Snow clearing strip for the clearing blade of a snowplough
Patent Information
- Application Number
- EP2024805430
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-10-26
- Filing Date
- 2024-10-25
- Publication Date
- 2025-12-31
- Estimated Expiration
- 2044-10-25
AI Technical Summary
The production of snow clearing strips with metallic wear strips reinforced with hard metal inserts is labor-intensive and can lead to issues with wear resistance due to the intensive heating during the hard soldering process, which causes harmful structure changes in the material.
The metallic wear strips are formed as form cast parts made of iron-hard casting, with hard metal inserts fixed by pouring the iron hardening process, simplifying the manufacturing process and enhancing wear resistance.
This approach significantly simplifies the production of snow clearing strips while maintaining or improving wear resistance, reducing the risk of material degradation and cracking.
Smart Images
Figure EP2024080292_01052025_PF_FP_ABST
Abstract
Description
[0001] Snow removal bar for the blade of a snow plow
[0002] The invention relates to a snow clearing strip for the clearing blade of a snow plow with a front steel plate and a rear steel plate which can be fixed together by means of fastening means to the lower edge of the clearing blade and between which an elastic rubber body is vulcanized, wherein one or more metallic wear strips are embedded in this rubber body with limited mobility, which wear strips have a clearing edge which touches the road surface to be cleared and which is reinforced by one or more hard metal inserts.
[0003] Snow clearing blades of this type are known, for example, from DE 10 2016 114 457 A1. The snow clearing blades resulting from this publication have proven extremely effective in practical use, particularly where particularly intensive wear and thus short downtimes are to be expected due to the operating conditions of the snow plow (e.g., high driving speeds and clearing snow). The improved wear resistance results primarily from the high abrasion resistance of the hard metal inserts, such as tungsten carbide, in the metal wear strips. Snow clearing blades reinforced with hard metal inserts are described, for example, in CH 550 897.
[0004] However, during the series production of the aforementioned snow clearing blades, which are known from the state of the art, it has become apparent that the manufacture of the metal wear strips reinforced with hard metal inserts is extremely labor-intensive and can lead to problems with wear resistance. The metal wear strips must be fitted with the hard metal inserts piece by piece before being embedded in the rubber compound of the rubber body. To do this, precisely fitting openings for the hard metal inserts must first be created in the metal wear strips, which are usually made of steel. This requires machining processes (cutting, drilling, milling, grinding, etc.). The hard metal inserts must then be precisely inserted into these openings and secured using a special brazing process.
[0005] The intense heating during brazing can cause harmful structural changes in the wear strip material in the embedding area of the hard metal inserts, impairing their wear resistance. Attempts to eliminate these structural changes by subsequently tempering the wear strip material can result in undesirable cracking in the hard metal insert material.
[0006] It is therefore an object of the invention to further develop the snow clearing blade of the type mentioned above in such a way that its manufacture is considerably simplified without impairing its wear resistance.
[0007] To achieve this object, the invention proposes, starting from a snow clearing bar of the type mentioned at the outset, that the metallic wear bars are each designed as cast parts made of chilled iron, and that the hard metal inserts are fixed in the wear bars by casting them with the chilled iron.
[0008] The teaching of the invention, on the one hand, combines all of the above-explained manufacturing steps for producing the metallic wear strips reinforced with hard metal inserts into a single operation, namely the production of a cast part made of chilled iron, and, on the other hand, avoids the soldering of the hard metal inserts into the metallic wear strips, which is detrimental to stability and wear resistance. A useful further development of the invention provides that the hard metal inserts are provided with projections and / or recesses and / or openings to create an additional positive fit within the volume of the metallic wear strips. This additional securing of the hard metal inserts by means of positive fit is possible in a particularly simple manner if, according to the teaching of the invention, the hard metal inserts are fixed in the metallic wear strips by casting the chilled iron around them.With the state-of-the-art method of soldering the hard metal inserts into the metallic wear strips, which merely acts as a material bond, this additional securing of the hard metal inserts in the metallic wear strips would be difficult to achieve.
[0009] Casting the carbide inserts is particularly successful when the carbide inserts are provided with support projections on their front and back sides, extending at least to the front and back of the metal wear strip. These support projections allow the carbide insert to be supported against the inner wall of the mold during the casting process without the need for special equipment.
