EP0600887B1 - Device and method for filling core-shooting heads with mould-core material - Google Patents

Abstract

Described is a device for filling a core-shooting head (1) with mould-core material (2), the device having a storage hopper (3) for the mould-core material (2), an outlet pipe (4) designed to allow mould-core material (2) out of the hopper (3) into the shooting head (1) and a closing device (5) designed to close the outlet pipe (4). In order to be able to meter the mould-core material uniformly into the shooting head (1), the filling device is designed such that the outlet pipe (4) is mounted on the machine casing (6) or a similar part of the machine so that it can move vertically to dip into the shooting head (1) and can be fixed at any height along its vertical travel.

Description

The invention relates to a device for filling shot heads with molding materials, with a storage container for the molding material, an outlet member for discharging the molding material into the shooting head and a closure device for closing the outlet member. Furthermore, the invention relates to a corresponding method for using the device in question.

Core shooters have been known in foundry technology for many years. For the casting of molded pieces, the foundry cores or molds are usually manufactured in separate parts, brought together and connected to one another to form a casting mold. An essential part of the core shooters are the so-called shot heads with the shot plates carrying the shot nozzles. Molding material, in particular core sand, i.e. Quartz sand already mixed or coated with binder has so far been filled into the shot heads in question and from there it is blown or shot into the respective molds with very high air pressure through the nozzles arranged in the shot plate.

In practice, the shot heads are almost completely filled with core sand, the filling of the shot heads having been carried out in the respective forms regardless of the required core sand volume. Due to the always strong filling of the shooting heads, the pressure required for shooting is extremely high. This pressure is usually between four and six bar. This high pressure is necessary in particular because a considerable amount of core sand is present between the shot nozzles and the inflow point of the compressed air used for shooting.

To accelerate the sand particles through the nozzle, the compressed air must blow through the entire sand volume in the shot head. In addition, there is always an uneven distribution of the core sand in the shooting heads, which means that the pressure required for continuous shooting must again be very high.

However, the core shooting with high air pressures that was previously mandatory is extremely problematic in practice, since the sand emerging from the firing nozzles always occurs on the walls of the mold to be filled and has an extremely abrasive effect there. In other words, the shot nozzles act like a sandblasting gun, so that the core sand emerging under high pressure gradually damages the shape to be filled or changes its geometry. Another disadvantage of core shooting with high air pressures can be seen in the fact that the high air pressures already lead to compaction of the core sand in the injection or shooting area when the core sand is shot into the mold. Consequently, a form-fitting filling of the form is prevented, in particular in the case of complicated geometries, at least considerable density gradients are created.

Furthermore, due to the high air pressures and the resulting strong impact of the sand on the walls of the respective form, binder adhering to the sand is literally blasted off or detached, and an uneven distribution of sand and binder arises not least due to the density differences between sand and binder. The gases released from the binder concentrations at high temperatures again prevent uniform compression or the formation of a defect-free core.

Finally, a major problem with the previously known core shooting is that the shot heads regardless of the volumes the cores to be fired are always filled to the same level. Consequently, even with very small dimensions of the cores to be fired, the compressed air required for firing must radiate through the core sand depot stored in the firing head or accelerate the core sand particles lying directly on the firing nozzles. On the one hand, the large dimensions of the shot heads required for shooting large cores, and on the other hand the considerable volume of core sand to be penetrated by the compressed air, make the high pressures previously described as extremely disadvantageous absolutely necessary.

The invention is therefore based on the object of specifying a device and a method for filling shot heads and molding materials, as a result of which the shot head can be portioned and thereby evenly filled with molding material in order to reduce the compressed air pressures required for core shooting.

The device according to the invention achieves the above object by the features of claim 1. Thereafter, the device mentioned above for filling shot heads with molded materials is designed and developed such that the outlet member for immersion in the shot head to be filled is held on a machine frame or the like, and is vertically movable and is freely definable in the area of its vertical mobility.

According to the invention, it was first recognized that the shot head can always be filled depending on the volume or the geometry of the core to be fired. Furthermore, a quasi pre-compression of the molding materials to be accelerated by the shooting nozzles in the shooting head is avoided by immersing the outlet member for filling the shooting head in it, so that the molding material is carefully poured into the shooting head. For this purpose, the outlet member is held on a machine frame or a stand or the like. Vertically movable and in

Range of its vertical mobility can be set as desired. In other words, "portions of molding material" can be metered into the shot head, the metering being carried out by means of the closure device for closing the outlet member.

