiligen Sandkörner auszuüben und sie zu einer Bewegung zu veranlassen. Auf diese Weise ist es möglich, auch an sehr formkritischen Bereichen eine erhebliche Steigerung der Packungsdichte hervorzurufen. Dieser Effekt wird durch die gleichzeitige mechanische Verpressung begleitet, so daß die bisherigen Nachteile des mechanischen Verpressens, nämlich insbesondere eine ungenügende Druckverteilung unter dem Pressenstempel ausgeglichen werden. Ein weiterer erfindungsgemäßer Vorteil liegt darin, daß durch das Spülen mit Luft die Feinstanteile des Formsandes in Richtung auf die Modellplatte und die auf dieser befestigten Modelle transportiert werden, wodurch sich an der Oberfläche der Modelle bzw. der Modellplatte eine sehr feinkörnige, eine hohe Packungsdichte aufweisende Sandschicht bildet, die zu einer besonders hohen Oberflächengüte des Gutstückes führt. Ein weiterer Vorteil dieser Bewegung der Feinstanteile des Sandes liegt darin, daß während der Luftspülung in den darüberliegenden Sandbereichen zum einen die Luftdurchlässigkeit erhöht wird und zum anderen die jeweils größeren Sandkörner in eine noch dichtere gegenseitige Anlage verpreßt werden können.The inventive method is characterized by a number of significant advantages. Since the initial impulse-like pressurization of compressed air only leads to a partial compression and to a partial increase in the packing density of the sand, it proves to be necessary, in particular at critical locations of the sand mold, to additionally adequately compress the sand there. This used to be done by shaking the sand, but this was due to the required environmental compatibility due to the great noise development is hardly practical anymore. In a subsequent pressing of the impulse-like pre-compacted sand, it is hardly possible to adequately compact critical points, for example bevels of a model, which have a draft that tends towards zero, in the area of adjoining edges. The reason for this is that a shape of the pressure distribution determined by the pre-compression and by the given geometry occurs under the press ram. In contrast, by means of the present method it is possible to pass air through all areas of the molding sand in order in this way to exert pressure on the respective grains of sand and to cause them to move. In this way it is possible to bring about a considerable increase in the packing density even in areas that are very critical of the shape. This effect is accompanied by the simultaneous mechanical pressing, so that the previous disadvantages of mechanical pressing, namely in particular an insufficient pressure distribution under the press ram are compensated for. Another advantage of the invention is that by rinsing with air, the fine particles of the molding sand are transported in the direction of the model plate and the models attached to it, which results in a very fine-grained, high packing density on the surface of the models or model plate Sand layer forms, which leads to a particularly high surface quality of the good. Another advantage of this movement of the very fine particles of the sand is that during the air rinsing in the sand areas above it, on the one hand the air permeability is increased and on the other hand the larger sand grains can be pressed into an even denser mutual system.
Ein weiterer Vorteil der Erfindung ist dadurch gegeben, daß durch die Spülung mit Luft der gesamte Sand fluidisiert wird, d.h. der Sand zeigt ein wesentlich günstigeres Fließverhalten, welches wiederum den Verpressungseffekt in vorteilhafter Weise verbessert.Another advantage of the invention is that by flushing with air all the sand is fluidized, i.e. the sand shows a much more favorable flow behavior, which in turn advantageously improves the compression effect.
Eine günstige Weiterentwicklung des erfindungsgemäßen Verfahrens kann dadurch gegeben sein, daß die Luftdurchleitung entweder in Form einer Luftspülung oder niedrigem Luftdruck oder unter hohem Luftdruck erfolgt. Die Auswahl eines geeigneten Luftdruckes für die Luftdurchleitung erfolgt in Abhängigkeit von der Art des Sandes und der Art des abzuformenden Modells. Weiterhin ist es erfindungsgemäß möglich, den Luftdruck an die Art der Verpressung des Sandes, d.h. an die Preßdrücke sowie an die Vorschubgeschwindigkeiten der Stempel der Presse anzupassen.A favorable further development of the method according to the invention can be given in that the air conduction takes place either in the form of an air purge or low air pressure or under high air pressure. A suitable air pressure for the air passage is selected depending on the type of sand and the type of model to be molded. Furthermore, it is possible according to the invention to adjust the air pressure to the type of sand compression, i.e. to adapt to the pressures and to the feed speeds of the stamps of the press.
