Snow clearing strip for the clearing blade of a snowplough

Abstract

The invention relates to a snow clearing strip (1) and a method for producing such a snow clearing strip for the clearing blade of a snowplough, wherein said snow clearing strip (1) has a front steel plate (2) and a rear steel place (3) which can be jointly secured to the lower edge of the clearing blade with the aid of fastening means and between which an elastic rubber body (4) is vulcanised, wherein furthermore in said rubber body (4) one or more metal wear strips (5) are embedded in a limitedly moveable manner, which are each provided with anchoring elements (5a, 5b, 5c) which engage in a form-fitting manner in the rubber body and which have a clearing edge (6) which comes into contact with a road surface (8) to be cleared, said clearing edge being reinforced by one or more hard metal inserts (7). The problem addressed by the invention is that of considerably simplifying the production of such a snow clearing strip without adverse effects on functionality or operational safety. To solve this problem, the invention proposes that the metal wear strips (5) are designed as cast pieces produced from chilled cast iron which are provided, in their embedding region, with projections (5a) and / or recesses (5b) and / or openings (5c) which are produced during the casting process and serve as form-fit anchoring elements (5a, 5b, 5c) in the rubber body (4), and that the hard metal inserts (7) are fixed in the wear strips (5) in that the chilled cast iron is cast around said metal inserts.

Description

[0001] The invention relates to a snow removal blade for the blade of a snowplow, comprising a front steel plate and a rear steel plate, which together can be fixed to the lower edge of the blade by means of fastening means and between which an elastic rubber body is vulcanized, wherein one or more metallic wear strips are embedded in this rubber body in a limited manner and which have a clearing edge that contacts the road surface to be cleared and which is reinforced by one or more hard metal inserts.

[0002] Snowplow blades of the type mentioned are known, for example, from US 7,765,726 B2, DE 10 2005 040 705 B4, and DE 10 2016 114 457 A1. The snowplow blades described in these publications have proven exceptionally effective in practical use, particularly where the operating conditions of the snowplow (e.g., high speed and clearing of black ice) are likely to result in particularly intensive wear and thus short service life. The improved wear resistance is primarily due to the high abrasion resistance of the hard metal inserts, made of materials such as tungsten carbide, within the metallic wear strips. Snowplow blades reinforced with hard metal inserts are described, for example, in CH 550 897.

[0003] However, during the series production of the aforementioned snowplow blades, which are known according to the state of the art, it has become apparent that the production of the metallic wear strips reinforced with carbide inserts is exceptionally labor-intensive and can lead to problems with wear resistance. This is because the metallic wear strips must be fitted with the carbide inserts piece by piece before being embedded in the rubber compound of the rubber body. For this purpose, precisely fitting receiving holes for the carbide inserts must first be machined into the metallic wear strips, which are usually made of steel. This involves machining processes (cutting, drilling, milling, grinding, etc.). The carbide inserts must then be fitted precisely into these receiving holes and fixed in place using a special brazing process.

[0004] The intense heating during brazing can cause detrimental structural changes in the wear strip material within the embedding area of ​​the hard metal inserts, impairing their wear resistance. Attempting to eliminate these structural changes through subsequent heat treatment of the wear strip material can lead to undesirable cracking in the hard metal insert material through the necessary heat treatment steps.

[0005] It is therefore an object of the invention to further develop the snow removal blade of the type mentioned above in such a way that its manufacture is considerably simplified without impairing its wear resistance.

[0006] To solve this problem, the invention proposes, starting from a snow removal blade of the type mentioned above, that the metallic wear strips are each designed as cast parts made of hard iron, and that the hard metal inserts are fixed in the wear strips by overmolding with the hard iron.

[0007] The teaching of the invention combines, on the one hand, all the manufacturing steps explained above for the production of the metallic wear strips reinforced with hard metal inserts into a single operation, namely in the production of a cast iron part, and, on the other hand, avoids the brazing of the hard metal inserts into the metallic wear strips, which is detrimental to stability and wear resistance.

[0008] While US Patent 5,027,878 A generally discloses the process of coating the surfaces of metal bodies with a wear-resistant layer of hard metal particles, where the hard metal particles are first bonded together to form appropriately shaped layers and then cast in conjunction with iron or other metals, this document does not refer to snowplow blades and provides no indication that the form-fitting embedding of hard metal particles in cast iron can be achieved in such a way as to create an extremely resistant wear strip suitable for snowplow blades of the type mentioned above.On the contrary, the flat layers of hard metal particles disclosed there are only slightly embedded in the metal body, so it can be assumed that the products disclosed there are not suitable for increasing the wear resistance of wear strips in snow removal blades of the type mentioned above.

