NL1023764C2 - Screen cloth for greenhouse window insect screen, has angular region with additional overlaps between weft yarns and pairs of warp yarns - Google Patents

Abstract

Additional overlaps (4-4) between the weft yarns (I-IV) and pairs of warp yarns are provided in at least one angular region of the cloth (1). The overlaps combine to form imaginary diagonals (6). A screen cloth, preferably an insect screen for a ventilation window, especially in a greenhouse, has a mesh structure formed by warp and weft yarns at least predominantly comprising a first synthetic material. At least some of the weft yarns are heat-shrinkable yarns comprising a second synthetic material which has a greater shrinkage under the influence of heat than the first material. The heat-shrinkable yarns form a harmonica structure extending between both sides of the fabric and interlacing with the warp yarns. Additional overlaps between the weft yarns and pairs of yarns are provided in at least one angular region of the fabric and these overlaps are spaced apart by given distances and located in between overlap strips (V). The overlaps combine to form imaginary diagonals between the strips.

Description

INSECT-RESISTING SCREEN CLOTH AND SCREEN DEVICE

The present invention relates to a screen device and screen cloth therefor as shown in the characterizing part of the following claim 1.

Such screen devices for insect-impermeable surround of aeration windows in greenhouses are generally known, among other things due to the market introduction and long-term development as a result of the Applicant. When opening an aeration window, these screens are taken upwards, and from a cassette which is arranged around the window and in which the mesh is folded and stored in a harmonica manner. In addition to the practical storage of the screen in the closed state of the window, the harmonica profile also serves the strength of the screen when it is unfolded. Initially, these functions were guaranteed in the screen device by the use of separate reinforcement elements, see for example NL-9202011 and EP-A-97201686. In combination with this, a cloth suitable for specific purposes was developed, known from the latter publication. Afterwards, in connection with the necessary cost savings, a search was made for constructions where the screen could find its own strength. It was thought that such rigidity was achieved in itself by applying specifically post-treated edges, for example by sewing or ultrasonically welding the edges of the screen's harmonics profile, which is known from NL-1015812. The advantage of these constructions was the sharp edge between the strips that form the harmonica profile. However, the operations were, at least for mass production, insufficiently cost-saving.

In subsequent developments it was shown that such firmness in itself could also be obtained by subjecting the fabric to a heat treatment, or by pleating. To this end, fabrics specifically for the horticultural screen fabric were developed by the Applicant, see for example 1018025, and specifically peeled machines were developed, known from NM019229 and NL-1020536, as a result of which plumbing technique known per se could be applied in the horticultural sector. In particular, the larger passage openings in the horticultural mesh required for aeration, as well as the much larger dimensions, initially made it difficult to retain the shape in the mesh fabric for a long time. Specific weft threads were incorporated into the fabric as a solution to this problem. A special solution in making fabrics for gauze cloth suitable for both horticulture and pleating technology was the incorporation of weft threads with a distinct thermal property, in particular a wire shrinking faster under the influence of heat. With such a fabric, a so-called self-forming screen cloth was obtained under the influence of added heat. Because the existing fabric, or at least the basic fabric, is preferably made of polyester, the specific weft thread was made of polyethylene which, at a temperature of about 100 degrees Celsius, other than polyester, tends to shrink strongly; Nevertheless, other plastics can also be used as a crimp wire.

By incorporating the so-called shrink wires partly connected to the fabric, that is, incorporated into the structure, and partly overlapping with the fabric, and alternately per strip alternately on either side of the fabric, it was possible in a simple manner afterwards by applying a heat treatment to a predefined harmonica pleat in the fabric. With this development, an advantageous technique suitable for mass production was obtained, that is to say that a harmonica structure can be applied advantageously. However, the new technique is still capable of improvement with regard to the formation of a desired book form known from NL-1019229.

