A composite liner plate for a jaw crusher

Abstract

This utility model relates to a composite liner for a jaw crusher, comprising a liner body and several toothed plates mounted thereon, the toothed plates being spaced apart, with the width of the groove formed between adjacent toothed plates being smaller than the width of the toothed plate; it also includes a metal-ceramic block, which has at least two through holes; the metal-ceramic block is evenly distributed on the working surface of the toothed plates; the surface of the metal-ceramic block is not higher than the working surface of the toothed plates. This utility model, by providing through holes inside the metal-ceramic block, allows molten metal to seep into the metal-ceramic block during casting, forming a "metal anchor" structure after cooling and solidification, providing the metal-ceramic block with a pull-out force perpendicular to the interface, effectively preventing the metal-ceramic block from laterally sliding or falling off under impact loads.

Description

Technical Field

[0001] This utility model relates to the field of mining equipment technology, specifically to a composite liner for a jaw crusher. Background Technology

[0002] A jaw crusher mainly consists of a frame, working mechanism, transmission mechanism, adjusting device, safety device, and lubrication system. The frame is the fundamental component of the jaw crusher, typically welded from cast steel or high-strength steel plates, providing stable support for the entire machine and withstanding the enormous forces during the crushing process. The fixed jaw and moving jaw are the core components for material crushing. The moving jaw oscillates periodically, driven by an eccentric shaft. Materials are crushed through mutual squeezing and grinding. Jaw crushers are commonly used in mining and stone processing, where the materials are complex and diverse. When processing high-hardness materials such as quartz and iron ore, the liners need to withstand enormous compressive and frictional forces. Prolonged high-intensity impacts can cause the surface material of the liners to gradually fatigue and peel off, accelerating liner wear.

[0003] Authorization Announcement No.: CN 220803419 U, Application Date: 2023.09.21, Utility Model Name: A Wear-Resistant Liner for a Jaw Crusher. This utility model relates to the technical field of jaw crushers, specifically a wear-resistant liner for a jaw crusher, comprising: a chute for fixed installation on a base plate; two sets of chutes provided on the base plate; two sets of sliders movably inserted into the chute; a liner plate fixedly installed on the front side of the two sets of sliders; and multiple sets of jaw teeth provided on the front side of the liner plate. When this utility model is used to disassemble and replace parts of the liner and jaw teeth due to wear, the fixing components at the lower end of the base plate are first removed. Then, the liner and jaw teeth at the smallest end of the base plate are slid out and removed. The two sets of liner and jaw teeth at the upper end of the base plate are slid downwards. Then, the fixing plate at the upper end is removed, and the new liner and jaw teeth are installed on the base plate. The liner and jaw teeth are fixed on the upper and lower ends of the base plate by the two sets of fixing plates, thereby fixing the liner and jaw teeth on the base plate and improving the utilization rate of the liner and jaw teeth.

[0004] The aforementioned existing technology employs a fragmented design for the liner and jaw teeth, aiming to improve component utilization through partial replacement and avoid overall disassembly. However, in actual operation of a jaw crusher, the joints between adjacent jaw teeth are weak points. The tiny gaps existing at these joints can become channels for the intrusion of fine materials and corrosive media when crushing wet materials or ores containing corrosive components. During the crushing process, fine material particles can become embedded in these gaps.

[0005] Furthermore, no corresponding technical insights were provided for improving the wear resistance of jaw teeth. Utility Model Content

[0006] In view of the defects in the existing technology, such as the weak point at the splice of the jaw teeth becoming a channel for the intrusion of fine materials and corrosive media, the purpose of this utility model is to provide a composite liner that can enhance the overall wear resistance and impact resistance of the jaw crusher.

[0007] The technical solution provided by this utility model is as follows:

[0008] A composite liner for a jaw crusher includes a liner body and a plurality of toothed plates located thereon, wherein the toothed plates are spaced apart and the width of the groove formed between adjacent toothed plates is smaller than the width of the toothed plates.

[0009] It also includes a metal-ceramic block, which has at least two through holes; the metal-ceramic block is evenly distributed on the working surface of the toothed plate; the surface of the metal-ceramic block is not higher than the working surface of the toothed plate.

