EP0203322B1 - Apparatus for compacting a foundry moulding material by means of compressed gas - Google Patents

Apparatus for compacting a foundry moulding material by means of compressed gas Download PDF

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Publication number
EP0203322B1
EP0203322B1 EP86104663A EP86104663A EP0203322B1 EP 0203322 B1 EP0203322 B1 EP 0203322B1 EP 86104663 A EP86104663 A EP 86104663A EP 86104663 A EP86104663 A EP 86104663A EP 0203322 B1 EP0203322 B1 EP 0203322B1
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EP
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Prior art keywords
pressure
medium cylinder
valve
piston
pressure medium
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EP86104663A
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German (de)
French (fr)
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EP0203322A1 (en
Inventor
Norbert Damm
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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 mold space, the closure member of which is connected to a pressure medium cylinder as a drive, suddenly releases the valve opening in the pressure vessel, moves into the pre-pressure space and can be brought into the closed position by means of the pressure medium cylinder.
  • outlet pressure in the pressure vessel the higher these parameters must be, whereby outlet pressures that are in the range of the pressure of operational compressed air networks are aimed at, in order not to have to do too much construction work for the production of compressed gas on the one hand and for the control of the pressure on the other hand.
  • 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.
  • 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 invention is therefore based on a known device according to EP-A-0 062 331, in which the closure member opens into the pre-pressure space and is moved from the closed to the open position and vice versa by means of a pressure medium cylinder, so that a dead space within the molding space is avoided can be.
  • EP-A-0 062 331 in which the closure member opens into the pre-pressure space and is moved from the closed to the open position and vice versa by means of a pressure medium cylinder, so that a dead space within the molding space is avoided can be.
  • the invention has for its object to develop the device described above so that a high opening speed for the closure member is achieved with less design effort and a gas pressure that is in the range of the network pressure of conventional compressed air networks.
  • the closure member is thus closed against the at least partially relieved pressure accumulator under the effect of the pressure from the hydraulic high pressure source.
  • the pressure accumulator is set to the working pressure while the high-pressure circuit on the opposite side of the piston is shut off brought, then the high-pressure side is opened, so that the hydraulic fluid runs out of the pressure medium cylinder at a speed> 10 m / s and the piston lifts the closure member abruptly under the high-pressure gas pressure, so that it opens in a few milliseconds against the working pressure in the pressure vessel.
  • 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 the intermediate drain tank.
  • the piston speed itself can only have values in the range of approx. 5 m / sec. to reach.
  • Pressure cylinders are described in "Pneumatic controls", Vogelverlag 1973, pp. 70-75 and in “Introduction to pneumatics", published by Festo, Berkheim 1974/75, p. 89, the pistons of which are on one side by a hydraulic high pressure source and on the opposite side with gas pressure.
  • the pistons of which are on one side by a hydraulic high pressure source and on the opposite side with gas pressure.
  • these writings also give no indication of the additional drain tank according to the invention and the unusually high drainage speed of the pressure oil achieved thereby when the valve is opened.
  • the pressure medium cylinder has a small displacement volume of, for. B. 150 to 500 cm 3 .
  • the high-pressure-side outflow is decoupled from other high-pressure circuits and connected to the outflow tank via a line of relatively large cross-section, with the outflow tank expediently having a vent line.
  • the flow resistance for the expiring displacement volume is kept as low as possible
  • the decoupling from the other 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 stroke 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 20 and 50 bar, which is directly or indirectly, for. B. acts on the piston via a hydraulic cushion. 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 final pressure is between 100 and 300 bar.
  • the ratio of the pressure accumulator volume to the displacement volume of the pressure medium cylinder is at least 5: 1, preferably 10: 1 to 15: 1.
  • the pressure accumulator consists of a cylinder filled with gas and closed by a movable piston, which is connected on the gas pressure side opposite to a hydraulic high pressure source, by means of which the gas pressure accumulator is brought to the final pressure necessary for the opening movement can.
  • the device according to the invention is further characterized by a throttle which becomes effective towards the end of the stroke movement of the piston of the pressure medium cylinder and ensures that the piston and thus the closure member are braked over a short distance.
  • the high pressure source is connected to the pressure medium cylinder via a control slide, a check valve and a ring line, and that the ring line is connected to the discharge tank via a controllable check valve.
  • the ring line has the largest possible cross section in order to allow the pressure medium to drain off quickly.
  • control slide in a first position Connects the pressure medium cylinder to the high pressure source and opens the control line of the controllable check valve so that it closes and in a second position connects the control line to the high pressure source, so that the check valve opens against the pressure in the branch line and connects the pressure medium cylinder to the drain tank.
  • the pressure accumulator is connected to the hydraulic high-pressure source via a control slide and that the control slide connects the pressure accumulator to the hydraulic source in a first position, so that the gas in the pressure accumulator and on the stroke side in the pressure medium cylinder with a simultaneously present high pressure the opposite side of the piston of the pressure medium cylinder is compressed to final pressure and connects in a second position to a drain tank.
  • 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 top of the bottom 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 to just below the bottom 7. Before the compression, these two assemblies are brought together and pressed tightly together at their interface.
  • valve plate 11 is seated on a guide rod 14, which at the same time forms the piston rod of a piston 15 of a pressure medium cylinder 16. This and the controller are described below with reference to FIG. 2:
  • the pressure medium cylinder 16 is arranged in a hydraulic circuit, the pressure source being designated by 17. This is, for example, a hydraulic pump that is fed from a tank 18.
  • the pressure medium passes from the pressure source 17 via a control slide 19 and a check valve 20 into the feed line 21, which opens into the working chamber 22 of the pressure medium cylinder 16 and also leads to a controllable check valve 23.
  • the pressure medium cylinder 16 has a gas pressure chamber 24 below the piston 15, which is connected to a gas pressure accumulator 25.
  • This gas pressure accumulator 25 is divided into a gas pressure chamber 27 and a hydraulic pressure chamber 28 by a movable piston 26.
  • the hydraulic pressure chamber 28 is connected via a control slide 29 to a high-pressure source 30, which is fed from the supply tank 18.
  • the piston 15 of the pressure medium cylinder 16 is extended on the hydraulic side with a piston rod 31 which extends through the working chamber 22.
  • This upper piston rod 31 carries a cylindrical shoulder 32 and a conically tapered shoulder 33 directly on the shoulder of the piston 15, which forms a throttle with the cylindrical constriction 34 during the upward stroke movement of the piston 15.
  • the hydraulic line 21 is connected to a branch line 35 which leads to the controllable check valve 23, the control line 36 of which can be connected to the pressure source 17 via the control slide 19.
  • the pressure medium chamber is connected via lines 21 and 35 to an outlet tank 37 and a vent line 38, which is depressurized.
  • the drain line 39 of the drain tank 37 opens into the hydraulic tank 18th
  • the gas pressure chamber 24 of the pressure medium cylinder 16 with an open connection to the gas pressure accumulator 25 receives a low pressure pre-filling of z. B. 30 to 40 bar.
  • the volume ratio of the gas pressure spaces 24 and 27 is approximately 1:10 to 1:15.
  • the gas pressure prefilling in 24 and 27 is slightly compressed.
  • the model plate 1 with the filled molding box 3 and filling frame 4 is clamped to the frame 9.
  • the gas pressure vessel 5 is filled to operating pressure via the pressure connection 6.
  • the valve 10 is in the closed position. After the shaping device 1, 3, 4 has been clamped to the frame 9, the control slide 29 is brought into the switching position "B". The hydraulic chamber 28 of the gas pressure accumulator 25 is thereby switched to the high pressure source 30. The gas pressure chambers 27 and 24 are compressed to an operating pressure of approx. 200 + 250 bar. At this time, the valve plate 11 is in a highly preloaded state, but is still blocked on the side of the pressure chamber 40.
  • valve plate 11 In order to suddenly release the pressure vessel 5 and to compress the molding material present in the molding box and filling frame, the valve plate 11 must be brought into the open position (left half of FIG. 1). For this purpose, the control slide 19 is switched to the "A" position. There is then the pressure of the pressure source 17 in the control line 36, so that the check valve 23 opens. The pressure medium runs out of the working space 22 under the action of the pressure accumulator 24 via the check valve 23 into the drain tank 37 via the relatively large discharge cross sections of the lines 21, 35. Towards the end of the lowering movement of the piston 15, the discharge cross section between the piston rod 31 and the constriction 34 is reduced by the conical extension 33 on the piston rod 31, so that the piston and thus the valve plate 11 are braked.
  • the pressure medium to be displaced runs out of the working space 22 at a speed of more than 10 m / s, preferably between 20 and 30 m / s.
  • the drain tank 37 can be vented via the line 38 between the work cycles, so that its contents can flow into the system tank 18.
  • valve plate 11 After compression of the molding material, the valve plate 11 is first brought into the closed position as above. The pressure chamber 40 created below the fixed base plate 7 is vented via the valve 10. After the separation of model and compact form, a new work cycle begins.