[0009] Finally, it is known from GB 1 480 057 A to cast carbide lamellae into the wear edge of a snowplow blade made entirely of metal. However, such snowplow blades, known for a long time, have not proven effective in practice because the all-metal blades are largely inflexible, so that when the wear edge impacts fixed obstacles in the road surface, the carbide lamellae are broken out of the blade's wear edge. This is fundamentally different with the snowplow blades according to the invention, because there the wear strips are embedded in a flexible rubber body vulcanized between two steel plates, so that the wear strips, made of cast iron and reinforced by the carbide inserts, can deflect any impacts.

[0010] A further advantageous embodiment of the invention provides that the cemented carbide inserts are provided with projections and / or recesses and / or openings within the metallic wear strips to create an additional positive fit. This additional securing of the cemented carbide inserts by positive fit is achieved in a particularly simple manner if, according to the teachings of the invention, the cemented carbide inserts are fixed in the metallic wear strips by overmolding with the cast iron. This additional securing of the cemented carbide inserts in the metallic wear strips would be difficult to achieve with the brazing of the cemented carbide inserts into the metallic wear strips, which is known from the prior art and only results in a material bond.

[0011] The casting of the carbide inserts is particularly successful when the carbide inserts are provided with support projections on both their front and back sides, extending at least to the front and back of the metallic wear strip. These support projections allow the carbide insert to be braced against the inner wall of the mold during the casting process, eliminating the need for any special equipment.

[0012] Additionally, it can be advantageous if the support projections extend beyond the front and back of the metallic wear strip by the amount of a coating applied to the walls of the mold during casting. This ensures absolutely precise fixation of the carbide component during the casting process, even if the inner walls of the mold are coated with a sizing agent. A further advantageous embodiment of the snowplow blade according to the invention provides that the metallic wear strips, in their embedding area within the rubber body of the snowplow blade, are provided with projections and / or recesses (5b) and / or openings, which serve as a positive-locking anchor in the rubber compound of the rubber body (4) and are integral components of the metallic wear strips formed as a molded part.

[0013] This ensures that, at the same time as the metallic wear strips are manufactured as cast parts, their anchoring elements are also produced as suitable shapes of the respective cast part.

[0014] These measures eliminate, in particular, the labor-intensive and cumbersome attachment of anchoring elements to the metal wear strips. Furthermore, this measure also simplifies the assembly of all individual parts of the snowplow blade before vulcanizing the rubber body, because the number of parts to be joined is significantly reduced.

[0015] To increase road safety for traffic following the snowplow, it is further provided that the front steel plate and / or the rear steel plate are provided with openings into which the projections of the metallic wear strip embedded in the rubber mass of the rubber body engage with sufficient clearance, these projections of the metallic wear strip being dimensioned in such a way that the metallic wear strip cannot fall out of the space between the front steel plate and the rear steel plate even if the rubber mass embedding it is lost, i.e., that the distance between the protruding ends of the projections is greater than the distance between the front steel plate and the rear steel plate.

[0016] A specialized embodiment of the clearing blade according to the invention, designed for specific applications, provides that the lower edges of the wear strips lie in a plane with the lower edges of the front steel plate beneath the rear steel plate, this plane being at an acute angle to the road surface to be cleared. A clearing blade designed in this way rests at an acute angle on the road surface to be cleared with a relatively large contact area – consisting of the two steel plates, the metallic wear strips with hard metal inserts, and the intermediate rubber layers of the rubber body. This large contact area with soft rubber components ensures particularly gentle clearing of the road surface, for example, of snow.

[0017] If, on the other hand, a more aggressive snow removal blade is required, for example, to additionally remove frozen ice from the road surface during so-called black ice removal, another embodiment of the invention proposes that the lower edges of the metallic wear strips project downwards beyond the lower edges of the front and rear steel plates and are thickened in the projecting area. Such thickening can be easily produced on the wear strips, which are each designed as a casting, using a suitably designed mold and ensures a significantly longer service life for such a snow removal blade used for black ice removal.