[0010] Furthermore, the metal-ceramic block includes single-row metal-ceramic blocks and multi-row metal-ceramic blocks;

[0011] The through holes of the single-row metal-ceramic block are arranged in a straight line, while the through holes of the multi-row metal-ceramic block are arranged in an array; the toothed plate is cast with single-row metal-ceramic blocks and / or multi-row metal-ceramic blocks.

[0012] Furthermore, along the width direction of the toothed plate, there is a gap between the edge of the toothed plate and the edge of the metal-ceramic block.

[0013] Furthermore, the net distance between the edge of the toothed plate and the edge of the metal-ceramic block is not less than 12mm.

[0014] Furthermore, the metal-ceramic blocks are spaced apart along the length of the toothed plate.

[0015] Furthermore, the net distance between two adjacent metal-ceramic blocks is 12mm to 18mm.

[0016] Furthermore, the through hole is circular or square.

[0017] Furthermore, when the through hole is circular, its diameter is A, and A ranges from 18mm to 23mm;

[0018] When the through hole is square, its side length is B, and the range of B is 20mm~25mm.

[0019] Furthermore, when the through hole is circular, the net distance between adjacent through holes is C, where A / 2 ≤ C ≤ A;

[0020] When the through hole is square, the net distance between adjacent through holes is D, and B / 2≤D≤B.

[0021] Furthermore, the net distance from the edge of the through hole to the edge of the metal-ceramic block is not less than 10 mm.

[0022] Furthermore, each of the metal-ceramic blocks is arranged laterally or longitudinally on the toothed plate.

[0023] Compared with the prior art, the technical solution provided by this utility model has the following advantages:

[0024] (1) The present invention has metal-ceramic blocks evenly distributed on the toothed plate. The metal-ceramic blocks have the characteristics of good toughness of metal and ultra-high hardness and excellent wear resistance of ceramic. During the material crushing process, they can effectively resist the frequent impact and severe friction of hard materials such as ore and rock, which significantly improves the wear resistance of the toothed plate and greatly extends the service life of the toothed plate.

[0025] (2) This utility model provides a through hole inside the metal-ceramic block, allowing molten metal to seep into the block during casting. After cooling and solidification, it forms a "metal anchor" structure, providing the metal-ceramic block with a pull-out force perpendicular to the interface, effectively preventing the metal-ceramic block from sliding laterally or falling off under impact loads. When dealing with high impact conditions during ore crushing, it ensures that the metal-ceramic block consistently exhibits its high hardness and high wear resistance, maintaining the wear resistance of the liner surface, effectively reducing equipment maintenance frequency and lowering operating costs. Attached Figure Description

[0026] Figure 1 This is an overall structural diagram of the composite liner in one embodiment of this application;

[0027] Figure 2 This is a schematic diagram of a metal-ceramic block cast on a toothed plate in one embodiment of this application;

[0028] Figure 3 This is a three-dimensional structural diagram of a single-row metal-ceramic block with circular through holes in one embodiment of this application;

[0029] Figure 4 This is a front view of a single-row metal-ceramic block with circular through holes in one embodiment of this application;

[0030] Figure 5 This is a three-dimensional structural diagram of a single-row metal-ceramic block with square through holes in one embodiment of this application;

[0031] Figure 6 This is a front view of a single-row metal-ceramic block with square through holes in one embodiment of this application;

[0032] Figure 7 This is a three-dimensional structural diagram of a multi-row metal-ceramic block with circular through holes in one embodiment of this application;

[0033] Figure 8 This is a front view of a multi-row metal-ceramic block with circular through holes in one embodiment of this application;

[0034] Figure 9 This is a three-dimensional structural diagram of a multi-row metal-ceramic block with through holes in one embodiment of this application;

[0035] Figure 10 This is a front view of a multi-row metal-ceramic block with hexagonal through holes in one embodiment of this application.

[0036] Explanation of the labels in the diagram:

[0037] Tooth plate 1;

[0038] Liner body 2;

[0039] Metal-ceramic block 3; single-row metal-ceramic block 31, multi-row metal-ceramic block 32. Detailed Implementation

[0040] To further understand the content of this utility model, a detailed description of this utility model will be provided in conjunction with the accompanying drawings and embodiments.