Eine weitere vorteilhafte Ausgestaltung kann dadurch gegeben sein, daß die Luftdurchleitung entweder während des gesamten Preßvorgangs erfolgt oder nur während eines Teils des Preßvorgangs. In Abhängigkeit von der Form des Modells und der Art des Sandes kann es ausreichend sein, die Fluidisierungseffekte und die Bewegung der einzelnen Sandkörner nur während des Beginns der mechanischen Verpressung auszunutzen. Es kann sich jedoch auch als wirksam erweisen, die Durchleitung von Luft während des gesamten Preßvorganges vorzunehmen.A further advantageous embodiment can be given in that the air is passed through either during the entire pressing process or only during part of the pressing process. Depending on the shape of the model and the type of sand, it may be sufficient to take advantage of the fluidization effects and the movement of the individual grains of sand only during the start of mechanical compression. However, it can also be effective to conduct air through the entire pressing process.
Eine weitere vorteilhafte Ausgestaltung des erfindungsgemäßen Verfahrens erfolgt dadurch, daß zur anfänglichen, kurzzeitigen Druckbeaufschlagung auf den gefüllten Formkasten eine druckdichte Haube aufgesetzt wird. Durch eine derartige Haube ist es möglich, die kurzzeitige, impulsartige Druckbeaufschlagung auf den Formsand über den gesamten Formkasten gleichmäßig zu verteilen und somit möglichst gleichmäßige Strömungsverhältnisse hervorzurufen.A further advantageous embodiment of the method according to the invention is achieved in that a pressure-tight hood is placed on the filled molding box for the initial, brief pressurization. With such a hood, it is possible to evenly distribute the short-term, pulse-like pressurization onto the molding sand over the entire molding box thus to create flow conditions that are as uniform as possible.
Erfindungsgemäß kann die Verpressung des Sandes sowohl mittels einer Vielstempelpresse als auch mittels einer ebenen Preßplatte erfolgen. Die Auswahl eines geeigneten Preßwerkzeuges hängt entscheidend von der Form des Modells sowie von dem gewünschten Verpressungsgrad ab. Mittels einer Vielstempelpresse ist es auf besonders einfache Weise möglich, bestimmte Bereiche des Formsandes gezielt stärker zu verdichten, beispielsweise Bereiche, die an Modellbereichen mit einem gegen Null gehenden Winkel der Modellschräge angrenzen.According to the invention, the sand can be compressed both by means of a multi-punch press and by means of a flat press plate. The selection of a suitable press tool depends crucially on the shape of the model and the desired degree of compression. Using a multi-ram press, it is possible in a particularly simple manner to specifically compress certain areas of the molding sand, for example areas that adjoin model areas with an angle of the model bevel that goes towards zero.
Eine besonders vorteilhafte Weiterbildung des erfindungsgemäßen Verfahrens ist dadurch gegeben, daß die Luftdurchleitung durch an formkritischen Stellen des Modells oder der Modellplatte angeordnete Luftdurchtrittsöffnungen erfolgt. Auf diese Weise ist es möglich, die durch die Druckbeaufschlagung hervorgerufenen Strömungsverhältnisse durch den Formsand gezielt zu beeinflussen. Es ist beispielsweise möglich, einen Großteil der durchgeleiteten Luft an einem bestimmten, kritischen Modellbereich aus dem Modellkasten abzuführen, so daß in diesem Bereich eine besonders hohe Anlagerung an Feinstanteilen des Sandes und eine besonders dichte Packung der Sandkörner erfolgt. Weiterhin ist es möglich, auch diese Bereiche des Formsandes zu verdichten, welche wegen der üblichen Druckverteilung unter dem Pressenstempel nicht mit einem ausreichenden Preßdruck beaufschlagt werden könnten.A particularly advantageous development of the method according to the invention is provided in that the air is passed through air passage openings arranged at shape-critical points of the model or the model plate. In this way it is possible to specifically influence the flow conditions caused by the pressurization through the molding sand. It is possible, for example, to remove a large part of the air passed through the model box at a specific, critical model area, so that in this area there is a particularly high accumulation of fine particles of the sand and a particularly dense packing of the sand grains. Furthermore, it is also possible to compact these areas of the molding sand, which, because of the usual pressure distribution under the press ram, could not be subjected to a sufficient pressing pressure.
