EP0152573B1 - Apparatus for compacting foundry-moulding material using pressure gas - Google Patents

Apparatus for compacting foundry-moulding material using pressure gas Download PDF

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Publication number
EP0152573B1
EP0152573B1 EP84114951A EP84114951A EP0152573B1 EP 0152573 B1 EP0152573 B1 EP 0152573B1 EP 84114951 A EP84114951 A EP 84114951A EP 84114951 A EP84114951 A EP 84114951A EP 0152573 B1 EP0152573 B1 EP 0152573B1
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EP
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Prior art keywords
pressure
accordance
piston
fact
working space
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EP84114951A
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German (de)
French (fr)
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EP0152573A1 (en
Inventor
Norbert Ing. Grad. Damm
Günter Ing. grad. Müller
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BMD Badische Maschinenfabrik Durlach GmbH
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BMD Badische Maschinenfabrik Durlach GmbH
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    • 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 compressing foundry molding material by means of compressed gas, consisting of a pressure vessel forming a pre-pressure chamber for the compressed gas, a molding space arranged underneath from a molding box with a filling frame and a model plate with a model that closes the molding box below, onto which the molding material is compressed is loosely heaped up, and a large-area valve arranged between the pressure vessel and the molding space, the closure member of which releases the valve opening in a few milliseconds with the aid of the pressure in the pressure vessel, moves into the molding space and can be brought into the closed position by means of a pressure medium cylinder.
  • outlet pressures are sought which are in the range of the pressure of operational compressed air networks in order not to have to spend too much constructive effort on the one hand for the production of compressed gas and on the other hand for the control of the pressure.
  • the device must have a closure member which on the one hand closes the largest possible cross section for overflowing the compressed gas and on the other hand has the lowest possible mass in order to release the cross section as quickly as possible.
  • This also requires opening drives which bring the closure member into the open position in a few milliseconds and thus release the cross section. The aforementioned requirements cannot be achieved with conventional valve designs.
  • the object of the invention is to further develop the device described above in such a way that an even greater opening speed for the closure member is achieved with less design effort.
  • the pressure medium cylinder not only takes on the closing function, but also the opening and damping function for the closure member.
  • the clamping device and damping device necessary in the previously described device are dispensed with.
  • this discharge speed must be> 10 m / s, that is to say in a range which is 10 times higher than the return oil speeds customary in hydraulics.
  • This significantly higher flow rate for the displacement volume can be achieved by appropriate design measures.
  • the piston speed itself can only have values in the range of approx. 5 m / sec. to reach.
  • the working space of the pressure medium cylinder has a small displacement volume of e.g. B. 150 to 500 cm 3 .
  • the drain is decoupled from the other high-pressure circuit and connected to a drain tank via a line of relatively large cross-section.
  • the flow resistance for the expiring displacement is kept as low as possible
  • the decoupling from the otherwise high pressure circuit ensures that the amount of pressure medium to be displaced is small.
  • the drain tank gives the possibility to get a quick pressure reduction on the drain side.
  • the pressure accumulator the pressure of which acts on the other side of the piston, is in the closed position of the closure member, that is to say in the raised end position of the piston under a gas pressure between 50 and 200 bar, which is directly or indirectly, for. B. a hydraulic cushion acts on the piston. From approx. 50 bar, the effect of a gas pressure cushion, which in principle is already present even at lower pressures, advantageously increases in the sense of an additional acceleration.
  • the ratio of pressure accumulator volume to displacement volume of the pressure medium cylinder is at least 5: 1.
  • the device according to the invention is further characterized by a throttle which becomes effective towards the end of the lowering movement of the piston and which ensures that the piston and thus the closure member are braked over a short distance.
  • the piston rod connecting the piston to the closure member has a section which is flared in relation to the cylinder bushing of the piston rod within the pressure medium cylinder and that the piston rod extends through the inlet and outlet opening of the working space, which in connection with the conically enlarged section the piston rod forms the throttle.
  • the damping behavior can be further optimized with additional axially notches incorporated into the conical heel.
  • the throttle braking the piston is therefore integrated in the pressure medium cylinder.
  • the fastest possible drain is favored in that the inlet and outlet opening of the working space forming part of the throttle opens into at least two inlet and outlet channels.
  • the piston has a projection which projects into the space of the pressure accumulator and which has a stop which interacts with an end position limiter for the lowering movement of the piston.
  • the high pressure source is connected to the two channels of the pressure medium cylinder via a control slide, a check valve and a branching pipe thereafter, and that the discharge tank is connected to the branch lines via a controllable check valve.
  • the branch lines have the largest possible cross-section in order to allow the pressure medium to drain off quickly.
  • control slide connects the pressure medium cylinder to the high pressure source in a first position and opens the control line of the controllable check valve so that it closes and connects the control line to the high pressure source in a second position. so that the check valve opens against the pressure in the branch line and connects the pressure medium cylinder to the drain tank.
  • Figure 2 shows an embodiment of the control of the pressure medium cylinder.
  • a pressure vessel 5 - in the illustrated embodiment for receiving compressed air - which is connected via a connection 6 from a pressure accumulator or - at low admission pressure - is fed from the company's compressed air network.
  • the pressure vessel has a plate 7 which is provided with a plurality of openings 8 in a rust-like manner in the area above the molding space.
  • a frame 9 is flanged to the underside of the base 7, to which in turn an exhaust air line with a valve 10 is connected.
  • the pressure vessel 5 with the frame 9 on the one hand and the model plate 1 with model 2, molding box 3 and filling frame 4 can be moved relative to one another in order to be able to fill the molding space with molding material. Before the compression, these two assemblies are brought together and pressed tightly together at their interface.
  • valve plate 11 sits on a guide rod 14 which merges into the piston rod 16 of the piston 15 of a pressure medium cylinder 17. This is described below with reference to FIG. 2:
  • the pressure medium cylinder 47 which corresponds to the pressure medium cylinder 17 in FIG. 1, is arranged in a high-pressure circuit, the high-pressure source being designated by 41.
  • the high-pressure source 41 This is, for example, a hydraulic pump that is fed from a tank 66.
  • the pressure medium passes via a control slide 42 and a check valve 43 into branch lines 44, which are each connected to a channel 48 in the pressure medium cylinder 47.
  • the channels 48 in turn open into a central opening 49 of the pressure medium cylinder, which establishes the connection to the working space 50 of the pressure medium cylinder.
  • the pressure medium cylinder 47 has a pressure accumulator 51 above the piston 45, which is connected to a gas pressure receiver 53 via a check valve 52.
  • the piston 45 forms the lower, movable end of the pressure accumulator 51.
  • a partition 54 is arranged within the pressure accumulator and forms a limit position for the piston 45 and thus for the closure member 11.
  • the partition wall 54 is provided with a plurality of openings in order to allow the pressure in the pressure accumulator 51 to act unhindered on the piston 45.
  • the piston in turn, is provided with a stop 56 via a shoulder 55 which rests on an elastic element 57 in the lower end position of the piston 45, that is to say in the open position of the closure member 11.
  • the piston rod 46 is provided in its area lying within the working space 50 with a conically widened section 58 which forms a kind of throttle when the piston 45 is lowered in connection with the opening 49. Furthermore, the working space 50 of the pressure medium cylinder 47 can be connected via a line 59 to a further fine throttle 60, which in turn is connected to one of the two branch lines 44.
  • the branch lines 44 are connected via a controllable check valve 61, the control line of which can be connected to the high-pressure source 41 via the control slide 42, to an outlet tank 63, the outlet 64 of which opens into the system tank 66 and which is also equipped with a vent 65.
  • the control slide 42 In order to bring the closure member 11 from the open position shown on the right in FIG. 1 to the closed position (left half of FIG. 1), the control slide 42 is brought into the position "B". In this position, the connection between the high-pressure source 41 and the working space 50 of the pressure medium cylinder 47 is established by opening the check valve 43. At the same time, the control line 62 of the controllable check valve 61 is connected to the system tank, ie without pressure, so that the check valve 61 closes. The pressure medium flows through the branch lines 44 and the channels 48 into the working space 50, lifts the piston 45 and thus the piston rod 46 and the guide rod 14 with the closure member 11 until it has finally reached the closed position (left half of FIG. 1).
  • the model plate 1 with the filled molding box 3 and filling frame 4 is clamped to the frame 9.
  • the valve 10 is in the closed position.
  • the medium in the pressure accumulator 51 is prestressed at the same time. Any leakage losses in the pressure accumulator 51 are supplemented by the print template 53.
  • the pressure in the pressure accumulator 51 increases, for example, to approximately 100 bar.
  • the closure member 11 is brought into the open position (right half of FIG. 1).
  • the control slide 42 in the position "A" switched.
  • the pressure of the high pressure source 41 is then present in the control line 62, so that the check valve 61 opens.
  • the pressure medium runs out of the working space 50 under the action of the pressure in the pressure accumulator 51 via the check valve 61 into the discharge tank 63.
  • the outlet cross-section between the piston rod 46 and the outlet opening 49 is reduced by the conical section 58 on the piston rod 46, so that the piston 45 and thus the closure member 11 are braked.
  • the pressure medium to be displaced runs out of the working space 50 at a speed of more than 10 m / s, preferably between 20 and 30 m / s.
  • the drain tank 63 can be vented between the compression cycles via the line 65, so that its contents can flow into the system tank 66.