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 mit einem Druckmittelzylinder als Antrieb verbunden ist, die Ventilöffnung im Druckbehälter schlagartig freigibt, sich dabei in den Vordruckraum bewegt und mittels des 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 mold space, the closure member of which is connected to a pressure medium cylinder as a drive, suddenly releases the valve opening in the pressure vessel, moves into the pre-pressure space and can be brought into the closed position by means of the pressure medium cylinder.

In der älteren Patentanmeldung (DE: P 32 43 951.2, US: 453,093, JP: 57-227 830, EP: 8211 0996.4) 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 Aufwand betreiben 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 older patent application (DE: P 32 43 951.2, US: 453,093, JP: 57-227 830, EP: 8211 0996.4) a method and an apparatus for compacting foundry molding material, in particular molding sand, by means of compressed gas, e.g. 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 model top and the model plate compresses, 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. The lower the outlet pressure in the pressure vessel, the higher these parameters must be, whereby outlet pressures that are in the range of the pressure of operational compressed air networks are aimed at, in order not to have to do too much construction work for the production of compressed gas on the one hand and for the control of the pressure on the other hand. 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 der weiteren älteren Patentanmeldung (DE: P 33 21 622.3, US: 617,920, JP: 59-122 180, EP: 8410 6795.2) 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 Druckmittelzyl inder, 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 other older patent application (DE: P 33 21 622.3, US: 617,920, JP: 59-122 180, EP: 8410 6795.2), 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 its opening movement is directed into the mold space. As a closing drive for the closure member, a pressure medium cylinder is used, the piston of which is connected to a guide rod of 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.

