PLASTIC FILM FOR COVERNING LINEAR SOFT FRUIT CULTIVATIONS

Abstract

The application refers to a plastic film for protecting linear soft fruit cultivations such as table grapes, raspberries, blueberries, blackberries, red currants, cherries etc. Soft fruit cultivation is commonly performed in a linear fashion so that any cultivation work can be facilitated. Soft fruits are susceptible to weather conditions especially when they are ripe enough for collection to start and in particular to hail, rain, humidity, and frost as well as the intense sun radiation that can cause skin burns to the fruit.

Claims

1. Plastic film for covering linear soft fruit cultivations that bears reinforced sections in terms of thickness (X) along both edges as well as a reinforced section (Y) along a mid-section lengthways, said reinforcement produced by extruding the film with variable thickness across the width or by gluing, welding, sewing additional stripes of the same or different material or by directly extruding or laminating additional material on sections (X) and (Y) or by folding the lengthways edges and welding the fold on the plastic film at the whole section (X) and reinforcing section (Y) separately that is characterised by fact that a plastic cord is glued, welded or extruded along both lengthways sides being partially or entirely inclined in relation to the main lengthways axis with said inclination being constant or changing direction and following a repetitive pattern with period P.sub.i and bearing holes at both sections (X), adjacent to the inclined cord and at the positions that are closer to the edge however towards the side of the cord that is facing the main lengthways axis of the plastic film; said cord has a diameter (D) less than 10 mm and due to said inclination of the cord, the cord distributes the exerted load at the whole reinforced area of the plastic film in both longitudinal and traverse directions, thus increasing the strength of the plastic film.

2. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that the inclined cord has the form of a waveform curve with period (P.sub.i) and amplitude (a.sub.i).

3. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that on every lengthways edge the plastic films bears several plastic cords that are glued, welded or extruded and are placed on the same surface or on both surfaces of the plastic film and are described by a symmetrical waveform curve f(x)=a*sin x l f(x)=a*sin x.

4. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that on every lengthways edge the plastic films bears several plastic cords that are glued, welded or extruded and are placed on the same surface or on both surfaces of the plastic film and have different periods (P.sub.i) and amplitudes (a.sub.i) among them.

5. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that the cross section of the plastic cord employed can be of any shape and/or of variable geometry along the length of the film.

6. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that the plastic cord or cords are discontinuous as to the lengthways axis of the plastic film and exhibit a repetitive pattern.

7. Plastic film for covering linear soft fruit cultivations according to claim 1 that is characterised by the fact that the plastic cord or plastic cords are inclined in relation to main lengthways axis of the plastic film and form a repetitive pattern with period P.sub.i either having the same inclination or different inclinations intersecting each other or not thus forming a continuous or discontinuous zig zag form.

Description

[0012] Below the invention is described in the respective schematics:

[0013] FIG. 1: A conventional plastic film (1) placed above the cultivation line. Depicted are the reinforced sections (X) and (Y), the eyelets (3), the ropes/strings/elastic bands (6), the supporting structure (2), the wire ropes (7) that bind the plastic film to the supporting structure

[0014] FIGS. 2A and 2B: Plastic film (1) with eyelets (3), (metallic or plastic), reinforced sections (X) and (Y) and a detail of the load distribution around an individual eyelet (2B).

[0015] FIGS. 3A, 3B and 3C: Plastic film (1) with an incorporated cord (5), glued, welded, or extruded on the plastic film along both its lengthways sides, the reinforced sections (X), the cut or punched holes (4). And a detail of the load distribution close to the binding position. Depicted is also the cross section of the film (section A-A) (38) showing the cross sectional geometry of the plastic cord. FIG. 3C depicts the load distribution at the hole (4)

[0016] FIGS. 4A, 4B and 4C: Plastic film (1) with a waveform cord (5) that is glued, welded or extruded on the plastic film (1) along both its lengthways sides, reinforced sections (X), the holes (4) (4A) and a detail of the force distribution near the binding position (4B). Depicted is also the cross section of the film (section A-A) (4B). Figure (4C) depicts the wider load distribution of the waveform plastic cord

[0017] FIG. 5: Plastic film (1) for covering linear soft fruit cultivations that bears two plastic waveform cords (5.1 and 5.2) on both its lengthways sides that have between them the same or different period and/or amplitude. Depicted are also the reinforced sections (X and Y) and the holes (4) as well as cross sections of the film (section A-A) (5B). Figure (5C) depicts the load distribution around antisymmetric waveform plastic cords.