Description

Die Erfindung betrifft eine Vorrichtung zum Verdichten von Gießerei-Formstoff mittels Druckgas, bestehend aus einem einen Vordruckraum bildenden Druckbehälter für das Druckgas, einem darunter angeordneten Formraum aus Formkasten mit Füllrahmen und einer den Formkasten unten abschließenden Modellplatte mit Modell, auf das der Formstoff vor der Verdichtung lose aufgeschüttet wird, und einem zwischen dem Druckbehälter und dem Formraum angeordneten großflächigen Ventil, dessen Verschlußorgan die Ventilöffnung unter Mitwirkung des Drucks im Druckbehälter in einigen Millisekunden freigibt, sich dabei in den Formraum hineinbewegt und mittels eines Druckmittelzylinders in die Schließlage bringbar ist.The invention relates to a device for compressing foundry molding material by means of compressed gas, consisting of a pressure vessel forming a pre-pressure chamber for the compressed gas, a molding space arranged underneath from a molding box with a filling frame and a model plate with a model that closes the molding box below, onto which the molding material is compressed is loosely heaped up, and a large-area valve arranged between the pressure vessel and the molding space, the closure member of which releases the valve opening in a few milliseconds with the aid of the pressure in the pressure vessel, moves into the molding space and can be brought into the closed position by means of a pressure medium cylinder.

In der gemäß Art. 54 (3) bei der Frage der erfinderischen Tätigkeit nicht zu berücksichtigenden Patentanmeldung EP-A-0 084 627 ist ein Verfahren und eine Vorrichtung zum Verdichten von Gießerei-Formstoff, insbesondere Formsand, mittels Druckgas, z. B. Druckluft oder durch explosive Verbrennung erzeugtes Druckgas, beschrieben, wobei das Druckgas schlagartig aus einem Druckbehälter in den Formraum entspannt wird, dabei auf die freie Formstoff-Oberfläche einwirkt und die Formstoffpartikel unter gegenseitigem Impulsaustausch sowie durch Verzögerung der beschleunigten Formstoffmasse auf der Modelloberseite und der Modellplatte verdichtet, wobei zusätzlich Fluidisierungseffekte unter Reduzierung der Partikelreibung eintreten. Wesentlich ist hierbei ein hoher Gasmassendurchsatz bei schnellstmöglichem Druckanstieg im Formraum. Diese Parameter müssen umso höher liegen, je niedriger der Ausgangsdruck im Druckbehälter ist, wobei Ausgangsdrucke angestrebt werden, die im Bereich des Drucks betrieblicher Druckluftnetze liegen, um einerseits für die Druckgaserzeugung, andererseits für die Beherrschung des Drucks keinen allzu großen konstruktiven Aufwandbetreiben zu müssen. Dies führt dazu, daß die Vorrichtung ein Verschlußorgan aufweisen muß, das einerseits einen größtmöglichen Querschnitt zum Überströmen des Druckgases verschließt, andererseits eine geringstmögliche Masse aufweist, um den Querschnitt schnellstmöglich freizugeben. Ferner erfordert dies Öffnungsantriebe, die das Verschlußorgan in wenigen Millisekunden in die Öffnungslage bringen und somit den Querschnitt freigeben. Mit herkömmlichen Ventilkonstruktionen lassen sich die vorgenannten Voraussetzungen nicht erreichen.In the patent application EP-A-0 084 627, which is not to be considered in the question of inventive step in accordance with Art. 54 (3), a method and an apparatus for compressing foundry molding material, in particular molding sand, by means of compressed gas, for. B. compressed air or compressed gas generated by explosive combustion, wherein the compressed gas is suddenly released from a pressure vessel into the mold space, thereby acting on the free surface of the molding material and the molding particles with mutual exchange of momentum and by delaying the accelerated molding material mass on the top of the model and Model plate compacted, with additional fluidization effects occurring while reducing particle friction. What is essential here is a high gas mass throughput with the fastest possible pressure increase in the molding space. These parameters have to be higher the lower the outlet pressure in the pressure vessel, whereby outlet pressures are sought which are in the range of the pressure of operational compressed air networks in order not to have to spend too much constructive effort on the one hand for the production of compressed gas and on the other hand for the control of the pressure. This means that the device must have a closure member which on the one hand closes the largest possible cross section for overflowing the compressed gas and on the other hand has the lowest possible mass in order to release the cross section as quickly as possible. This also requires opening drives which bring the closure member into the open position in a few milliseconds and thus release the cross section. The aforementioned requirements cannot be achieved with conventional valve designs.

