EP1345716B1 - Feeder comprising a tubular body - Google Patents

Abstract

This present invention concerns a feeder system for a cast piece with a feeder and/or feeder head and a tubular body, characterized in that the tubular body connects the feeder and/or feeder head directly or indirectly with the cast piece and/or the mold cavity and wherein the tubular body is made of cardboard or steel having a high carbon content.

Description

The invention relates to a feeder system for a casting with a feeder (head) and a tube-like body.

In the production of molded parts in the foundry, liquid metal is poured into a casting mold. During the solidification process, the volume of the filled material is reduced. Therefore, so-called feeders, i. open or closed spaces in or on the mold, used to compensate for the volume deficit in the solidification of the casting and to prevent voids in the casting. For this purpose, the feeders are connected to the casting or to the vulnerable casting area and are usually arranged above or on the side of the mold cavity.

Numerous feeders are known in the art. For example, DE 196 42 838 A1 describes a feeder for a metallic casting in the form of a bell with a recessed bell rim formed by an attached flat ring member.

DE 41 19 192 A1 describes a resilient mandrel for holding feeders. The feeder inserts are attached to a mandrel connected to the mold and preferably formed in the upper box. Since the material of the feeder is very yielding and the sand pressure during molding in the molding plant can easily lead to damage of the feeder used, it is known to form the spring resiliently axially movable, so that the molded feeder the sand pressure in the direction of the model can dodge.

DE 42 00 183 A1 relates to a two-part feeder with an adjacent to the casting Feiserfuß of an exothermic material and to be applied to the Feiserfuß, the cavity having upper part, wherein the Feiserfuß has an elongated-oval connection opening to the casting and the oval connection opening to the passage a spinner is fixed to the casting model during the molding operation.

Normally, the feeders are arranged approximately at the gate height and also equipped with a heat-insulating material or exothermic masses so that the melt located in the feeder solidifies later than the casting itself. After solidification, the feeder remains connected to the casting so that the remainder of the feeder must then be separated. The clean and easy separation of the feeder from the casting is problematic in many cases. Regularly, after cutting off the feeder, the casting surface must still be deburred and smoothed. This is a complex and correspondingly expensive operation, which can also lead to damage to the surface of the casting at the junction with the feeder. In order to reduce such damage and to facilitate the separation of the feeder, so-called refractive cores (also called breaking edge, sanding strip or constrictor core) are frequently provided. These are placed between the feeder and the mold and require appropriate attachment surfaces.

Overall, the known feeders are either relatively expensive in their construction or handling in the production of the mold and / or ensure no easy and precise separation of the residual feed from the finished casting or require a relatively large top surface.

The aim of the present invention was thus to provide a feeder system which avoids the disadvantages of the prior art and in particular has a simple structure, can be easily attached to the casting mold or formed, only requires small attachment surfaces and still requires a precisely positioned breaking edge directly on the casting allows easy and safe separation of the residual feed from the finished casting.

This object is achieved by a feeder system according to claim 1. Advantageous embodiments are specified in the subclaims.

In the present case, the term feeder includes any known in the art or familiar to the expert form of feeders, feeder covers, feeder inserts and feeder caps and heating pads.

The present invention is in principle useful for all types of feeders in which the tube-like body can be arranged in the manner indicated below.

In particular, the present invention is suitable for so-called. Mini-feeder, which are conventionally formed with breaker core or by using a spring mandrel.

The feeder system according to the invention consists of at least two parts. On the one hand, it is on the side facing away from the casting Side of a feeder or head is provided, which provides a cavity for receiving the liquid metal during casting.

Towards the casting, a tube-like body connects, which connects, directly or indirectly, the cavity formed by the feeder head with the cavity of the mold.

The tube-like body may have any length and wall thickness and diameter suitable in the individual case. The wall thickness, depending on the material used, is generally between 0.1 mm and 10 mm, in particular between 0.3 mm and 5 mm, particularly preferably 0.3 mm to 0.5 mm. The optimum dimensions can be determined on a case-by-case basis by means of routine tests or are known to the person skilled in the art on the basis of his experience. The wall thicknesses also vary due to the material and may be e.g. for sheet steel and when using a spring mandrel minispeiser at about 0.3 mm to 0.5 mm.

