Description

The present invention relates to a method for inserting fibres into a substrate and also for providing such fibres on a natural surface.

The insertion of fibres into a substrate is known per se from European patent EP 0 554 330 granted in the name of the present applicant, which was derived from WO9207142. From said patent there is known an artificial lawn consisting of a substructure and a top layer provided thereon, wherein the top layer comprises regularly spaced fibres which, seen in the longitudinal direction of the fibre, extend deeper into the ground than above the ground, with natural grass seeded between the fibres in a nutrient medium on the substructure. Other systems for artificial lawns are disclosed in, for example, EP0724825, EP2626468, NL1004656, WO2006008579, WO9400639, W09956523 and DE7702392.

In EP 0 554 330, for example, a relatively small part of the fibres, which are provided at regularly spaced locations in the natural grass lawn, extends above the nutrient medium, whilst the greater part of their length extends within the top layer and the substructure. Such fibres can be regarded as separate fibres, because fibres inserted in the substrate are not physically interconnected. Each time a fibre is inserted into the substrate, the fibre is cut off to the desired length.

US patent No. US 6,094,860 discloses an artificial lawn comprising a mat consisting of two layers, viz a first, fully biodegradable layer of a material such as jute, and a second, non-biodegradable layer such as a synthetic web.

Dutch patent NL 1007279 in the name of the present applicant relates to a device for inserting elongate artificial grass stalks cut off from wirelike material into the ground, which device comprises a frame that can be moved over the ground.

German publication DE 20 2008 005223 discloses an artificial grass line which is formed on a ground surface, for example an artificial grass sports field.

FR 2006203 relates to a nonwoven mat for consolidating embankments, dikes, channels and sports fields for the purpose of preventing erosion, which mat consists of at least one layer of synthetic fibres selected from polyamide fibres, polyester fibres and polyolefin fibres, wherein the fibres together with a binder are welded and/or sewn or stitched together. US patent No. US 6,524,027 relates to a method for stabilising the soil embankment of a slope having less than 45 degrees of inclination, wherein a geosynthetic layer is laid across the slope adjacent the surface, such that the vegetation on the slope is stabilised to assist in securing the soil adjacent the surface of the slope.

Synthetic fibres are used not only in sports fields, but also at private homes, for example, mainly instead of natural grass. In addition to that, synthetic fibres are also used for clothes and protective clothing, such as fireproof suits, but also for producing lightweight bicycles and certain car parts, such as car hoods and car roofs. An important advantage is that synthetic fibres are easy to handle and light in weight and that they are not subject to corrosion.

Grass present as natural vegetation forms in many cases an important part of civil engineering structures such as dikes. Such dikes have been used since time immemorial along, for example, rivers or other flowing or non-flowing bodies of water with changing water levels. In the case of exceptionally high water levels, the dike can become unstable and fail. This can be the result of a rise in the water pressure in and under the dike. This has an adverse effect on the effective ground pressure, resulting in the loss of shear strength whereby the stability decreases. The dike can hereby crumble away and shift or fail along a deep sliding plane on the rear side (i.e. the side remote from the water to be retained, also referred to as stability zone). A dike breach can ensue.

Because of global warming, particularly due to the emission of greenhouse gases, it is anticipated that the sea level will rise in the coming decades. This means that in certain regions existing dikes will have to be modified. Particularly in the Netherlands, a part of which is below sea level, the problem of dikes (which are too low) has been placed high on the agenda of the Dutch government.

In order to make dikes capable of withstanding exceptionally high water levels, dikes are traditionally reinforced or strengthened, for example by placing a stabilisation structure and/or piping in the stabilisation zone of the dike. Or by using space-saving structural elements such as sheet piling, diaphragm walls and the like. When a dike does not have sufficient strength to withstand the pressure of the water, it can be strengthened by civil engineering operations. One way is by arranging an inner embankment, such as in the case of a coastal dike. In addition to that, a dike can be strengthened or a different material can be used for the covering layer. In the case of widening use is made of several materials such as clay granules, cellular concrete, polystyrene foam and aeolian sand.

A recent development relates to a so-called 'JLD dike stabilizer', i.e. a plastic pin which strengthens dikes so that they once again meet safety requirements. A dike is strengthened on the inside by the stabilizer. The pin is inserted in a few minutes with a small machine and is made from a special type of flexible plastic.

