EP2670899A1

EP2670899A1 - Nets for agriculture

Info

Publication number: EP2670899A1
Application number: EP10805655.7A
Authority: EP
Inventors: Mirco Santino Darra
Original assignee: Individual
Current assignee: Individual
Priority date: 2010-12-09
Filing date: 2010-12-09
Publication date: 2013-12-11
Also published as: WO2012077144A1

Abstract

The present invention is a net (1) for agriculture comprising a plurality of warp yarns (2; 12; 22; 32; 42; 52) and a plurality of weft yarns (3; 13; 23; 33; 43; 53) interwoven with each other. At least one of the warp yarns (2, 12; 22, 32; 42, 52) or of the weft yarns (3; 13; 23; 33; 43; 53) features a non-circular cross section. The invention concerns also a warp yarn (2; 12; 22; 32; 42; 52) or weft yarn (3; 13; 23; 33; 43; 53) for making an agricultural net (1).

Description

NETS FOR AGRICULTURE

TECHNICAL FIELD OF THE INVENTION

The present invention concerns the technical field of nets for agriculture.

In particular, the present invention refers to the manufacture of insect nets used to cover cultivations and protect them from insects and/or aphids and their eggs.

DESCRIPTION OF THE STATE OF THE ART

The use of nets arranged on bearing structures to protect the underlying cultivations is known in the field of agriculture.

A first known type of protection nets consists of nets arranged as a covering to ensure protection from hail, which are frequently used, for example, in vineyards and/or orchards.

Another type of protection nets of known type is constituted by the so-called insect nets, that is, nets made up of plaited and woven yarns, normally according to a weft and warp pattern, sufficiently close, on one hand, to prevent the passage of insects and/or aphids or their eggs that could reach the cultivations from the outside and, on the other hand, to allow the passage of light and of a sufficient quantity of air for the growth of the cultivations.

In addition to ensuring protection from the outside, said nets also favour the so- called biological fight, meaning the fight against harmful insects through the introduction of other insects that are natural predators of the former and are not harmful to the cultivations. The greenhouses provided with the nets described above prevent said predatory insects from flying out of them.

For this purpose, the nets described above are made of a polymeric material, in particular high-density polyethylene, preferably transparent and ensuring protection against UV rays.

Protection against UV rays can be obtained, as known, by spreading a thin protective film on the outer surface of the yarns that make up the net. In this case the net is transparent, even if it tends to lose part of its protective characteristics over time, due to the wear of said external layer.

As an alternative, the yarns can be manufactured by adding protective substances inside them, for example titanium dioxide, in which case the net can ensure protection against UV rays for a longer period, even though it becomes opaque and is not transparent any longer.

More particularly, the manufacture of the nets includes the use of yarns with circular cross section, made of said polymeric material and plaited using the known weaving techniques, that is, arranging them in a first direction side by side and parallel to each other, and in a second direction side by side and parallel to each other, the second direction being preferably perpendicular to the first one. Said nets are manufactured using frames that starting from the base material consisting of polyethylene yarns produce the fabric with weft and warp yarns. The preparation of the warp consists in transferring the yarn, wound on bobbins or reels, to the special area of the frame where it is divided in two series, that is, the even and the odd. The two series are divided placing one of them above and the other below, thus obtaining a passage through which the weft yarn is inserted. Once the weft yarn has been inserted, the series exchange place, meaning that the upper one moves down and vice versa, thus producing a crossing that locks the weft yarn. The latter is then pushed against the preceding weft and the fabric is thus produced.

The use of a projectile to which the yarn is clipped is known for the insertion of the weft yarn between the two series of warp yarns. The projectile is launched at high speed from one side of the frame to the other by means of a special device. However, said nets of known type pose some drawbacks.

A first drawback posed by said nets of known type lies in that following the weaving process the weft and warp yarns often present imperfections in their configuration, and this means that the interlaced structure does not form a homogeneous pattern, so that in some areas the adjacent weft and warp yarns can be closer than in other areas, thus losing their parallel configuration.