In den weiteren Patentanmeldungen EP-A-0 129 210 und EP-A-0131 723 von welcher der unabhängige Anspruch 1 ausgeht und die beide der Erfindung näher kommen, aber gleichfalls gemäß Art. 54 (3) bei der Frage der erfinderischen Tätigkeit nicht zu berücksichtigen sind, wird das Druckgefälle zwischen Druckbehälter und Formraum zur Öffnung des Ventils ausgenutzt, indem das Verschlußorgan innerhalb des Druckbehälters geführt und seine Öffnungsbewegung in den Formraum hinein gerichtet ist. Als Schließantrieb für das Verschlußorgan dient ein Druckmittelzylinder, dessen Kolben mit einer Führungsstange des Verschlußorgans verbunden ist. In der Schließlage wird die Führungsstange mittels einer Klemmeinrichtung festgesetzt. Zumindest während der Öffnungsbewegung ist der Druckmittelzylinder von der Führungsstange abgekoppelt, um nicht gegen den Druck im Druckmittelzylinder arbeiten zu müssen. Danach wird die Antriebsverbindung wieder hergestellt und das Verschlußorgan mittels der Führungsstange wieder in die Schließlage gebracht.In the further patent applications EP-A-0 129 210 and EP-A-0131 723, from which the independent claim 1 is based and which both come closer to the invention, but likewise according to Art. 54 (3), do not address the question of inventive step are taken into account, the pressure drop between the pressure vessel and the mold space is used to open the valve by guiding the closure member within the pressure vessel and directing its opening movement into the mold space. A pressure medium cylinder, the piston of which is connected to a guide rod of the closure member, serves as the closing drive for the closure member. In the closed position, the guide rod is fixed by means of a clamping device. At least during the opening movement, the pressure medium cylinder is decoupled from the guide rod in order not to have to work against the pressure in the pressure medium cylinder. Then the drive connection is re-established and the closure member is brought back into the closed position by means of the guide rod.

Hiervon ausgehend liegt der Erfindung die Aufgabe zugrunde, die zuvor beschriebene Vorrichtung so weiterzubilden, daß bei geringerem konstruktiven Aufwand eine noch größere Öffnungsgeschwindigkeit für das Verschlußorgan erreicht wird.Proceeding from this, the object of the invention is to further develop the device described above in such a way that an even greater opening speed for the closure member is achieved with less design effort.

Diese Aufgabe wird erfindungsgemäß dadurch gelöst, daß der durch einen Kolben begrenzte Arbeitsraum des Druckmittelzylinders an eine Hochdruckquelle angeschlossen ist, und der Kolben mit seiner dem Arbeitsraum gegenüberliegenden Seite den beweglichen Abschluß eines mit Gas beaufschlagten Druckspeichers bildet und der Arbeitsraum einen Abfluß aufweist, der so ausgebildet ist, daß das Druckmittel mit einer Geschwindigkeit ;= 10 m/s abläuft bei gleichzeitiger Beschleunigung durch die Wirkung des Drucks im Druckspeicher sowohl des Kolbens als auch des Verschlußorgans in die Öffnungsstellung.This object is achieved in that the working space of the pressure medium cylinder, which is delimited by a piston, is connected to a high-pressure source, and the piston with its side opposite the working space forms the movable closure of a pressure accumulator charged with gas, and the working space has a drain which is designed in this way is that the pressure medium runs at a speed; = 10 m / s with simultaneous acceleration due to the effect of the pressure in the pressure accumulator of both the piston and the closure member in the open position.

Bei der erfindungsgemäßen Ausbildung übernimmt der Druckmittelzylinder nicht nur die Schließfunktion, sondern auch die Öffnungs- und Dämpfungsfunktion für das Verschlußorgan. Es entfällt die bei der zuvor beschriebenen Vorrichtung notwendige Klemmeinrichtung und Dämpfungsvorrichtung.In the embodiment according to the invention, the pressure medium cylinder not only takes on the closing function, but also the opening and damping function for the closure member. The clamping device and damping device necessary in the previously described device are dispensed with.