Alle vorgenannten Ausführungsformen haben den Nachteil, daß das großflächige Verschlußorgan in den Formraum öffnet, so daß entsprechend dem Hubweg und der in Hubrichtung vorhandenen geometrischen Abmessung des Verschlußorgans ein Freiraum oberhalb der Formstoffoberfläche vorgesehen werden muß, der als Totraum während des Verdichtungsvorgangs erst mit dem Verdichtungsgas aufgefüllt werden muß. Dadurch wird der Druckgradient (zeitlicher Anstieg des Drucks im Formraum), der für das Verdichtungsergebnis maßgeblich ist, reduziert und es müssen unnötige Gasmassen beschleunigt werden. Auch ist der Druckgasverbrauch entsprechend hoch.All of the above-mentioned embodiments have the disadvantage that the large-area closure member opens into the mold space, so that, according to the stroke and the geometrical dimension of the closure member present in the stroke direction, a free space above the surface of the molding material must be provided, which space is only filled up with the compression gas during the compression process must become. As a result, the pressure gradient (temporal increase in the pressure in the mold space), which is decisive for the compression result, is reduced and unnecessary gas masses have to be accelerated. The compressed gas consumption is also correspondingly high.

Die Erfindung geht deshalb von einer bekannten Vorrichtung gemäß EP-A-0 062 331 aus, bei der das Verschlußorgan in den Vordruckraum öffnet und mittels eines Druckmittelzylinders aus der Schließ- in die Öffnungsstellung und umgekehrt bewegt wird, so daß ein Totraum innerhalb des Formraums vermieden werden kann. Bei den bekannten Vorrichtungen dieses Aufbaus ist es allerdings nicht möglich, die Öffnungsbewegung des Verschlußorgans gegen den Gasdruck schnell genug, d. h. in wenigen Millisekunden, durchzuführen, weshalb bei diesen Vorrichtungen Drucke im Vordruckraum von 20 bar und mehr vorgeschlagen werden, die wiederum wie eingangs erwähnt, zu einem unvertretbar hohen konstruktiven Aufwand führen.The invention is therefore based on a known device according to EP-A-0 062 331, in which the closure member opens into the pre-pressure space and is moved from the closed to the open position and vice versa by means of a pressure medium cylinder, so that a dead space within the molding space is avoided can be. In the known devices of this structure, however, it is not possible to fast enough the opening movement of the closure member against the gas pressure, i. H. in a few milliseconds, which is why, in the case of these devices, pressures in the pre-pressure space of 20 bar and more are proposed, which in turn, as mentioned at the beginning, lead to an unacceptably high level of design effort.

Der Erfindung liegt die Aufgabe zugrunde, die eingangs beschriebene Vorrichtung so weiterzubilden, daß bei geringerem konstruktiven Aufwand und einem Gasdruck, der im Bereich des Netzdrucks üblicher Druckluftnetze liegt, eine hohe Öffnungsgeschwindigkeit für das Verschlußorgan erreicht wird.The invention has for its object to develop the device described above so that a high opening speed for the closure member is achieved with less design effort and a gas pressure that is in the range of the network pressure of conventional compressed air networks.

Diese Aufgabe wird erfindungsgemäß durch die Merkmale des Patentanspruches 1 gelöst. Das Schließen des Verschlußorgans erfolgt also entgegen dem zumindest teilentlasteten Druckspeicher unter Wirkung des Druckes aus der hydraulischen Hochdruckquelle. Zum Öffenen des Verschlußorganes wird der Druckspeicher hingegen auf den Arbeitsdruck bei gleichzeitig abgesperrtem Hochdruckkreislauf auf der gegenüberliegenden Seite des Kolbens gebracht, dann wird die Hochdruckseite geöffnet, sodaß die Hydraulikflüssigkeit mit einer Geschwindigkeit > 10 m/s aus dem Druckmittelzylinder abläuft und der Kolben das Verschlußorgan unter dem hochgespannten Gasdruck schlagartig abhebt, so daß dieses in wenigen Millisekunden entgegen dem Arbeitsdruck im Druckbehälter öffnet.This object is achieved by the features of claim 1. The closure member is thus closed against the at least partially relieved pressure accumulator under the effect of the pressure from the hydraulic high pressure source. To open the closure member, however, the pressure accumulator is set to the working pressure while the high-pressure circuit on the opposite side of the piston is shut off brought, then the high-pressure side is opened, so that the hydraulic fluid runs out of the pressure medium cylinder at a speed> 10 m / s and the piston lifts the closure member abruptly under the high-pressure gas pressure, so that it opens in a few milliseconds against the working pressure in the pressure vessel.

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 300 bar/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 auch zum Schließen des Verschlußorgans dient, bewirkt 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 den zwischengeschalteten Ablauftank 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 surface of the molding material must take place with a pressure gradient of approx. 200 to 300 bar / s in order to obtain 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 effected by the pressure medium cylinder, which also serves to close the closure member, this presupposes high outflow speeds for the pressure medium volume displaced by the piston during the opening movement at a predetermined pressure in the pressure accumulator. 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 the intermediate drain tank. The piston speed itself can only have values in the range of approx. 5 m / sec. to reach.