As a rule, the tube-like body has a length of between about 15 and about 300 mm, in particular between about 35 and about 100 mm. The length of the tube-like body is chosen in an embodiment according to the invention so that at least the distance between the feeder (before molding, possibly on the mandrel) and the casting is bridged.

The inner diameter of the tube-like body can in principle be chosen arbitrarily, wherein the opening should be large enough to ensure the flow of the melt into and out of the feeder during the casting and solidification process. The diameter of the tube-like body is usually oriented, but not necessarily, on the feeder inner diameter, as according to one embodiment of the present invention Invention, the tube-like body in the feeder (head) is fitted or plugged. However, it is also a different attachment to or in the feeder (head) possible.

The tubular body may have any cross-sectional shape, in particular a round, oval or polygonal or polygonal geometry.

According to one embodiment of the present invention, the tube-like body is a tube with a substantially uniform cross-section over its entire length. Preferably, the ratio of wall thickness to the overall diameter of the tube is between about 1: 2 and 1: 200, in particular 1: 5 to 1: 120, and particularly preferably 1:10 to 1: 100. The ratio of length to overall diameter of the tube is preferably between about 1: 4 and 15: 1, in particular 1: 1 and 6: 1. In particular, the ratios depend on the shape of the feeder and the casting mold.

The feeder head may be formed of any insulating and / or exothermic material known in the art to ensure that the melt in the feeder solidifies later than the casting itself. For example, the feeder can be prepared from the exothermic feeder compositions disclosed in DE 199 25 167 of the same Applicant.

The tube-like body may be formed of any suitable material which has a corresponding strength and does not exert any disturbing reactions on the casting to be fed. These materials are known to those skilled in the art and include, for example, metal, plastic, cardboard, ceramics or similar materials.

According to a preferred embodiment, the tube-like body consists of a casting program similar material, such as aluminum or iron sheet.

The tube-like body is in an advantageous embodiment of the present invention with the outer circumference closely to the feeder or feeder head and is preferably attached to the feeder (head) by means known to those skilled in the art, e.g. by means of an adhesive such as hot glue or water glass, by a wedge or by means of fit. He can also simply be plugged into the feeder (head).

According to a further preferred embodiment of the invention, however, the tube-like body is movable relative to the feeder or feeder head and / or the casting or the hollow body at least within certain limits. As a result, on the one hand, a particularly uncomplicated attachment of the feeder can be ensured, and on the other hand an optimal positioning of the breaking edge can be effected by the displacement occurring between the feeder and the tube-like body or casting during the molding or compacting of the molding material.

Thus, due to the compaction of the molding material and the relative displacement between the feeder or tubular body and the casting or hollow body, the distance between the pipe-like body and the casting can be easily adjusted prior to molding such that after molding or densification of the molding material the tube-like body forms an optimally positioned crushing edge which is as close as possible to the finished casting.

According to the invention, the tube-like body tapers towards the casting-facing end or has a tapering section or a narrowing of the inner diameter.

According to a preferred embodiment of the invention, the tube-like body tapers toward the casting and forms a breaking edge directly at the transition to the casting mold or in the immediate vicinity. Of course, according to an embodiment of the invention, only a certain portion, preferably the portion facing the casting, may have a taper or a constriction of the (inner) diameter. Thus, on the one hand, the tube-like body serves to provide a deformable neck of the feeder and, on the other hand, to provide a precise and firmly positioned breaking edge. The breaking edge is preferably provided as a constriction of the opening or the inside diameter at or in the vicinity of the casting-facing end of the tube-like body.

Furthermore, as stated above, the dimensioning of the tube-like body optimizes the position and shape of the breaking edge, for example by using a relatively narrow tube with a small diameter or a corresponding arrangement of the feeder or feeder head, so that the latter after molding or Compressing the molding material quite close (yet not directly on the) casting lies.

According to a preferred embodiment, the feeder system according to the invention, as mentioned above, further comprises a mandrel, in particular a spring mandrel.

The feeder connected to the pipe (pipe-like body) is held up by the spring mandrel accordingly. The tube stands on the form or on the beveled base of the spring mandrel. During the molding process, the feeder is guided down the pipe to the corresponding end position by the spring mandrel. The tube remains firmly in the original position. This ensures that a defined breaking edge is provided directly on the casting.