Praktische Versuche mit den bekannten Vorrichtungen haben gezeigt, daß für Formkasten mittlerer Größe der Druckaufbau über der Formstoff-Oberfläche mit einem Druckgradienten von ca. 200 bis 300bar/s erfolgen muß, um eine einwandfreie Verdichtung zu erhalten. Hieraus ergeben sich bei einem großflächigen Verschlußorgan mit optimierter geringer Masse und einem Ausgangsdruck, wie er in betriebsinternen Druckluftnetzen herrscht, eine Geschwindigkeit für das Verschlußorgan, die über 1 m/s liegen muß. Soll, wie dies erfindungsgemäß vorgesehen ist, die Öffnungsbewegung durch den Druckmittelzylinder, der zum Schließen des Verschlußorgans dient, unterstützt werden, so setzt dies bei einem vorgegebenen Druck im Druckspeicher hohe Abflußgeschwindigkeiten für das während der Öffnungsbewegung vom Kolben verdrängte Druckmittelvolumen voraus. Gemäß der Erfindung muß diese Abflußgeschwindigkeit > 10 m/s sein, also in einem Bereich liegen, der um den Faktor 10 höher liegt wie die in der Hydraulik üblichen Rückölgeschwindigkeiten. Diese wesentlich höhere Abflußgeschwindigkeit für das Verdrängungsvolumen läßt sich durch entsprechende konstruktive Maßnahmen erreichen. Die Kolbengeschwindigkeit selbst kann dabei lediglich Werte im Bereich von ca. 5 m/sec. erreichen.Practical tests with the known devices have shown that for medium-sized mold boxes, the pressure build-up over the molding material surface must take place with a pressure gradient of approximately 200 to 300 bar / s in order to obtain a perfect compression. In the case of a large-area closure member with an optimized low mass and an outlet pressure such as that prevailing in internal compressed air networks, this results in a speed for the closure member which must be above 1 m / s. If, as is provided according to the invention, the opening movement is to be supported by the pressure medium cylinder, which serves to close the closure member, this sets high discharge velocities for the during the opening movement from a given pressure in the pressure accumulator Piston displaced pressure medium volume ahead. According to the invention, this discharge speed must be> 10 m / s, that is to say in a range which is 10 times higher than the return oil speeds customary in hydraulics. This significantly higher flow rate for the displacement volume can be achieved by appropriate design measures. The piston speed itself can only have values in the range of approx. 5 m / sec. to reach.

Gemäß einem ersten Ausführungsbeispiel weist der Arbeitsraum des Druckmittelzylinders ein kleines Verdrängungsvolumen von z. B. 150 bis 500 cm3 auf. Je geringer das Verdrängungsvolumen ist, um so kürzer kann die Abflußzeit bzw. Hubzeit bei gegebenen Querschnitten sein.According to a first embodiment, the working space of the pressure medium cylinder has a small displacement volume of e.g. B. 150 to 500 cm 3 . The lower the displacement volume, the shorter the discharge time or stroke time for given cross sections.

Gemäß einem weiteren Ausführungsbeispiel ist der Abfluß vom sonstigen Hochdruck-Kreislauf abgekoppelt und über eine Leitung relativ großen Querschnittes an einen Ablauftank angeschlossen.According to a further embodiment, the drain is decoupled from the other high-pressure circuit and connected to a drain tank via a line of relatively large cross-section.

Mit diesem Ausführungsbeispiel wird einerseits der Strömungswiderstand für das ablaufende Verdrängungsvolumen so gering als möglich gehalten, andererseits wird durch die Abkopplung vom sonstingen Hochdruck-Kreislauf erreicht, daß die zu verschiebende Druckmittelmenge gering ist. Der Ablauftank gibt die Möglichkeit, abflußseitig einen schnellen Druckabbau zu erhalten.With this embodiment, on the one hand the flow resistance for the expiring displacement is kept as low as possible, on the other hand the decoupling from the otherwise high pressure circuit ensures that the amount of pressure medium to be displaced is small. The drain tank gives the possibility to get a quick pressure reduction on the drain side.

In der Praxis hat sich für die Hochdruckquelle ein Druck zwischen 100 und 300 bar als zweckmäßig erwiesen. Diese Drucke lassen sich in der Hydraulik ohne weiteres erreichen.In practice, a pressure between 100 and 300 bar has proven to be expedient for the high pressure source. These pressures can be easily achieved in hydraulics.

Der Druckspeicher, dessen Druck auf die andere Seite des Kolbens wirkt, steht in der Schließlage des Verschlußorgans, also in der angehobenen Endlage des Kolbens unter einem Gasdruck zwischen 50 und 200 bar, der unmittelbar oder mittelbar, z. B. ein Hydraulikpolster, auf den Kolben wirkt. Ab ca. 50 bar steigt der Effekt eines Gasdruckpolsters, der prinzipiell auch schon bei geringeren Drücken vorhanden ist, im Sinne einer zusätzlichen Beschleunigung in vorteilhafter Weise stark an.The pressure accumulator, the pressure of which acts on the other side of the piston, is in the closed position of the closure member, that is to say in the raised end position of the piston under a gas pressure between 50 and 200 bar, which is directly or indirectly, for. B. a hydraulic cushion acts on the piston. From approx. 50 bar, the effect of a gas pressure cushion, which in principle is already present even at lower pressures, advantageously increases in the sense of an additional acceleration.

Es hat sich ferner als vorteilhartt erwiesen, wenn das Verhältnis von Druckspeichervolumen und Verdrängungsvolumen des Druckmittelzylinders mindestens 5 : 1 beträgt.It has also proven to be advantageous if the ratio of pressure accumulator volume to displacement volume of the pressure medium cylinder is at least 5: 1.

Praktische Versuche mit der erfindungsgemäß ausgebildeten Vorrichtung haben ergeben, daß sich die Öffnungsgeschwindigkeit des Verschlußorgans etwa verdoppeln läßt, wobei der konstruktive Aufwand erheblich verringert wird.Practical tests with the device designed according to the invention have shown that the opening speed of the closure member can be approximately doubled, the construction effort being considerably reduced.

Die erfindungsgemäße Vorrichtung zeichnet sich weiterhin aus durch eine gegen Ende der Absenkbewegung des Kolbens wirksam werdende Drossel, die dafür sorgt, daß der Kolben und damit das Verschlußorgan auf kurzer Strecke abgebremst werden.The device according to the invention is further characterized by a throttle which becomes effective towards the end of the lowering movement of the piston and which ensures that the piston and thus the closure member are braked over a short distance.

In einer bevorzugten Ausführung ist vorgesehen, daß die den Kolben mit dem Verschlußorgan verbindende Kolbenstange innerhalb des Druckmittelzylinders einen gegenüber der Zylinderdurchführung der Kolbenstange konisch erweiterten Abschnitt aufweist und daß die Kolbenstange die Zu- und Ablauföffnung des Arbeitsraums durchgreift, die in Verbindung mit dem konisch erweiterten Abschnitt der Kolbenstange die Drossel bildet. Mit zusätzlich in den konischen Absatz eingearbeiteten, axial verlautenden Kerben läßt sich das Dämpfungsverhalten weiter optimieren.In a preferred embodiment it is provided that the piston rod connecting the piston to the closure member has a section which is flared in relation to the cylinder bushing of the piston rod within the pressure medium cylinder and that the piston rod extends through the inlet and outlet opening of the working space, which in connection with the conically enlarged section the piston rod forms the throttle. The damping behavior can be further optimized with additional axially notches incorporated into the conical heel.