[0010] Additionally, it may be expedient for the support projections to protrude beyond the front and back of the metallic wear rail by the amount of a coating applied to the walls of the casting mold during casting. This ensures absolutely precise fixation of the hard metal system during the casting process, even if the inner walls of the mold used are provided with a coating. An advantageous embodiment of the snow removal bar according to the invention further provides that the metallic wear rails are provided with projections and / or depressions and / or openings in their embedding area in the rubber body of the snow removal bar, which serve as a positive anchoring in the rubber mass of the rubber body and are integral components of the metallic wear rails designed as a cast part.This ensures that, at the same time as the metal wear strips are manufactured as cast parts, their anchoring elements are also manufactured as suitable molds of the respective cast part. This measure eliminates, in particular, the labor-intensive and complicated process of attaching anchoring elements to the metal wear strips. Furthermore, this measure also simplifies the assembly of all individual parts of the snow removal strip before vulcanizing the rubber body, because the number of parts to be joined is significantly reduced.
[0011] In order to increase road safety for the traffic following the respective snow plough, 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 play, wherein these projections of the metallic wear strip are 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.
[0012] A specialized embodiment of the clearing bar according to the invention for particular applications provides that the lower edges of the wear strips lie in a plane with the lower edges of the front steel plate under the rear steel plate, with this plane running at an acute angle to the road surface to be cleared. A clearing bar designed in this way rests at an acute angle on the road surface to be cleared with a relatively large contact surface—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 surface with soft rubber components ensures particularly gentle removal of debris, for example, from snow, from the road surface to be cleared.
[0013] If, on the other hand, a more aggressive snow removal blade is required, for example, to additionally clear frozen ice from the road surface during so-called black ice clearing, a further embodiment of the invention proposes that the lower edges of the metallic wear strips protrude downwards beyond the lower edges of the front steel plate and the rear steel plate and are thickened in the protruding area. Such a thickening can be easily produced on the wear strips, each of which is designed as a cast piece, using a correspondingly designed mold and ensures significantly longer service life for such a snow removal blade used for black ice clearing.
[0014] A particularly preferred embodiment of the snow clearing strip according to the invention provides that the metallic wear strips project downwards over the lower edges of the front steel plate and the rear steel plate and that on the surfaces of the front and / or the rear of the wear strips, inclined or curved snow sliding ramps running parallel to the lower edges of the front steel plate or the rear steel plate are arranged between the surfaces of the wear strips on the one hand and the outer sides of the front steel plate or the rear steel plate on the other hand.
[0015] These snow ramps provide a seamless transition between the surfaces of the wear strips on the one hand and the outer surfaces of the front and rear steel plates on the other. These snow ramps ensure that snow or ice does not splash up during rapid movement over the surfaces of the wear strip and steel plates, thus obstructing the snowplow driver's view. This very useful detail can also be implemented on cast wear strips without additional effort, as it is only necessary to design the molds used for production accordingly. A further advantage is that the ramps reinforce the cross-section of the metal wear strip where it is most subject to bending stress during use of the snow plow.
[0016] The invention further relates to a method for producing a snow clearing bar of the type described above, in which the metallic wear bars provided with hard metal inserts are produced as cast pieces from chilled cast iron, wherein the hard metal inserts are fixed in the volume of the metallic wear bar by casting them with a chilled cast iron melt.
[0017] When carrying out this process, the hard metal inserts are fixed in the correct position within a casting mold using suitable holding devices before being encased in the chilled cast iron melt and then encased in the chilled cast iron melt.
[0018] A particularly preferred embodiment of this method provides that support projections are used as holding means for the hard metal inserts, which support projections are located on the front and back of the hard metal inserts and are supported on the inner wall of the casting mold during the casting process.