[0041] The structures, proportions, and sizes illustrated in the accompanying drawings are merely for illustrative purposes and to aid those skilled in the art in understanding and reading the invention. They are not intended to limit the scope of the invention and therefore have no substantial technical significance. Any modifications to the structure, changes in proportions, or adjustments to size, without affecting the effectiveness and purpose of the invention, should still fall within the scope of the technical content disclosed in this utility model. Furthermore, terms such as "upper," "lower," "left," "right," and "middle" used in this specification are merely for clarity and not intended to limit the scope of implementation. Changes or adjustments to their relative relationships, without substantially altering the technical content, should also be considered within the scope of the invention's implementation.

[0042] Jaw crusher liners mainly consist of fixed jaw plates and movable jaw plates, which are key components of the crusher used directly for crushing materials.

[0043] Fixed jaw plates are typically installed on the front wall of the crusher frame as a fixed support surface for crushing operations. Their structure is relatively stable and tightly connected to the frame. During the crushing process, they provide a relatively static pressure surface for the material, ensuring that they do not loosen or shift when subjected to material impact and compression.

[0044] The movable jaw plate is connected to the eccentric shaft via a suspension device. Driven by the eccentric shaft, it makes a periodic reciprocating motion toward the fixed jaw plate, sometimes approaching and sometimes moving away. When the movable jaw plate approaches the fixed jaw plate, the material is crushed by forces such as compression, splitting, and impact between the two jaw plates. When the movable jaw plate moves away from the fixed jaw plate, the crushed material is discharged from the discharge port by gravity.

[0045] During the operation of a jaw crusher, the liners come into direct contact with materials such as ore and rock. After the material enters the crushing chamber, the movable jaw plates crush the material through reciprocating motion by squeezing, splitting, and impact. In this process, the liners bear enormous impact and compressive forces. Under such high-intensity mechanical loads for a long time, liners with ordinary structures are prone to wear, deformation, and even cracking.

[0046] This application discloses a composite liner for a jaw crusher, comprising a liner body 2 and a plurality of toothed plates 1 disposed thereon, the toothed plates 1 being spaced apart. The movable jaw plate and the fixed jaw plate each comprise the liner body 2 and the toothed plates 1.

[0047] It is worth noting that the width of the groove formed between adjacent jaw plates 1 is smaller than the width of jaw plate 1. When the jaw crusher is running, the material is gradually crushed into small particles under the mutual squeezing and biting action of the fixed jaw plate and the movable jaw plate. At this time, the crushed small particles will quickly slide into the groove under the action of their own gravity and crushing force. Compared with the traditional liner design, this structure effectively avoids secondary crushing of small particles in the crushing area, greatly improves crushing efficiency, and reduces unnecessary energy consumption. At the same time, the material sliding into the groove can move more smoothly towards the discharge port, reducing the risk of material blockage and ensuring the continuous and stable operation of the crusher.

[0048] This application discloses a composite liner for a jaw crusher, which further includes metal-ceramic blocks 3 evenly distributed on the jaw plate 1. The metal-ceramic blocks 3 have through holes. The liner body 2 and the jaw plate 1 are integrally formed by casting molten metal, and the molten metal is fused with the metal-ceramic blocks 3 through the through holes. The thickness of the metal-ceramic blocks 3 is 10mm to 70mm.

[0049] From a wear resistance perspective, traditional liners are prone to surface wear when crushing hard materials such as quartz and iron ore, leading to frequent liner replacements and impacting production efficiency. The addition of the metal-ceramic block 3 creates a high-hardness, wear-resistant layer on the liner surface, significantly extending the service life of the toothed plate 1 and reducing downtime for maintenance. Regarding impact resistance, molten metal fills the through-holes in the metal-ceramic block 3. When crushing large materials, the impact force is evenly dispersed through the synergistic effect of the metal-ceramic block 3 and the metal matrix.

[0050] From the perspective of reducing liner weight, the metal-ceramic block 3, composed of a metallic and ceramic phase composite, has a lower density compared to traditional single-metal materials, effectively reducing liner weight. Furthermore, due to the excellent wear resistance of the metal-ceramic block 3, the liner experiences less wear during use, reducing the need for liner thickening due to excessive wear. Traditional liners often require increased thickness to ensure service life, leading to a significant increase in weight. However, thanks to the properties of the metal-ceramic block 3, the composite liner does not require excessive thickening, thus effectively controlling the overall weight. The lightweight composite liner not only reduces energy consumption during jaw crusher operation and minimizes mechanical wear caused by load, but also lowers labor and material costs during equipment installation and maintenance.

