EP1507638A1 - Cast iron tile and method for the production of cast iron tile - Google Patents

Cast iron tile and method for the production of cast iron tile

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Publication number
EP1507638A1
EP1507638A1 EP03725128A EP03725128A EP1507638A1 EP 1507638 A1 EP1507638 A1 EP 1507638A1 EP 03725128 A EP03725128 A EP 03725128A EP 03725128 A EP03725128 A EP 03725128A EP 1507638 A1 EP1507638 A1 EP 1507638A1
Authority
EP
European Patent Office
Prior art keywords
tile
wall
cast iron
thread
cast
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP03725128A
Other languages
German (de)
French (fr)
Other versions
EP1507638B1 (en
Inventor
Angelo Schmandra
Eckhard Willms
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
BHS Sonthofen GmbH
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BHS Sonthofen GmbH
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Filing date
Publication date
Application filed by BHS Sonthofen GmbH filed Critical BHS Sonthofen GmbH
Publication of EP1507638A1 publication Critical patent/EP1507638A1/en
Application granted granted Critical
Publication of EP1507638B1 publication Critical patent/EP1507638B1/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B02—CRUSHING, PULVERISING, OR DISINTEGRATING; PREPARATORY TREATMENT OF GRAIN FOR MILLING
    • B02C—CRUSHING, PULVERISING, OR DISINTEGRATING IN GENERAL; MILLING GRAIN
    • B02C17/00—Disintegrating by tumbling mills, i.e. mills having a container charged with the material to be disintegrated with or without special disintegrating members such as pebbles or balls
    • B02C17/18—Details
    • B02C17/22—Lining for containers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01F—MIXING, e.g. DISSOLVING, EMULSIFYING OR DISPERSING
    • B01F35/00—Accessories for mixers; Auxiliary operations or auxiliary devices; Parts or details of general application
    • B01F35/50—Mixing receptacles
    • B01F35/511—Mixing receptacles provided with liners, e.g. wear resistant or flexible liners
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28B—SHAPING CLAY OR OTHER CERAMIC COMPOSITIONS; SHAPING SLAG; SHAPING MIXTURES CONTAINING CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28B7/00—Moulds; Cores; Mandrels
    • B28B7/34—Moulds, cores, or mandrels of special material, e.g. destructible materials
    • B28B7/342—Moulds, cores, or mandrels of special material, e.g. destructible materials which are at least partially destroyed, e.g. broken, molten, before demoulding; Moulding surfaces or spaces shaped by, or in, the ground, or sand or soil, whether bound or not; Cores consisting at least mainly of sand or soil, whether bound or not
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B28—WORKING CEMENT, CLAY, OR STONE
    • B28C—PREPARING CLAY; PRODUCING MIXTURES CONTAINING CLAY OR CEMENTITIOUS MATERIAL, e.g. PLASTER
    • B28C5/00—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions
    • B28C5/08—Apparatus or methods for producing mixtures of cement with other substances, e.g. slurries, mortars, porous or fibrous compositions using driven mechanical means affecting the mixing
    • B28C5/0862—Adaptations of mixing containers therefor, e.g. use of material, coatings