[0018] A particularly preferred embodiment of the snow removal blade according to the invention provides that the metallic wear strips project downwards beyond the lower edges of the front steel plate and the rear steel plate, and that snow-gliding ramps, running parallel to the lower edges of the front steel plate or the rear steel plate, are arranged on the surfaces of the front and / or the rear of the wear strips, respectively, between the surfaces of the wear strips on the one hand and the outer surfaces of the front steel plate or the rear steel plate on the other hand.

[0019] These snow ramps provide a smooth transition between the surfaces of the wear strips and the outer surfaces of the front and rear steel plates. This prevents snow or ice from splashing up when moving quickly across the wear strip and steel plates, thus avoiding obstructing the snowplow driver's view. This highly useful feature can be easily incorporated into cast wear strips without additional effort, simply by modifying the existing molds. A further advantage is that the ramps reinforce the cross-section of the metal wear strip in the area most subjected to bending stress during snow removal.

[0020] The invention further relates to a method for manufacturing a snow removal blade of the type described above, in which the metallic wear strips provided with hard metal inserts are manufactured as cast iron pieces, wherein the hard metal inserts are fixed in the volume of the metallic wear strip by overmolding with a hard iron melt.

[0021] In this process, the hard metal inserts are fixed in the correct position within a casting mold using suitable holding devices before being overmolded with the chilled iron molten metal.

[0022] A particularly preferred embodiment of this method provides that support projections are used as holding means for the hard metal inserts, which are located on the front and back of the hard metal inserts and are supported on the inner wall of the mold during the casting process.

[0023] Exemplary embodiments of the invention are explained in more detail in the following margin of the drawing. The drawing shows: Figure 1 : schematically a side view of a snow removal blade according to the invention in a first embodiment, partially cut away; Figure 1a : schematically a cross-section through the snow removal blade according to Figure 1a along the intersection line AA in Figure 1 ; Figure 1b : schematically a cross-section through the snowplow blade according to Figure 1a along the intersection line BB in Figure 1 ; Figure 2: schematically a side view of a snow removal blade according to the invention in a second embodiment, partially cut away; Figure 2a : schematically a cross-section through the snowplow blade according to Figure 2a along the intersection line AA in Figure 2 ; Figure 3 : schematically a side view of a snow removal blade according to the invention in a third embodiment, partially cut open; Figure 3a : schematically a cross-section through the snowplow blade according to Figure 3a along the intersection line AA in Figure 3 ; Figure 4 : schematically a side view of a snow removal blade according to the invention in a fourth embodiment, partially cut away; Figure 4a : schematically a cross-section through a snowplow blade according to Figure 4a along the intersection line AA in Figure 4 ; Figure 4b : schematically a cross-section through a snowplow blade according to Figure 4a along the intersection line BB in Figure 4 ; Figure 5: schematically a side view of a metallic wear strip designed as a casting with cast-in hard metal inserts for the snow removal blade according to Figure 1 ; Figure 5a : schematically a cross-section through the in Figure 5 depicted metallic wear strip; Figure 5b : schematically a perspective view of the in Figure 5 shown metallic wear strip; Figure 6 : schematically a side view of the metallic wear strip designed as a casting with cast-in hard metal inserts and snow-gliding ramps for the snowplow blade according to Figure 4 ; Figure 6a : schematically a narrow-side view of the in Figure 6 depicted metallic wear strip; Figure 6b : schematically a perspective view of the in Figure 6 shown metallic wear strip; Figure 7 : schematically a side view of one of the hard metal inserts of the snowplow blade according to Figure 4 ; Figure 7a: schematically a narrow-side view of the in Figure 7 shown hard metal insert; Figure 7b : schematically a perspective view of the in Figure 7 shown hard metal inserts; Figure 8 : schematically a side view of one of the hard metal inserts with positive locking elements for the snowplow blade according to Figure 1 ; Figure 8a : schematically a narrow-side view of the in Figure 8 shown hard metal insert; Figure 8b : schematically a perspective view of the in Figure 8 shown hard metal insert. Figure 9a : a preferred embodiment of the metallic wear strip with hard metal insert in a front view (partially cut away); Figure 9 b: the in Figure 9a The metallic wear strip shown is viewed from the rear: Figure 9c : a cut along line AA in Figure 9a ; Figure 9d : a cut along line BB in Figure 9a ; Figure 9e: in perspective view one of the in the metallic wear strip according to the Figures 9a to 9d embedded hard metal inserts.