[0019] Embodiments of the invention are explained in more detail below with reference to the drawings. They show:
[0020] Figure 1: schematically shows a side view of a snow clearing bar according to the invention in a first embodiment, partially cut away;
[0021] Figure 1a: schematically shows a section through the snow clearing bar according to Figure 1a along the section line AA in Figure 1; Figure 1b: schematically shows a section through the snow clearing bar according to Figure 1a along the section line BB in Figure 1;
[0022] Figure 2: schematically shows a side view of a snow clearing bar according to the invention in a second embodiment, partially cut away;
[0023] Figure 2a: schematically a section through the snow clearing bar according to Figure 2a along the section line AA in Figure 2;
[0024] Figure 3: schematic side view of a snow clearing bar according to
[0025] Invention in a third embodiment, partially cut away;
[0026] Figure 3a: schematic section through the snow clearing bar according to Figure
[0027] 3 along the section line AA in Figure 3;
[0028] Figure 4: schematically shows a side view of a snow clearing bar according to the invention in a fourth embodiment, partially cut away;
[0029] Figure 4a: schematic section through a snow clearing bar according to Figure
[0030] 4 along section line AA in Figure 4;
[0031] Figure 4b: schematically a section through a snow clearing bar according to Figure 4 along the section line BB in Figure 4;
[0032] Figure 5: schematically a side view of a metallic wear bar designed as a cast piece with cast-in hard metal inserts for the snow clearing bar according to Figure 1;
[0033] Figure 5a: schematically a section through the metallic wear strip shown in Figure 5;
[0034] Figure 5b: schematically shows a perspective view of the metallic wear bar shown in Figure 5; Figure 6: schematically shows a side view of the metallic wear bar formed as a cast piece with cast-in hard metal inserts and snow sliding ramps for the snow clearing bar according to Figure 4;
[0035] Figure 6a: schematically a narrow side view of the metallic wear strip shown in Figure 6;
[0036] Figure 6b: schematically a perspective view of the metallic wear strip shown in Figure 6;
[0037] Figure 7: schematic side view of one of the hard metal inserts of the
[0038] Snow removal bar according to Figure 4;
[0039] Figure 7a: schematically a narrow side view of the hard metal insert shown in Figure 7;
[0040] Figure 7b: schematically a perspective view of the hard metal inserts shown in Figure 7;
[0041] Figure 8: schematic side view of one of the hard metal inserts with
[0042] Form-locking elements for the snow clearing bar according to Figure 1;
[0043] Figure 8a: schematically a narrow side view of the hard metal insert shown in Figure 8;
[0044] Figure 8b: schematically a perspective view of the hard metal insert shown in Figure 8.
[0045] Figure 9a: a preferred embodiment of the metallic wear strip with hard metal insert in a view from the front (partially cut open);
[0046] Figure 9b: the metallic wear strip shown in Figure 9a in a
[0047] Rear view: Figure 9c: a section along line AA in Figure 9a;
[0048] Figure 9d: a section along the line BB in Figure 9a;
[0049] Figure 9e: in perspective view one of the metallic
[0050] Wear strip with hard metal inserts embedded in figures 9a to 9d.
[0051] In Figures 1, 1a, 1b, 2, 2a, 3, 3a, 4, 4a and 4b, the snow clearing bar is designated as a whole by the reference number 1.
[0052] As the respective sectional views of the individual snow clearing blades 1 show, they are each provided with a front steel plate 2 on their front side in the direction of travel of the snow plow and with rear steel plates 3 on their rear side in the direction of travel of the snow plow. The front steel plate 2 and the rear steel plate 3 can be secured together with fastening means not shown in the drawing, e.g., fastening screws, to the lower edge of the clearing blade of a snow plow (also not shown).
[0053] A rubber body 4 is vulcanized between the front steel plate 2 and the rear steel plate 3. One or more metallic wear strips 5—three in the illustrated embodiments—are embedded in this rubber body 4, allowing limited movement. The limited mobility 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.
[0054] The metallic wear strips 5 are each embedded in the rubber body 4 in such a way 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 with hard metal inserts 7, preferably made of tungsten carbide or similar hard metals.
[0055] According to the teaching of the invention, the metallic wear strips 5 are each designed as one-piece castings made of chilled iron casting, which are provided in their embedding area in the rubber body 4 with anchoring elements in the form of projections 5a, recesses 5b and / or openings 5c that engage positively in the rubber mass. 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 operations. Furthermore, according to the teaching of the invention, the hard metal inserts 7 of the metallic wear strips 5 are fixed in the metallic wear strips 5 by encapsulating them with chilled iron casting and therefore do not need to be soldered or otherwise fastened into receiving openings of the metallic wear strips 5 in a separate operation.Overall, the particular advantage of the teaching of the invention is that the novel production of the metallic wear strips 5 significantly reduces the total labor required for the production of snow removal strips and at the same time improves their functionality.
[0056] In the embodiment of the snow clearing bar according to the invention shown in Figures 1, 1a and 1b, the lower edges 6 (clearing edges) of the metallic wear bars 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, wherein this plane runs at an acute angle to the road surface 8 to be cleared. As already explained in the introduction to the description, this results in a particularly large contact surface on the road surface 8 to be cleared, so that this road surface 8 can be cleared of snow or ice in a particularly gentle manner. Furthermore, in this embodiment of the snow clearing bar according to the invention, the hard metal inserts 7 are provided with form-locking elements 7a, which engage positively in the volume of the metallic wear bars 5 and are thereby additionally secured against falling out.These form-locking elements 7a can be designed as projections, as shown. However, they can equally well be formed by recesses, openings, or recesses in the body of the hard metal inserts 7.
