Field of the invention
[0001] The invention is related to the field of engineering and relates to the design of
maintenance equipment for roads, streets and similar large areas, more specifically,
the design of a road maintenance plough or snow plough blade. An element of the plough
blade, made of wear resistant material, is mounted in a flexible case, which is attached
between metal plates, the blade having cooling means for cooling the blade that is
heated up due to the friction between the blade and road surface.
State of the art
[0002] Similar solutions are known in the state of the art, related to a plough blade with
means for cooling the blade.
[0003] DE 102005040705 discloses a plough blade with a rubber or plastic body and wear casing, which is
incorporated in the wearing area of the body and consists partially or fully of hard
highly wear resistant material. The blade body includes cooling means for the blade.
[0004] Hard alloy blades without separate cooling means are also known in the state of the
art.
[0005] In the hard alloy blades known as the state of the art, the proportion of hard alloy
is generally small and thus a large amount of material is wasted when the hard alloy
part wears out (steel is scrapped, rubber or other flexible parts are discarded).
In traditional hard alloy blades, the hard alloy pieces are rigidly attached to the
blade body and thus cause excessive damage to the road surface and surface markings,
and are not able to withstand impacts from uneven road surface. In the blades disclosed
in
DE 102005040705, the hard alloy part is flexibly installed in a steel jacket (vulcanized with rubber
or enclosed in plastic), but in the preferred embodiment, the wear resistant element
itself is mounted inside a larger steel piece and the wear resistant element is rather
small. The friction between the blade and the road surface produces heat which must
be dissipated to avoid excessive heating of the blade. Otherwise the blade will wear
rapidly. In addition to the wear of the blade, excessive heat also damages the flexible
material surrounding the wear resistant element, which may melt or become fragile.
As a result, the wear resistant element of the blade may fall out from the flexible
material during operation. To solve this,
DE 102005040705 has provided cooling openings for blades, which are not very large and efficient.
Cooling openings may clog during operation and decrease cooling efficiency. At the
same time, a wide blade vulcanized in rubber does not heat up as much as a traditional
hard alloy blade, but it also does not remove hardened and cold snow as efficiently.
Summary of the invention
[0006] The objective of this invention is to improve the design of a plough blade and its
wear resistant hard material element, to ensure that both the blade and its wear resistant
hard material elements can be cooled more efficiently and the wear resistant hard
material element of the blade would remain in its position during the entire service
life of the blade. In order to achieve this objective, the wear resistant hard material
element of the blade has a heel connected to the part of element in contact with the
road surface with a neck, while openings with the shape of the heel of the element
are provided in the metal plate surrounding the wear resistant hard material element,
ensuring that the heels partially protrudes from the heel-shaped openings. This ensures
the efficient and direct contact of the hard material blade with the external environment,
including snow, water, ice and air. The efficient cooling of the element is ensured
as a result of the direct contact of the wear resistant hard material element with
the external environment. The lough blade element of the invention has been made of
a wear resistant hard material or is covered with a layer of wear resistant hard material
on one or several sides, in order to ensure the high wear resistance of the blade
and longer service life. The wear resistant hard material element of the blade is
mounted in a casing made of a flexible material, such as an elastomer, surrounding
the plough blade element and in turn located between two metal plates or steel plates
in the preferred embodiment. The steel plates include attachment means, in the preferred
embodiment in the form of openings for the connection of the blade to the plough.
List of figures
[0007] A better understanding of the present invention is obtained by reference to the detailed
description of an exemplary embodiment of the invention set out below, together with
the accompanying figures, where:
FIG 1 is a front view of the blade of the invention;
FIG 2 is a view of the section A-A in figure FIG 1;
FIG 3 is an alternative blade of the invention;
FIG 4 is a view of the section B-B of figure FIG 3;
FIG 5 shows a wear resistant hard material element of the blade with a trapezoidal
heel;
FIG 6 shows a wear resistant hard material element of the blade with a round heel.
Exemplary embodiment of the invention
[0008] The snow plough blade 1 (see FIG 1 and 2) has a front plate 2 and a rear plate 3.