Die den Kolben abbremsende Drossel ist also in den Druckmittelzylinder integriert.The throttle braking the piston is therefore integrated in the pressure medium cylinder.

Ein schnellstmöglicher Ablauf wird gemäß einem weiteren Ausführungsbeispiel dadurch begünstigt, daß die einen Teil der Drossel bildende Zu-und Ablauföffnung des Arbeitsraums in wenigstens zwei Zu- und Ablaufkanäle mündet.According to a further exemplary embodiment, the fastest possible drain is favored in that the inlet and outlet opening of the working space forming part of the throttle opens into at least two inlet and outlet channels.

Gemäß einem weiteren Merkmal der Erfindung weist der Kolben einen in den Raum des Druckspeichers ragenden Ansatz auf, der einen mit einem Endlagenbegrenzer für die Absenkbewegung des Kolbens zusammenwirkenden Anschlag aufweist.According to a further feature of the invention, the piston has a projection which projects into the space of the pressure accumulator and which has a stop which interacts with an end position limiter for the lowering movement of the piston.

In bevorzugter Ausführung ist weiterhin vorgesehen, daß die Hochdruckquelle über einen Steuerschieber, ein Rückschlagventil und eine sich danach verzweigende Leitung mit den beiden Kanälen des Druckmittelzylinders verbunden ist, und daß an die Zweigleitungen über ein aufsteuerbares Rückschlagventil der Ablauftank angeschlossen ist. Dabei weisen, wie bereits zuvor angedeutet, die Zweigleitungen einen größtmöglichen Querschnitt auf, um einen schnellen Ablauf des Druckmittels zu ermöglichen.In a preferred embodiment it is further provided that the high pressure source is connected to the two channels of the pressure medium cylinder via a control slide, a check valve and a branching pipe thereafter, and that the discharge tank is connected to the branch lines via a controllable check valve. As already indicated above, the branch lines have the largest possible cross-section in order to allow the pressure medium to drain off quickly.

Schließlich ist gemäß einem weiteren Ausführungsbeispiel vorgesehen, daß der Steuerschieber in einer ersten Stellung den Druckmittelzylinder mit der Hochdruckquelle verbindet und die Steuerleitung des aufsteuerbaren Rückschlagventils öffnet, so daß dieses schließt und in einer zweiten Stellung die Steuerleitung mit der Hochdruckquelle verbindet. so daß das Rückschlagventil gegen den Druck in der Zweigleitung öffnet und den Druckmittelzylinder mit dem Ablauftank verbindet.Finally, according to a further exemplary embodiment, it is provided that the control slide connects the pressure medium cylinder to the high pressure source in a first position and opens the control line of the controllable check valve so that it closes and connects the control line to the high pressure source in a second position. so that the check valve opens against the pressure in the branch line and connects the pressure medium cylinder to the drain tank.

Nachstehend ist die Erfindung anhand eines in der Zeichnung dargestellten Ausführungsbeispiels beschrieben. In der Zeichnung zeigen:The invention is described below with reference to an embodiment shown in the drawing. The drawing shows:

Figur 1 einen Schnitt durch eine Ausführungsform der Vorrichtung und1 shows a section through an embodiment of the device and

Figur 2 eine Ausführungsform der Steuerung des Druckmittelzylinders.Figure 2 shows an embodiment of the control of the pressure medium cylinder.

In der Zeichnung sind nur die zum Verständnis der Erfindung notwendigen Teile der Verdichtungsvorrichtung einer Gießerei-Formmaschine wiedergegeben. Es sind insbesondere nicht gezeigt der Maschinenständer, die Einrichtung zum Heben und Senken von Formkasten und Füllrahmen sowie gegebenenfalls zum Ausstoßen der fertigen Form aus dem Formkasten. Ebensowenig sind die Einrichtungen zum Heranbringen des Modells und zum Einfüllen des Formsandes wiedergegeben, da diese Bauteile im Gießerei-Maschinenbau bekannt sind.In the drawing, only the parts of the compression device of a foundry molding machine necessary for understanding the invention are shown. In particular, the machine stand, the device for lifting and lowering the molding box and filling frame and, if appropriate, for ejecting the are not shown finished mold from the molding box. The facilities for bringing up the model and for filling in the molding sand are also not shown, since these components are known in foundry mechanical engineering.

Auf einer Modellplatte 1 mit einem Modell 2 sitzt ein Formkasten 3 und auf diesem ein Füllrahmen 4. Oberhalb dieses Formraums ist ein Druckbehälter 5 - beim wiedergegebenen Ausführungsbeispiel zur Aufnahme von Druckluft - angeordnet, der über einen Anschluß 6 aus einem Druckspeicher oder - bei niedrigem Vordruck- aus dem betrieblichen Druckluftnetz gespeist wird.On a model plate 1 with a model 2 sits a molding box 3 and on this a filling frame 4. Above this molding space is a pressure vessel 5 - in the illustrated embodiment for receiving compressed air - which is connected via a connection 6 from a pressure accumulator or - at low admission pressure - is fed from the company's compressed air network.

Der Druckbehälter weist als Boden 7 eine Platte auf, die im Bereich oberhalb des Formraums rostartig mit einer Vielzahl von Öffnungen 8 versehen ist. An der Unterseite des Bodens 7 ist ein Rahmen 9 angeflanscht, an den wiederum eine Abluftleitung mit einem Ventil 10 angeschlossen ist. Der Druckbehälter 5 mit dem Rahmen 9 einerseits und die Modellplatte 1 mit Modell 2, Formkasten 3 und Füllrahmen 4 sind gegeneinander beweglich, um den Formraum mit Formstoff füllen zu können. Vor dem Verdichten werden diese beiden Baugruppen zusammengebracht und an ihrer Trennfläche dicht zusammengepreßt.The pressure vessel has a plate 7 which is provided with a plurality of openings 8 in a rust-like manner in the area above the molding space. A frame 9 is flanged to the underside of the base 7, to which in turn an exhaust air line with a valve 10 is connected. The pressure vessel 5 with the frame 9 on the one hand and the model plate 1 with model 2, molding box 3 and filling frame 4 can be moved relative to one another in order to be able to fill the molding space with molding material. Before the compression, these two assemblies are brought together and pressed tightly together at their interface.