Definitions

  • the present invention relates to a cast iron tile for lining the inner wall of a trough-shaped container, in particular the mixing trough of a concrete mixer.
  • the tile has a recess for attaching the tile to the inner wall, in the peripheral wall of which a thread is cast.
  • the present invention further relates to a method for producing such a hard cast tile.
  • Generic tiles are used to protect areas of the inner wall of mixers that are subject to heavy wear with a wear-resistant lining. Often it is not the entire inner wall that is lined, but only the areas that are subject to heavy wear, with tiles that are significantly more wear-resistant than conventional steel sheets. It can thus be achieved that the inner wall of a mixing trough is subject to an essentially uniform wear. For this purpose, it has proven useful to produce such tiles from chilled cast iron, a very hard, brittle material that can only be processed by grinding.
  • a fastening element for example a screw bolt
  • the fastening element has a head at its end facing the inner surface of the trough, the cross section of which is enlarged. Accordingly, the recess formed in the tile has a stepped shape that matches the shape of the head of the Fastener corresponds.
  • the main disadvantage of this fastening method is that it only lasts as long as the head of the fastening element has not yet been worn away. However, since the head inevitably has a smaller thickness than the tile, the tile already falls off the wall of a mixing trough if it is not completely worn out.
  • screws or nuts with an acute thread profile for example a metric iso thread with a flank angle of 60 °
  • Screws and nuts provided with such fastening threads are intended to clamp components firmly together.
  • pointed threads which have a small pitch angle and a large flank angle, a large amount of friction between the internal and external threads can be brought about, which makes an independent loosening of the connection difficult.
  • such threads are not produced by casting, but formed on a workpiece by means of other shaping techniques, for example by turning, cutting, drilling or milling.
  • these molding techniques cannot be used for extremely hard and brittle materials such as chilled cast iron.
  • the object of the present invention is to provide an improved chilled cast iron tile with a cast-in thread for fastening to a trough-shaped container and a method for producing this chilled cast iron tile.
  • a hard cast tile of the type mentioned above is provided according to the invention, in which the thread is designed as a round thread.
  • the use of round threads is known per se from drive technology.
  • round threads are used in the drive spindles of linear drives, since they have less friction between external and internal threads compared to, for example, pointed threads and are therefore very easy to move. Due to this low friction and the high ease of movement, round threads are not suitable for permanently fastening workpieces to one another, and especially not when this screw connection is exposed to strong, fluctuating loads, such as vibrations, such as those that occur constantly when a concrete mixer is in operation. There is then a risk that the screw connection will gradually loosen under the impact of these vibrations. Surprisingly, however, it has been shown that a cast round thread can nevertheless ensure a permanently stable attachment of a tile to the inner wall of a mixing trough.
  • Zircon sand and is formed with a round thread.
  • the casting process itself, according to which the tiles are produced, can be one of the methods known in the prior art. Methods are particularly suitable in which the casting is cast from molding sands or ceramic materials by means of lost negative molds.
  • FIG. 1 is a cross-sectional view of an inventive
  • Fig. 2 is a cross-sectional view of an inventive
  • FIG. 1 shows a cross-sectional view of a hard cast tile 10, which is provided for lining the inner wall of a trough-shaped container, in particular a mixing trough of a concrete mixer.
  • the chilled cast iron tile 10 has a concentric recess 1 2, the cylindrical wall of which is provided with a round thread 1 4.
  • the recess 1 2 and the round thread 14 run in the hard cast tile 10 in FIG. 1 over the entire thickness d of the hard cast tile, so that it is broken.
  • a screw provided with a corresponding round thread is inserted from the outside through a corresponding opening in the wall of the mixing trough and screwed to the tile 10 so that its rear side R is firmly attached to the Inner wall of the mixing trough is in contact.
  • the screw used for fastening has a length such that the screw is flush with the inside I of the tile when the tile is firmly clamped.
  • the recess 1 2 extends from the rear side R of the tile 10 only a part of the thickness d of the tile 10, that is, it does not form an opening, but only a recess ,
  • the tile 10 is made of chilled cast iron. This is very hard, brittle and can only be processed by grinding. It also has a high wear resistance, which is why it is strong for cladding parts subject to wear. These can be the inner walls of concrete mixers, for example, which are subjected to high stress due to the abrasive effect of concrete mixes to be moved as a mix.
  • a round thread 14 is cast into the cylindrical wall of the recess 1 2 for fastening the chilled cast iron tile 10 to the inner wall of a mixing trough. Because of the hardness and brittleness of the hard cast iron, it is not sensible to mill, cut or screw in such a thread in a hard cast iron workpiece, but the thread must be made when the hard cast tile is being cast.
  • FIG. 2 shows a detail of a negative casting mold 20 used for casting the hard casting tile shown in FIG. 1 in a cross-sectional view.
  • the section shown in Fig. 2 shows a concentric approach 22, which is used to form the recess 1 2 of the hard cast tile 10.
  • the extension 22 protrudes from the rear wall R of the hard cast tile wall 24 of the negative mold 20 by a distance d.
  • the cylindrical side wall of the extension 22 is provided with a negative round thread 26, which is used to form the round thread 14 of the hard cast tile 10.
  • zircon sand is used as the molding material, which has a grain size with a diameter of less than 0.2 mm.
  • this molding material it is possible to produce a sufficiently smooth surface for the formation of a screwable round thread when casting hard casting, without the negative casting mold 20 having to be finished before the casting. Dispensing with the finishing of the negative casting mold improves the reliability of the casting process, provided that the roughness of the surface of the casting remains within the tolerable range, since the casting of the Gasses released gases can escape through the pores of the negative mold.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Mechanical Engineering (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Food Science & Technology (AREA)
  • Manufacturing & Machinery (AREA)
  • Ceramic Engineering (AREA)
  • Structural Engineering (AREA)
  • Devices For Post-Treatments, Processing, Supply, Discharge, And Other Processes (AREA)
  • Molds, Cores, And Manufacturing Methods Thereof (AREA)
  • Moulds, Cores, Or Mandrels (AREA)
  • Furnace Housings, Linings, Walls, And Ceilings (AREA)

Abstract

The invention relates to a cast iron tile (10) for lining the inner wall of a vat-shaped container and to a method for the production of said cast iron tile (10). The cast iron tile (10) has a recess (12) serving to fix the tile to the inner wall. A round thread (14) is cast in in the peripheral wall of said recess.