The plate 2 faces the direction of travel and its surface is bent in the whole width
of the blade in the part facing the road surface, so that a groove or slot is formed
in the part facing the road surface between the front and rear plates in the whole
width of the blade where the hard material element of the blade 4 is installed. The
element is fixed inside the groove either by being cast in rubber, adhesion using
flexible polymers, or using other flexible binders 5 (polyurethane, silicone or similar).
This also ensures the resiliency of the blade element 4 on an uneven road surface.
The hard material blade element 4 has a heel 6, having a round or trapezoidal shape
in a preferred embodiment. The heel 6 is connected to the part of blade element in
contact with the road surface by a neck 7, the minimum width of which is smaller than
the maximum width of the heel. A substantially heel-shaped opening 8 is made in the
front plate 2 of the blade in the area of the heel 6 of the blade. A part of heel
6 of element 4 of the blade partially protrudes from the heel-shaped opening 8 made
in the blade frame. Such interaction of the heel of the blade element and the heel-shaped
opening has 2 main objectives:
- 1. As the hard material blade element is worn, the flexible material casing surrounding
the blade element and front and rear plates will also wear. Thus, as the blade element
wears off, the area of the surface keeping the blade element in position also decreases,
creating the risk that in the final stage of wear, the blade element will fall out
of the groove. Due to the interaction of the heel and the heel-shaped opening of the
front plate, the detachment of the blade element is prevented, as the neck area of
the heel of the blade element will come into contact with the lower part of the heel-shaped
opening in the front plate.
- 2. This protruding part of the heel of the blade element is in direct contact with
snow, ice, water, and air, thus helping to dissipate the heat caused by the friction
between the blade and the road surface.
[0009] The heel of the hard material element may have various shapes, such as a triangular,
round, trapezoidal, or any other shape (FIG 5, 6), ensuring the cooling as well as
the safe installation of the element in the flexible material casing in the groove
between the front and rear plates.
[0010] Cooling conduits 9 may be provided in the front plate 2 of the blade for additional
cooling of the blades (see FIG 3), providing the blade elements additional contact
with the external environment, facilitating the cooling conduits to ensure better
overall cooling of the elements.
1. A snow plough blade comprising a wear resistant element in a flexible casing and a
means for connecting the blade to the plough, characterized in that the wear resistant element has a heel, the means for connecting the blade to the
plough has a substantially heel-shaped opening, whereas the element heel protrudes
partially from the heel-shaped opening.
2. The snow plough blade of claim 1, characterized in that the dimensions of the substantially heel-shaped opening are adapted to receive the
heel of the blade element.
3. The snow plough blade of claim 1, characterized in that the means for connecting the blade to the plough includes a front plate and a rear
plate, whereas the front plate faces the direction of travel and the part of the front
plate facing the road surface is bent in the whole width of the blade.
4. The snow plough blade of claim 1, characterized in that the heel of the blade element is connected to the part of the blade element contacting
the road surface with a neck.
5. The snow plough blade of claim 1, characterized in that the interaction of the heel, the neck ,and the heel-shaped opening of the front plate
prevents the blade element from being released downwards from the flexible casing.
6. The snow plough blade of claim 1, characterized in that the heel of the element is substantially of a shape selected from: a round shape,
a reverse trapezoidal shape with round or sharp corners, a polygonal shape with round
or sharp corners.
7. The snow plough blade of claim 1, characterized in that the flexible casing is selected from: polymer, elastomer, rubber, silicone, plastic
or similar, or a combination thereof.
8. The snow plough blade of claim 1, characterized in that slots transverse to the lower edge are located in the lower edge of the front plate
of the means for connecting the blade to the plough.
9. The snow plough blade of claim 8, characterized in that the slots extend substantially to the heel.
10. The snow plough blade of claim 1, characterized in that the wear resistant element is made of cermet.
11. The snow plough blade of claim 1, characterized in that the wear resistant element is covered with recycled cermet powder.
12. The snow plough blade of claim 1, characterized in that the wear resistant element is made of thermally processed wear resistant steel, such
as HARDOX®.