Mit dem Boden 7 bzw. dessen die Öffnungen 8 aufweisenden Bereich wirkt ein Verschlußorgan in Form einer starren Ventilplatte 11 zusammen, die gleichfalls eine Vielzahl von Öffungen 12 besitzt. Ferner sitzt auf der Oberseite der Ventilplatte innerhalb des Bereichs der Öffnungen 12, wie auch der Öffnungen 8 im Boden 7, ein Dichtungsbelag 13. Wie aus der linken Hälfte der Darstellung erkennbar, sind die Öffnungen 8 im Boden 7 und die Öffnungen 12 in der Ventilplatte 11 so gegeneinander versetzt, daß sie sich in der Schließlage nicht überdecken.A closure member in the form of a rigid valve plate 11, which likewise has a multiplicity of openings 12, interacts with the bottom 7 or its area having the openings 8. Furthermore, on the top of the valve plate, within the area of the openings 12, as well as the openings 8 in the base 7, there is a sealing coating 13. As can be seen from the left half of the illustration, the openings 8 in the base 7 and the openings 12 in the valve plate 11 so offset against each other that they do not overlap in the closed position.

Die Ventilplatte 11 sitzt an einer Führungsstange 14, die in die Kolbenstange 16 des Kolbens 15 eines Druckmittelzylinders 17 übergeht. Dieser ist nachfolgend anhand der Figur 2 beschrieben:The valve plate 11 sits on a guide rod 14 which merges into the piston rod 16 of the piston 15 of a pressure medium cylinder 17. This is described below with reference to FIG. 2:

Der Druckmittelzylinder 47, der dem Druckmittelzylinder 17 der Figur 1 entspricht, ist in einem Hochdruck-Kreislauf angeordnet, wobei die Hochdruckquelle mit 41 bezeichnet ist. Hierbei handelt es sich beispielsweise um eine Hydraulikpumpe, die aus einem Tank 66 gespeist wird. Von der Hochdruckquelle 41 gelangt das Druckmittel über einen Steuerschieber 42 und ein Rückschlagventil 43 in Zweigleitungen 44, die an je einen Kanal 48 im Druckmittelzylinder 47 angeschlossen sind. Die Kanäle 48 wiederum münden in eine zentrale Öffnung 49 des Druckmittelzylinders, die die Verbindung zum Arbeitsraum 50 des Druckmittelzylinders herstellt. Der Druckmittelzylinder 47 weist oberhalb des Kolbens 45 einen Druckspeicher 51 auf, der über ein Rückschlagventil 52 an eine Gas-Druckvorlage 53 angeschlossen ist. Dabei bildet der Kolben 45 den unteren, im übringen beweglichen Abschluß des Druckspeichers 51. Innerhalb des Druckspeichers ist eine Trennwand 54 angeordnet, die eine Endlagenbegrenzung für den Kolben 45 und damit für das Verschlußorgan 11 bildet. Die Trennwand 54 ist mit mehreren Öffnungen versehen, um den Druck im Druckspeicher 51 ungehindert auf den Kolben 45 wirken zu lassen. Der Kolben seinerseits ist über einen Ansatz 55 mit einem Anschlag 56 versehen, der in der unteren Endlage des Kolbens 45, also in der Öffnungsstellung des Verschlußorgans 11 auf einem elastischen Element 57 aufliegt.The pressure medium cylinder 47, which corresponds to the pressure medium cylinder 17 in FIG. 1, is arranged in a high-pressure circuit, the high-pressure source being designated by 41. This is, for example, a hydraulic pump that is fed from a tank 66. From the high-pressure source 41, the pressure medium passes via a control slide 42 and a check valve 43 into branch lines 44, which are each connected to a channel 48 in the pressure medium cylinder 47. The channels 48 in turn open into a central opening 49 of the pressure medium cylinder, which establishes the connection to the working space 50 of the pressure medium cylinder. The pressure medium cylinder 47 has a pressure accumulator 51 above the piston 45, which is connected to a gas pressure receiver 53 via a check valve 52. In this case, the piston 45 forms the lower, movable end of the pressure accumulator 51. A partition 54 is arranged within the pressure accumulator and forms a limit position for the piston 45 and thus for the closure member 11. The partition wall 54 is provided with a plurality of openings in order to allow the pressure in the pressure accumulator 51 to act unhindered on the piston 45. The piston, in turn, is provided with a stop 56 via a shoulder 55 which rests on an elastic element 57 in the lower end position of the piston 45, that is to say in the open position of the closure member 11.

Die Kolbenstange 46 ist in ihrem innerhalb des Arbeitsraums 50 liegenden Bereich mit einem konisch erweiterten Abschnitt 58 versehen, der bei der Absenkbewegung des Kolbens 45 in Verbindung mit der Öffnung 49 eine Art Drossel bildet. Ferner kann der Arbeitsraum 50 des Druckmittelzylinders 47 über eine Leitung 59 mit einer weiteren Feindrossel 60 verbunden sein, die wiederum an eine der beiden Zweigleitungen 44 angeschlossen ist.The piston rod 46 is provided in its area lying within the working space 50 with a conically widened section 58 which forms a kind of throttle when the piston 45 is lowered in connection with the opening 49. Furthermore, the working space 50 of the pressure medium cylinder 47 can be connected via a line 59 to a further fine throttle 60, which in turn is connected to one of the two branch lines 44.

Die Zweigleitungen 44 sind über ein aufsteuerbares Rückschlagventil 61, dessen Steuerleitung über den Steuerschieber 42 mit der Hochdruckquelle 41 verbindbar ist, an einen Ablauftank 63 angeschlossen, dessen Abfluß 64 in den Systemtank 66 mündet und der ferner mit einer Entlüftung 65 ausgestattet ist.The branch lines 44 are connected via a controllable check valve 61, the control line of which can be connected to the high-pressure source 41 via the control slide 42, to an outlet tank 63, the outlet 64 of which opens into the system tank 66 and which is also equipped with a vent 65.