Description

Hartguss-Kachel und Herstellungsverfahren für eine Hartguss-KachelChilled cast tile and manufacturing process for a chilled cast tile
Beschreibungdescription
Die vorliegende Erfindung betrifft eine Hartguss-Kachel zur Auskleidung der Innenwand eines wannenförmigen Behälters, insbesondere des Mischtrogs eines Betonmischers. Die Kachel weist eine Ausnehmung zur Befestigung der Kachel an der Innenwand auf, in deren Umfangswand ein Gewinde eingegossen ist. Ferner betrifft die vorliegende Erfindung ein Verfahren zur Herstellung einer solchen Hartguss-Kachel.The present invention relates to a cast iron tile for lining the inner wall of a trough-shaped container, in particular the mixing trough of a concrete mixer. The tile has a recess for attaching the tile to the inner wall, in the peripheral wall of which a thread is cast. The present invention further relates to a method for producing such a hard cast tile.
Gattungsgemäße Kacheln werden eingesetzt, um starkem Verschleiß ausgesetzte Stellen der Innenwand von Mischern durch eine verschleißbeständige Auskleidung zu schützen. Oft wird nicht die komplette Innenwand, sondern lediglich deren stark verschleißbeanspruchte Stellen mit solchen im Vergleich zu herkömmlichen Stahlblechen deutlich verschleißbeständigeren Kacheln ausgekleidet. So kann erreicht werden, dass die Innenwand eines Mischtrogs einem im Wesentlichen gleichmäßigen Verschleiß unterliegt. Zu diesem Zweck hat es sich bewährt, solche Kacheln aus Hartguss herzustellen, einem sehr harten, spröden und nur durch Schleifen bearbeitbaren Material.Generic tiles are used to protect areas of the inner wall of mixers that are subject to heavy wear with a wear-resistant lining. Often it is not the entire inner wall that is lined, but only the areas that are subject to heavy wear, with tiles that are significantly more wear-resistant than conventional steel sheets. It can thus be achieved that the inner wall of a mixing trough is subject to an essentially uniform wear. For this purpose, it has proven useful to produce such tiles from chilled cast iron, a very hard, brittle material that can only be processed by grinding.
Zur Befestigung von Hartguss-Kacheln an der Wand eines Mischtrogs ist es im Stand der Technik bekannt, eine Ausnehmung in den Kacheln vorzusehen, durch die ein der Befestigung der Kachel an der Wand dienendes Befestigungselement, z.B. ein Schraubbolzen, hindurchgeführt wird, das seinerseits, etwa durch Verschrauben, an der Wand fixiert ist. Das Befestigungselement weist an seinem der Troginnenfläche zugewandten Ende einen Kopf auf, dessen Querschnitt vergrößert ist. Dementsprechend weist auch die in der Kachel ausgebildete Ausnehmung eine abgestufte Form auf, die der Form des Kopfes des Befestigungselements entspricht. Bei dieser Befestigungsmethode ist vor allem nachteilig, dass sie nur so lange Bestand hat, wie der Kopf des Befestigungselements noch nicht durch Verschleiß abgetragen worden ist. Da der Kopf jedoch zwangsläufig eine geringere Dicke aufweist als die Kachel, fällt die Kachel bereits von der Wand eines Mischtrogs ab, wenn sie noch nicht vollständig verschlissen ist.For the attachment of chilled cast iron tiles to the wall of a mixing trough, it is known in the prior art to provide a recess in the tiles through which a fastening element, for example a screw bolt, used to attach the tile to the wall is passed, which in turn, for example by screwing, is fixed to the wall. The fastening element has a head at its end facing the inner surface of the trough, the cross section of which is enlarged. Accordingly, the recess formed in the tile has a stepped shape that matches the shape of the head of the Fastener corresponds. The main disadvantage of this fastening method is that it only lasts as long as the head of the fastening element has not yet been worn away. However, since the head inevitably has a smaller thickness than the tile, the tile already falls off the wall of a mixing trough if it is not completely worn out.
Um die Lebensdauer solcher Hartguss-Kacheln zu verlängern, ist man bestrebt, sie möglichst so lange zu verwenden, bis an einer oder mehreren Stellen ihre Oberfläche völlig abgetragen ist. Um dies zu erreichen, ist versucht worden, Hartguss-Kacheln an der Wand eines Mischtrogs derart zu befestigen, dass eine mit einem Gewinde versehene Ausnehmung in den einzelnen Hartguss-Kacheln vorgesehen wird, in das ein an der Außenwand fixiertes Befestigungselement eingeschraubt wird. Auf diese Weise kann erreicht werden, dass die Kachel an der Trogwand haftet, bis die letzten ein bis zwei Gewindegänge des Gewindes verschleißbedingt abgetragen worden sind. Es hat sich jedoch herausgestellt, dass das Herstellen eines Gewindes in solchen Hartguss-Kacheln extrem schwierig ist. Wegen der Härte und Sprödigkeit von Hartguss kann dieser nur schleifend bearbeitet werden, so dass das Gewinde