[0057] In the embodiment according to Figures 2 and 2a, the metallic wear strips 5 project downwards over the lower edges of the front steel plate 2 and the rear steel plate 3 and are thickened in the projecting area. This results in a significantly longer service life of the snow removal strip thus formed, particularly during so-called black snow clearing. The positive fit of the metallic wear rails 5 in the rubber body 4 is achieved here by curved depressions 5b of the metallic wear strips 7 in their embedding area, which merge upwards and downwards into adjoining projections 5a (thickened areas). The additional positive locking of the hard metal inserts 7 in the metallic wear strips 5 is achieved here by the fact that the hard metal inserts 7 are wedge-shaped in cross-section, i.e.have a wedge-shaped projection 7a which widens upwards and engages positively into the body of the metallic wear strip 5 made of chilled cast iron.
[0058] The embodiment according to Figures 3 and 3a largely corresponds to the embodiment according to Figures 2 and 2a, with the difference that here the metallic wear strips 5 embedded in the rubber body 4 are provided in the embedding area on their surfaces with wave-shaped alternating projections 5a and depressions 5b, which ensure the required positive connection in the rubber body 4.
[0059] In the embodiment of the snow clearing bar according to Figures 4, 4a and 4b, the metallic wear strips 5 also project downwards over the lower edges of the front steel plate 2 and the rear steel plate 3 and are thickened in the projecting area. Furthermore, snow sliding ramps 9a and 9b are arranged in the surfaces of the front and rear of the metallic wear strips 5, which run parallel to the lower edges of the front steel plate 2 and the rear steel plate 3 and are inclined or curved on their upper sides. As already discussed in the introduction to the description, these snow sliding ramps 9a and 9b ensure, when such a snow clearing bar is used, a gradual transition between the surfaces of the wear strip 5 on the one hand and the adjoining surfaces of the front steel plate 2 and the rear steel plate 3 on the other. These sliding ramps 9a and 9b also9b are one-piece components of the metallic wear strips 5, each made of chilled cast iron.
[0060] Figures 5, 5a and 5b show the metallic wear strips 5 used in the snow clearing bar according to Figure 1 before they are vulcanized into the rubber body 4. These metallic wear strips 5 are made of chilled cast iron, e.g. GGG-40 LT, 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 snow clearing bar 1, and contain the hard metal inserts 7 in the area of their lower edge 6. These hard metal inserts 7 are fixed in the volume of the wear strips 5 by encasing the hard metal inserts in the chilled cast iron during the casting of the wear strips 7. For additional security, the hard metal inserts 7 are provided with projections 7a, which fix the hard metal inserts 7 in the volume of the wear strips 5 in addition to the material bond by means of a positive fit.
[0061] Figures 6, 6a and 6b show the metallic wear strips 5 used in the snow clearing bar according to Figure 4 before they are vulcanized into the rubber mass of the rubber body 4 of the snow clearing bar 1. This metallic wear strip 5 is also made of chilled cast iron (e.g. GGG-40 LT) and is provided in its embedding area with anchoring elements, here in the form of projections 5a and openings 5c, which engage positively in the rubber mass of the rubber body 4 of the snow clearing bar 1. In addition, these wear strips 5 are provided on their front and rear sides with the aforementioned snow sliding ramps 9a and 9b, which are an integral part of the metallic wear strip 5, i.e., are also made of chilled cast iron.Finally, the lower edge 6 of the metallic wear strip 5 is reinforced by hard metal inserts 7, which here are designed as simple cuboid blocks encased in chilled cast iron, as can be seen, for example, in Figures 7, 7a, and 7b. Figures 8, 8a, and 8b illustrate in detail the hard metal inserts 7 used in the snow clearing strip according to Figure 1, embedded in its wear strip 5, which are provided with projections 7a that engage positively with the volume of the metallic wear strips 5.
[0062] Figures 9a to 9e illustrate a particular embodiment of the embedding of 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 side 7.1 and their rear side 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 fix the hard metal insert 7 in the correct position in a casting mold during the encapsulation with the chilled iron casting, so that complicated holding devices for positioning the hard metal insert 7 within the casting mold during the casting process can be dispensed with.