Zwar sind in "Pneumatische Steuerungen", Vogelverlag 1973, S. 70-75 und in "Einführung in die Pneumatik", herausgegeben von der Firma Festo, Berkheim 1974/75, S. 89 Druckmittelzylinder beschrieben, deren Kolben auf der einen Seite von einer hydraulischen Hochdruckquelle und auf der gegenüberliegenden Seite mit Gasdruck beaufschlagt werden. Ein Bezug zu Gießereimaschinen findet sich dort jedoch nicht, ebensowenig die Zuordnung des Drucköles für die Schließbewegung, der Druckluft für die Öffnungsbewegung. Schließlich geben diese Schriften auch keine Hinweise auf den erfindungsgemäßen, zusätzlichen Ablauftank und die dadurch erzielte, ungewöhnlich hohe Abflußgeschwindigkeit des Drucköls bei der Ventilöffnung.Pressure cylinders are described in "Pneumatic controls", Vogelverlag 1973, pp. 70-75 and in "Introduction to pneumatics", published by Festo, Berkheim 1974/75, p. 89, the pistons of which are on one side by a hydraulic high pressure source and on the opposite side with gas pressure. However, there is no reference to foundry machines, nor is the assignment of the pressure oil for the closing movement or the compressed air for the opening movement. Finally, these writings also give no indication of the additional drain tank according to the invention and the unusually high drainage speed of the pressure oil achieved thereby when the valve is opened.

Gemäß einem Ausführungsbeispiel weist der Druckmittelzylinder hochdruckseitig ein kleines Verdrängungsvolumen von, z. B. 150 bis 500 cm3 auf. Je geringer das Verdrängungsvolumen ist, umso kürzer kann die Abflußzeit bzw. Hubzeit bei gegebenen Querschnitten sein.According to one embodiment, the pressure medium cylinder has a small displacement volume of, for. 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 hochdruckseitige Abfluß von sonstigen Hochdruck-Kreislauf abgekoppelt und über eine Leitung relativ großen Querschnittes an den Ablauftank angeschlossen, wobei zweckmäßig der Ablauftank eine Entlüftungsleitung aufweist.According to a further exemplary embodiment, the high-pressure-side outflow is decoupled from other high-pressure circuits and connected to the outflow tank via a line of relatively large cross-section, with the outflow tank expediently having a vent line.

Mit diesem Ausführungsbeispiel wird einerseits der Strömungswiderstand für das ablaufende Verdrängungsvolumen so gering als möglich gehalten, andererseits wird durch die Abkopplung vom sonstigen 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 volume is kept as low as possible, on the other hand the decoupling from the other 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 Hubseite des Kolbens wirkt, steht in der Schließlage des Verschlußorgans, also in der angehobenen Endlage des Kolbens unter einem Gasdruck zwischen 20 und 50 bar, der unmittelbar oder mittelbar, z. B. über 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. Der Enddruck liegt wiederum zwischen 100 und 300 bar.The pressure accumulator, the pressure of which acts on the stroke 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 20 and 50 bar, which is directly or indirectly, for. B. acts on the piston via a hydraulic cushion. 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 final pressure is between 100 and 300 bar.

Es hat sich ferner als vorteilhaft erwiesen, wenn das Verhältnis von Druckspeichervolumen und Verdrängungsvolumen des Druckmittelzylinders mindestens 5 : 1, vorzugsweise 10 : 1 bis 15 : 1 beträgt.It has also proven to be advantageous if the ratio of the pressure accumulator volume to the displacement volume of the pressure medium cylinder is at least 5: 1, preferably 10: 1 to 15: 1.

Gemäß einem weiteren Ausführungsbeispiel ist vorgesehen, daß der Druckspeicher von einem mit Gas gefüllten und durch einen beweglichen Kolben abgeschlossenen Zylinder besteht, der an der Gasdruckseite gegenüberliegenden Seite an eine hydraulische Hochdruckquelle angeschlossen ist, mittels der der Gasdruckspeicher auf den für die Öffnungsbewegung notwendigen Enddruck gebracht werden kann.According to a further embodiment, it is provided that the pressure accumulator consists of a cylinder filled with gas and closed by a movable piston, which is connected on the gas pressure side opposite to a hydraulic high pressure source, by means of which the gas pressure accumulator is brought to the final pressure necessary for the opening movement can.

Die erfindungsgemäße Vorrichtung zeichnet sich weiterhin aus durch eine gegen Ende der Hubbewegung des Kolbens des Druckmittelzylinders 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 stroke movement of the piston of the pressure medium cylinder and ensures that the piston and thus the closure member are braked over a short distance.

In bevorzugter Ausführung ist weiterhin vorgesehen, daß die Hochdruckquelle über einen Steuerschieber, ein Rückschlagventil und eine Ringleitung mit dem Druckmittelzylinder verbunden ist, und daß die Ringleitung über ein aufsteuerbares Rückschlagventil an den Ablauftank angeschlossen ist. Dabei weist, wie bereits beschrieben, die Ringleitung 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 pressure medium cylinder via a control slide, a check valve and a ring line, and that the ring line is connected to the discharge tank via a controllable check valve. As already described, the ring line has 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, it is provided according to a further embodiment that the control slide in a first position Connects the pressure medium cylinder to the high pressure source and opens the control line of the controllable check valve so that it closes and in a second position connects the control line to the high pressure source, so that the check valve opens against the pressure in the branch line and connects the pressure medium cylinder to the drain tank.