[0018] FIG. 6: Plastic film (1) for covering linear soft fruit cultivations that bears two waveform plastic cords (5.1 and 5.2) on both its lengthways sides that have between them different periods and/or different amplitudes. Depicted are also the reinforced sections (X and Y) and the holes (4) as well as cross section of the film (section A-A) with the load distribution.

[0019] FIG. 7: Plastic film (1) for covering linear soft fruit cultivations that bears plastic cord (5) or cords that have the form of a discontinuous waveform curve. Depicted are also the reinforced sections (X and Y) and the holes (4) as well as cross section of the film (section A-A) with the load distribution

[0020] FIG. 8: Plastic film (1) for covering linear soft fruit cultivations that bears plastic cord (5) or cords that have the form of a discontinuous inclined linear line. Depicted are also the reinforced sections (X and Y) and the holes (4) as well as cross section of the film (section A-A) with the load distribution

[0021] FIG. 9: Plastic film (1) for covering linear soft fruit cultivations that bears a plastic cord that is inclined in relation to the main lengthways axis and follows a zig zag pattern. Depicted are also the reinforced sections (X and Y) and the holes (4) as well as cross section of the film (section A-A) with the load distribution

[0022] FIG. 10: Depicts in cross sectional view one of the two longitudinal reinforced areas (X) that bears plastic cord (5) or cords (5.1 and 5.2) that can have a cross-sectional footprint of any shape and can be located on one (S1) (FIG. 10.1 to 10.5) or both surfaces (S1 and S2) of the film (FIG. 10.6).

[0023] According to the first embodiment of the invention (FIG. 4) a plastic film (1) is produced by employing a polyolefin such as LDPE, LLDPE, EVA etc. or a combination thereof. The plastic film can have any length (L) and width (B) that can be produced in any manner such as blown or cast film extrusion as monolayer or multilayer incorporating any additives so that it could exhibit any thermal, optical and mechanical properties. The plastic film that is produced in such a fashion so that it has varying thickness across its width and in particular thicker at a section (X) at both its lengthways edges as well as at a stripe (Y) along the mid longitudinal axis of the plastic film. Alternatively, the reinforced areas (X) and (Y) can be produced by either gluing, welding or sewing additional plastic film stripes or weaves of the same or different material or by folding the two edges and welding the two surfaces at the whole width (X) and additionally gluing, welding, sewing a stripe at the section (Y). Lastly the reinforcement could be achieved by directly extruding or laminating additional material on the plastic film at sections (X) and (Y). On both reinforced sections lengthways of the plastic film (X) a plastic cord is glued, welded or extruded employing the same material as the plastic film or different to it that is a waveform curve that has any period (P.sub.i) and amplitude (a)<(X) and preferably period 50 cm and amplitude 15 cm. Holes (4) are then cut or punched on the film at the troughs of the waveform curve having a diameter (D) and being placed very near to the plastic cord so that a rope or elastic band can be used to tie the film to the supporting structure. The period of the holes (z) can be the same as the period of the waveform curve or different and a multiple of it.

[0024] According to the second embodiment the invention (FIG. 5) the plastic film is produced in such a fashion so that it has varying thickness across its width and in particular thicker at a section (X) at both its lengthways edges as well as at a stripe (Y along the mid longitudinal axis of the plastic film. Alternatively, the reinforced areas (X) and (Y) can be produced by either gluing, welding or sewing additional plastic film stripes or weaves of the same or different material or by folding the two edges and welding the two surfaces at the whole width (X) and additionally gluing, welding, sewing a stripe at the section (Y). Lastly the reinforcement could be achieved by directly extruding or laminating additional material on the plastic film at sections (X) and (Y). On both lengthways reinforced sides (X) several and preferably two plastic cords (5.1 and 5.2) are glued, welded or extruded on the film employing the same material as the plastic film or any material different to it, having the form of a waveform curve with periods (P.sub.i) and (P.sub.j) and amplitudes (a.sub.i) and (a.sub.j) and preferably the two plastic cords are antisymmetric that can be for example described by the equations f(x)=*sin x and f(x)=*sin x respectively. Holes (4) are then cut or punched on the film at the troughs of the waveform curve having a diameter (D) and being placed very near to the troughs of the plastic cords so that a rope or elastic band can be used to tie the film to the supporting structure. The period of the holes (z) can be the same as the period of the waveform curves or different and a multiple of it.