According to the invention, it has thus been recognized that the filling of the shot head must always take place as a function of the core to be shot. Due to the lower filling quantity of the shot head, the pressures required to accelerate the molding material or sand particles or the shooting pressure can be reduced from a maximum of six bar to less than three bar. In addition to the low shot pressures, a minimal throughput time of the molding material or sand is achieved. Both the molds to be filled and the shot nozzles are effectively protected due to the lower shot pressure and therefore have a significantly longer service life.

With regard to the design of the outlet member, it is of particular advantage if it is tubular. The storage container is advantageously essentially funnel-shaped, so that at least when the outlet member connects directly to the storage container, both components together form a type of funnel with a filler neck. In the context of such a configuration, the outlet member is held by the storage container, so that the outlet member can be moved vertically together with the storage container.

However, it would also be conceivable that the outlet member is connected to the storage container via a flexible hose or the like. In such a case, the storage container could be arranged in a stationary manner and only the outlet member could be held so as to be vertically movable.

The vertical movement of the outlet member and, if applicable, of the storage container could take place in a further advantageous manner via a lifting mechanism articulated on the machine frame and acting between the machine frame and the outlet member or storage container. This lifting mechanism could have at least one drive and, where appropriate, vertical guides or guide elements, so that the drive and the guides are jointly responsible for the lifting movement of the outlet member or the storage container. The drive itself could be designed as a cylinder-piston arrangement, so that guidance, namely the guidance of the piston in the cylinder, would already be provided by the provision of the cylinder-piston arrangement.

In particular for the loadable arrangement of the storage container or the outlet member above the firing head to be filled, especially when the storage container is heavily filled, it is particularly advantageous if at least two, preferably three, drives or cylinder-piston arrangements are provided. Separate tours can then be omitted.

So that a targeted filling of the shot head can now actually take place, that is to say that a given amount of core sand can be filled into the shot head in the case of predetermined core dimensions, the vertical movement of the outlet member and, if appropriate, of the storage container can be detected by means of a displacement sensor. This can be a displacement sensor that is attached to the machine frame on the one hand, and is operatively connected to the storage container or the outlet member via a linkage on the other hand. The arrangement can also be provided in the reverse sense. In any case, it is essential that the displacement sensor detects the stroke movement of the piston of the cylinder-piston arrangement relative to the machine frame. The measuring sensor used to detect the relative movement between the outlet member and machine frame and thus also relative to the firing head can be carried out in a further advantageous manner and as an alternative to the configuration discussed above. The displacement sensor could work inductively, capacitively or according to the eddy current principle. Optical detection would also be conceivable. In a particularly advantageous manner, the displacement sensor could work by means of ultrasound and be provided, for example, as an integral part of the cylinder-piston arrangement which brings about the stroke of the outlet element, so that the movement of the piston is detected directly.

In particular with regard to a largely uniform distribution of the core sands within the shot head, it is of particular advantage if the outlet member and possibly the storage container as a whole can be pivoted essentially horizontally about a pivot axis. This pivotability is preferably 360 °, i.e. the outlet member and possibly the storage container can be pivoted or rotated infinitely about a pivot axis. The pivot axis runs essentially parallel to the outlet member, namely outside the outlet member. It is also essential that the outlet member and the pivot axis are matched to the shot head or its inlet opening in such a way that 360 ° pivoting within the shot head is possible without hitting the walls thereof. Consequently, the molding material or core sand to be fired or to be blown through the weft nozzles can be approximately evenly distributed within the firing head by, for example, multiple swiveling of the outlet member, so that the bulk density of the core sand which arises in the firing head has no or only insignificant density gradients.

With regard to the pivotability of the outlet member or the storage container about the pivot axis, it is further advantageous if a preferably electric drive motor is provided for this. It could also be a so-called servomotor act that can implement movements with millimeter precision and with any change of direction.