On a dike itself a revetment is usually arranged. This revetment can be natural in the form of grass but can also consist of synthetic materials. Dikes are covered for various reasons, but the most important function of the revetment is to prevent erosion by wave overtopping. It moreover increases the water-tightness. In addition, the revetment of a dike ensures that it can be used for other functions and can also result in limited maintenance. The revetment can also be a factor in the aesthetic perception of a dike, such as its integration into the landscape. Dikes which are not used/loaded intensively are in most cases covered with grass.

If the grass that is naturally present does not provide sufficient protection, use is made of other materials such as stones, rubble, asphalt, gabions and special synthetic mats (geotextile). The choice of the material depends on, among other factors, the risk of flooding, the type of dike, the cost and the appearance of the covering material. If one material does not perform the function adequately, a combination of materials can be used so that the dike will fulfil its function.

It is further known that the stability of dikes can be undermined by the presence of certain animals, such as moles. Moles dig underground tunnel systems which have an adverse effect on dike stability.

From Dutch patent publications NL 1023362 and NL 1003138 there is known an element for reveting a bank or a dike. Further known from NL 1009578 is an implementation method for arranging sheeting or foil on a slope or dike.

One aspect of the present invention is to provide a method for inserting fibres into a substrate, wherein the number of operations required for inserting the fibre into the substrate is minimised.

Another aspect of the present invention is to provide a method for inserting fibres into a special substrate, wherein a stability-increasing effect is imparted to the vegetation that is naturally present. The present invention thus relates to a method for inserting fibres into a substrate, wherein the fibres are inserted into the substrate using a pin capable of substantially vertical up-and-down movement, characterised in that the method comprises the following steps:

i) providing an endless fibre,

ii) connecting an end of said pin to the fibre of step i), iii) moving the end of said pin connected to the fibre of step ii) in vertical direction to a desired depth in the substrate,

iv) removing said pin from the substrate while leaving the fibre behind in the substrate,

v) connecting an end of said pin once again to the fibre as according to i),

vi) moving the end of said pin connected to the fibre as according to v) in vertical direction to a desired depth in the substrate, wherein the position of the fibre arranged in the substrate as according to iii) differs from the position of the fibre arranged in the substrate as according to vi).

If the insertion of fibres takes place in this manner, one or more of the above aspects are achieved, in particular that the fibre which runs through the substrate serves to fix the roots of the natural vegetation, in particular the grass, thereto, thereby imparting additional reinforcement to both the grass and the fibres. The term "substrate" is to be understood to mean natural soil or a piece of land, for example a grassland or field of grass, a body of a dike, a sports field, arable land and the like, on the upper surface of which a human activity can be carried out, for example driving a vehicle, but also practising sports, recreating, jogging and walking. Also civil engineering structures are to be understood to be included therein, for example banks, noise barriers, playgrounds, hiking paths, festival grounds. The term "substrate" as used herein should by no means be interpreted as being a product, for example an item of clothing. The term "vertical direction" must be understood to mean a direction which has the purpose of inserting the fibre into the substrate. Such a direction can therefore extend at a particular angle to the upper surface, but also substantially perpendicularly. The choice of the angle can also be adapted during performing of the present method in accordance with requirements. Although mention is made here of grass, the present invention is not limited to a specific type of dike vegetation. Usual dike vegetation consists for the greater part of different types of grass and in lesser part of diverse types of herb depending on, among other factors, the location relative to the sun (the south side of the dike is warmer and drier than the north side), and the composition of the soil, for example clay or sand. The dike vegetation is important for the resistance of the dike to water erosion at high water levels and precipitation, and the dike must preferably have a deeply rooted, dense sward.

The present method as discussed above is in particular suitable for anchoring sods, for example sods used in the construction of such a sports field. The present method for inserting fibres into a substrate can for example be used at the boundary surface between two sods adjacent to each other, wherein the anchoring takes place by inserting the "endless fibre" alternately in one and the other sod. In a specific embodiment, a few "stitches" of the endless fibre may also be made in one sod, after which one or more stitches are made in the adjacent sod, which operation can be repeated, for example over part of the regions adjacent to each other. The sods are thus "laced together", thereby effecting an anchoring.