[0024] In the Figures 1, 1a, 1b , 2, 2a , 3, 3a , 4, 4a and 4b The entire snow removal blade is designated with the reference symbol 1.

[0025] As the respective sectional views of the individual snow removal blades 1 show, each blade is provided with a front steel plate 2 on its front side (in the direction of travel of the snowplow) and with rear steel plates 3 on its rear side (in the direction of travel of the snowplow). The front steel plate 2 and the rear steel plate 3 can be fixed together to the lower edge of the snowplow blade (also not shown) by means of fasteners not shown in the drawing, e.g., fastening screws.

[0026] A rubber body 4 is vulcanized between the front steel plate 2 and the rear steel plate 3. One or more – in the illustrated embodiments, three – metallic wear strips 5 are embedded in this rubber body 4 with limited movement. The limited movement of these metallic wear strips 5 relative to the surrounding steel plates 2 and 3 results from the elasticity of the surrounding rubber mass of the rubber body 4.

[0027] The metallic wear strips 5 are each embedded in the rubber body 4 such that their lower edge 6, referred to as the clearing edge, rests on the road surface to be cleared. To reduce wear, these lower edges 6 of the metallic wear strips 5 are each reinforced by hard metal inserts 7, preferably made of tungsten carbide or similar hard metals.

[0028] According to the invention, the metallic wear strips 5 are each designed as one-piece castings made of cast iron, which, in their embedding area in the rubber body 4, are provided with anchoring elements in the form of projections 5a, recesses 5b and / or openings 5c that engage positively in the rubber compound. The production and positioning of these anchoring elements 5a, 5b and 5c takes place simultaneously with the production of the metallic wear strips 5, namely the casting process, and requires no additional work steps. Furthermore, according to the invention, the hard metal inserts 7 of the metallic wear strips 5 are simultaneously fixed in the metallic wear strips 5 by being encased in the cast iron during this casting process and therefore do not need to be soldered or otherwise fastened in receiving openings of the metallic wear strips 5 in a separate work step.Overall, the particular advantage of the teaching of the invention lies in the fact that the novel manufacturing of the metallic wear strips 5 significantly reduces the overall work required for the manufacture of the snow removal strip 1 and at the same time improves its functionality.

[0029] During the Figures 1, 1a and 1bIn the illustrated embodiment of the snow removal blade according to the invention, the lower edges 6 (clearing edges) of the metallic wear strips 5, reinforced with the hard metal inserts 7, lie in a plane with the lower edges of the front steel plate 2 and the rear steel plate 3, this plane being at an acute angle to the road surface 8 to be cleared. As already explained in the introduction, this results in a particularly large contact area on the road surface 8 to be cleared, thus enabling particularly gentle removal of snow or ice from this road surface 8. Furthermore, in this embodiment of the snow removal blade according to the invention, the hard metal inserts 7 are provided with positive locking elements 7a, which engage positively in the volume of the metallic wear strips 5 and are thereby additionally secured against falling out.These positive locking elements 7a can be designed as projections, as shown. However, they can also be formed by recesses, openings, or indentations in the body of the hard metal inserts.

[0030] In the exemplary embodiment according to the Figures 2 and 2aThe metallic wear strips 5 project downwards beyond the lower edges of the front steel plate 2 and the rear steel plate 3 and are thickened in the projecting area. This allows for significantly longer service life of the snowplow blade, particularly during so-called black snow removal. The positive locking of the metallic wear strips 5 in the rubber body 4 is achieved by arcuate recesses 5b in the metallic wear strips 7 in their embedding area, which transition into subsequent projections 5a (thickenings) above and below. The additional positive locking of the hard metal inserts 7 in the metallic wear strips 5 is achieved by the fact that the hard metal inserts 7 have a wedge-shaped cross-section, i.e.,have an upwardly widening wedge-shaped projection 7a, which engages in a form-fitting manner with the body of the metallic wear strip 5 made of cast iron.

[0031] The exemplary embodiment according to the Figures 3 and 3a largely corresponds to the embodiment shown in the Figures 2 and 2a , with the difference that here the metallic wear rails 5 embedded in the rubber body 4 are provided on their surfaces in the embedding area with wave-like alternating projections 5a and recesses 5b which ensure the required positive locking in the rubber body 4.