[0051] The cermet block 3 is located on the working surface of the toothed plate 1 and does not protrude from the working surface. Therefore, it can form a unique wear protection mechanism, avoiding stress concentration caused by the cermet block 3 protruding from the working surface. Stress concentration can easily lead to cracks at the joint between the cermet block 3 and the toothed plate 1, which can then cause the cermet block 3 to loosen or even fall off.

[0052] The composite liner of this application is designed with the metal-ceramic block 3 flush with the working surface, which allows stress to be evenly distributed along the working surface, ensuring the structural stability of the composite liner under long-term high-load working environment.

[0053] Another approach is to place the surface of the metal-ceramic block 3 slightly below the working surface by 0.5 to 3 mm, which can form a unique wear protection mechanism. After the working surface is worn to a certain extent, the metal-ceramic block 3 is gradually exposed and bears the main wear load (similar to the "gradient wear" mechanism), forming a natural "hard support layer".

[0054] Along the width direction of the toothed plate 1, there is a gap between the edge of the toothed plate 1 and the edge of the metal-ceramic block 3. More specifically, the net distance between the edge of the toothed plate 1 and the edge of the metal-ceramic block 3 is not less than 12mm. This gap provides sufficient space for the molten metal to encapsulate the metal-ceramic block 3, allowing the molten metal to flow and fill fully during the casting process, forming a uniform and firm encapsulation layer. This tight encapsulation structure is equivalent to putting a sturdy "armor" on the metal-ceramic block 3. When the composite liner is subjected to huge impacts and friction during crushing operations, it can effectively prevent the metal-ceramic block 3 from loosening or falling off due to uneven stress, greatly improving the reliability and stability of the overall structure of the composite liner.

[0055] Along the length of the toothed plate 1, the metal-ceramic blocks 3 are spaced apart, with a net distance of 12mm to 18mm between adjacent metal-ceramic blocks. From the perspective of the encapsulation effect, when molten metal is injected, this spacing ensures that it fully penetrates the periphery of each metal-ceramic block 3, forming a complete and uniform encapsulation layer. It also prevents the molten metal from failing to completely fill the space due to insufficient spacing, resulting in a loose encapsulation. This ensures that the metal-ceramic blocks 3 and the toothed plate 1 work closely together during use, fully leveraging the performance advantages of the composite liner.

[0056] In terms of structural strength, a reasonable gap setting helps to optimize the overall mechanical properties of the liner. A clear distance of 12mm to 18mm allows the metal-ceramic blocks 3 to form a "spaced support" structure on the toothed plate 1, enhancing the structural stability of the composite liner under complex working conditions.

[0057] Each metal-ceramic block 3 has at least two through holes. When the through holes are circular, the diameter A ranges from 18mm to 23mm, and the net distance between adjacent through holes is C, where A / 2 ≤ C ≤ A. When the through holes are square, the side length B ranges from 20mm to 25mm, and the net distance between adjacent through holes is D, where B / 2 ≤ D ≤ B. It is worth noting that the net distance mentioned here refers to the vertical distance between the edges of adjacent through holes.

[0058] In addition, through holes can also be regular polygons other than squares, such as regular hexagons. In this case, the diameter of the circumcircle of the through hole is 20mm~25mm, and the net distance between adjacent through holes is not less than the radius of the circumcircle of the through hole and not greater than the diameter of the circumcircle of the through hole.

[0059] The clear distance between adjacent through holes can ensure the structural strength of the metal-ceramic block 3. The diameter of the through holes is required to ensure that the molten metal of the liner body 2 and the toothed plate 1 is fully filled in the through holes, forming a uniformly distributed "metal anchor" reinforcement structure, which enhances the mechanical interlocking performance between the metal-ceramic block 3 and the movable jaw plate and the fixed jaw plate, and ultimately improves the overall wear resistance and impact resistance of the composite liner.

[0060] To ensure the structural strength of the metal-ceramic block 3, the clear distance from the edge of the through hole to the edge of the metal-ceramic block 3 shall be no less than 10 mm, forming an annular protective layer with a width of no less than 10 mm. It is worth noting that the clear distance mentioned here refers to the vertical distance between the edge of the through hole and the edge of the metal-ceramic block 2.