This manufacturing defect determines the formation of fabric meshes that are larger than expected and desired, meaning meshes through which the insects and/or aphids or their eggs can pass or through which the predatory insects can exit in organic cultivations. Therefore, the net partially loses the required capacity to protect cultivations from the outside and/or from the inside.

Another drawback posed by said nets of known type lies in that during use the fabric of said nets can be subjected to deformations, so that the interlaced structure loses its homogeneity characteristics. This happens, for example, when some material, for example hail, accumulates on the net and its weight causes the fabric to deform due to the movement of the weft and warp yarns. Furthermore, said loss of homogeneity can occur during handling of the nets.

Also in this case the dimensions of the fabric meshes exceed those expected and desired, meaning that insects and/or aphids or their eggs can pass through them or predatory insects can fly out of them in organic cultivations. Therefore, the net partially loses the required capacity to protect cultivations from the outside and/or from the inside.

Furthermore, said nets can wear out or break over time in the areas where said non-homogenoeus points are created, so that it is necessary to replace them.

The main object of the present invention is therefore to solve at least partially the problems that characterize the nets of known type.

In particular, it is one object of the present invention to propose a net for agriculture whose characteristics are homogeneous over its entire extension.

It is another object of the present invention to propose a net for agriculture that during use can maintain its homogeneity characteristics over its entire extension, which does not occur with the nets of known type.

It is a further object of the present invention to propose a net for agriculture that lasts longer than the nets of known type.

It is a further object of the present invention to propose a net for agriculture with better aeration characteristics than the nets of known type.

SUMMARY OF THE PRESENT INVENTION

The present invention is based on the general consideration that it should be possible to make the surface characteristics of a net for agriculture homogeneous and/or to improve them and/or to improve the aeration characteristics of the same by shaping the cross section of the yarns that make it up.

According to a preferred embodiment, the object of the present invention is a net according to claim 1, meaning a net for agriculture comprising a plurality of interwoven warp yarns and weft yarns, at least one of said warp yarns or said weft yarns featuring a non-circular cross section.

Advantageously, the non-circular shape of the yarns makes it possible to increase the contact points at the crossings between warp yarns and weft yarns, and therefore to increase the friction force between them.

In a preferred embodiment of the net that is the subject of the present invention, both the warp yarns and the weft yarns feature a non-circular cross section.

Advantageously, the friction force at the crossings is higher.

In a particular embodiment of the invention, the non-circular shape is substantially of the polygonal type.

More preferably, said non-circular shape features one or more points.

Advantageously, during weaving the electrostatic charges concentrate on said points and improve the net manufacturing process.

In a preferred embodiment of the invention said points are rounded in shape. Alternatively, said points are sharp.

Advantageously, the accumulation of electrostatic charges is further increased. Preferably, the non-circular shape is substantially the shape of a star with several points.

Alternatively, the non-circular shape comprises one or more lobes.

Advantageously, the yarns are easier to manufacture.

In another preferred embodiment of the invention the non-circular shape is substantially the shape of an eight.

In another preferred embodiment of the invention the non-circular shape is substantially a square shape.

The yarns preferably comprise a polymeric material.

More preferably, said polymeric material comprises polyethylene.

Advantageously, said yarns are easier to manufacture.

The maximum size of the cross section of the yarns for insect nets is preferably included between 0.12 mm and 0.25 mm, preferably included between 0.18 mm and 0.23 mm, and even more preferably included between 0.20 mm and 0.22 mm.

The insect net preferably comprises a number of warp and weft yarns per square centimetre included between 6x6 and 23x14, preferably included between 16x10 and 22x12, and even more preferably equal to 20x12.

The maximum size of the cross section of the yarns for anti hail or shading nets is preferably included between 0.24 mm and 0.34 mm, preferably included between 0.25 mm and 0.34 mm, and even more preferably included between 0.30 mm and 0.32 mm.

The anti hail net preferably comprises a number of warp and weft yarns per square centimetre equal to 5x4, or equal to 2.6x4, or even equal to 2.2x3.2.

The shading net preferably comprises a number of warp and weft yarns per square centimetre equal to 10x20, or equal to 6x10, or even equal to 5x5.

In a preferred embodiment of the invention the net is woven according to a cloth pattern (plain weaving).