Ferner kann gemäß einer Ausführungsform vorgesehen sein, daß der Druckspeicher über einen Steuerschieber an die hydraulische Hochdruckquelle angeschlossen ist und daß der Steuerschieber in einer ersten Stellung den Druckspeicher mit der Hydraulikquelle verbindet, so daß das Gas im Druckspeicher und hubseitig im Druckmittelzylinder bei gleichzeitig anstehendem Hochdruck auf der gegenüberliegenden Seite des Kolbens des Druckmittelzylinders auf Enddruck komprimiert wird, und in einer zweiten Stellung mit einem Ablauftank verbindet.Furthermore, it can be provided according to one embodiment that the pressure accumulator is connected to the hydraulic high-pressure source via a control slide and that the control slide connects the pressure accumulator to the hydraulic source in a first position, so that the gas in the pressure accumulator and on the stroke side in the pressure medium cylinder with a simultaneously present high pressure the opposite side of the piston of the pressure medium cylinder is compressed to final pressure and connects in a second position to a drain tank.

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

In der Zeichnung zeigen:

  • Figur 1 einen Schnitt durch eine Ausführungsform der Vorrichtung und
  • Figur 2 eine Ausführungsform der Steuerung des Druckmittelzylinders.
The drawing shows:
  • 1 shows a section through an embodiment of the device and
  • 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 finished mold from the molding box are not shown. The facilities for bringing up the model and for filling 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 Oberseite 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 bis unmittelbar unterhalb des Bodens 7 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 top of the bottom 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 to just below the bottom 7. 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 Öffnungen 12 besitzt. Ferner sitzt auf der Unterseite der Ventilplatte innerhalb des Bereichs der Öffnungen 12 ein Dichtungsbelag 13. Die Öffnungen 8 im Boden 7 und die Öffnungen 12 in der Ventilplatte 11 sind 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 underside of the valve plate within the area of the openings 12 there is a sealing coating 13. The openings 8 in the base 7 and the openings 12 in the valve plate 11 are offset from one another in such a way that they do not overlap in the closed position.

Die Ventilplatte 11 sitzt an einer Führungsstange 14, die zugleich die Kolbenstange eines Kolbens 15 eines Druckmittelzylinders 16 bildet. Dieser und die Steuerung sind nachfolgend anhand der Figur 2 beschrieben:The valve plate 11 is seated on a guide rod 14, which at the same time forms the piston rod of a piston 15 of a pressure medium cylinder 16. This and the controller are described below with reference to FIG. 2:

Der Druckmittelzylinder 16 ist in einem Hydraulik-Kreislauf angeordnet, wobei die Druckquelle mit 17 bezeichnet ist. Hierbei handelt es sich beispielsweise um eine Hydraulikpumpe, die aus einem Tank 18 gespeist wird. Von der Druckquelle 17 gelangt das Druckmittel über einen Steuerschieber 19 und ein Rückschlagventil 20 in die Zuleitung 21, die sowohl in den Arbeitsraum 22 des Druckmittelzylinders 16 mündet, als auch zu einem steuerbaren Rückschlagventil 23 führt.The pressure medium cylinder 16 is arranged in a hydraulic circuit, the pressure source being designated by 17. This is, for example, a hydraulic pump that is fed from a tank 18. The pressure medium passes from the pressure source 17 via a control slide 19 and a check valve 20 into the feed line 21, which opens into the working chamber 22 of the pressure medium cylinder 16 and also leads to a controllable check valve 23.

Der Druckmittelzylinder 16 weist unterhalb des Kolbens 15 einen Gasdruckraum 24 auf, der an einen Gasdruckspeicher 25 angeschlossen ist. Dieser Gasdruckspeicher 25 ist durch einen beweglichen Kolben 26 in einen Gasdruckraum 27, sowie in einen Hydraulikdruckraum 28 unterteilt. Der Hydraulikdruckraum 28 ist über einen Steuerschieber 29 mit einer Hochdruckquelle 30 verbunden, die aus dem Versorgungstank 18 gespeist wird.The pressure medium cylinder 16 has a gas pressure chamber 24 below the piston 15, which is connected to a gas pressure accumulator 25. This gas pressure accumulator 25 is divided into a gas pressure chamber 27 and a hydraulic pressure chamber 28 by a movable piston 26. The hydraulic pressure chamber 28 is connected via a control slide 29 to a high-pressure source 30, which is fed from the supply tank 18.

Der Kolben 15 des Druckmittelzylinders 16 ist auf der Hydraulikseite mit einer den Arbeitsraum 22 durchgreifenden Kolbenstange 31 verlängert. Diese obere Kolbenstange 31 trägt unmittelbar am Ansatz des Kolbens 15 einen zylindrischen Ansatz 32 und einen konisch verjüngten Ansatz 33, der bei der Aufwärtshubbewegung des Kolbens 15 mit der zylindrischen Verengung 34 eine Drossel bildet.The piston 15 of the pressure medium cylinder 16 is extended on the hydraulic side with a piston rod 31 which extends through the working chamber 22. This upper piston rod 31 carries a cylindrical shoulder 32 and a conically tapered shoulder 33 directly on the shoulder of the piston 15, which forms a throttle with the cylindrical constriction 34 during the upward stroke movement of the piston 15.