[0061] The metal-ceramic blocks 3 are classified according to the type of through holes, including single-row metal-ceramic blocks 31 and multi-row metal-ceramic blocks 32. Among them, the through holes of the single-row metal-ceramic blocks 31 are arranged in a straight line, while the through holes of the multi-row metal-ceramic blocks 32 are arranged in an array.

[0062] Depending on the actual working conditions of the jaw crusher, single-row metal-ceramic blocks 31, multi-row metal-ceramic blocks 32, or a combination of both can be flexibly selected. Individual metal-ceramic blocks 3 can be arranged horizontally or vertically on the toothed plate 1.

[0063] When the width of the toothed plate 1 is small, due to space constraints and stress characteristics, a single-row metal ceramic block 31 is selected and arranged longitudinally along the length of the boss 1. This can ensure the wear resistance of the key areas of the working surface and avoid the problems of insufficient casting space and reduced bonding strength caused by multiple rows.

[0064] When the toothed plate 1 is wide, multiple rows of metal-ceramic blocks 32 can be arranged longitudinally, utilizing their arrayed through-hole structure to enhance overall wear resistance and impact resistance. Alternatively, two single rows of metal-ceramic blocks 31 can be arranged longitudinally in parallel, ensuring casting quality while expanding the wear-resistant coverage area to meet the needs of wide toothed plates under high-intensity grinding conditions. Of course, single-row metal-ceramic blocks 31 and multiple rows of metal-ceramic blocks 32 can also be cast simultaneously on the toothed plate 1 as needed.

[0065] The preparation method of the composite liner is as follows:

[0066] S1: Prefabricated metal-ceramic block 3 with through holes;

[0067] S2: Create a white foam mold for the liner body 2 and the toothed plate 1, reserving a fitting part on its usable surface to match the metal-ceramic block 3. Place the metal-ceramic block 3 into the fitting part;

[0068] S3: Evenly cover the surface of the foam white mold embedded with metal ceramic blocks 3 with refractory coating and let it dry to form an effective barrier layer;

[0069] S4: Place the foam white mold coated with refractory paint in a sand box and fill it with molding sand;

[0070] S5: Negative pressure evacuation to compact the molding sand and fix the foam white mold and metal-ceramic block 3;

[0071] S6: The molten metal of the liner body 2 and toothed plate 1 is injected into the sand box through the gate, so that the foam white mold is heated and vaporized and disappears. The molten metal fills the space of the original foam model and undergoes an interfacial metallurgical bonding reaction with the metal ceramic block 2. A bottom pouring system is used when casting the molten metal.

[0072] S7: After the molten metal cools and solidifies, remove the blank workpiece and perform processing and heat treatment in sequence to obtain the final product.

[0073] The preparation process of the metal-ceramic block 3 in step S1 is carried out according to the following steps:

[0074] Raw material selection and proportioning: High-temperature resistant casting inorganic binder, FeCrC self-fluxing alloy powder, and ceramic particles are precisely proportioned at a mass ratio of 0.4:3:7 to 0.5:4:8. The ceramic particles are selected from 10-20 mesh zirconia-alumina, black fused alumina, silicon carbide, or boron carbide. These particles have high hardness and strong wear resistance, significantly improving the wear resistance of the liner. The binder is a compound of high-temperature resistant inorganic mineral powder and inorganic resin, possessing excellent high-temperature bonding performance and capable of withstanding the strong impact of molten metal above 1400℃, ensuring the structural stability of the liner under high-temperature conditions. The FeCrC alloy powder particle size is controlled between 0.5 and 30 μm, and its addition amount is 25% to 35% of the ceramic particle mass. FeCrC alloy powder has good self-fluxing properties, and at high temperatures, it can form a strong metallurgical bond with ceramic particles and binder, enhancing the overall strength of the composite liner.

[0075] Mixing Process: The above raw materials are placed in a mixer and thoroughly mixed using mechanical stirring. During the stirring process, the FeCrC alloy powder is uniformly adhered to the surface of the ceramic particles by controlling the stirring speed and time, forming metal-ceramic hybrid particles with a binder coating. This mixing process ensures sufficient contact and uniform dispersion of the raw materials, laying the foundation for the subsequent casting process and ensuring the uniform and stable performance of all parts of the composite liner.