The production process is advantageously simple.

According to an alternative embodiment of the invention, the net is woven according to a leno weave pattern. According to a preferred embodiment of the invention, the net of the invention is an insect net.

According to a second aspect of the invention, the subject of the present invention is a yarn according to claim 14, meaning a weft or warp yarn for making nets for agriculture, said yarn featuring a non-circular cross section.

More preferably, said non-circular shape features one or more points.

Preferably, the non-circular shape is substantially the shape of a star with several points.

Alternatively, the non-circular shape comprises one or more lobes.

The yarn preferably comprises a polymeric material.

More preferably, said polymeric material comprises polyethylene.

More preferably, said polyethylene is high-density polyethylene (HD).

The maximum size of the cross section of the yarn for insect nets is preferably included between 0.12 mm and 0.25 mm, preferably included between 0.18 mm and 0.23 mm, and even more preferably included between 0.20 mm and 0.22 mm.

BRIEF DESCRIPTION OF THE DRAWINGS

Further advantages, objects and characteristics, as well as further embodiments of the present invention are defined in the claims and will be illustrated in the following description, with reference to the enclosed drawings; in the drawings, corresponding or equivalent characteristics and/or components are identified by the same reference numbers. In particular:

- Figure 1 shows the utilization of a net obtained according to a first embodiment of the invention;

- Figure 2 shows a piece of the net of Figure 1 ;

- Figure 3 shows a schematic enlarged view of the net of Figure 2;

- Figure 4 shows an enlarged view of a detail of a net belonging to the known art; - Figure 5a shows an enlarged view of a detail of a net obtained according to a first embodiment of the invention with a first configuration of the crossing pattern between warp and weft yarns;

- Figure 5b shows an enlarged detail of Figure 5a;

- Figure 5c shows an enlarged view of a detail of a net obtained according to the first embodiment of the invention with a second configuration of the crossing pattern between warp and weft yarns;

- Figure 6a shows an enlarged view of a detail of a net obtained according to a variant embodiment of the invention with a first configuration of the crossing pattern between warp and weft yarns;

- Figure 6b shows an enlarged view of a detail of a net obtained according to the embodiment of Figure 6a with a second configuration of the crossing pattern between warp and weft yarns;

- Figures from 7 to 11 show variant embodiments of the net according to the view of Figure 5a;

- Figure 12 shows a variant embodiment of the type of fabric;

- Figure 13 shows a variant embodiment of the net of Figure 2.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

Although the present invention is described below with reference to its embodiments illustrated in the drawings, the present invention is not limited to the embodiments described below and illustrated in the drawings. On the contrary, the embodiments described and illustrated herein clarify some aspects of the present invention, the scope of which is defined in the claims.

The present invention has proven to be particularly advantageous when applied to insect nets used to completely cover agricultural cultures. It should however be pointed out that the present invention is not limited to the manufacture of insect nets but can be conveniently applied to the manufacture of nets for agriculture of different types, for example anti hail nets or shading nets for greenhouses.

Figure 1 shows a net 1 according to a first preferred embodiment of the invention.

The net 1 is shown when used in a structure of the greenhouse type, that is, covering the agricultural culture to be grown and protected against insects and/or aphids and their eggs or against the escape of the predatory insects in cultivations adopting biological fight. For this purpose the net 1 closes all the sides of the structure.

In variant embodiments, however, the net 1 could be arranged in a different way, for example covering only the underlying culture, as in the case of a vineyard or orchard where the net serves only to ensure protection against hail.

Figure 2 shows a detail of a piece of the net 1 of the invention.

The net 1 is constituted by a plurality of warp yarns 2 and a plurality of weft yarns 3 arranged perpendicular to each other and interwoven so as to form a homogeneous fabric.

In the embodiment described herein the warp yarns 2 and the weft yarns 3 are interwoven according to a traditional cloth pattern (or plain weaving) that is easy to carry out, as schematically shown in Figure 3.