It is therefore an object of the present invention to complete the self-shaping of the known cloth, such that the aforementioned, functionally favorable book shape can be obtained by star formation of the cloth and to provide a further developed weaving structure for this purpose. According to the invention this object is achieved with a screen cloth in which the measures according to the characterizing part of claim 1 are applied. By applying the principle of overlapping with the aid of a crimp wire also outside the provided for this purpose straight and predetermined edges of the harmonica profile, namely in an imaginary diagonal line in accordance with what is indicated, the latter Dutch patent publication becomes surprisingly simple thus obtained the said self-forming property for the corners. It is important here that at the start of the imaginary oblique strip, additional overlaps, the overlaps in the at least projected straight strip, are reflected in the weaving structure on the other side of the fabric. The additional overlaps H preferably each consist of three warp threads included at regular mesh spacing.

A further preferred measure relates to the fact that an additional overlap has been provided around the other shrinked-in thread 35.

3

The invention will now be explained in more detail by way of example with reference to a drawing:

Figure 1 shows schematically the structure of a fabric according to the invention; Figure 2 forms a series of cross-sections of Figure 1 according to a view in the weaving direction of the fabric;

Figure 3 shows a cross-sectional view, seen in the weaving direction of the fabric of Figure 1, of the effect of folding the fabric by means of a heat treatment; Figure 4 shows the effect of Figure 3 for a number of consecutive folds of an harmonic profile;

Figure 5 shows the cloth according to the invention in a representation according to Figure 4 in the open position of a screening device;

Figure 6 shows a manner known per se and preferred for forming an angle in the screen device;

Figure 7 shows in detail a special elaboration of the invention, wherein the fabric according to the invention is locally adapted in a manner suitable for forming an angle as shown in Figure 6;

Figure 8 shows a repeating pattern in a cloth according to the special elaboration of the invention according to Figure 7;

Figure 9 shows in detail that the mirroring of overlap through a crimp wire in the provided book area of a screen portion! is determined by the line 6 in Figure 8.

In the figures, corresponding structural parts will be indicated by the same reference numerals.

Figure 1 shows a fabric for a screen cloth 1 according to a special embodiment of the invention. In this fabric, warp threads V oriented in the production direction are present, and perpendicular thereto so-called weft threads I-IV. Part of this is designed as a crimping wire II known per se, which partially overlaps the remaining fabric. In the embodiment known per se, the at least relative shrinkage of the crimp wire is realized by designing it in polyethylene while the other wires are made of polyester. Nevertheless, other plastics are possible of which one shrinks to a greater or lesser extent at a certain temperature and the other does not. In the fabric 1 according to the invention, the overlap is reduced to the theoretical minimum of three warp threads V. A specific warp wiring V is provided at the place of the overlap 35, here in the form 1023764 'I of a second, or double, adjacent thread V. In this way, on the one hand, a very sharply observable folding edge in the harmonica profile to be formed is obtained, while on the other hand, a bending promoting the weft threads I, III, IV is obtained locally. This is achieved on the one hand in particular by carrying out at least the central chain wiring double, or at least larger in effective diameter, and can be promoted by, as in the example shown, carrying out the flanking chain wiring at least substantially adjacent. The application of the last-mentioned measure has the effect that an weft thread I, III is even more easily inclined to undergo a further bending in that, as a result of the sliding of the flanking chain wiring V at the location of the central I chain wiring V, the final desired bend has been forced.

Figure 2 shows the aforementioned effect and the associated configuration as a result of a cross-section in a view according to the arrow A in Figure 1, while Figure 3 shows the effect of a heat treatment of the fabric according to Figures 1 and 2. Figure 4 shows the per se known measure with overlap of the crimp wire II on either side of the screen cloth, as well as the effect thereof for the harmonic profile, at least in the folded state. Figure 5 shows this effect in a partial representation of the unfolded state of a screen device. Figures 4 and 5, on the one hand, show the intended regularly folded effect, such as is known per se from pleating technology and from ultrasonic welding technology for screen devices - NL> 1015812 - and the sharply folded, but also reinforced, structure I of the folding edge , comparable to the reinforcement known by additional material during ultrasonic welding and / or stitching of the folding edges.