In the context of the present invention, any core, mandrel or spring mandrel that appears suitable for the person skilled in the art can be used. Towards the casting, the tube-like body can either grip completely over the spring mandrel or stand up on its base. In both cases, a connection is made (directly or indirectly) between the mold cavity and the tube-like body.

According to a further advantageous embodiment of the invention, the tubular body can be used as Federdorn- or guide mandrel replacement. The feeder is guided over the tube-like body which rests on the mold. If necessary centering over a fixed mandrel, which can be of different lengths. Preferably, the fixed mandrel has a maximum length of the tube-like body. In many cases, however, it may be advantageous for the fixed mandrel to be shorter than the tubular body and the latter is at least partially pushed over the fixed mandrel. During compression, the feeder then slides over the tube-like body. According to an advantageous embodiment of the invention, the feeder is destroyed at the top by the tube-like body. The food particles are embedded in the molding sand.

The tube-like body must be adjusted for each casting so that the distance between feeder and casting still leads to a sufficient supply. Often this distance will be between 5 to 25 mm.

Upwards, the tube-like body may be open or closed.

According to an advantageous embodiment of the invention, the tube-like body, if it is open on the side facing away from the casting, can be supported by a relatively long mandrel, in which case preferably the tubular body is made of a solid material, such as steel sheet, e.g. with a material thickness of about 0.7 mm. However, other solid materials such as plastic, e.g. PE, or ceramic, advantageous. Preferably, the tube-like body is perforated in the upper region in order to ensure a good ignition of the feeder. For casting down holes or openings in the tube-like body should not be present, as far as this would lead to the penetration of molding sand during molding.

According to a further embodiment of the invention, it has been found that in some cases it may also be preferred for ease of handling that the tube-like body is not connected directly to the casting or the hollow body before molding or compression of the molding material or get up on the spring thorn (if available).

In this case, the feeder system can be designed so that the tube-like body moves during the molding or the compression of the molding material to the casting or hollow body. According to this embodiment of the invention, the tubular body is relatively thin-walled, so that it can cut during the molding or the compression of the molding material through this to the casting. This can be further facilitated by the fact that the tube-like body is provided at the end facing the casting with a kind of cutting edge or whose wall thickness decreases there or is particularly low.

Advantageously, the feeder system is dimensioned in this case and arranged opposite the casting, so that a defined crushing edge is formed between the feeder and the casting with a coordinated spring deflection after molding or complete compression of the molding material on the pipe-like body.

Preferably, the tube-like body in order to push or cut well during the compression of the molding material to the casting, on the one hand a relatively thin mold wall, which allows a penetration through the molding material to the casting or the hollow body. Preferably, a wall thickness of the tube-like body of about 0.05 to 1 mm, in particular 0.2 to 0.5 mm using a solid material such as steel, plastic or ceramic is used. Of course, the tube wall must have sufficient stability, so that it is not destroyed during the compression of the molding material so that no durchspeisbare connection between hollow body and feeder more. Therefore, the particular preferred wall thickness of the tube-like body depends on the material used. Suitable wall thicknesses will be apparent to those skilled in the art, depending on the material chosen, or may be optimized through routine experimentation.

According to a preferred embodiment, the cutting operation is assisted in that the tube-like body finds a stop or a support in the feeder and is thus pressed together with the feeder or the feeder head to the casting.

This support can be done by means of a stop or a support. In this case, stop should be understood here to be a special shape on a wall, in particular an inner wall of the feeder or feeder head, which contacts the end of the tube-like body facing away from the casting punctiform or flat at least during the molding or compression of the molding material.

Of course, the support of the tube-like body relative to the feeder or feeder head also by a corresponding bonding, wedging or fitting between the tube-like body and feeder or feeder head done, as already described for example in DE 100 59 481.6, or by a support point or ., A support surface which supports the tube-like body relative to the feeder or feeder head at least after molding or compression of the molding material.

If a spring mandrel is present, the tube-like body preferably does not sit on the foot of the spring mandrel before the molding or compression of the molding material, but pushes during the compression of the molding material to the foot of the spring mandrel before. According to the invention it is also possible that the tube-like body in the absence of a spring mandrel independently cuts or pushes to the casting or hollow body.

It has been found that the feeder system according to the invention can be very simply and universally attached to the molds and molded, and ensures a reproducible and optimally positioned crushing edge, even when using a mandrel or spring mandrel. After forming and possibly removing the core or (spring) mandrel, the tube-like body remains in the mold. The assembly of the feeder system can be done either at the factory or only at the customer on the mold.