One aspect of the present method is that, particularly between step iv) and step v), a step of severing the fibre does not take place. In practice, such an operation of severing the fibre takes up a large part of the time for installing the fibre construction. And because according to the present method use is made of an endless fibre, which is preferably supplied on a roll, the fibres arranged in the substrate will be connected to each other. The fibres will in particular be inserted into the substrate and the fibre will subsequently exit the substrate again and then be reinserted into the substrate. This has the result that a part of the fibre will come to lie over the upper surface. Thus there will not be a situation as in the above- discussed European patent EP 0 554 330 granted in the name of the present applicant, in which the length of the fibre, i.e. the stalks which protrude over a height of 1-1 .5 cm above ground level, is such that the part protruding above the nutrient medium is held in place and will not be displaced by a sliding movement on the ground. Furthermore, after the method according to the present invention has been carried out, the fibre will be present in the ground as a kind of "loop". After all, a specific fibre length is arranged in the substrate in step iii), after which the fibre, because it is in fact an endless fibre here, will again exit from the substrate, after which a desired number of steps ii) - vi) will be carried out again. The "loop" is thus situated in the substrate and, particularly at the position where the pin is guided into the substrate, there will be a length of fibre which "disappears" into the substrate and a length of fibre which "appears" from the substrate, wherein the length of fibre exiting the substrate can be reinserted as a fibre into the substrate, in particular at a position differing from the previous insertion of the fibre. The fibre arranged in the substrate thus "returns" at the deepest point in the substrate. It may be desirable in specific embodiments to vary such deepest points during the present method.

According to a specific embodiment of the present method, steps ii) - vi) are repeated in such a manner that the thus obtained positions of fibres arranged in the substrate can be considered to be a row of fibres.

It is preferable in that regard if steps ii) - vi) are repeated in such a manner that regularly spaced rows of fibres are obtained, wherein the spacing between said rows of the fibres arranged in the substrate preferably ranges from 10- 50 mm, in particular from 20-40 mm.

It is furthermore preferable if the spacing between the fibres arranged in a row in the substrate is 10-75 mm, in particular 10-50 mm, preferably 20-40 mm.

In addition to the above embodiment of side-by-side rows, wherein the fibres are as it were positioned as "pairs" in the side-by-side rows, the regularly spaced rows may also be staggered relative to each other. This is therefore an embodiment in which the fibres arranged in the substrate are "offset", as it were.

Because the present method makes use of an endless fibre, which is to be understood to mean a fibre which is supplied on a roll or a reel, for example, and is not cut or clipped into separate fibre lengths during the method, it is desirable that the fibre lying between successive fibres vertically inserted into the substrate abuts the upper surface of the substrate. In the case of a sports field, for example, the fibre bearing against the upper surface of the substrate will not lead to situations in which a player's shoes, in particular the studs thereof, "catch" on the fibre. Because of the presence of the natural grass, the player will experience the present lawn as a natural lawn.

In order to ensure that the fibre is laid "tightly" over the upper surface, it is desirable that during at least one of the steps ii) - vi) a pressure element is used for pressing the fibre abutting the upper surface against the upper surface. A suitable pressure element is for example a pressure roller moving over the upper surface. In order to ensure that the fibre is laid "tightly" over the upper surface, it is further desirable that the fibre is held under tension upon repeated application of steps ii) - vi).

To obtain a good anchoring in the ground, it is desirable that the fibres are inserted to a depth of 10 - 30 cm, preferably 10 - 25 cm, into the substrate.

Suitable fibres that can be mentioned include fibres as disclosed in N L 1006606. In addition to that, EP 0 996 781 discloses a yarn suitable for the present invention, viz. a yarn which comprises, as an addition to polyamide, a polyolefin compound, selected in particular from the group of polypropylene, LLDPE, and a block copolymer of polypropylene and polyethylene. It has also been found possible, however, to use a yarn comprising one or more of a polyolefin compound, selected in particular from the group of polypropylene, LLDPE, and a block copolymer of polypropylene and polyethylene. Fibres of the polyester, aramid or carbon type, possibly as combinations of one or more thereof, possibly also in conjunction with one or more of the aforementioned materials, may be suitable in specific embodiments.