nicht durch Umformen, etwa Drehen oder Fräsen, hergestellt werden kann, sondern beim Gießen der Hartguss-Kachel hergestellt werden muss.In order to extend the lifespan of such chilled cast iron tiles, efforts are made to use them as long as possible until their surface is completely worn away in one or more places. In order to achieve this, attempts have been made to fasten chilled cast iron tiles to the wall of a mixing trough in such a way that a threaded recess is provided in the individual chilled cast iron tiles, into which a fastening element fixed to the outer wall is screwed. In this way it can be achieved that the tile adheres to the trough wall until the last one or two turns of the thread have been removed due to wear. However, it has been found that it is extremely difficult to create a thread in such chilled iron tiles. Because of the hardness and brittleness of chilled cast iron, it can only be machined by grinding, so that the thread cannot be produced by forming, such as turning or milling, but must be produced when casting the chilled cast iron tile.
Herkömmlicherweise werden zur Befestigung von Werkstücken Schrauben bzw. Muttern mit einem spitzen Gewindeprofil, beispielsweise einem metrischen Isogewinde mit einem Flankenwinkel von 60°, verwendet. Mit solchen Befestigungsgewinden versehene Schrauben und Muttern sollen Bauteile fest miteinander verspannen. Durch die Verwendung von Spitzgewinden, welche einen kleinen Steigungswinkel und einen großen Flankenwinkel aufweisen, lässt sich eine große Reibung zwischen Innen- und Außengewinde bewirken, welche ein selbstständiges Lösen der Verbindung erschwert. Üblicherweise werden solche Gewinde jedoch nicht durch Gießen hergestellt, sondern mittels anderer Formungstechniken, beispielsweise durch Drehen, Schneiden, Bohren oder Fräsen, an einem Werkstück ausgebildet. Diese Formungstechniken kommen bei extrem harten und spröden Materialien wie Hartguss jedoch nicht in Betracht.Conventionally, screws or nuts with an acute thread profile, for example a metric iso thread with a flank angle of 60 °, are used for fastening workpieces. Screws and nuts provided with such fastening threads are intended to clamp components firmly together. Through the use of pointed threads, which have a small pitch angle and a large flank angle, a large amount of friction between the internal and external threads can be brought about, which makes an independent loosening of the connection difficult. Usually, however, such threads are not produced by casting, but formed on a workpiece by means of other shaping techniques, for example by turning, cutting, drilling or milling. However, these molding techniques cannot be used for extremely hard and brittle materials such as chilled cast iron.
Frühere Versuche, Hartguss-Kacheln mit eingegossenen Gewinden herzustellen, verliefen unbefriedigend. So konnte bei Verwendung von Keramikgussformen bzw. -kernen zur Ausbildung eines Gewindes wegen starker Blasenbildung beim Abguss nicht die für ein Gewinde erforderliche Regelmäßigkeit der Oberfläche des Gussstücks und Abbildungsgenauigkeit erreicht werden. Bei Verwendung von Quarzsandformen, die vor dem Gießen der Hartguss-Kacheln mit einer geeigneten Schlichte versehen wurden, musste das gegossene Gewinde nachbearbeitet werden, da es nicht über die gewünschte Glätte verfügte. Da Hartguss nur schleifend bearbeitbar ist, ist dies jedoch eine sehr aufwendige Maßnahme, und deshalb nicht wünschenswert.Previous attempts to produce chilled cast iron tiles with cast threads were unsatisfactory. For example, when using ceramic casting molds or cores to form a thread, the regularity of the surface of the casting and the accuracy of imaging required for a thread could not be achieved due to strong blistering during casting. When using quartz sand molds, which were given a suitable size before the hard cast tiles were poured, the cast thread had to be reworked because it did not have the desired smoothness. Since chilled cast iron can only be machined by grinding, this is a very complex measure and is therefore not desirable.
Letzten Endes haben diese Versuche daher dazu geführt, dass der Stand der Technik sich wieder der erstgenannten Lösung des Problems der Befestigung von Hartguss-Kacheln an der Wand eines Behälters zugewandt hat.Ultimately, these attempts have therefore resulted in the prior art once again turning to the first-mentioned solution to the problem of fastening chilled cast iron tiles to the wall of a container.
Aufgabe der vorliegenden Erfindung ist es, eine verbesserte Hartguss- Kachel mit eingegossenem Gewinde zur Befestigung an einem wannenförmigen Behälter sowie ein Verfahren zur Herstellung dieser Hartguss-Kachel anzugeben.The object of the present invention is to provide an improved chilled cast iron tile with a cast-in thread for fastening to a trough-shaped container and a method for producing this chilled cast iron tile.