Furthermore, the feeder system according to the invention makes other methods such as the use of a commercially available breaker core, e.g. a croning refractive core to produce a suitable breaking edge superfluous.

As far as according to the above embodiments according to the invention also on the arrangement of the feeder or feeder head, the tube-like body, the spring or guide mandrel or the fixed mandrel relative to the casting or hollow body reference has been made, another aspect of the present invention also relates to a casting assembly comprising the feeder system defined above and the casting / the hollow body (and a molding material) or a method for preparing a casting mold using the feeder system according to the invention.

According to a further aspect, the invention relates to the use of a tube-like body for forming a deformable feeder neck with breaking edge in feeders for castings according to claim 18.

• Fig. 1 einen herkömmlichen Speiser mit Federdorn darstellt;
• Fig. 2 ein erfindungsgemäßes Speisersystem mit rohrähnlichem Körper darstellt, der eine Verjüngung zum Gussstück hin aufweist;
• Fig. 3a ein erfindungsgemäßes Speisersytem mit rohrähnlichem Körper vor dem Formen bzw. der Verdichtung des Formstoffs darstellt;
• Fig. 3b ein erfindungsgemäßes Speisersytem mit rohrähnlichem Körper nach der Verdichtung des Formstoffs darstellt; und
• Figs. 4a und 4b eine weitere erfindungsgemäße Ausführungsform des Speisersystems darstellen, wobei der rohrähnliche Körper im vom Gussstück abgewandten Teil Öffnungen bzw. Löcher aufweist.

The invention will be explained in more detail with reference to the accompanying drawings, in which

• Fig. 1 shows a conventional feeder with spring mandrel;
• Fig. 2 illustrates a feeder system according to the invention with a tube-like body having a taper towards the casting;
• Fig. 3a illustrates a feeder system according to the invention with a tube-like body prior to molding or densification of the molding material;
• Fig. 3b represents a feeder system according to the invention with a tube-like body after the compression of the molding material; and
• Figs. 4a and 4b illustrate a further embodiment of the feeder system according to the invention, the tube-like body having openings or holes in the part facing away from the casting.

1, a conventional feeder 1 is placed from an exothermic and / or insulating mass via a spring mandrel 2 on the casting 4. For separating or knocking off the feeder remainder no optimal breaking edge is formed.

In Fig. 2, an inventive feeder system is shown, wherein over the spring pin 2, a tube-like body 3 is guided, which tapers towards the casting 4. As a result, a breaking edge 5 is formed. The tube-like body tapers towards the casting and sits on the foot or base 6 of the spring mandrel. On the pipe, a feeder (head) 1 is placed, wherein a hot glue seam 7 is provided for sealing between the feeder and pipe circumference. After this Shapes the feeder takes the position characterized by rough hatching, whereby the relative movement between the tube-like body and feeder takes place and the positioning of the crushing edge on the tube-like body with respect to the casting remains unchanged. Thus, an optimal positioning of the crushing edge is guaranteed regardless of the final position of the feeder after molding.

In Fig. 3, a feeder system according to the invention is shown, wherein on the inner wall of the feeder (head) 1 there is a projection or a stop 8 for the tube-like body 3 is provided. The tube-like body 3 tapers towards the casting or hollow body 4 and can cut through the molding material during the molding or the compression of the molding material or advance toward the casting.

As stated in the description, the spring travel in the compression of the molding material can be adjusted so that the breaking edge forms at the foot of the mandrel 2 near the casting. It is also possible that the tube-like body has no taper and is formed substantially cylindrical.

In Fig. 3a, the feeder system is shown prior to the compression of the molding material, wherein the casting facing the end of the tube-like body is not seated on the foot 9 of the spring mandrel or is directly connected to the casting or the hollow body.

In Fig. 3b, the feeder system is shown after the compression of the molding material, wherein the tubular body is directly connected to the hollow body or on the foot 9 of the spring pin 2, if present, or the casting is seated.

In Figs. 4a and 4b, another embodiment of the invention is shown, wherein the tube-like body 3 has holes or openings 10 in the part facing away from the casting. In the illustrated embodiment, the tube-like body is already on the casting 4 prior to molding or compression of the molding material. After molding or compression of the molding material (FIG. 4b), the feeder head 1 has been intentionally destroyed in the upper region 1 ', a relative movement taking place between the tube-like body 3 and the feeder head 1.