In terms of design, the drive motor could be operatively connected to the outlet member or the storage container by means of suitable holding means and a turntable. For example, the motor could intervene in the outer part of the slewing ring using appropriate means. Accordingly, the inner part of the slewing ring would then be firmly connected to a mounting plate or the like.

In particular from the point of view of saving space, the drive motor for pivoting the outlet member and possibly the storage container and the cylinder-piston arrangement for lifting or lowering the outlet member or storage container could be integrated into a module in a very particularly advantageous manner. In other words, the drive motor for pivoting the outlet member would then be arranged at the lower end of the cylinder-piston arrangement, i.e. firmly mounted on the emerging piston or on its extension of the cylinder-piston arrangement.

With regard to an exactly definable filling quantity of the core sands to be filled into the shot head, it is of particular advantage if the closure device is arranged at the outlet end of the outlet member. In such a configuration, the core sands would be fillable or storable from the lower end of the outlet member to the upper end of the storage container. Only when the closure device is opened do the core sands - after immersing them in the shot head - enter them and preferably exclusively to the immersion depth of the outer end of the outlet member.

For a particularly simple and effective configuration of the closure device, it is designed as a closure flap which can be pivoted in front of the outlet end of the outlet member and at least largely seals there. The closure flap thus lies approximately in the plane formed by the lower edge of the outlet member and can be pivoted in it for the outlet opening of the outlet member or pivoted away from the region of the outlet opening. The outlet member and the closure flap are dimensioned such that the closure flap can be pivoted away when the outlet member is immersed in the shooting head in such a way that the outlet end is at least largely unhindered or released.

The pivot axis of the closure flap runs essentially parallel to the outlet member, namely outside the outlet member. In the context of an advantageous embodiment of the teaching according to the invention, the pivot axis of the outlet element and the pivot axis of the closure flap essentially correspond in terms of geometry, so that the closure flap smoothing or leveling the filled-in core sand performs the same pivoting movement as the outlet element, with smoothing or Leveling of the core sand filled in the shot head results in almost the same plane.

It is now essential for the pivoting movement of the closure flap that it can be fixed in any pivot positions in the entire pivoting range. This means that the degree of opening of the outlet member can be adjusted, whereby on the one hand the pouring speed and on the other hand the bulk quantity can be significantly influenced.

With regard to the actuation of the closure flap, it is particularly advantageous if it is pivoted by means of a cylinder-piston arrangement. For power transmission or transmission the linear movement of the cylinder-piston arrangement into a rotary or swivel movement of the closure flap engages the cylinder-piston arrangement via a swivel lever and a guide rod rotatable by the swivel lever on the closure flap.

So that the core sands in the storage container do not stick to less steep walls of the storage container due to adhesion, the storage container is advantageously associated with a vibration device that vibrates the wall of the storage container. If the outlet member is firmly connected to the storage container, the vibration movement is of course also transmitted to the outlet member, so that the core sands can be effortlessly brought into the shot head. Precisely because of the vibration device, however, it is a further advantage if at least one oscillating element is arranged between the storage container or the outlet element and the machine frame, preferably between the storage container or outlet element and the rotating ring, in order to prevent vibration being transmitted to the machine frame. For example, an electric motor with an eccentric rotating or mass part could be used as the vibration device.

The method according to the invention achieves the above object by claim 14. According to this, a method for filling shot heads with core sands, in particular using a device according to one of claims 1 to 13, is characterized by the following method steps:
First of all, the outlet member and - in the case of a direct connection between the outlet member and the storage container - the storage container is brought into the rest position, ie into the upper position. This position ensures that the shot head can be conveyed under the outlet member. In the resting position the storage container is filled with core sand, the flap being closed. Consequently, on the one hand the outlet member and on the other hand the storage container can be filled up to the upper edge in accordance with the filling density of the core sand. The shooting head is then positioned under the outlet member. At this point it should be noted that the positioning of the shot head under the outlet member can also take place at an earlier point in time, for example before the storage container is filled with core sand. It only has to be ensured that there is sufficient space under the outlet member for positioning the shot head.