Eine weitere günstige Weiterbildung der Erfindung ist dadurch gegeben, daß die Luftdurchtrittsöffnungen in Form von Spaltöffnungen ausgebildet sind. Dabei kann es sich insbesondere als günstig erweisen, wenn die Luftdurchtrittsöffnungen eine lichte Weite aufweisen, welche geringer ist als der Durchmesser der Körner des Sandes. Durch letztere Maßnahme wird verhindert, daß Sand aus dem Formkasten in die Luftbahnen gespült wird. Durch die erstgenannte Maßnahme ist es möglich, die Luftdurchtrittsöffnungen besonders einfach und kostengünstig herzustellen und nach dem jeweiligen Formvorgang zu reinigen, da die Reinigung einer Vielzahl einzelner Bohrungen oder Ausnehmungen einen sehr hohen Wartungsaufwand verlangt.Another favorable further development of the invention is provided in that the air passage openings are designed in the form of stomata. It can prove to be particularly advantageous if the air passage openings have a clear width which is less than the diameter of the grains of the sand. The latter measure prevents sand from being flushed out of the molding box into the air paths. The first-mentioned measure makes it possible to produce the air passage openings particularly simply and inexpensively and to clean them after the respective molding process, since the cleaning of a large number of individual bores or recesses requires a very high level of maintenance.
Die Erfindung ist nicht auf die beschriebene Durchleitung von Luft beschränkt, vielmehr ist es im Rahmen der Erfindung auch möglich, anstelle von Luft ein reagierendes Gas durch den Formsand durchzuleiten, um beispielsweise chemische Reaktionen in dem Formsand, die zu einer weiteren Verfestigung desselben führen, vorzunehmen. Auch ist es möglich, während des Preßvorganges den Formsand zuerst mit Luft und dann mit einem reagierenden Gas zu durchspülen.The invention is not limited to the passage of air described, rather it is also possible within the scope of the invention to pass a reactive gas through the molding sand instead of air, for example to carry out chemical reactions in the molding sand which lead to further solidification thereof . It is also possible to flush the molding sand first with air and then with a reactive gas during the pressing process.
Claims (11)
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| AT88710050T ATE70750T1 (en) | 1987-12-01 | 1988-11-30 | METHOD OF COMPACTION OF MOLDING SAND. |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3740611A DE3740611C2 (en) | 1987-12-01 | 1987-12-01 | Process for compacting molding sand |
| DE3740611 | 1987-12-01 |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| EP0319453A2 EP0319453A2 (en) | 1989-06-07 |
| EP0319453A3 EP0319453A3 (en) | 1990-05-16 |
| EP0319453B1 true EP0319453B1 (en) | 1991-12-27 |
Family
ID=6341599
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| EP88710050A Expired - Lifetime EP0319453B1 (en) | 1987-12-01 | 1988-11-30 | Method for ramming moulding sand |
Country Status (3)
| Country | Link |
|---|---|
| EP (1) | EP0319453B1 (en) |
| AT (1) | ATE70750T1 (en) |
| DE (1) | DE3740611C2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE4114362A1 (en) * | 1991-05-02 | 1992-11-05 | Wagner Heinrich Sinto Masch | METHOD FOR PRODUCING A SAND FORM |
| DE4409791A1 (en) * | 1994-03-22 | 1995-09-28 | Wagner Heinrich Sinto Masch | Device for the production of casting molds |
| DE4419300C2 (en) * | 1994-06-01 | 1999-05-20 | Kuenkel Wagner Prozesstechnolo | Compression process with downward moving membrane press plate |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE2608740C2 (en) * | 1976-03-03 | 1978-05-11 | Eugen Dipl.-Ing. 8871 Burtenbach Buehler | Process for compacting molding sand |
| DE2844464C2 (en) * | 1978-10-12 | 1983-03-24 | Bühler, Eugen, Dipl.-Ing., 8871 Burtenbach | Method and device for compacting casting molds |
| DE3034653A1 (en) * | 1980-09-13 | 1982-04-29 | Buderus Ag, 6330 Wetzlar | Moulding sand compaction unit - comprising independently movable rams sepd. by sand injection openings |
| US4620584A (en) * | 1985-05-24 | 1986-11-04 | Witt Raymond H | Green sand mold filling system |
-
1987
- 1987-12-01 DE DE3740611A patent/DE3740611C2/en not_active Expired - Lifetime
-
1988
- 1988-11-30 AT AT88710050T patent/ATE70750T1/en not_active IP Right Cessation
- 1988-11-30 EP EP88710050A patent/EP0319453B1/en not_active Expired - Lifetime
Non-Patent Citations (1)
| Title |
|---|
| GIESSEREI, Band 74, nr 4, 18.Feb. 1987, Seiten 92-94, Düsseldorf, DE * |
Also Published As
| Publication number | Publication date |
|---|---|
| DE3740611A1 (en) | 1989-06-15 |
| DE3740611C2 (en) | 1998-07-23 |
| ATE70750T1 (en) | 1992-01-15 |
| EP0319453A2 (en) | 1989-06-07 |
| EP0319453A3 (en) | 1990-05-16 |
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| PUAI | Public reference made under article 153(3) epc to a published international application that has entered the european phase |
Free format text: ORIGINAL CODE: 0009012 |
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