The warp yarns 2 in fact perform on the weft yarns 3 a continuous and constant alternating movement from top to bottom and, vice versa, the weft yarns 3 perform on the warp yarns 2 a continuous and constant alternating movement from top to bottom. However, in variant embodiments of the invention different weaving patterns are possible, intended to obtain different types of fabric of known type, like for example herringbone, sateen, leno weave, as shown in Figure 12, or fabrics containing also diagonal yarns, as shown for example in the embodiment illustrated in Figure 13.

The warp yarns 2 and weft yarns 3 are preferably made of transparent high- density polyethylene, coloured or neutral, preferably UV stabilized.

Protection against UV rays can be obtained, as known, by spreading a thin protective film on the outer surface of the yarns that make up the net.

As an alternative, the yarns can be manufactured by adding protective substances inside them, for example titanium dioxide, in which case the net is opaque and not transparent.

The insect net described herein preferably comprises a number of warp and weft yarns per square centimetre included between 6x6 and 23x14, preferably included between 16x10 and 22x12, and even more preferably equal to 20x12. The warp yarns 2 and weft yarns 3 therefore create a fabric as shown in Figure 3, in which between the warp yarns 2 and the weft yarns 3 there are openings 10, also called meshes, that are quadrilateral in shape. Said values are indicative and refer in particular to insect nets. It should however be noted that variant embodiments of the invention may comprise different materials for making the net, as well as different dimensions and number of the yarns making up the warp and weft. Said parameters can vary both in insect nets and in nets intended for different uses, like for example anti hail and/or shading nets.

By way of example, in the case of anti hail nets, the net preferably comprises a number of warp and weft yarns per square centimetre equal to 5x4, or equal to 2.6x4, or even equal to 2.2x3.2.

In the case of shading nets, the net preferably comprises a number of warp and weft yarns per square centimetre equal to 10x20, or equal to 6x10, or equal to 5x5.

In the embodiment of the invention described herein, the warp yarns 2 and weft yarns 3 are the same and feature a shaped cross section, as shown in Figure 5a. Said figure shows an enlarged detail of a crossing area with a first configuration of the crossing pattern between a warp yarn 2 and a weft yarn 3, and also shows the cross section of the warp yarn 2.

In particular, the cross section has a substantially hexagon-shaped polygonal profile, or better a star-shaped profile with six points 4. The six points 4, slightly rounded, are connected to one another by intermediate arcs of a circle 6.

More particularly, as shown in Figure 5b, each yarn 2 is characterized by a maximum size Dl equal to 0.1504 mm, corresponding to the diameter of the circumference that circumscribes the shaped profile, a minimum size D2 equal to 0.1262 mm, corresponding to the diameter of the circumference inscribed in the shaped profile, a curvature radius Rl of the points 4 equal to 0.009 mm, and a curvature radius of the intermediate arcs of a circle 6 equal to 0.1631mm.

The maximum size Dl is preferably included between 0.14 mm and 0.18 mm, more preferably between 0.15 mm and 0.17 mm, and even more preferably equal to 0.1504 mm, as explained above.

The star shape is particularly suitable for making the yarns through a straining process.

The warp yarns 2 and weft yarns 3 contact each other, as already explained, in corresponding crossing areas inside the fabric that makes up the net 1. During the weaving of the net 1, the warp and weft yarns are arranged at random with respect to each other in the crossing areas, since they are able to rotate around their longitudinal development axis. In said crossing points there can therefore be substantially two configurations, respectively shown in Figures 5a and 5c.

With reference to the configuration shown in Figure 5a, the shape of the yarn of the invention makes it possible to obtain a stronger contact at the height of each crossing between a warp yarn 2 and a weft yarn 3 compared to the fabrics of known type.

In fact, with reference to an enlarged detail of a crossing area between a warp yarn 2' and a weft yarn 3' of a net of known type, as shown in Figure 4, the star shape of the invention makes it possible to obtain a larger contact surface between the weft yarn 3 and the underlying warp yarn 2. In particular, the warp yarn 2 and the weft yarn 3 come into contact in two distinct areas 7 and 8, as shown in Figure 5a, and not in a single contact area 7' as it happens in the known art. Therefore, the friction force that is generated between the warp yarn 2 and the weft yarn 3 at each crossing point is higher than in the known art and the arrangement of the crossings of the net 1 can be maintained more effectively. This is particularly advantageous when the net is subjected to external deformation forces, like for example to the force of hail stones, wind gusts, or the force exerted during handling. In fact, friction at the crossing points tends to maintain the configuration of the fabric in which the meshes have the desired pre-detenriined size. The net 1 is more resistant and has a greater capacity to bear external deformation forces. The net 1 is therefore homogeneous and its homogeneity lasts longer over time.