Claims (27)

1. Feeder system for a casting with a feeder and a tubular body, wherein the tubular body connects the feeder directly or indirectly to the casting, tapers towards the end which faces the casting and has a tapering portion or a contraction of the inside diameter and therefore helps to form a breaking edge.
2. Feeder system according to Claim 1, characterised in that the feeder is formed as a feeder head.
3. Feeder system according to either of the preceding Claims, characterised in that the tubular body is formed in a cylindrical manner.
4. Feeder system according to any one of the preceding Claims, characterised in that a stop or a support for the end of the tubular body which lies opposite the casting is provided in the feeder.
5. Feeder system according to any one of the preceding Claims, characterised in that the stop is a projection on the inside of the feeder.
6. Feeder system according to any one of the preceding Claims, characterised in that the stop or the support consists of a plurality of support points.
7. Feeder system according to any one of the preceding Claims, characterised in that the stop or the support consists of an annular support surface.
8. Feeder system according to any one of the preceding Claims, characterised in that the stop or the support is provided at the lateral inner wall of the feeder.
9. Feeder system according to any one of the preceding Claims, characterised in that the stop or the support is provided at the upper inner wall of the feeder.
10. Feeder system according to any one of the preceding Claims, characterised in that the tubular body is relatively thin-walled, so that it can be cut or advance towards the casting during the start of moulding or compression of the moulding material.
11. Feeder system according to any one of the preceding Claims, characterised in that the tubular body can move with respect to the feeder.
12. Feeder system according to any one of the preceding Claims, characterised in that a spring mandrel or guide mandrel is also provided, and the tubular body can be at least partly pushed over this.
13. Feeder system according to any one of the preceding Claims, characterised in that the tubular body does not stand by way of the side which faces the casting on the spring or guide mandrel before starting to mould or compressing the moulding material.
14. Feeder system according to any one of the preceding Claims, characterised in that the tubular body is seated on the base of the spring or guide mandrel at least after starting to mould or compressing the moulding material and a breaking edge is thereby formed near the casting.
15. Feeder system according to Claim 12, characterised in that the tubular body replaces the spring or guide mandrel, and a stationary mandrel is optionally provided to centre the tubular body.
16. Feeder system according to Claim 15, characterised in that the stationary mandrel is at most as long as the tubular body, and the tubular body is pushed at least partly over the stationary mandrel.
17. Feeder system according to Claim 15, characterised in that the stationary mandrel is shorter than the tubular body, and the tubular body is pushed at least partly over the stationary mandrel.
18. Use of a tubular body, which tapers towards the end which faces the casting and has a tapering portion or a contraction of the inside diameter, for forming a feeder neck which can be moulded on and has a breaking edge in feeders for castings.
19. Casting arrangement, comprising a feeder system according to any one of the preceding Claims, a casting or a moulded hollow body and a moulding material.
20. Casting arrangement according to Claim 19, also comprising a spring or guide mandrel.
21. Casting arrangement according to Claim 19 or 20, characterised in that the tubular body does not stand by way of the side which faces the casting on the mould before starting to mould or compressing the moulding material.
22. Casting arrangement according to any one of Claims 19 to 21, characterised in that the tubular body can move with respect to the casting.
23. Method for providing a casting arrangement according to any one of Claims 19 to 22, characterised in that the tubular body is fitted before starting to mould or compressing the moulding material and the feeder is subsequently mounted.
24. Method according to Claim 23, characterised in that the tubular body is not directly connected to the casting or the moulded hollow body before starting to mould or compressing the moulding material, but is rather cut up to the casting during compression of the moulding material.
25. Method according to Claim 23 or 24, characterised in that the tubular body does not stand on a provided mandrel before starting to mould or compressing the moulding material, but is rather cut up to the casting during compression of the moulding material.
26. Method according to Claim 23, characterised in that the tubular body forms a breaking edge on the side which faces the casting, and the feeder does not lie directly on the casting after starting to mould or compressing the moulding material
27. Method according to Claim 23, characterised in that the upper part of the feeder is destroyed by the tubular body during the start of moulding or compression of the moulding material.

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