[0025] According to the third embodiment of the invention the plastic film is produced in such a fashion so that it has varying thickness across its width and in particular thicker at a section (X) at both its lengthways edges as well as at a stripe (Y) along the mid longitudinal axis of the plastic film. Alternatively, the reinforced areas (X) and (Y) can be produced by either gluing, welding or sewing additional plastic film stripes or weaves of the same or different material or by folding the two edges and welding the two surfaces at the whole width (X) and additionally gluing, welding, sewing a stripe at the section (Y). Lastly the reinforcement could be achieved by directly extruding or laminating additional material on the plastic film at sections (X) and (Y). The plastic cords could be glued, welded or extruded on both surfaces of the film. In addition, the plastic cords that are described by equations such as f(x)=*sin x and f(x)=*sin x could be placed for example cord (5.1) on surface (S1) and cord (5.2) on surface (S2) or vice versa (FIG. 10). Holes (4) are then cut or punched on the film at the troughs of the waveform curve having a diameter (D) and being placed very near to the troughs of the plastic cords so that a rope or elastic band can be used to tie the film to the supporting structure. The period of the holes (z) can be the same as the period of the waveform curves or different and a multiple of it.

[0026] According to the fourth embodiment of the invention the plastic film is produced in such a fashion so that it has varying thickness across its width and in particular thicker at a section (X) at both its lengthways edges as well as at a stripe (Y) along the mid longitudinal axis of the plastic film. Alternatively, the reinforced areas (X) and (Y) can be produced by either gluing, welding or sewing additional plastic film stripes or weaves of the same or different material or by folding the two edges and welding the two surfaces at the whole width (X) and additionally gluing, welding, sewing a stripe at the section (Y). Lastly the reinforcement could be achieved by directly extruding or laminating additional material on the plastic film at sections (X) and (Y). The plastic cord or one of the plastic cords or all of the plastics cords could be glued, welded or extruded on one or one both surfaces of the film as modulated waveforms namely a combination of waveforms with periods (P.sub.i, P.sub.j, P.sub.k . . . ) and amplitudes (a.sub.i, a.sub.j, a.sub.k, . . . ). Holes (4) are then cut or punched on the film at the troughs of the waveform curve having a diameter (D) and being placed very near to the troughs of the plastic cords so that a rope or elastic band can be used to tie the film to the supporting structure. The period of the holes (z) can be the same as the period of the waveform curves or different and a multiple of it.

[0027] According to the fifth less preferable embodiment of the invention the plastic film is produced in such a fashion so that it has varying thickness across its width and in particular thicker at a section (X) at both its lengthways edges as well as at a stripe (Y) along the mid longitudinal axis of the plastic film. Alternatively, the reinforced areas (X) and (Y) can be produced by either gluing, welding or sewing additional plastic film stripes or weaves of the same or different material or by folding the two edges and welding the two surfaces at the whole width (X) and additionally gluing, welding, sewing a stripe at the section (Y). Lastly the reinforcement could be achieved by directly extruding or laminating additional material on the plastic film at sections (X) and (Y). The plastic cord or plastic cords are comprised of several inclined linear lines of the same or different inclinations in relation to the main lengthways axis that follow instead of a waveform a zig zag pattern (FIG. 9) that is either continuous or intermittent.

[0028] It is also important to note that in case there are several plastic cords on each lengthways sides they could have different periods (P.sub.i) and amplitudes (a.sub.i) among them as well as along the lengthways side. They could for example in the case of having two cords on each side be described by different equations such as f(x)=*sin x and f(x)=*sin(x/2). Lastly there could be different periods and amplitudes among all plastic cords on the plastic film.

[0029] Furthermore, there could be discontinuous inclined lines in relation to the main lengthways axis or waveform plastic cords applied on the film namely applied on selected sections along the lengthways sides of the plastic film and not to its entire length (FIGS. 7 & 8)

[0030] The geometry of the cross-section of the plastic cord could be circular, semi circular, trapezoid, square, rectangular, elliptical as well as of variable geometry along the length of the film (FIG. 10). In cases where there are more than one plastic cords they could be of different cross sectional geometry as well.

[0031] In addition, the material employed to produced the plastic cord could have additives such as glass fibres and/or elastomers so that it exhibits exceptional mechanical properties.