[0076] Molding Process: A foaming mold is selected as the molding carrier, and the uniformly mixed metal-ceramic granules are quantitatively filled into the mold cavity. A combined mechanical compaction and vibration process is employed. During compaction, pressure is applied through a hydraulic system to initially densify the material; simultaneously, the vibration device is activated, utilizing vibration energy to promote the filling and sliding of material particles, expelling internal air, eliminating voids, and achieving a high degree of material density. After compaction and vibration treatment, the mold is left to stand, allowing the material to further solidify naturally, forming a stable green body structure, providing a good foundation for subsequent drying processes.

[0077] Drying Process: The shaped green body is transferred to a temperature-controlled drying device. A stepped heating strategy is adopted, gradually heating to 200-250℃ at a heating rate of 80-150℃ / h. This heating rate effectively avoids excessive temperature difference between the inside and outside of the green body due to rapid heating, which can cause thermal stress and lead to defects such as cracking and deformation. After reaching the target temperature, a heat preservation treatment is performed to allow the internal moisture of the green body to evaporate fully and to promote the initial curing of the binder. After the heat preservation is completed, the heating system is turned off, and the green body is allowed to cool slowly to room temperature with the furnace. During this process, a series of physicochemical reactions occur inside the green body, ultimately forming a porous metal-ceramic block 3.

[0078] This structure not only endows the metal-ceramic block 3 with lightweight and high-strength properties, but also reduces the overall weight of the composite liner and improves the comprehensive performance of the liner.

[0079] The present invention and its embodiments have been described above illustratively. This description is not restrictive, and the figures shown are only one embodiment of the present invention; the actual structure is not limited thereto. Therefore, if those skilled in the art are inspired by this description and design similar structures and embodiments without departing from the inventive spirit of the present invention, such designs should fall within the protection scope of the present invention.

Claims

1. A composite liner for a jaw crusher, comprising a liner body (2) and a plurality of toothed plates (1) thereon, wherein the toothed plates (1) are spaced apart and the width of the groove formed between adjacent toothed plates (1) is less than the width of the toothed plate (1). Its features are: It also includes, Metal-ceramic block (3) is provided with no less than two through holes; the metal-ceramic block (3) is evenly distributed on the working surface of the toothed plate (1); the surface of the metal-ceramic block (3) is not higher than the working surface of the toothed plate (1).

2. The composite liner for a jaw crusher according to claim 1, characterized in that: The metal-ceramic block (3) includes a single-row metal-ceramic block (31) and a multi-row metal-ceramic block (32); The through holes of the single-row metal-ceramic block (31) are arranged in a straight line, and the through holes of the multi-row metal-ceramic block (32) are arranged in an array; the toothed plate (1) is cast with single-row metal-ceramic blocks (31) and / or multi-row metal-ceramic blocks (32).

3. A composite liner for a jaw crusher according to claim 1, characterized in that: Along the width direction of the toothed plate (1), there is a gap between the edge of the toothed plate (1) and the edge of the metal ceramic block (3).

4. A composite liner for a jaw crusher according to claim 3, characterized in that: The net distance between the edge of the toothed plate (1) and the edge of the metal-ceramic block (3) is not less than 12 mm.

5. A composite liner for a jaw crusher according to claim 1, characterized in that: The metal-ceramic blocks (3) are spaced apart along the length of the toothed plate (1).

6. A composite liner for a jaw crusher according to claim 5, characterized in that: The net distance between two adjacent metal-ceramic blocks (3) is 12mm to 18mm.

7. A composite liner for a jaw crusher according to claim 1, characterized in that: The through-hole is circular or square.

8. A composite liner for a jaw crusher according to claim 5, characterized in that: When the through hole is circular, its diameter is A, and the range of A is 18mm to 23mm; When the through hole is square, its side length is B, and the range of B is 20mm to 25mm.

9. A composite liner for a jaw crusher according to claim 8, characterized in that: When the through hole is circular, the net distance between adjacent through holes is C, and A / 2≤C≤A; When the through hole is square, the net distance between adjacent through holes is D, and B / 2≤D≤B.

10. A composite liner for a jaw crusher according to claim 1, characterized in that: The net distance from the edge of the through hole to the edge of the metal ceramic block (3) shall not be less than 10 mm.

11. A composite liner for a jaw crusher according to claim 1, characterized in that: Each of the metal-ceramic blocks (3) is arranged laterally or longitudinally on the toothed plate (1).

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