[0032] In the exemplary embodiment of the snow removal blade according to the Figures 4, 4a and 4bThe metallic wear strips 5 also project downwards beyond the lower edges of the front steel plate 2 and the rear steel plate 3 and are thickened in the projecting area. Furthermore, snow-guiding ramps 9a and 9b, respectively, are arranged on the surfaces of the front and rear of the metallic wear strips 5, running parallel to the lower edges of the front steel plate 2 and the rear steel plate 3, and with their upper surfaces inclined or curved. As already discussed in the introductory section of the description, these snow-guiding ramps 9a and 9b ensure, when such a snow removal blade is used, a gradual transition between the surfaces of the wear strip 5 on the one hand and the adjacent surfaces of the front steel plate 2 and the rear steel plate 3 on the other. These snow-guiding ramps 9a and 9b also9b are one-piece components of the metallic wear strips 5, each made of cast iron.

[0033] The Figures 5.5 a and 5b show the snow removal strip according to Figure 1The metallic wear strips 5 used are prepared before being vulcanized into the rubber body 4. These metallic wear strips 5 are made of cast iron, e.g., GGG-40 LT, and are provided in their embedding area with anchoring elements in the form of projections 5a that engage positively in the rubber body 4 of the snowplow blade 1. In the area of ​​their lower edge 6, they contain the hard metal inserts 7. These hard metal inserts 7 are fixed within the volume of the wear strips 5 by being cast in the cast iron during the casting process. For additional securing, the hard metal inserts 7 are provided with projections 7a, which, in addition to the material bond, fix the hard metal inserts 7 within the volume of the wear strips 5 by positive locking.

[0034] The Figures 6,6 a and 6b show the snow removal strip according to Figure 4The metallic wear strips 5 used are shown before their vulcanization into the rubber compound of the rubber body 4 of the snowplow blade 1. These metallic wear strips 5 are also made of cast iron (e.g., GGG-40 LT) and are provided in their embedding area with anchoring elements, here in the form of projections 5a and openings 5c, which engage positively in the rubber compound of the rubber body 4 of the snowplow blade 1. In addition, these wear strips 5 are provided on their front and back with the snow-guiding ramps 9a and 9b already mentioned above, which are an integral part of the metallic wear strip, i.e., also made of cast iron. Finally, the lower edge 6 of the metallic wear strip 5 is also reinforced here by hard metal inserts 7, which are designed here as simple cuboid blocks cast with cast iron, such as those made, for example, from the Figures 7, 7a and 7b emerge.

[0035] The Figures 8, 8a and 8b Finally, they illustrate in detail the snow removal strip according to Figure 1 used, in whose wear strip 5 embedded hard metal inserts 7, which are provided with projections 7a that engage in a form-fitting manner into the volume of the metallic wear strips 5.

[0036] The Figures 9a to 9eFigure 1 illustrates a particular embodiment of embedding hard metal inserts 7 in one of the metallic wear strips 5. Here, for example, hard metal inserts 7 made of tungsten carbide are provided on their front 7.1 and rear 7.2 with support projections 10.1 and 10.2, which extend at least to the front wall 5a and the rear wall 5b of the metallic wear strip 5. With the aid of these support projections 10.1 and 10.2, it is possible to position the hard metal insert 7 correctly in a casting mold during the casting process with the hard iron casting, thus eliminating the need for complicated holding devices for positioning the hard metal insert 7 within the casting mold during the casting process.

[0037] Furthermore, these support projections 10.1 and 10.2 also serve as positive locking elements for fixing the hard metal insert 7 in the volume of the metallic wear strip 5 after the completion of the metallic wear strip.

[0038] If the casting process uses a mold whose inner wall is coated with a sizing agent, the support projections 10.1 and 10.2 are dimensioned such that they protrude slightly, i.e., at least beyond the thickness of the sizing agent coating of the casting mold, beyond the front wall 5.1 and the rear wall 5.2 of the metallic wear strip 5. This ensures that the hard metal insert 7 can be securely fixed within the volume of the casting mold even when its walls are coated with a sizing agent. Reference symbol list

[0039] 1: Snow removal blade 2: Front steel plate 2a: Opening in front steel plate 3: Rear steel plate 3a: Opening in rear steel plate 4: Rubber body 5: Metallic wear strip 5a: Projections of the metallic wear strip 5b: Recesses of the metallic wear strip 5c: Perforations in the metallic wear strip 6: Lower edge (clearing edge) of the metallic wear strip 7: Carbide inserts 7a: Projections of carbide inserts 7.1: Front side of the carbide inserts 7.2: Back side of the carbide inserts 8: Road surface 9a: Snow sliding surface 9b: Snow sliding surface 10.1: Support projections on the front of the carbide inserts 10.2: Support projections on the back of the carbide inserts

