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EP-4669809-B1 - SNOW CLEARING STRIP FOR THE CLEARING BLADE OF A SNOWPLOUGH

EP4669809B1EP 4669809 B1EP4669809 B1EP 4669809B1EP-4669809-B1

Inventors

  • KÜPER, Roland

Dates

Publication Date
20260513
Application Date
20241025

Claims (12)

  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.

Description

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. Snow removal blades of the aforementioned type are, for example, made from the US 7 765 726 B2 , the DE 10 2005 040 705 B4 or the DE 10 2016 114 457 A1 The snowplow blades resulting from 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) lead to particularly intensive wear and thus short service life. The improved wear resistance results primarily from 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 used, for example, in the... CH 550 897 described. 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 hard metal inserts is particularly labor-intensive and leads to This can lead to problems with wear resistance. The metallic wear strips must be fitted with carbide inserts, one by one, before being embedded in the rubber compound of the rubber body. For this, precisely fitting recesses 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 recesses and fixed in place using a special brazing process. 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. 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. 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. 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 made of hard iron casting, and, on the other hand, the stability and wear resistance The disadvantageous soldering of the hard metal inserts into the metallic wear strips was avoided. From the US 5 027 878 A While it is generally known to coat the surfaces of metal bodies with a wear-resistant layer of hard metal particles, the hard metal particles are first bonded together to form appropriately shaped layers and then cast in conjunction with iron or other metals. However, this publication 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 aforementioned type. On the contrary, the flat layers of hard metal particles disclosed therein are only cast to a minimal depth into the metal body, so it must be assumed that the products disclosed therein are not suitable for increasing the wear resistance of wear strips in snowplow blades of the aforementioned type. From the GB 1 480 057 A It is known to cast carbide lamellae into the wear edge of a snowplow blade made entirely of metal. However, such long-established snowplow blades have not proven effective in practice because the all-metal blades are largely inflexible, causing the carbide lamellae to break out of the blade's wear edge when it impacts fixed obstacles in the road surface. The snowplow blades according to the invention are fundamentally different because the wear strips are embedded in a flexible rubber body vulcanized between two steel plates, allowing the wear strips, made of cast iron and reinforced with carbide inserts, to deflect impacts. A further advantageous embodiment of the invention provides that the hard me