In addition to the abovementioned fibres, also functionalised fibres are used, for instance biodegradable fibres. Possible examples include: hemp fibre, jute, kapok, coconut fibre, sisal and flax. The abovementioned natural fibres can optionally be used in combination with synthetic fibres. Fibres of the core-cladding type, wherein special properties, for example hydrophilicity and resilience, can be attributed both to the core material and to the cladding material. In addition to different material properties, the fibres may also have different colours.

In a special embodiment of the present method it is desirable that steps ii) - vi) are carried out using a number of pins. In this way a desired production capacity is achieved. It is also possible in that regard that specific types of fibre are applied for specific pins, thus obtaining a substrate in which a number of different types of fibre are arranged.

In a specific embodiment it is desirable that steps ii) - vi), using a number of pins, are not carried out simultaneously. In such an embodiment the pins will have a different cycle or frequency.

In a specific embodiment it is desirable that steps ii) - vi), using a number of pins, are carried out simultaneously, whereby a particular manner of insertion is in fact realized. In a specific embodiment it is desirable that a mesh be used to improve the anchoring of the fibres arranged vertically in the substrate, which mesh is positioned on the upper surface and which is connected to the fibres in such a manner that the fibres abutting the upper surface of the substrate enclose said mesh. As a suitable mesh a grid can be mentioned, for example, in particular a metal or plastic grid.

The present invention further relates to a natural substrate provided with fibres inserted into said substrate, which fibres extend into said substrate in a direction away from the upper surface thereof, wherein said fibres are interconnected near the upper surface of said substrate. In a special embodiment of such a substrate, said fibres are spaced a regular distance apart, with the spacing between said fibres preferably ranging from 10 - 75 mm.

The present invention also relates to a natural substrate provided with fibres inserted in accordance with the above-discussed method.

A natural substrate can for example be a sports field, in particular selected from the group of soccer field and hockey field but also athletics, tennis, cricket and baseball fields. A particularly suitable substrate is a substrate made up of one or more sods, which sods are "sewn" together using the endless fibres according to the present invention.

Another example of a natural substrate is a water barrier, in particular a dike, comprising an inner slope, a crown and an outer slope, wherein the fibres are arranged particularly in at least one of the elements of inner slope, crown and outer slope. Although mention is made in the introduction of the insertion of fibres into the natural vegetation, it should also be understood that the invention relates to a situation wherein a dike, which does not (yet) have natural vegetation, is first provided with the fibres, after which the natural vegetation will form around the inserted fibres at a later stage. Other, suitable substrates comprises civil engineering structures selected from the group of sound barrier, playground, footpath, festival ground and recreation park.

In such a natural substrate it is preferable if the fibres combined with the aforementioned mesh are located near an obstacle, for example a staircase or a fence. Other examples of obstacles are roads or a strengthening revetment, such as concrete. The present invention also relates to the use of the present method for strengthening slopes, for example in road construction. In addition to that the present inventors have found that the substrate obtained with the present method has the particular effect of creating a digging/nesting location unattractive to moles and mice.

The present invention in particular relates to a natural substrate wherein said substrate comprises a mesh for improving the anchoring of the fibres arranged in the substrate, which mesh is positioned on the upper surface and which is connected to the fibres in such a manner that the fibres abutting the upper surface of the substrate enclose said mesh.

The present invention further relates to the use of a mesh positioned on the upper surface of a substrate for the purpose of preventing destabilisation of said substrate, wherein the mesh is connected to fibres arranged in said substrate in such a manner that the fibres abutting the upper surface of the substrate enclose said mesh, which fibres are interconnected near the upper surface of said substrate.

The phrase "preventing destabilisation of the substrate" is understood to mean preventing the formation of digging and nesting sites for moles and/or mice, for example. Suitable applications include civil engineering construction, in particular road constructions.

The invention will be now be explained by means of a few examples and associated figures, which are not to be construed as limiting the scope of protection, however.

Figures 1A-F are schematic representations of the present method.

Figures 2G-J are schematic representations of the present method.

Figures 3A-B show a special embodiment of the present application. Figure 4 shows a special embodiment of the present application.