In the second possible configuration of the crossing between the warp yarn 2 and the weft yarn 3, shown in Figure 5c, the warp yarn 2 is substantially arranged so that one point rests against the weft yarn 3. The figure shows two warp yarns 2 positioned side by side inside the net 1.

In this configuration, the shape of the yarn of the invention makes it possible to improve the aeration of the net 1 compared to the nets of known type.

In fact, as shown in the figure, where C indicates the circular profile of a yarn of the known art, the free surface SI between two adjacent warp yarns 2, through which air passes from one side of the net 1 to the other, is larger than the free surface SN between the warp yarns C of a net of the known art.

Analogously, the free surface between two adjacent weft yarns of the net 1 of the invention is larger than the free surface between two weft yarns of a net of the known art. Therefore, with the same number of weft or warp yarns per square centimetres, the surface through which the air passes is larger than the surface through which the air passes of the nets of the known art.

Higher aeration means an advantageous decrease in the quantity of water needed to irrigate cultures in greenhouses.

According to the above and to the arrangement of the warp yarns 2 and weft yarns 3 at their crossing area, the net 1 of the invention alternatively offers an advantage in terms of either higher friction or better aeration compared to the nets of the known art.

Furthermore, the net 1 of the invention has less manufacturing defects.

The holder of the present patent has verified, in fact, that a net 1 obtained with yarns 2, 3 of the type just described presents a lower percentage of defects than the nets of known type. The term "defect", as explained above, means the presence, in the fabric that makes up the net 1, of imperfections due to the lack of parallelism between the warp yarns 2 or weft yarns 3, with the consequent presence of areas with meshes that are larger than desired to protect the cultures from insects and/or aphids and their eggs.

The shaped profile of the warp and weft yarns considerably contributes to attenuate the negative effects caused by the accumulation of electrostatic charges during weaving, due in particular to the sliding of the projectile to which the yarn is clipped and which is launched at high speed from one side of the frame to the other. Said charge accumulations that occur on the adjacent warp and weft yarns, in fact, may cause them to mutually move away from or nearer to each other because of the electrostatic attraction or rejection forces, thus determining imperfections in the meshes and lack of homogeneity in the fabric.

Providing the shaped profile with points causes the charges generated during weaving to accumulate, and said accumulation on said points that are spatially distributed around the yarn determines a compensation between the electrostatic attraction or rejection forces between the same warp or weft yarns, and of the electrostatic attraction or rejection forces between the warp and weft yarns. A homogeneous interlaced structure will therefore be obtained over the entire extension of the net 1.

The above, therefore, shows that the shape of the yarns offers further advantages in terms of homogeneity of the fabric of the net during production compared to the nets of the known art. This beneficial effect on the net's production technique increases the quality of the final product ready to be installed.

As already explained, the warp and weft yarns are preferably the same and have a non-circular shape. However, in variant embodiments of the invention only the warp yarns may be non-circular, while the weft yarns may have a circular shaped profile of known type, or vice versa. Again, some warp and/or weft yarns may have a non-circular shape, while the remaining ones may be circular as in the known art.

Figures 6a and 6b show a further variant embodiment of the net of the invention, in which the profile is substantially square.

In the first configuration of the yarn crossing pattern shown in Figure 6a, the shape of the yarn of the invention makes it possible to obtain a stronger contact at the height of each crossing point between a warp yarn 62 and a weft yarn 63 compared to the fabrics of known type.

In particular, the warp yarn 62 and the weft yarn 63 come into contact in two distinct areas 67 and 68, offering the advantages described above in terms of friction.

In the second possible configuration of the crossing pattern between the warp yarn 62 and the weft yarn 63, shown in Figure 6b, the warp yarn 62 is substantially arranged so that one point rests against the weft yarn 63. The figure shows two warp yarns 62 positioned side by side inside the net.