Zur Lösung dieser Aufgabe ist erfindungsgemäß eine Hartguss-Kachel der oben genannten Art vorgesehen, bei der das Gewinde als Rundgewinde ausgebildet ist. Der Einsatz von Rundgewinden ist an sich bekannt, und zwar aus der Antriebstechnik. Beispielsweise werden Rundgewinde bei Antriebsspindeln von Lineartrieben eingesetzt, da sie im Vergleich beispielsweise zu Spitzgewinden über eine geringere Reibung zwischen Außen- und Innengewinde verfügen und daher sehr leichtgängig sind. Auf Grund dieser geringen Reibung und der hohen Leichtgängigkeit eignen sich Rundgewinde nicht zur dauerhaften Befestigung von Werkstücken aneinander, und dies insbesondere dann nicht, wenn diese Schraubverbindung starken, schwankenden Belastungen ausgesetzt ist, beispielsweise Erschütterungen, wie sie im Betrieb eines Betonmischers ständig auftreten. Es besteht dann nämlich die Gefahr, dass sich die Schraubverbindung unter dem Eindruck dieser Erschütterungen allmählich löst. Überraschenderweise hat sich jedoch gezeigt, dass ein eingegossenes Rundgewinde gleichwohl eine dauerhaft stabile Befestigung einer Kachel an der Innenwand eines Mischtrogs gewährleisten kann.To achieve this object, a hard cast tile of the type mentioned above is provided according to the invention, in which the thread is designed as a round thread. The use of round threads is known per se from drive technology. For example, round threads are used in the drive spindles of linear drives, since they have less friction between external and internal threads compared to, for example, pointed threads and are therefore very easy to move. Due to this low friction and the high ease of movement, round threads are not suitable for permanently fastening workpieces to one another, and especially not when this screw connection is exposed to strong, fluctuating loads, such as vibrations, such as those that occur constantly when a concrete mixer is in operation. There is then a risk that the screw connection will gradually loosen under the impact of these vibrations. Surprisingly, however, it has been shown that a cast round thread can nevertheless ensure a permanently stable attachment of a tile to the inner wall of a mixing trough.
Bei einem Rundgewinde können vergleichsweise große Abweichungen zwischen Innengewinde und eingeschraubtem Außengewinde toleriert werden. Dies erleichtert das Gießen des Gewindes erheblich. Auch das Herstellen von Modell, Negativ-Gussform und Gussstück ist wegen des Fehlens scharfer Kanten viel einfacher als bei anderen Gewinden. Dies führt dazu, dass beim Gießen eines Rundgewindes auf komplizierte und aufwendige Maßnahmen, insbesondere auf Nachbearbeitungsmaßnahmen weitgehend verzichtet werden kann. Somit ist es möglich, Hartguss- Kacheln auf eine effiziente und konkurrenzfähige Weise zu erzeugen, welche gegenüber dem gegenwärtig verwendeten Hartguss-Kacheln über eine zusätzliche Verschleißreserve verfügen.In the case of a round thread, comparatively large deviations between the internal thread and the screwed-in external thread can be tolerated. This makes casting the thread considerably easier. Making the model, negative mold and casting is also much easier than with other threads due to the lack of sharp edges. The result of this is that complicated and complex measures, in particular post-processing measures, can largely be dispensed with when casting a round thread. It is thus possible to produce chilled iron tiles in an efficient and competitive manner, which have an additional wear reserve compared to the currently used chilled iron tiles.
Bei dem erfindungsgemäßen Gussverfahren zur Herstellung von Hartguss- Kacheln ist vorgesehen, dass zumindest ein der Ausbildung derIn the casting method according to the invention for producing hard cast tiles, it is provided that at least one of the forms of the
Ausnehmung dienender Abschnitt der Negativ-Gussform der Kachel ausRecess-serving section of the negative mold of the tile
Zirkonsand und mit einem Rundgewinde geformt wird. Das Gussverfahren selbst, nach dem die Kacheln hergestellt werden, kann eines der im Stand der Technik bekannten Verfahren sein. Insbesondere eignen sich Verfahren, bei denen das Gussstück mittels verlorener Negativ-Gussformen aus Formsanden oder keramischen Materialien gegossen werden.Zircon sand and is formed with a round thread. The casting process itself, according to which the tiles are produced, can be one of the methods known in the prior art. Methods are particularly suitable in which the casting is cast from molding sands or ceramic materials by means of lost negative molds.