The special wiring V which is included near the folding edge 25 as a result of the invention prevents the screen cloth 1, at least the folding edges thereof, seen over the width of a screen device from collapsing inwards or outwards when drafted. In particular, due to the greatly reduced degree of overlap by the crimp wire II and the tight confinement of the specific chain wiring after a heat treatment, in retrospect, the folding edges 30 resemble the rigid reinforcing bars that are used in the first versions of the screen - see NL-1003304 - were included in the screen. In the present embodiment, in which, as a result of the material used, the screen cloth 1 of itself is already relatively sturdy, and moreover relatively light, a reinforcement and folding method according to the present invention suffice. An advantage in addition to the indicated effects 35 of the present embodiment is that all threads are of a corresponding thickness, and moreover, outside the shrink threads II, from the same material, namely polyester. In connection with the use in greenhouses, where the fabric is strongly exposed to sunlight and humidity, the wires L-V are all designed as monofilament.

The invention is not limited to the embodiment shown, but may in an alternative be embodied, for example, with a thicker crimping wire II. As a result, the desired anchoring of this thread in the fabric between the folding edges provided in the cloth 1 can also be obtained with a greater mutual distance from the flanking weft threads 1, -III. In the exemplary embodiment shown, these are arranged at least substantially abuttingly, that is to say, with a gap only determined by the thickness of a braided warp thread. This has the effect that a crimping wire is so firmly incorporated in the fabric that the shrinkage thereof is largely cut by the overlapping part thereof.

In the alternative embodiment, the small disadvantage of a different thickness is offset by the advantage that the permeability factor of the fabric is increased. In this connection, it is preferable according to the invention that the number of meshes included between two crimp wires, at least meshes of size which in the warp direction are considerably larger than the diameter of a wire and that are preferably 1 mm, is greater than two. An intermediate solution can be found by matching the mesh width of a crimp thread II to a flanking weft thread with a certain factor, for example a quarter, of the mesh width otherwise provided in the fabric. In the preferred embodiment, this is 1 mm, while the mesh height is 0.8 mm.

Figures 6 to 9 show a further, special elaboration of the principle according to the invention. Figure 6 shows a corner construction known per se from NL-1019229, and desired, construction, figure 7 a weaving structure serving to form that corner construction in the fabric, and Figure 8 a repeating pattern of a fabric according to the invention produced on the roll, wherein in a part H, the so-called Y and in the corner part H, V-shaped structure of overlaps, as indicated with reference to Figure 7, is included at indicated places.

In the desired corner construction, the two corner parts H of a screen cloth of a screen device, together with a main surface 2 and two associated side cheeks 3, are formed in one piece. Here, the outer edges of the harmonica shape are arranged in the main surface 2 and in a side cheek 3 (see also Fig. 8) on alternating levels situated between each other. The angle of the screen is formed by diagonal 1 n? 37 R4 'folding folds from the outer harmonic edge in either a main face 2 or in a side cheek 3, to a likewise outer harmonic edge in a side cheek I or a main face respectively. Here, the angle formed is shown in plan view by a line extending generally forty-five degrees between the outer edges of main surface 2 and side cheek 3.

Figure 7 shows an adaptation of the structure of the fabric according to the invention for obtaining the desired fold according to Figure 6 I with a heat treatment. For this purpose, at the place in the cloth where the corner is provided, the structure is adapted such that the overlap of the crimp wire 1 is marked from the beginning of the corner, preferably in the cloth 1, by one or more, preferably two for that purpose. specifically included weft threads VI, split in two directions I so that a Y-profile is created locally in the fabric. In this case, for example, the trunk of the Y-profile is formed by an overlap, or an outer edge in a main surface 2, and the two branches 6 show the course of the overlaps in the book area H 15 H of the screen cloth, which in the chain direction according to the invention are necessary for forming the diagonally extending folds 6 in a screen cloth 1. In this part of the cloth the overlaps 4 ', 4 ”, 4'" of the crimp wire II are arranged on either side of the projection of the folding seam V, as is provided, for example, in the left-hand part 2 of the cloth in relation to the marking weft threads VI in Figure 7. In this example, an overlap 4 'starts with the crimping thread II flanking a marking thread VI, immediately outside the the projection of the intended fold continuous specific wiring V. The overlap 4 'covers three regularly included warp threads and repeats itself around the other weft shrink thread II, at some distance in the weft direction, in particular every three warp threads. Thus, the first crimping wire II in an angle part H of the cloth 1 begins its overlap on the first warp thread next to the specific wiring V, it is terminated after the third warp thread, no overlap takes place at the second shrink thread and the third shrink thread begins its overlap with the seventh thread and ends after the tenth thread, with which the pattern arranged in a corner part H is repeated. With 30 th intermediate crimping wires II from the corner region H, which at least do not have an overlap with a folding seam in consideration, the position thereof is nevertheless indicated by the reference numeral 5, to indicate that the H crimping wire in question is positioned at the corner line 6 H is included on the same side of the cloth 1 as the overlapping parts 4 ', 4 ", 4" "of the flanking shrink wires II.