In the next step, the outlet member is immersed in the shot head, the immersion depth being predetermined by the required filling of the shot head with core sand. This filling in turn depends on the volume and the realizable density of the core to be fired. In the immersed state, the outlet member is in its working position. In the next step, the closure flap is at least partially opened - for partial filling of the shot head to a predetermined filling level. Due to the immersion depth, the filling takes place essentially to the lower edge of the outlet element. If necessary, the outlet member is closed by the closure flap, whereby the closure flap roughly smoothes out the filled core sand. The outlet member is moved within the possible 360 ° rotation or pivoting into a further working position at a given immersion depth, so that the area next to the previously filled point within the shot head can be filled further. So in a further position the outlet member is opened again by the closure flap and the filling process can be repeated as required with different positions of the outlet member until the desired fill level is reached. Likewise, the outlet member can gradually after filling the shot head are pulled upwards, so that a predeterminable filling height can be achieved with the lowest possible falling height of the core sand particles. Thus there is only a certain bulk density of the core sands within the shot head, but in no case a compression corresponding to the tap density or even a higher density.

Furthermore, the filled-in core sand is smoothed out both by the pivoting movement of the closure flap and by the pivoting movement of the outlet element itself. This enables an exact filling dimension to be achieved. Repeated swiveling or filling enables the realization of any filling heights.

Finally, the outlet member is closed by the closure flap when the shot head is sufficiently filled and pulled out of the shot head into its rest position.

Fig. 1

in einer schematischen Seitenansicht, geschnitten, ein Ausführungsbeispiel einer erfindungsgemäßen Vorrichtung zum Füllen von Schußköpfen mit Kernsanden, wobei sich die Vorrichtung in ihrer Arbeitsposition befindet und

Fig. 2

in schematischer Darstellung den Gegenstand aus Fig. 1 im Schnitt entlang der Linie II-II.

There are now various possibilities for advantageously designing and developing the teaching of the present invention. For this purpose, on the one hand, reference is made to the claims subordinate to claim 1, and on the other hand to the following explanation of an embodiment of the invention with reference to the drawing. In connection with the explanation of the preferred exemplary embodiment of the invention with reference to the drawing, generally preferred configurations and developments of the teaching are also explained. In the drawing shows

Fig. 1

in a schematic side view, sectioned, an embodiment of a device according to the invention for filling shot heads with core sands, the device being in its working position and

Fig. 2

in a schematic representation the object of Fig. 1 in section along the line II-II.

Fig. 1 shows a sectional schematic representation of a device for filling shot heads 1 with molding materials, wherein the embodiment chosen here is core sand. Essential components of the device are a storage container 3 for core sand 2, an outlet member 4 for discharging the core sand 2 into the shot head 1 and a closure device 5 for closing the outlet member 4.

According to the invention, the outlet member 4 is vertically movably mounted on a machine frame 6 for immersion in the shooting head 1 to be filled and can be arbitrarily - steplessly - fixed in the area of vertical mobility.

Fig. 1 shows in connection with Fig. 2 that the outlet member 4 is substantially tubular. The storage container 3 is funnel-shaped. Fig. 1 further clearly shows that the outlet member 4 connects directly to the storage container 3, so that the outlet member 4 is held by the storage container 3 and together with the storage container 3 is vertically movable.

The vertical movement of the outlet member 4 or the outlet member 4 together with the storage container 3 takes place via an articulated on the machine frame 6 and acting between the machine frame 6 and the outlet member 4 or the storage container 3. The lifting mechanism 7 has in the embodiment chosen here two drives, which also serve as vertical guides. More specifically, these are cylinder-piston arrangements 8.

The vertical movement of the outlet member 4 or the storage container 3 can be detected by means of a non-contact displacement sensor 9. This displacement sensor 9 detects the stroke movement of the piston 10 of the cylinder-piston arrangement 8 relative to the machine frame 6. In the exemplary embodiment selected here, the displacement sensor 9 works by means of ultrasound.

1 and 2 show together that the outlet member 4 and the storage container 3 as a whole are endless about a pivot axis 11, i.e. can be swiveled horizontally through 360 ° and more. The pivot axis 11 runs parallel to the outlet member 4 and specifically outside the outlet member 4. FIG. 2 shows that the outlet member 4 and the pivot axis 11 are matched to the shooting head 1 or its inlet opening 12 such that the 360 ° Swiveling within the shot head 1 is easily possible.