Nachstehend ist die Funktion der Vorrichtung beschrieben:The function of the device is described below:

Um das Verschlußorgan 11 aus der in Figur 1 rechts wiedergegebenen geöffneten Stellung in die Schließstellung (linke Hälfte der Figur 1) zu bringen, wird der Steuerschieber 42 in die Position "B" gebracht. In dieser Position ist die Verbindung zwischen der Hochdruckquelle 41 und dem Arbeitsraum 50 des Druckmittelzylinders 47 unter Öffnen des Rückschlagventils 43 hergestellt. Zugleich ist die Steuerleitung 62 des aufsteuerbaren Rückschlagventils 61 an den Systemtank angeschlossen, also drucklos, so daß das Rückschlagventil 61 schließt. Das Druckmittel strömt über die Zweigleitungen 44 und die Kanäle 48 in den Arbeitsraum 50 ein, hebt den Kolben 45 und damit die Kolbenstange 46 und die Führungsstange 14 mit dem Verschlußorgan 11, bis dieses schließlich die Schließstellung (linke Hälfte der Figur 1) erreicht hat. Vor oder während dieses Vorgangs wird die Modellplatte 1 mit dem gefüllten Formkasten 3 und Füllrahmen 4 mit dem Rahmen 9 verspannt. Das Ventil 10 befindet sich in der Schließlage. Während des Anhebens des Kolbens 45, das beispielsweise unter einem Druck von ca. 250 bar geschieht, wird gleichzeitig das Medium im Druckspeicher 51 vorgespannt. Eventuelle Leckverluste im Druckspeicher 51 werden durch die Druckvorlage 53 ergänzt. Der Druck im Druckspeicher 51 steigt beispielsweise auf ca. 100 bar.In order to bring the closure member 11 from the open position shown on the right in FIG. 1 to the closed position (left half of FIG. 1), the control slide 42 is brought into the position "B". In this position, the connection between the high-pressure source 41 and the working space 50 of the pressure medium cylinder 47 is established by opening the check valve 43. At the same time, the control line 62 of the controllable check valve 61 is connected to the system tank, ie without pressure, so that the check valve 61 closes. The pressure medium flows through the branch lines 44 and the channels 48 into the working space 50, lifts the piston 45 and thus the piston rod 46 and the guide rod 14 with the closure member 11 until it has finally reached the closed position (left half of FIG. 1). Before or during this process, the model plate 1 with the filled molding box 3 and filling frame 4 is clamped to the frame 9. The valve 10 is in the closed position. During the lifting of the piston 45, which takes place, for example, under a pressure of approximately 250 bar, the medium in the pressure accumulator 51 is prestressed at the same time. Any leakage losses in the pressure accumulator 51 are supplemented by the print template 53. The pressure in the pressure accumulator 51 increases, for example, to approximately 100 bar.

Zum schlagartigen Entspannen des Druckbehälters 5 und zum Verdichten, des im Formkasten und Füllrahmen vorhandenen Formstoffs wird das Verschlußorgan 11 in die Öffnungslage (rechte Hälfte der Figur 1) gebracht. Hierzu wird der Steuerschieber 42 in die Stellung "A" umgeschaltet. Es steht dann der Druck der Hochdruckquelle 41 in der Steuerleitung 62 an, so daß das Rückschlagventil 61 öffnet. Über die relativ großen Ablaufquerschnitte der Öffnung 49, der Kanäle 48 und der Zweigleitungen 44 läuft das Druckmittel aus dem Arbeitsraum 50 unter Wirkung des Drucks im Druckspeicher 51 über das Rückschlagventil 61 in den Ablauftank 63 ab. Gegen Ende der Absenkbewegung des Kolbens 45 wird der Ablaufquerschnitt zwischen Kolbenstange 46 und Ablauföffnung 49 durch den konischen Abschnitt 58 an der Kolbenstange 46 reduziert, so daß der Kolben 45 und damit das Verschlußorgan 11 abgebremst werden. Während der Öffnungsbewegung läuft das zu verdrängende Druckmedium aus dem Arbeitsraum 50 mit einer Geschwindigkeit von mehr als 10 m/s, vorzugsweise zwischen 20 und 30 m/s ab.To abruptly relax the pressure vessel 5 and to compress the molding material present in the molding box and filling frame, the closure member 11 is brought into the open position (right half of FIG. 1). For this purpose, the control slide 42 in the position "A" switched. The pressure of the high pressure source 41 is then present in the control line 62, so that the check valve 61 opens. Via the relatively large discharge cross-sections of the opening 49, the ducts 48 and the branch lines 44, the pressure medium runs out of the working space 50 under the action of the pressure in the pressure accumulator 51 via the check valve 61 into the discharge tank 63. Towards the end of the lowering movement of the piston 45, the outlet cross-section between the piston rod 46 and the outlet opening 49 is reduced by the conical section 58 on the piston rod 46, so that the piston 45 and thus the closure member 11 are braked. During the opening movement, the pressure medium to be displaced runs out of the working space 50 at a speed of more than 10 m / s, preferably between 20 and 30 m / s.

Der Ablauftank 63 kann zwischen den Verdichtungstakten über die Leitung 65 entlüftet werden, so daß sein Inhalt in den Systemtank 66 abfließen kann.The drain tank 63 can be vented between the compression cycles via the line 65, so that its contents can flow into the system tank 66.

Claims (14)