Die hydraulische Leitung 21 ist mit einer Zweigleitung 35 verbunden, die zu dem steuerbaren Rückschlagventil 23 führt, dessen Steuerleitung 36 über den Steuerschieber 19 mit der Druckquelle 17 verbindbar ist. Der Druckmittelraum ist in entsperrtem Schaltzustand des Rückschlagventils 23 über die Leitungen 21 und 35 mit einem Ablauftank 37 und einer Entlüftungsleitung-38 druckentlastet verbunden. Die Abflußleitung 39 des Ablauftanks 37 mündet in den Hydrauliktank 18.The hydraulic line 21 is connected to a branch line 35 which leads to the controllable check valve 23, the control line 36 of which can be connected to the pressure source 17 via the control slide 19. In the unlocked switching state of the check valve 23, the pressure medium chamber is connected via lines 21 and 35 to an outlet tank 37 and a vent line 38, which is depressurized. The drain line 39 of the drain tank 37 opens into the hydraulic tank 18th

Nachfolgend ist die Funktion beschrieben:The function is described below:

Um die Ventilplatte 11 aus der in Figur 1 links wiedergegebenen, geöffneten Stellung in die Schließlage (rechte Hälfte Figur 1) zu bringen, wird der Steuerschieber 19 in die Schaltposition "B" gebracht. In dieser Schaltstellung ist die Verbindung zwischen der Druckquelle 17 und dem Arbeitsraum 22 des Druckmittelzylinders 16 unter Öffnung des Rückschlagventils 20 hergestellt. Zugleich ist die Steuerleitung 36 des aufsteuerbaren Rückschlagventils 23 drucklos geschaltet, so daß das Rückschlagventil 23 schließt. Das Druckmittel füllt somit den Arbeitsraum 22 und die Ventilplatte 11 bis diese die Schließlage (recht Hälfte Figur 1) unter Vorspannung der Dichtung 13 erreicht. Zu diesem Zeitpunkt befindet sich der Steuerschieber 29 in Schaltposition "A". Der Gasdruckraum 24 des Druckmittelzylinders 16 mit offener Verbindung zum Gasdruckspeicher 25 erhält eine Niederdruck-Vorfüllung von z. B. 30 bis 40 bar. Das Volumenverhältnis der Gasdruckräume 24 und 27 beträgt etwa 1 : 10 bis 1 : 15. Mit der Schließhubbewegung der Ventilplatte 11 wird die Gasdruckvorfüllung in 24 und 27 geringfügig komprimierte. Nach der Schließhubbewegung des Ventiltellers 11 wird die Modellplatte 1 mit dem gefüllten Formkasten 3 und Füllrahmen 4 mit dem Rahmen 9 verspannt. Der Gasdruckbehälter 5 wird über den Druckanschluß 6 auf Betriebsdruck gefüllt.To the valve plate 11 from the left in Figure 1 bring reproduced, open position in the closed position (right half Figure 1), the control slide 19 is brought into the switching position "B". In this switching position, the connection between the pressure source 17 and the working space 22 of the pressure medium cylinder 16 is established by opening the check valve 20. At the same time, the control line 36 of the controllable check valve 23 is depressurized, so that the check valve 23 closes. The pressure medium thus fills the working chamber 22 and the valve plate 11 until it reaches the closed position (right half of FIG. 1) with the seal 13 pretensioned. At this time, the control slide 29 is in switching position "A". The gas pressure chamber 24 of the pressure medium cylinder 16 with an open connection to the gas pressure accumulator 25 receives a low pressure pre-filling of z. B. 30 to 40 bar. The volume ratio of the gas pressure spaces 24 and 27 is approximately 1:10 to 1:15. With the closing stroke movement of the valve plate 11, the gas pressure prefilling in 24 and 27 is slightly compressed. After the closing stroke movement of the valve plate 11, the model plate 1 with the filled molding box 3 and filling frame 4 is clamped to the frame 9. The gas pressure vessel 5 is filled to operating pressure via the pressure connection 6.

Das Ventil 10 befindet sich in Schließlage. Nach dem Verspannen der Formeinrichtung 1, 3, 4 mit dem Rahmen 9 wird der Steuerschieber 29 in Schaltposition "B" gebracht. Der Hydraulikraum 28 des Gasdruckspeichers 25 wird dadurch an die Hochdruckquelle 30 geschaltet. Die Gasdruckräume 27 und 24 werden auf einen Betriebsdruck von ca. 200 + 250 bar komprimiert. Zu diesem Zeitpunkt befindet sich die Ventilplatte 11 in hoch vorgespanntem, jedoch auf der Seite des Druckraums 40 noch blockiertem Zustand.The valve 10 is in the closed position. After the shaping device 1, 3, 4 has been clamped to the frame 9, the control slide 29 is brought into the switching position "B". The hydraulic chamber 28 of the gas pressure accumulator 25 is thereby switched to the high pressure source 30. The gas pressure chambers 27 and 24 are compressed to an operating pressure of approx. 200 + 250 bar. At this time, the valve plate 11 is in a highly preloaded state, but is still blocked on the side of the pressure chamber 40.