Figure 1A schematically shows a first step of the present method, wherein a fibre indicated at numeral 3 is inserted into a substrate 1 having an upper surface 5. The fibre 3, only part of which is shown for ease of illustration, is brought into contact with a pin or hook 2. Also present on the upper surface 5 is a pressure roller 4. After one end of said pin 2 has been connected to the fibre 3, the end of said pin 2 is inserted in vertical direction, viz. in the direction of arrow 6, to a desired depth in the substrate 1 , as shown in figures 1 B and 1 C. Once the desired depth in the substrate 1 is reached, said pin 2 is removed in vertical direction, viz in the direction of arrow 7, from the substrate 1 , leaving behind the fibre 3 in a shaft or space 12 of the substrate 1 (see figure 1 D). The pin 2 is then removed from the substrate 1 in its entirety and readied for a next insertion of the fibre 3 into the substrate 1 (see figure 1 E). The pin 2 is now horizontally moved a specified distance over the upper surface 5, viz. in the direction of arrow 8, during which movement also the pressure roller 4 is moved in the direction of arrow 8 over the upper surface 5. The pressure roller 4 presses the fibre 3 that exits from the shaft or space 12 of the substrate 1 onto the upper surface 5 whilst the fibre 3 is kept slightly tensioned (see figure 1 F). Thus, an incoming fibre and an outgoing fibre are present in the shaft or space 12, which outgoing or exiting fibre is pressed against the substrate 1 by means of the pressure roller 4 and readied for a next insertion step into the substrate, for which use is made again of the pin 2.

Figure 2G schematically shows the continuation of the above- discussed steps, wherein an end of said pin 2 is connected to the fibre 3 again and the pressure roller 4 presses the fibre 3 that exits from the shaft or space 12 against the upper surface 5. The pin 2 with the fibre 3 connected thereto is then moved again in vertical direction, viz in the direction of the arrow 9, to a desired depth in the substrate 1 , wherein the position of the fibre previously inserted into the substrate 1 is different from the position of the fibre now being inserted into the substrate 1 (see figure 2H). Subsequently, said pin 2 is removed in vertical direction, viz in the direction of arrow 10, from the substrate 1 , leaving behind the fibre 3 in the shaft or space 13 of the substrate 1 (see figure 2I). The pin 2 is then removed from the substrate 1 in its entirety and readied for a next insertion of the fibre 3 into the substrate 1 (see figure 2J).

Although figures 1A-F and 2G-J only show the insertion of two fibres into a substrate, it should be understood that the above-discussed steps can be repeated many times so as to thus obtain a desired pattern of fibres arranged in the substrate. It should further be noted that in specific embodiments it is desirable that several fibres are inserted into the substrate simultaneously, for example by using various pins. In specific embodiments it is also possible that several fibres are inserted into one and the same shaft or space. It is also possible for the present method to be carried out on a substrate in which, in addition to the possible presence of natural fibres, also other fibres are present.

Figures 3A-B provide a special embodiment of the present application, in which a grid or mesh 20 is used, in particular in combination with a fixed body 19, for example a stone curb (see figure 3A). Such a grid or mesh 20 particular functions to improve the anchoring of the fibres arranged vertically in the substrate (not shown), wherein the mesh is positioned on the upper surface and is connected to the fibres in such a manner that the fibres abutting the upper surface of the substrate enclose said mesh, wherein said fibres are interconnected near said upper surface of said substrate. In such an embodiment, the fibres are inserted into the substrate through an opening of the mesh, for example, in which case a next position is another opening of the mesh. As according to the present method the fibres are interconnected near the upper surface and are arranged in the substrate in the respective opening of the mesh, the mesh 20 is anchored to the substrate via the fibres.

Within that framework, figure 3B provides an embodiment in which a mesh 20 is present in the top layer of natural vegetation 21 , wherein, using the present invention, fibres have been inserted via shafts 23, 24, 25, 26 and 27 (see figure 3B. As shown clearly in fig 3B, the fibres inserted into the substrate via said shaft are interconnected near the upper surface of the substrate, thereby anchoring the mesh 20 to the substrate.

Figure 4 provides a special embodiment of the present application, which clearly shows that the fibre 3 has been arranged in the substrate 1 via respective shafts 12, 13, 14, 15, 16, 17 and 18. The fibre 3 can be regarded as a continuous or endless fibre, because the fibre exiting the shaft 12, for example, has been inserted into the adjacent shaft 13 via the upper surface and subsequently, after exiting from said shaft 13, into the shaft 14 via the upper surface extending between the shaft 13 and the next shaft 14.