1. Apparatus for compacting foundry-moulding material using pressure gas, consisting of a pressure vessel (5) for the pressure gas, forming a preliminary pressure chamber of a moulding chamber situated thereunder and comprising a moulding box (3) with filling frame (4), and of a pattern plate (1) forming the lower termination of the moulding box and having a pattern (2) onto which the moulding material is loosely deposited before the compacting, and of a large-area valve which is positioned between the pressure vessel the moulding chamber and of which the closure device (11) releases the valve aperture (8), with the cooperation of the pressure in the pressure vessel (5), in a few milliseconds, which said device moves into the moulding chamber in this process and can be moved into the closure position by means of a pressure medium cylinder, while the working space (50) of the pressure-medium cylinder (47), the said space being delimited by a piston (45) is connected up to a high-pressure source (41), while that side of the piston (45) which is opposite to the working space (50) forms the movable termination of a pressure accumulator (51) subjected to gas and working space has a discharge (44),(48),(61),(63), so constucted that the pressure-medium is discharged at a speed of at least 10 m/s, the movement of the piston (45) and also of the closure device (11) into the open position being at the same time accelerated by the effect of the pressure in the pressure accumulator (51).
2. Apparatus in accordance with Claim 1, characterized by the fact that the working space (50) of the pressure-medium cylinder (47) has a small displacement volume, e.g. between 150 and 500 cm3.
3. Apparatus in accordance with Claim 1 or 2, characterized by the fact that the discharge (44), (48),(49) of the working space (50) is disconnected by switching elements (61), (43), from the remainder of the high-pressure circuit (41) and is connected via a pipe (44) of relatively ample cross section to a discharge tank (63).
4. Apparatus in accordance with one of Claims 1-3, characterized by the fact that the pressure of the high-pressure source (51) amounts to between 100-300 bar. 5. Apparatus in accordance with one of Claims 1-4, characterized by the fact that the accumulator, when the closure device (11) occupies a closed position, is directly or indirectly subjected to a gas pressure of between (50) and 200 bar.
6. Apparatus in accordance with one of Claims 1-5, characterized by the fact that the ratio of the pressure accumulator volume to the displacement volume of the pressure-medium cylinder (47) is at least 5 : 1.
7. Apparatus in accordance with one of Claims 1-6, characterized by a throttle (49), (58),(59),(60), taking effect towards the end of the descending movement of the piston (45).
8. Apparatus in accordance with Claim 7, characterized by the fact that the piston rod (46) connecting the piston (45) with the closure device (11) is provided, inside the pressure-medium cylinder (47), with a portion (58) widened conically in respect of the passage of the piston rod through the cylinder, while the piston rod (45) passes through the feed and discharge aperture (49) of the working space (50), which aperture combines with the conically widened portion (58) of the piston rod (46) to from the throttle.
9. Apparatus in accordance with one of Claims 1-8, characterized by the fact that the feed and discharge aperture (49) of the working space (50) leads into at least two feed and discharge channels (48).
10. Apparatus in accordance with one of Claims 1-9, characterized by the fact that the piston (45) has an attachment (55) extending into the space of the pressure accumulator (51) and provided with a stop (56) interacting with an end position limiting device (54),(57) for the descending movement of the piston (45).
11. Apparatus in accordance with one of Claims 1-10, characterized by the fact that the high-pressure source (41) is connected with both channels (48) of the pressure-medium cylinder (47) via a control slide (42), a non-return valve (43) and a closed circular pipeline (44), while the discharge tank (63) is connected to the closed circular pipeline (44) via a non-return valve (61) which can be actuated.
12. Apparatus in accordance with Claim 11, characterized by the fact that the control slide (42), in a first position, connects the pressure-medium cylinder (47) with the high-pressure source (41) and opens the control line (62) of the non-return valve (61) capable of being actuated, so that the non-return valve (61) opens in opposition to the pressure in the closed circular pipeline (44) and connects the pressure-medium cylinder (47) with the discharge tank (63).
13. Apparatus in accordance with one of Claims 1-12, characterized by the fact that the working space (50) is connected, via a non-return valve (61) capable of being actuated, to a discharge tank (63) provided with a ventilating system (65).
14. Apparatus in accordance with Claim 13, characterized by the fact that the discharge tank (63) discharges it to a tank (66) of the system.
EP84114951A 1983-12-09 1984-12-07 Apparatus for compacting foundry-moulding material using pressure gas Expired EP0152573B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19833344520 DE3344520A1 (en) 1983-12-09 1983-12-09 DEVICE FOR COMPRESSING FOUNDRY MOLD BY PRESSURE GAS
DE3344520 1983-12-09

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EP0152573A1 EP0152573A1 (en) 1985-08-28
EP0152573B1 true EP0152573B1 (en) 1988-04-27

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US (1) US4619307A (en)
EP (1) EP0152573B1 (en)
JP (1) JPS61500601A (en)
DD (1) DD229324A5 (en)
DE (2) DE3344520A1 (en)
WO (1) WO1985002568A1 (en)

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DE3836876C2 (en) * 1988-10-29 1994-06-09 Badische Maschf Gmbh Method and device for compacting foundry molding material
CH686412A5 (en) * 1992-03-10 1996-03-29 Fischer Georg Giessereianlagen A method of compacting molding sand for molds.

Citations (1)

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Publication number Priority date Publication date Assignee Title
EP0131723A1 (en) * 1983-06-18 1985-01-23 BMD Badische Maschinenfabrik Durlach GmbH Device for compacting foundry mould material by means of pressurized gas

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Publication number Priority date Publication date Assignee Title
DE1961234C3 (en) * 1969-12-05 1975-02-06 Kramatorskij Nautschno-Issledowatel' Skij I Projektno-Technologitscheskij Institut Maschinostrojenija, Kramatorsk (Sowjetunion) Method and device for compacting casting molding compounds
SU665977A1 (en) * 1976-04-08 1979-06-08 Краматорский Научно-Исследовательский И Проектно-Технологический Институт Машиностроения Casting mould making apparatus
SU793696A1 (en) * 1979-03-19 1981-01-07 Краматорский Научно-Исследовательскийи Проектно-Технологический Институтмашиностроения Pulse head
CH642288A5 (en) * 1980-02-18 1984-04-13 Fischer Ag Georg METHOD AND DEVICE FOR COMPRESSING MOLDING MATERIAL, ESPECIALLY FOR CASTING MOLDS.
WO1982003348A1 (en) * 1981-04-02 1982-10-14 Koebel Alfons Method and device for pneumatically compacting molding sand
DE3149172A1 (en) * 1981-12-11 1983-06-30 Georg Fischer AG, 8201 Schaffhausen "METHOD FOR PRODUCING MOLDED BODIES USING GAS PRESSURE"
EP0170765B1 (en) * 1981-12-28 1988-08-31 BMD Badische Maschinenfabrik Durlach GmbH Device for compacting foundry moulding material
CH657790A5 (en) * 1982-10-27 1986-09-30 Fischer Ag Georg DEVICE FOR COMPRESSING GRAINY MOLDS.

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Publication number Priority date Publication date Assignee Title
EP0131723A1 (en) * 1983-06-18 1985-01-23 BMD Badische Maschinenfabrik Durlach GmbH Device for compacting foundry mould material by means of pressurized gas

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US4619307A (en) 1986-10-28
DE3344520C2 (en) 1989-01-12
DE3470673D1 (en) 1988-06-01
WO1985002568A1 (en) 1985-06-20
EP0152573A1 (en) 1985-08-28
DD229324A5 (en) 1985-11-06
JPS61500601A (en) 1986-04-03
DE3344520A1 (en) 1985-06-20

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