7

At the location of the projection of the folding edge V from the main surface 2 in the corner part H of the cloth, there is an overlap 4 ', 4 ", 4'" through the crimp wire II, preferably with the exception of the crimp wire flanking directly on a marker wire VI II, place on the other side of the screen cloth 1. As a result, the fold for the inner edge of a side cheek 3 already starts here. The marking wires VI are preferably in the form of a multifilament and colored. The multi-filament is relatively limp, which is advantageous for the self-formation of the corner during a heat treatment. The susceptibility of multi-filament to contamination can be masked by the use of a dark or deviant tint. However, a white color is preferred because of its noticeability during the automatic production of the screen cloth.

Figure 8 shows, with a larger perspective, a possible structure of a screen cloth 1 to be produced on a roll, with a repeating pattern. Included in this pattern is a part 3 for a side cheek from the screen device to be formed, a corner part H with V-shaped profiles of overlap locations of the crimp wire II, a main surface 2, and a second side cheek 3 incorporated in mirror image. The transition between a main surface 2 and a side cheek 3, preferably with an angle part H included therein, is in each case marked by at least one marking weft thread VI. The latter is preferably colored differently. A marking wire can also be included between the side cheek parts 3 of two provided cloth parts for a screening device. This is preferably only deviating in color and can be formed by a monofilament thread.

With a screen 1 in accordance with the pattern of Figure 8, one or more standard dimensions for the width of the main surface are always assumed - in the screen this concerns the chain length of the central part 2, whereby a maximum depth dimension of a side cheek 3. For side cheeks with a lower depth, part of the length of part 3 is cut off.

Figure 9 shows that at the transition from a main surface to a side surface in a screen, the overlap of the shrink wires II to the other side of the screen cloth 30, namely along the line 6, which the future diagonal folding lines at an angle of a screen.

The invention relates not only to the foregoing described but also to all details in the figures, at least insofar as they are immediately and unambiguously traceable to a person skilled in the art, and to all that is described in the following set of claims.

10? 37 64

Claims (24)