Zum schlagartigen Entspannen des Druckbehälters 5 und zum Verdichten des im Formkasten und Füllrahmen vorhandenen Formstoffs muß die Ventilplatte 11 in die Öffnungslage (linke Hälfte der Figur 1) gebracht werden. Hierzu wird der Steuerschieber 19 in die Stellung "A" umgeschaltet. Es steht dann der Druck der Druckquelle 17 in der Steuerleitung 36 an, so daß das Rückschlagventil 23 öffnet. Über die relativ großen Ablaufquerschnitte der Leitungen 21, 35 läuft das Druckmittel aus dem Arbeitsraum 22 unter Wirkung des Druckspeichers 24 über das Rückschlagventil 23 in den Ablauftank 37 ab. Gegen Ende der Absenkbewegung des Kolbens 15 wird der Ablaufquerschnitt zwischen der Kolbenstange 31 und der Verengung 34 durch den konischen Ansatz 33 an der Kolbenstange 31 reduziert, so daß der Kolben und damit die Ventilplatte 11 abgebremst werden. Während der Öffnungsbewegung läuft das zu verdrängende Druckmedium aus dem Arbeitsraum 22 mit einer Geschwindigkeit von mehr als 10 m/s, vorzugsweise zwischen 20 und 30 m/s ab. Der Ablauftank 37 kann zwischen den Arbeitstakten über die Leitung 38 entlüftet werden, so daß sein Inhalt in den Systemtank 18 abfließen kann.In order to suddenly release the pressure vessel 5 and to compress the molding material present in the molding box and filling frame, the valve plate 11 must be brought into the open position (left half of FIG. 1). For this purpose, the control slide 19 is switched to the "A" position. There is then the pressure of the pressure source 17 in the control line 36, so that the check valve 23 opens. The pressure medium runs out of the working space 22 under the action of the pressure accumulator 24 via the check valve 23 into the drain tank 37 via the relatively large discharge cross sections of the lines 21, 35. Towards the end of the lowering movement of the piston 15, the discharge cross section between the piston rod 31 and the constriction 34 is reduced by the conical extension 33 on the piston rod 31, so that the piston and thus the valve plate 11 are braked. During the opening movement, the pressure medium to be displaced runs out of the working space 22 at a speed of more than 10 m / s, preferably between 20 and 30 m / s. The drain tank 37 can be vented via the line 38 between the work cycles, so that its contents can flow into the system tank 18.

Nach erfolgter Formstoffverdichtung wird zunächst die Ventilplatte 11 wie vorstehend in Schließlage gebracht. Der unterhalb der feststehenden Bodenplatte 7 entstandene Druckraum 40 wird über das Ventil 10 entlüftet. Nach der Trennung von Modell und verdichteter Form beginnt ein neuer Arbeitszyklus.After compression of the molding material, the valve plate 11 is first brought into the closed position as above. The pressure chamber 40 created below the fixed base plate 7 is vented via the valve 10. After the separation of model and compact form, a new work cycle begins.

Claims (13)