Während man bei der Herstellung von gegossenen Spitzgewinden darauf angewiesen ist, unbedingt eine möglichst glatte Oberfläche zu erzeugen, ermöglicht es der Einsatz eines Rundgewindes gemäß der vorliegenden Erfindung, eine deutlich rauhere Oberfläche in Kauf zu nehmen. Dies bedeutet, dass die an eine Schlichte zu stellenden Anforderungen wesentlich geringer sind. Es hat sich gezeigt, dass bei Verwendung von Zirkonsand als Formstoff für die Negativ-Gussform sogar ganz auf den Auftrag einer Schlichte verzichtet werden kann. Ein nicht zu unterschätzender Vorteil, der durch den Verzicht auf eine Schlichte erzielt wird, besteht darin, dass eine gewisse Gasdurchlässigkeit der Negativ- Gussform beim Guss erhalten bleibt. Auf diese Weise kann beim Gießen der Kacheln frei werdendes Gas, das etwa in dem verwendeten Gussmaterial enthalten sein kann oder das nicht komplett aus der Gussform verdrängt wird, durch die Poren des Formstoffs der Gussform entweichen. Dies verringert das Risiko von Fehlstellen an den gegossenen Kacheln durch die Bildung von Blasen (sogenannte Lunker) an der Oberfläche der relativ gasundurchlässigen Schlichte.While in the production of cast pointed threads it is absolutely necessary to produce a surface that is as smooth as possible, the use of a round thread according to the present invention makes it possible to accept a significantly rougher surface. This means that the requirements to be met by a size are significantly lower. It has been shown that when using zircon sand as the molding material for the negative mold, there is even no need to apply a size. An advantage that should not be underestimated, which is achieved by dispensing with a size, is that a certain gas permeability of the negative casting mold is retained during casting. In this way, when the tiles are poured, gas which is released, which may be contained in the casting material used or which is not completely displaced from the casting mold, can escape through the pores of the molding material of the casting mold. This reduces the risk of defects on the cast tiles due to the formation of bubbles (so-called voids) on the surface of the relatively gas-impermeable size.
Es hat sich herausgestellt, dass eine ausreichend glatte Oberfläche des Rundgewindes auch ohne Einsatz einer Schlichte erzielt werden kann, wenn der zur Herstellung der Negativ-Gussform verwendete Zirkonsand eine Körnung mit einem Durchmesser von kleiner als 0,2 mm aufweist.It has been found that a sufficiently smooth surface of the round thread can also be achieved without the use of a size if the zircon sand used to produce the negative casting mold has a grain size of less than 0.2 mm.
Die vorliegende Erfindung wird im Folgenden an einem Ausführungsbeispiel an Hand der beigefügten Figuren näher beschrieben. Es zeigt Fig. 1 eine Querschnittsansicht einer erfindungsgemäßenThe present invention is described in more detail below using an exemplary embodiment with reference to the attached figures. It shows Fig. 1 is a cross-sectional view of an inventive
Hartguss-Kachel mit einer Ausnehmung, die ein Rundgewinde aufweist;Chilled cast iron tile with a recess that has a round thread;
Fig. 2 eine Querschnittsansicht einer erfindungsgemäßenFig. 2 is a cross-sectional view of an inventive
Negativ-Gussform zur Herstellung der in Fig. 1 gezeigten Hartguss-Kachel.Negative mold for the production of the hard cast tile shown in FIG. 1.
In Fig. 1 ist eine Querschnittsansicht einer Hartguss-Kachel 10 gezeigt, welche zur Auskleidung der Innenwand eines wannenförmigen Behälters, insbesondere eines Mischtrogs eines Betonmischers, vorgesehen ist. Zur Befestigung an der Innenwand weist die Hartguss-Kachel 10 eine konzentrische Ausnehmung 1 2 auf, deren zylinderförmige Wand mit einem Rundgewinde 1 4 versehen ist. Die Ausnehmung 1 2 und das Rundgewinde 14 verlaufen bei der Hartguss-Kachel 10 in Fig. 1 über die gesamte Dicke d der Hartguss-Kachel hinweg, so dass diese durchbrochen ist. Zur Befestigung der Hartguss-Kachel an der Innenwand eines Mischtrogs wird beispielsweise eine mit einem entsprechenden Rundgewinde versehene Schraube von außen durch eine entsprechende Öffnung in der Wand des Mischtrogs gesteckt und mit der Kachel 1 0 verschraubt, so dass diese mit ihrer Rückseite R fest an der Innenwand des Mischtrogs anliegt. Idealerweise weist die zur Befestigung verwendete Schraube eine solche Länge auf, dass bei fest verspannter Kachel die Schraube bündig mit der Innenseite I der Kachel abschließt. Alternativ zu der in Fig. 1 gezeigten Anordnung ist es selbstverständlich auch denkbar, dass die Ausnehmung 1 2 sich von der Rückseite R der Kachel 10 her lediglich einen Teil der Dicke d der Kachel 10 erstreckt, also nicht eine Durchbrechung, sondern lediglich eine Vertiefung bildet.1 shows a cross-sectional view of a hard cast tile 10, which is provided for lining the inner wall of a trough-shaped container, in particular a mixing trough of a concrete mixer. For attachment to the inner wall, the chilled cast iron tile 10 has a concentric recess 1 2, the cylindrical wall of which is provided with a round thread 1 4. The recess 1 2 and the round thread 14 run in the