1. Screening cloth (1), in particular for the purpose of a screening device for insect-proofing surrounded by a window frame, more in particular of a greenhouse for growing crops, which cloth has a mesh-like structure with in the production direction warp threads (V) extending from the fabric and weft threads (I-IV) extending transversely to the direction of production. which warp and weft threads I are formed at least predominantly from a first plastic, which weft threads (I-IV) are partly formed by threads, so-called shrink threads, of a second plastic (III) which shrinks as a result of a heat treatment I undergoes, at least, a crimping action greater than that of the deeds (I, III, IV, V) of the first plastic, and which crimping wires within a provided harmonica structure, parts of it alternately on either side of the cloth, at least warp threads ( V) overlaps in order to bring about the harmonica structure as referred to under the influence of a heat treatment, characterized in that, at predetermined distances, an additional I overlaps (4 ', 4 ", at a predetermined distance, in an at least I corner part of the screen cloth (1), 4 "") are arranged between two adjacent overlap strips (V) visible in the warp direction (A), which additional overlaps (4 ', 4 ", 4" ") together form an imaginary oblique line n (6) between these overlap strips (V). Cloth according to claim 1, characterized in that the oblique line (6) is present on either side of an overlap strip (V) so that a Y-shaped structure is created. 3. Cloth as claimed in claims 1 or 2, characterized in that with the commencement of the additional overlaps (VI), or with the onset of the V-shaped part of a Y-structure in the cloth (1), the overlap of the crimp wire (II) Stops in the straight overlap strip (V), to the other side of the fabric (1). A cloth according to one or more of the preceding claims, characterized in that additional overlaps are arranged around the other shrinked-in thread (II). 5. Cloth as claimed in any of the foregoing claims, characterized in that an additional overlap (4 ', 4 ”, 4' '') running between two overlap strips (V) takes effect near a specific, at least with respect to, the other weft threads (Ι, ΙΙΙ; II) deviating weft thread (VI) that is particularly marked in ferret. Fabric according to the preceding claim, characterized in that the deviating weft thread (VI) forms part of two identical, flanking weft threads (VI). The fabric according to one or more of the preceding claims, characterized in that the deviating weft thread (VI) is formed as a multifilament, and the remaining threads (1-V) as a monofilament. 8. Cloth as claimed in one or more of the foregoing claims, characterized in that a cloth (1) graduated on roll alternately consists of length parts (2) in which no Y-shaped additional overlapping pattern is included, for example for the main surface of a screening device, and from longitudinal parts (3) in which near the ends thereof the aforementioned Y-shaped patterns are included, for example for the side cheeks (3) of a screening device. 9. Cloth as claimed in one or more of the foregoing claims, characterized in that a further marking thread is punched in centrally in a part (3) of the cloth provided for a side cheek. Screening device provided with a screen cloth according to one or more of the preceding claims. 11. Cloth as claimed in one or more of the foregoing claims, characterized in that the cloth (1) is provided with at least one specific chain wiring (V) at the location of a provided folding edge for the harmonic profile, and that the overlap by the shrink wires (II) only takes place at a location with the specific chain wiring (V). A screen cloth (1) according to claim 11, characterized in that the specific warp wiring (V) is formed by an adjacent pair of warp threads 25 (V). A screen cloth (1) according to claim 11 or 12, characterized in that the two adjacent chain wiring (V) of the chain wiring determining a harmonica fold are also specifically designed. 14. Screen cloth (1) according to claim 13, characterized in that the specific adjacent wiring is formed by an adjacent pair of chain threads (V). 1023784 "I 10 Screen fabric (1) according to one or more of the preceding claims, characterized in that the overlapped specific warp wiring is included in the fabric structure at least substantially adjacent. Screen fabric (1) according to one or more of the preceding claims, characterized in that both the warp and the weft threads (1-V) have an at least substantially corresponding thread thickness. 17. Screen cloth as claimed in one or more of the foregoing claims, characterized in that the threads of the first plastic are formed from polyester. 18. Screening cloth according to one or more of the preceding claims, characterized in that the threads of the second plastic are formed by polyethylene. 19. Screening cloth as claimed in one or more of the foregoing claims, characterized in that the weft and warp threads have a thickness in the range of 0.28 to 0.32 mm, in particular a thickness of 0.3 mm. 20. Screening cloth (1) according to one or more of the preceding claims, characterized in that the weft threads (I, III) of the first I plastic flanking on a crimp thread (II) are arranged adjacent the crimp thread (II) . Screen fabric (1) according to one or more of the preceding claims, characterized in that the warp and weft threads (1-V) are designed as a monofilament. 22. Screen cloth (1) according to one or more of the preceding claims, characterized in that the permeability factor of the mesh is greater than 0.5. A screen cloth (1) according to the preceding claim, characterized in that B mesh opening is 1 mm in the warp direction by 0.8 mm in the weft direction. The screen fabric (1) according to the preceding claim, characterized in that the B frequency of the number of weft threads (II). expressed in number of intermediate B mesh openings, is in the range of two to ten, and is preferably in the range of B three to five.