With regard to the pivoting movement of the outlet member 4 or the storage container 3, it is essential that the outlet member 4 is pivoted together with the storage container 3 by means of an electric drive motor 13. This is only indicated schematically in FIG. 1. The drive motor 13 is operatively connected to the outlet member 4 or the storage container 3 via corresponding holding means 14 and a rotating ring 15. Fig. 1 further shows that the drive motor 13 for pivoting the outlet member 4 or the storage container 3 and the cylinder-piston assembly 8 for lifting and lowering the outlet member 4 are integrated into one assembly.

Fig. 1 further clearly shows that the closure device 5 is arranged at the outlet end 16 of the outlet member 4. More precisely, the closure device 5 is designed as a closure flap 17 which can be pivoted in front of the outlet end 16 of the outlet member 4 and largely seals there. The outlet member 4 and 2, the closure flap 17 is dimensioned such that the closure flap 17 can be pivoted away when the outlet member 4 is immersed in the firing head 1 in such a way that the outlet end 16 is uncovered overall.

Both Fig. 1 and Fig. 2 shows that the closure flap 17 is pivotable about a pivot axis extending substantially parallel to the outlet member 4. The figures show overall that the pivot axis 11 of the outlet member 4 and the pivot axis 18 of the closure flap 17 correspond approximately geometrically. It is also essential that the closure flap 17 can be fixed in any pivot position in the entire pivot range, two pivot positions being indicated in the illustration selected in FIG. 2.

Furthermore, it is indicated in FIG. 1 that the closure flap 17 is pivoted by means of a cylinder-piston arrangement 19. This cylinder-piston arrangement 19 is operatively connected to the closure flap 17 via a swivel lever 20 and a guide rod 21. Thus, the linear movement of the cylinder-piston arrangement 19 - via the pivot lever 20 and the guide rod 21 - can be transformed into a pivoting movement of the closure flap 17.

Fig. 1 further shows that the storage container 3 is associated with the wall 22 of the storage container 3 vibrating vibrating device 23. So that the vibration used to shake the core sand into the outlet member 4 does not propagate to the machine frame 6, a vibration element 24 is provided to prevent vibration transmission to the machine frame 6, which is installed between the outlet member 4 or the storage container 3 and the rotating ring 15 .

Finally, it should only be pointed out here that the storage container 3 and the outlet element 4 can be provided with a weighing device for the exact determination of the filling quantity of the shot head 1. This weighing device would determine the weight difference between the empty storage container or empty outlet member and the storage container or outlet member filled with core sand in a particularly advantageous manner. It would also be possible to monitor the filling of the shot head precisely by means of a weight loss, with the desired pouring level being easily predeterminable via the weight and with known density or bulk density.

With regard to the method according to the invention, reference is made to the statements in the general part of the description.

In conclusion, it should be emphasized that the core of the present invention - precise setting of the filling quantity of molding material required for producing a core with approximately the same distribution of the molding material within the shot head - can also be realized with other filling devices or shot heads. The exemplary embodiment mentioned above merely serves to understand the teaching according to the invention, but does not restrict it.

Claims (14)