hard cast tile 10 in FIG. 1 over the entire thickness d of the hard cast tile, so that it is broken. To attach the chilled cast iron tile to the inner wall of a mixing trough, for example, a screw provided with a corresponding round thread is inserted from the outside through a corresponding opening in the wall of the mixing trough and screwed to the tile 10 so that its rear side R is firmly attached to the Inner wall of the mixing trough is in contact. Ideally, the screw used for fastening has a length such that the screw is flush with the inside I of the tile when the tile is firmly clamped. As an alternative to the arrangement shown in FIG. 1, it is of course also conceivable that the recess 1 2 extends from the rear side R of the tile 10 only a part of the thickness d of the tile 10, that is, it does not form an opening, but only a recess ,
Die Kachel 10 besteht aus Hartguss. Dieser ist sehr hart, spröde und nur durch Schleifen bearbeitbar. Er besitzt außerdem einen hohen Verschleißwiderstand, weswegen er zur Verkleidung stark verschleißbeanspruchter Teile verwendet wird. Dies können beispielsweise die durch die abrasive Wirkung von als Mischgut zu bewegenden Betongemischen stark beanspruchten Innenwände von Betonmischern sein.The tile 10 is made of chilled cast iron. This is very hard, brittle and can only be processed by grinding. It also has a high wear resistance, which is why it is strong for cladding parts subject to wear. These can be the inner walls of concrete mixers, for example, which are subjected to high stress due to the abrasive effect of concrete mixes to be moved as a mix.
Zur Befestigung der Hartguss-Kachel 10 an der Innenwand eines Mischtrogs ist ein Rundgewinde 14 in die zylindrische Wand der Ausnehmung 1 2 eingegossen. Wegen der Härte und Sprödigkeit des Hartgusses ist es nicht sinnvoll möglich, ein solches Gewinde in ein Werkstück aus Hartguss einzufräsen, einzuschneiden oder einzudrehen, sondern das Gewinde muss beim Gießen der Hartguss-Kachel hergestellt werden.A round thread 14 is cast into the cylindrical wall of the recess 1 2 for fastening the chilled cast iron tile 10 to the inner wall of a mixing trough. Because of the hardness and brittleness of the hard cast iron, it is not sensible to mill, cut or screw in such a thread in a hard cast iron workpiece, but the thread must be made when the hard cast tile is being cast.
In Fig. 2 ist ein Ausschnitt einer zum Gießen der in Fig. 1 gezeigten Hartguss-Kachel verwendeten Negativ-Gussform 20 in einer Querschnittsansicht gezeigt. Der in Fig. 2 gezeigte Ausschnitt zeigt einen konzentrischen Ansatz 22, der zur Ausbildung der Ausnehmung 1 2 der Hartguss-Kachel 10 dient. Der Ansatz 22 steht gegenüber der die Rückwand R der Hartguss-Kachel bildenden Wand 24 der Negativ- Gussform 20 um eine Strecke d vor. Die zylindrische Seitenwand des Ansatzes 22 ist mit einem Negativ-Rundgewinde 26 versehen, das der Ausbildung des Rundgewindes 14 der Hartguss-Kachel 10 dient.FIG. 2 shows a detail of a negative casting mold 20 used for casting the hard casting tile shown in FIG. 1 in a cross-sectional view. The section shown in Fig. 2 shows a concentric approach 22, which is used to form the recess 1 2 of the hard cast tile 10. The extension 22 protrudes from the rear wall R of the hard cast tile wall 24 of the negative mold 20 by a distance d. The cylindrical side wall of the extension 22 is provided with a negative round thread 26, which is used to form the round thread 14 of the hard cast tile 10.
Zur Herstellung der Negativ-Gussform 20 wird Zirkonsand als Formstoff benutzt, der eine Körnung mit einem Durchmesser von kleiner als 0,2 mm aufweist. Durch Verwendung dieses Formstoffs ist es möglich, beim Gießen von Hartguss eine ausreichend glatte Oberfläche für die Ausbildung eines schraubbaren Rundgewindes zu erzeugen, ohne dass die Negativ- Gussform 20 vor dem Gießen geschlichtet werden muss. Der Verzicht auf das Schlichten der Negativ-Gussform verbessert die Zuverlässigkeit des Gussverfahrens, vorausgesetzt, die Rauhigkeit der Oberfläche des Gussstücks bleibt im tolerierbaren Rahmen, da beim Gießen des Gussstücks freigesetzte Gase durch die Poren der Negativ-Gussform entweichen können. To produce the negative casting mold 20, zircon sand is used as the molding material, which has a grain size with a diameter of less than 0.2 mm. By using this molding material, it is possible to produce a sufficiently smooth surface for the formation of a screwable round thread when casting hard casting, without the negative casting mold 20 having to be finished before the casting. Dispensing with the finishing of the negative casting mold improves the reliability of the casting process, provided that the roughness of the surface of the casting remains within the tolerable range, since the casting of the Gasses released gases can escape through the pores of the negative mold.