1. Apparatus for compacting a foundry moulding material by means of compressed gas, comprising a pressure vessel forming a precompression chamber for the compressed gas, a moulding space arranged thereunder consisting of a moulding box and, sealing the moulding box at the bottom, a sand frame and a pattern plate with a pattern onto which the moulding material is loosely piled before compression, and a valve of large surface area arranged between the pressure vessel and the molding space, the valve having an obturating element of the valve which is connected with the pressure medium cylinder as a drive means, which frees the valve opening in the pressure vessel in a sudden manner while moving within the precompression chamber and which may be brought into a closure position by means of the pressure medium cylinder,
characterised in that
on the stroke side the piston (15) of the pressure medium cylinder (16) forms the movable seal of a gas-loaded pressure storage device (24, 25) and its opposite side is connected with a hydraulic high pressure source (17), and in that the high pressure side discharge (21) is connected via an additional discharge tank (37) to a tank (18) for hydraulic material in such a manner that the hydraulic pressure medium is discharged at a rate of > 10 m/s with a simultaneous acceleration of the piston (15) under the pressure in the pressure storage device (24, 25) and of the obturating element (11) in the elevated opening position.
2. Apparatus according to claim 1, characterised in that the pressure medium cylinder (16) has a small displacement volume, e.g. between 150 and 500 cm3, on the high pressure side.
3. Apparatus according to claim 1 or 2, characterised in that the high pressure side discharge (21) is blocked off from the remainder of the high pressure circuit by means of switching elements (20, 23) and is connected via a duct (21, 35) of large cross-section to the discharge tank (37).
4. Apparatus according to one of claims 1 to 3, characterised in that the discharge tank (37) has a vent duct (38).
5. Apparatus accordng to one of claims 1 to 4, characterised in that the pressure of the high pressure source (17) is between 100 and 300 bar.
6. Apparatus according to one of claims 1 to 5, characterised in that the pressure storage device (24, 25) is under a precompression of between 20 and 50 bar in the closed position of the obturating device (11).
7. Apparatus according to one of claims 1 to 6, characterised in that the ratio of volume of the pressure storage device to the volume of the displacement of the pressure medium cylinder (16) is at least 5 : 1, preferably 10 : 1 to 15 : 1.
8. Apparatus according to one of claims 1 to 7, characterised in that the pressure storage device (27) consists of a gas-filled cylinder (25) sealed by a movable piston (26), the cylinder being connected on the side opposite to the gas pressure side to the hydraulic high-pressure source (30).
9. Apparatus according to one of claims 1 to 8, characterised by a throttle (33, 34) which becomes effective towards the end of the stroke movement of the piston (15) of the pressure medium cylinder (16).
10. Apparatus according to claim 9, characterised in that the piston (15) has a piston rod (31) extending into the high pressure side cylinder chamber (22), the rod having in its turn a conical thickened portion (33) co-operating with a narrowed portion (34) in this cylinder chamber.
11. Apparatus according to one of claims 1 to 10, characterised in that the high pressure source (17) is connected via a control slide valve (19), a non-return valve (20) and a loop duct (21) to the pressure medium cylinder (16), and that the loop duct (21) is connected via a progressively controllable non-return relief valve (23) to the discharge tank (37).
12. Apparatus according to claim 11, characterised in that in a first position the control slide valve (19) connects the pressure medium cylinder (16) with the high pressure source (17) and relieves the control duct (36) of the progressively controllable non-return valve (23) of pressure so that the latter closes, and in a second position connects the control duct (36) with a high pressure source (17) so that the non-return valve (23) opens against the pressure in the loop duct (21) and connects the pressure medium cylinder (16) with the discharge tank (37).
13. Apparatus according to one of claims 1 to 12, characterised in that the pressure storage device (27) is connected to the hydraulic pressure source (30) via a control slide valve (29), and that in a first position the control slide valve (29) connects the pressure storage device (27) with the high pressure source (30) so that the gas in the pressure storage device and on the stroke side in the pressure medium cylinder (16) is compressed to its final pressure by the simultaneously arising high pressure on the opposite side of the piston (5) of the pressure medium cylinder (16), and in a second position the storage device is connected with the discharge.
EP86104663A 1985-05-25 1986-04-05 Apparatus for compacting a foundry moulding material by means of compressed gas Expired EP0203322B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
DE19853518980 DE3518980A1 (en) 1985-05-25 1985-05-25 DEVICE FOR COMPRESSING FOUNDRY MOLD BY PRESSURE GAS
DE3518980 1985-05-25

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EP0203322A1 EP0203322A1 (en) 1986-12-03
EP0203322B1 true EP0203322B1 (en) 1988-11-23

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EP (1) EP0203322B1 (en)
JP (1) JP2553044B2 (en)
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Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3836876C2 (en) * 1988-10-29 1994-06-09 Badische Maschf Gmbh Method and device for compacting foundry molding material
ES2012702A6 (en) * 1989-04-06 1990-04-01 Erana Agustin Arana Improvements in air impact sand-box moulding machines.
CH686412A5 (en) * 1992-03-10 1996-03-29 Fischer Georg Giessereianlagen A method of compacting molding sand for molds.

Family Cites Families (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SU425719A1 (en) * 1972-07-17 1974-04-30 институт машиностроени
SU521993A1 (en) * 1974-04-02 1976-07-25 Краматорский Научно-Исследовательский И Проектно-Технологический Институт Машиностроения Pulse head
DE2727297C3 (en) * 1976-06-25 1980-07-10 Georg Fischer Ag, Schaffhausen (Schweiz) Method and device for producing foundry sand molds
SU793696A1 (en) * 1979-03-19 1981-01-07 Краматорский Научно-Исследовательскийи Проектно-Технологический Институтмашиностроения Pulse head
EP0062331A1 (en) * 1981-04-02 1982-10-13 BMD Badische Maschinenfabrik Durlach GmbH Method and apparatus for pneumatically compacting moulding sand
EP0084627B1 (en) * 1981-12-28 1986-05-07 BMD Badische Maschinenfabrik Durlach GmbH Device for compacting foundry moulding material
DE3243951A1 (en) * 1981-12-28 1983-07-07 BMD Badische Maschinenfabrik Durlach GmbH, 7500 Karlsruhe Process and apparatus for the compression of foundry mould material
CH657790A5 (en) * 1982-10-27 1986-09-30 Fischer Ag Georg DEVICE FOR COMPRESSING GRAINY MOLDS.
DE3321622A1 (en) * 1983-06-15 1984-12-20 BMD Badische Maschinenfabrik Durlach GmbH, 7500 Karlsruhe DEVICE FOR COMPRESSING FOUNDRY MOLD
DE3321955A1 (en) * 1983-06-18 1984-12-20 BMD Badische Maschinenfabrik Durlach GmbH, 7500 Karlsruhe DEVICE FOR COMPRESSING FOUNDRY MOLD BY PRESSURE GAS

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JP2553044B2 (en) 1996-11-13
DE3661242D1 (en) 1988-12-29
US4846253A (en) 1989-07-11
DD247161A5 (en) 1987-07-01
JPS61269959A (en) 1986-11-29
DE3518980A1 (en) 1986-11-27
EP0203322A1 (en) 1986-12-03
DK241886D0 (en) 1986-05-23
DK241886A (en) 1986-11-26
DE3518980C2 (en) 1993-01-21

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