In this configuration, the shape of the yarn of the invention makes it possible to improve the aeration of the net compared to the nets of known type.

In fact, as shown in the figure, where C indicates the circular profile of a yarn of the known art, the free surface SI between two adjacent warp yarns 62, through which air passes from one side of the net to the other, is larger than the free surface SN between the warp yarns C of a net of the known art.

Analogously, the free surface between two adjacent weft yarns of the net of the invention is larger than the free surface between two weft yarns of a net of the known art.

Figure 7 shows a variant embodiment of the net of the invention, differing from the first embodiment described above with reference to Figures from 1 to 5 due only to the fact that the yarns 12, 13 have a pentagon-shaped profile, or better a star profile with five points, instead of an hexagon-shaped profile.

Figure 8 shows a further variant embodiment of the net of the invention in which the yarns 22, 23 substantially have the shape of a star with height points. Said profile, compared to the substantially polygonal profiles described above, determines enhanced characteristics of accumulation of electrostatic charges due to the sharper shape of the points.

Said effect is present to a higher degree in the further embodiment shown in Figure 8, where the yarns 32, 33 have a substantially circular shape with eight sharp points arranged on its perimeter.

Figure 10 shows, instead, a variant embodiment of the net of the invention in which the shape is substantially crushed, like an overturned eight, in which the warp yarn 42 and the weft yarn 43 come into contact in two distinct areas 47 and 48 with the advantages described above in terms of friction.

Figure 11 shows a further variant embodiment of the net of the invention in which the shape has four lobes, and the warp yarn 52 and the weft yarn 53 come into contact in two distinct areas 57 and 58 with the advantages described above in terms of friction.

In different variant embodiments of the invention the warp and weft yarns may have different shapes, for example consisting of a combination of any of the shapes shown and described above.

It has thus been shown that the present invention allows all the set objects to be achieved. In particular, the invention makes it possible to produce a net for agriculture with better homogeneity and aeration characteristics than the nets of known type.

While the present invention has been described with reference to the particular embodiments shown in the figures, it should be noted that the present invention is not limited to the specific embodiments illustrated and described herein; on the contrary, further variants of the embodiments described herein fall within the scope of the present invention, which is defined in the claims.

Claims

1. Net for agriculture (1) comprising a plurality of warp yarns (2; 12; 22; 32; 42;

52) and a plurality of weft yarns (3; 13; 23; 33; 43; 53) interwoven with each other, characterized in that at least one of said warp yarns (2; 12; 22; 32; 42; 52) or said weft yarns (3; 13; 23; 33; 43; 53) features a non-circular cross section.

2. Net (1) according to claim 1), characterized in that both said warp yarns (2, 12; 22, 32; 42, 52) and said weft yarns (3; 13; 23; 33; 43; 53) feature a non- circular cross section.

3. Net (1) according to any of the preceding claims, characterized in that said shape is substantially of the polygonal type.

4. Net (1) according to any of the preceding claims, characterized in that said shape features one or more points.

5. Net (1) according to claim 4), characterized in that said one or more points is rounded.

6. Net (1) according to claim 4), characterized in that said one or more points is sharp.

7. Net (1) according to any of the preceding claims, characterized in that said shape is substantially the shape of a star with several points.

8. Net (1) according to any of the preceding claims, characterized in that said shape is substantially the shape of an eight.

9. Net (1) according to any of the preceding claims, characterized in that said shape comprises one or more lobes.

10. Net (1) according to any of the preceding claims, characterized in that said yarns comprise a polymeric material.

11. Net (1) according to claim 10), characterized in that said polymeric material comprises polyethylene.

12. Net (1) according to any of the preceding claims, characterized in that it is woven according to a cloth pattern.

13. Net (1) according to any of the preceding claims, characterized in that it is an insect net.

14. Warp yarn (2; 12; 22; 32; 42; 52) or weft yarn (3; 13; 23; 33; 43; 53) for making an agricultural net (1), characterized in that it features a non- circular cross section.

15. Yarn (1) according to claim 14), characterized in that said shape is substantially of the polygonal type.