Claims

Ansprüche Expectations
1 . Hartguss-Kachel (10) zur Auskleidung der Innenwand eines wannenförmigen Behälters, insbesondere des Mischtrogs eines1 . Chilled cast iron tile (10) for lining the inner wall of a trough-shaped container, in particular the mixing trough
Betonmischers, umfassend eine der Befestigung der Kachel an der Innenwand dienende Ausnehmung (12), in deren Umfangswand ein Gewinde eingegossen ist, dadurch gekennzeichnet, dass das Gewinde als Rundgewinde (14) ausgebildet ist.Concrete mixer, comprising a recess (12) for fastening the tile to the inner wall, in the peripheral wall of which a thread is cast, characterized in that the thread is designed as a round thread (14).
2. Verfahren zur Herstellung einer Hartguss-Kachel (1 0), insbesondere nach Anspruch 1 , welche zur Auskleidung der Innenwand eines wannenförmigen2. A method for producing a hard cast tile (1 0), in particular according to claim 1, which for lining the inner wall of a tub-shaped
Behälters, insbesondere des Mischtrogs eines Betonmischers, bestimmt ist, und eine der Befestigung der Kachel an dieser Innenwand dienende, mit einem Gewinde versehene Ausnehmung ( 1 2) aufweist, dadurch gekennzeichnet, dass zumindest ein der Ausbildung der Ausnehmung dienender Abschnitt (22) der Negativ-Gussform (20) der Kachel aus Zirkonsand und mit einem Rundgewinde (26) geformt wird.Container, in particular the mixing trough of a concrete mixer, and has a threaded recess (1 2) for fastening the tile to this inner wall, characterized in that at least one section (22) serving to form the recess is the negative -Casting mold (20) the tile is formed from zircon sand and with a round thread (26).
3. Verfahren nach Anspruch 2, dadurch gekennzeichnet, dass der der Ausbildung der Ausnehmung dienende Abschnitt (22) der Negativ-Gussform (20) ungeschlichtet ist. Verfahren nach einem der Ansprüche 2 oder 3, dadurch gekennzeichnet, dass der Zirkonsand eine Körnung mit einem Durchmesser kleiner als 0,2 mm aufweist. 3. The method according to claim 2, characterized in that the portion (22) of the negative casting mold (20) serving to form the recess is unfinished. Method according to one of claims 2 or 3, characterized in that the zircon sand has a grain size with a diameter of less than 0.2 mm.
EP03725128A 2002-05-17 2003-04-30 Cast iron tile and method for the production of cast iron tile Expired - Lifetime EP1507638B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
DE10222079A DE10222079A1 (en) 2002-05-17 2002-05-17 Chilled-cast tiles for lining of esp. a concrete mixer trough has aperture in back with round thread, cast in negative mold with zircon sand section for thread, for higher quality
DE10222079 2002-05-17
PCT/EP2003/004578 WO2003097315A1 (en) 2002-05-17 2003-04-30 Cast iron tile and method for the production of cast iron tile

Publications (2)

Publication Number Publication Date
EP1507638A1 true EP1507638A1 (en) 2005-02-23
EP1507638B1 EP1507638B1 (en) 2006-03-15

Family

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Family Applications (1)

Application Number Title Priority Date Filing Date
EP03725128A Expired - Lifetime EP1507638B1 (en) 2002-05-17 2003-04-30 Cast iron tile and method for the production of cast iron tile

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Country Link
EP (1) EP1507638B1 (en)
CN (1) CN100340386C (en)
AU (1) AU2003227701A1 (en)
DE (2) DE10222079A1 (en)
PT (1) PT1507638E (en)
WO (1) WO2003097315A1 (en)

Family Cites Families (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3837888C2 (en) * 1988-11-08 1997-09-18 Liebherr Mischtechnik Gmbh Screw connection for fastening interchangeable, wear-resistant plate-shaped coverings
CN2053969U (en) * 1989-05-20 1990-03-07 梁尽忠 White pig iron-steel composite type lining board for ball mill
DE4304338A1 (en) * 1993-02-13 1994-08-18 Geping Dr Ing Wang Wear-resisting tile functional group with bonding means for the mixer linings
DE4432543C1 (en) * 1994-09-13 1996-04-04 Noell Serv & Maschtechn Gmbh Fixing device for wear plate in pulverising machine
DE19654797C2 (en) * 1996-12-31 1998-10-22 Bhs Sonthofen Maschinen & Anlagenbau Gmbh Lining a cylindrical inner surface of a mixer with tiles
CN2468699Y (en) * 2001-04-09 2002-01-02 熊弟康 Truck mixer
CN2475461Y (en) * 2001-04-12 2002-02-06 王秀英 A novel grinding plate for mixer

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
See references of WO03097315A1 *

Also Published As

Publication number Publication date
DE10222079A1 (en) 2003-11-27
AU2003227701A1 (en) 2003-12-02
PT1507638E (en) 2006-07-31
CN100340386C (en) 2007-10-03
DE50302668D1 (en) 2006-05-11
EP1507638B1 (en) 2006-03-15
WO2003097315A1 (en) 2003-11-27
CN1649708A (en) 2005-08-03

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