Claims

1. Snow-clearing strip (1) for the plow blade of a snowplow, with a front steel plate (2) and a rear steel plate (3), which can be jointly secured to the lower edge of the plow blade by means of fasteners and between which an elastic rubber body (4) is vulcanized-in, wherein one or more metallic wear strips (5) are embedded in this rubber body (4) with limited mobility, which wear strips have a clearing edge (6) that contacts the road surface (8) to be cleared which is reinforced by one or more hard metal inserts (7), characterized in that the metallic wear strips (5) are each formed as form cast part made of iron hard casting, and that the hard metal inserts (7) are fixed in the metallic wear strips (5) by being cast in with the iron hard casting.

2. Snow-clearing strip (1) according to claim 1, characterized in that the hard metal inserts (7) are provided with projections (7a) and / or recesses and / or openings to create an additional form-fit with the metallic wear strips (5).

3. Snow-clearing strip according to any one of claims 1 or 2, characterized in that the hard metal inserts (7) are each provided on their front side (7.1) and on their rear side (7.2) with support projections (10.1 and 10.2) which extend at least to the front side (5.1) and the rear side (5.2) of the metallic wear strip (5).

4. Snow-clearing strip according to claim 3, characterized in that the support projections (10.1 and 10.2) project beyond the front side (7.1) and the rear side (7.2) of the metallic wear strip (7) by an amount corresponding to the thickness of a dressing (Schlichte-Beschichtung) applied to the walls of the casting mold used during casting.

5. Snow-clearing strip (1) according to any one of claims 1 through 4, characterized in that the metallic wear strips (5) are provided, in their embedded region within the rubber body (4) of the snow-clearing strip (1), with projections (5a) and / or recesses (5b) and / or openings (5c), which act as form-fitting anchorage in the rubber compound of the rubber body (4) and which are integral components of the metallic wear strips (1) formed as form cast part.

6. Snow-clearing strip (1) according to claim 5, characterized in that the front steel plate (2) and / or the rear steel plate (3) are provided with openings (2a, 3a), into which the projections (5a) of the metallic wear strip (5) embedded in the rubber compound of the rubber body (4) engage with sufficient movement clearance, wherein these projections (5a) of the metallic wear strip (5) are dimensioned such that the metallic wear strip (5) cannot fall out of the space between the front steel plate (2) and the rear steel plate (3), even if the rubber compound embedding it is lost.

7. Snow-clearing strip (1) according to any one of claims 1 through 6, characterized in that the lower edges of the wear strips (5) lie in a plane with the lower edges of the front steel plate (2) and the rear steel plate (3), wherein this plane extends at an acute angle (a) to the road surface (8) to be cleared.

8. Snow-clearing strip (1) according to any one of claims 1-6, characterized in that the metallic wear strips (5) project downward beyond the lower edges of the front steel plate (2) and the rear steel plate (3) and are designed thickened in the projecting area.

9. Snow-clearing strip (1) according to any one of claims 1-6, characterized in that the metallic wear strips (5) project downward beyond the lower edges of the front steel plate (2) and the rear steel plate (3) and that oblique or curved snow glide ramps (9a, 9b) are arranged on the surfaces of the front side and / or rear side of the wear strips (5) parallel to the lower edges of the front steel plate (2) or the rear steel plate (3), which are arranged between the surfaces of the wear strips (5) on the one hand and the outer sides of the front steel plate (2) or the rear steel plate (3) on the other hand.

10. Method for manufacturing a snow-clearing strip according to any one of claims 1-9, characterized in that the metallic wear strips, which are provided with hard metal inserts (7), are manufactured as form cast parts made of iron hard cast, in which the hard metal inserts (7) are secured by casting hard iron melt around them.

11. Method according to claim 10, characterized in that the hard metal inserts (7) are secured in the correct position within the mold used by means of suitable holding devices prior to being cast with the hard iron melt.

12. Method according to claim 11, characterized in that as retaining devices for the hard metal inserts (7), which are located on the front side (7.1) and the rear side (7.2) of the hard metal inserts (7) and rest against the inner surface of the casting mold during the casting process, support projections (10.1 and 10.2) are used.

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