[0063] Furthermore, after the completion of the metallic wear strip, these support projections 10.1 and 10.2 also serve as form-locking elements for fixing the hard metal insert 7 in the volume of the metallic wear strip 5.
[0064] If the casting process involves working with a casting mold whose inner wall is coated with a coating, the support projections 10.1 and 10.2 are dimensioned such that they protrude slightly, i.e., at least by the thickness of the coating of the powder 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 in the volume of the casting mold even if its walls are coated with a coating.
[0065] - List of reference symbols -
[0066] Reference symbol list
[0067] 1 : Snow removal bar
[0068] 2: front steel plate 2a: opening in front steel plate
[0069] 3: rear steel plate
[0070] 3a: Opening in rear steel plate
[0071] 4: Rubber body
[0072] 5: metallic wear strip 5a: projections of the metallic wear strip
[0073] 5b: Recesses of the metallic wear strip
[0074] 5c: Breakthroughs of the metallic wear strip
[0075] 6: Lower edge (clearing edge) of the metallic wear strip
[0076] 7: Carbide inserts 7a: Projections of carbide inserts 7.1 : Front side of the carbide inserts
[0077] 7.2: Back of the carbide inserts
[0078] 8: Road surface
[0079] 9a: Snow gliding surface 9b: Snow gliding surface
[0080] 10.1 : Support projections on the front of the hard metal inserts 7
[0081] 10.2: Support projections on the back of the carbide inserts 7
[0082] - Patent claims -
Claims
Patent claims 1.
1. Snow clearing strip (1) for the clearing blade of a snow plow with a front steel plate (2) and a rear steel plate (3), which can be fixed together with the aid of fastening means to the lower edge of the clearing blade and between which an elastic rubber body (4) is vulcanized, wherein one or more metallic wear strips (5) are embedded in this rubber body (4) with limited mobility, said wear strips having a clearing edge (6) which touches the road surface (8) to be cleared and which is reinforced by one or more hard metal inserts (7), characterized in that the metallic wear strips (5) are each designed as cast parts made of chilled iron, and in that the hard metal inserts (7) are fixed in the metallic wear strips (5) by casting them around with the chilled iron.
2. Snow removal strip (1) according to claim 1, characterized in that the hard metal inserts (7) are provided with projections (7a) and / or depressions and / or openings to produce an additional positive connection with the metallic wear strips (5).
3. Snow removal strip according to one of the 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 supporting projections (10.1 and 10.2) which extend at least to the front (5.1) and the back (5.2) of the metallic wear strip (5).
4. Snow removal 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 the amount of a coating of the walls of the casting mold used during casting.
5. Snow removal strip (1) according to one of claims 1 to 4, characterized in that the metallic wear strips (5) are provided in their embedding area in the rubber body (4) of the snow removal strip (1) with projections (5a) and / or depressions (5b) and / or openings (5c), which act as a positive anchoring in the rubber mass of the rubber body (4) and are one-piece components of the metallic wear strips (1) designed as cast parts.
6. Snow removal 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 mass of the rubber body (4) engage with sufficient play, 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 mass embedding it is lost.
7. Snow clearing strip (1) according to one of claims 1 to 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), this plane extending at an acute angle (a) to the road surface (8) to be cleared.
8. Snow removal strip (1) according to one of the claims 1-6, characterized in that the metallic wear strips (5) project downwards over the lower edges of the front steel plate (2) and the rear steel plate (3) and are thickened in the projecting area.
9. Snow clearing strip (1) according to one of the claims 1-6, characterized in that the metallic wear strips (5) project downwards over the lower edges of the front steel plate (2) and the rear steel plate (3) and that on the surfaces of the front and / or rear of the wear strips (5) there are arranged inclined or curved snow sliding ramps (9a, 9b) running parallel to the lower edges of the front steel plate (2) or the rear steel plate (3) between the surfaces of the wear rails (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. A method for producing a snow clearing strip according to one of the claims 1-9, characterized in that the metallic wear strips (5) provided with hard metal inserts (7) are produced as cast pieces from chilled iron, into which the hard metal inserts (7) are fixed by casting with a chilled iron melt.
11. Method according to claim 10, characterized in that the hard metal inserts (7) are fixed in the correct position within the casting mold used by means of suitable holding devices before being encased with the chilled cast iron melt.
12. Method according to claim 11, characterized in that support projections (10.1 and 10.2) are used as holding devices for the hard metal inserts (7), which support projections are located on the front side (7.1) and the back side (7.2) of the hard metal inserts (7) and are supported on the inside of the casting mold during the casting process. - Summary -