1. Device for filling core-shooting heads (1) with mould-core materials (2), having a storage container (3) for the mould-core material (2), an outlet member (4) for discharging the mould-core material (2) into the core-shooting head (1) and a closing device (5) for closing the outlet member (4), characterised in that the outlet member (4) is mounted in a vertically movable manner on a machine frame (6) or the like such that it can dip into the core-shooting head (1) to be filled, and can be secured optionally in the range of its vertical mobility.
2. Device according to Claim 1, characterised in that the outlet member (4) is substantially tubular; and in that the storage container (3) is optionally substantially hopper-shaped.
3. Device according to Claim 1 or 2, characterised in that the outlet member (4) adjoins the storage container (3) directly such that the outlet member (4) is optionally held by the storage container (3) and can be moved vertically together with the storage container (3).
4. Device according to any one of Claims 1 to 3, characterised in that the vertical mobility of the outlet member (4) and optionally of the storage container (3) is brought about by means of an elevating mechanism (7) which is articulated on the machine frame (6) and acts between the machine frame (6) and the outlet member (4) or storage container (3); and in that the elevating mechanism (7) comprises at least one drive and optionally vertical guides, the drive optionally being constructed as a cylinder-piston arrangement (8).
5. Device according to any one of Claims 1 to 4, characterised in that the vertical movement of the outlet member (4) and optionally of the storage container (3) can be detected by means of a path-measuring sensor (9) which preferably operates in a contactless manner; and in that optionally the path-measuring sensor (9) detects the elevating movement of the piston (10) of the cylinder-piston arrangement (8) relative to the machine frame (6).
6. Device according to Claim 5, characterised in that the path-measuring sensor (9) operates inductively, capacitively, according to the eddy current principle, light-optically or by means of ultrasound.
7. Device according to any one of Claims 1 to 6, characterised in that the outlet member (4) and optionally the storage container (3) is or are respectively pivotable substantially horizontally overall about a pivot axis (11), preferably about 360°; in that the pivot axis (11) extends substantially parallel to the outlet member (4) externally of the latter; and in that the outlet member (4) and the pivot axis (11) are adapted to the core-shooting head (1) or to the inlet opening (12) thereof in such a way that the 360°-pivoting is possible within the core-shooting head (1).
8. Device according to Claim 7, characterised in that the outlet member (4) and optionally the storage container (3) are pivoted by means of a preferably electrical drive motor (13); and in that the drive motor (13) is operatively connected by holding means (14) and a turning ring (15) to the outlet member (4) or to the storage container (3).
9. Device according to any one of Claims 1 to 8, characterised in that the drive motor (13) for the pivoting of the outlet member (4) and optionally of the storage container (3) and the cylinder-piston arrangement (8) for the raising and lowering of the outlet member (4) or of the storage container (3) are integrated to form a sub-assembly.
10. Device according to any one of Claims 1 to 9, characterised in that the closing device (5) is disposed at the outlet end (16) of the outlet member (4); in that the closing device (5) is in the form of a closing flap (17) which can be pivoted in front of the outlet end (16) of the outlet member (4) and seals there at least to a large extent; and in that the outlet member (4) and the closing flap (17) are dimensioned such that the closing flap (17) can be pivoted away when the outlet member (4) dips into the core-shooting head (1) in such a way that the outlet end (16) can be uncovered at least to a large extent.
11. Device according to Claim 10, characterised in that the closing flap (17) is pivotable about a pivot axis (18) extending substantially parallel to the outlet member (4); in that the pivot axis (11) of the outlet member (4) and the pivot axis (18) of the closing flap (17) correspond to one another geometrically and approximately; and in that the closing flap (17) can optionally be secured in any pivoting positions in the entire pivoting range.
12. Device according to Claim 10 or 11, characterised in that the closing flap (17) is pivoted by means of a cylinder-piston arrangement (19); and in that the cylinder-piston arrangement (19) acts on the closing flap (17) by means of a pivot lever (20) and a guide rod (21).
13. Device according to any one of Claims 10 to 12, characterised in that a vibration device (23) which causes the wall (22) of the storage container (3) to vibrate is associated with the latter; and in that at least one vibrating component (24) for preventing the transmission of vibrations to the machine frame (6) is disposed between the storage container (3) or outlet member (4) and the machine frame (6), preferably between the storage container (3) or outlet member (4), and the turning ring (15).
14. Method of filling core-shooting heads with core sands using a device according to any one of Claims 1 to 13, characterised by the following method steps:

    - moving the outlet member and optionally the storage container into the rest position, ie. into the upper position;

    - filling the storage container with mould-core material, the closing flap being closed;

    - positioning the core-shooting head below the outlet member;

    - dipping the outlet member into the core-shooting head according to the level to be reached in the latter in the operating position;

    - opening the closing flap in order to fill partially the core-shooting head to the predetermined level;

    - if necessary closing the outlet member by means of the closure flap;

    - pivoting the outlet member through less than 360°;

    - optionally renewed opening of the outlet member by means of the closing flap;

    - optionally partially raising the outlet member during the filling process or between individual filling steps;

    - flattening the filled mould-core material by the pivoting movement of the closing flap and/or by the pivoting movement of the outlet member;

    - optionally repeating the pivoting and filling processes;

    - closing the outlet member when the head is sufficiently full; and

    - removing the outlet member into the rest position.

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