Insect-proof net guide system

Abstract

The present application relates to a net support system (100, 200) for spanning an adjustable ventilation opening wherein the net support system (100) comprises an insect-proof net (110) in order to prevent insects from passing through the adjustable ventilation opening. The insect-proof net (110) is folded in an accordion configuration so as to be folded in a stacked manner when the adjustable ventilation opening is closed and unfolded when the adjustable ventilation opening is open. The net support system (100) further comprises a guide structure (120) for the insect-proof net, where the guide structure (120) comprises a stretchable wire (121) connected to at least one net connector (132, 134) secured to the insect-proof net (110). The stretchable wire (121) holds the insect-proof net (110) in an accordion configuration when the insect-proof net (110) spans the ventilation opening.

Description

Technical Field

[0001] The present invention relates to a net support system for facilitating the opening and closing of adjustable ventilation openings in a greenhouse. Background Art

[0002] Good ventilation within a greenhouse is essential to mitigate problems that may arise in a greenhouse, such as elevated temperatures or humidity, or low carbon dioxide levels. The roof of a conventional glass greenhouse is usually provided with ventilation windows that can be opened and closed. In order to prevent unwanted insects from entering the greenhouse, and in some cases to prevent wanted insects from leaving the greenhouse, it is often necessary to use insect screens in such ventilation openings.

[0003] Insect screens used in ventilation openings that are repeatedly opened and closed must be flexible so as to fill the opening when the window is open, but they must also be able to fold without blocking the window from closing. One type of insect screen commonly used is the Figure 1 The accordion type screen structure shown. This accordion type screen structure is advantageously used in the ventilation openings present in Venlo type greenhouses to prevent unwanted insects from entering the greenhouse and gives a larger total mesh area, with the airflow through the ventilation openings typically being 20-40% higher than a flat mesh. It is also a flexible structure and is easily fixed in a greenhouse ventilation opening that is repeatedly opened and closed. An example of an accordion type structure is described in NL1007720 (C2).

[0004] The accordion net structure for roof vents (windows) in greenhouses is designed to fold neatly and form a small-sized package so as not to cause unwanted shadows on crops and to prevent damage by metal parts when opening and closing the vents. When the insect-proof net structure is not stiff enough, or when the wind is too strong, the accordion structure will fall in or out of the ventilation opening, and folding the accordion pleats into a neat package may not work. To avoid this, some type of mechanical support is needed to enable the pleated net structure to fold and unfold in an orderly manner each time the ventilation opening is opened or closed. US20210219502A1, WO2020226496 and NL2007745C2 disclose guide systems that will be used to solve this problem.

[0005] However, a common problem with existing guide systems is that when the louvers are open, the sheets in the upper portion of the accordion-like configuration tend to stretch out in a flat configuration, while the sheets in the lower portion tend to form a tightly folded stack at the bottom of the net structure due to gravity. This situation prevents optimal airflow through the insect screen, because maximum airflow through the insect screen is only provided when the sheets form a proper accordion-like configuration. These problems may occur with less stiff insect screens that have finer yarns and therefore "better airflow". Therefore, one object of the net support system of the present invention is to alleviate this problem.

[0006] Another problem with existing solutions is the need for delicate installation on site in the greenhouse ceiling, which is high up, hot work. The guide systems currently on the market include large rigid components that cannot be pre-installed or packaged in one unit with the insect screen structure. Summary of the invention

[0007] The object of the invention is to provide a simple and safe guiding system for an insect screen arranged in a ventilation opening which is repeatedly opened and closed.

[0008] The above objects are achieved by a net support system according to claim 1, a ventilated structure system according to claim 16 and a greenhouse according to claim 25. Further embodiments are set forth in the dependent claims, in the following description and in the drawings.

[0009] As described herein, a net support system for spanning adjustable ventilation openings is provided. The net support system includes an insect net to prevent insects from passing through the adjustable ventilation openings. The insect net is folded in an accordion-like configuration so as to be folded in a stack when the adjustable ventilation opening is closed and unfolded when the adjustable ventilation opening is opened. The net support system also includes a guide structure for the insect net, wherein the guide structure includes a stretchable line connected to at least one net connector fixedly attached to the insect net. The stretchable line holds the insect net in an accordion-like configuration when the insect net spans the ventilation opening. The technical advantage of the net support system described herein is that the thin sheets in the lower portion of the accordion-like structure are prevented from forming a tightly folded stack at the bottom of the net structure. This situation prevents optimal airflow through the insect net because the maximum airflow through the insect net is provided only when the thin sheets form a suitable accordion-like configuration.

[0010] In one example, the guide structure comprises at least a first guide device for the stretchable line. The first guide device is arranged on the first end or the second end of the front panel of the insect-proof net. The first guide device guides the net connection part of the stretchable line to pass through at least one net connection member in a direction parallel to the front panel. The technical advantage of arranging the first guide device on the first end or the second end of the front panel of the insect-proof net may be that they can be pre-installed on the net support system in the factory, thereby facilitating the on-site assembly of the net support system.

[0011] In one example, the guide structure comprises first and second wire attachment points for fixing a first end and a second end of a stretchable wire of the guide structure. The first wire attachment point is arranged at a position of a first distance d1 from the first guide device, so that when the first end of the stretchable wire is attached to the first wire attachment point, the net connection portion of the stretchable wire is guided through the first guide device so as to extend toward the first wire attachment point in a first extension portion of the stretchable wire in a direction different from the direction of the net connection portion. A technical advantage of guiding the first extension portion of the stretchable wire toward the first wire attachment point in a direction different from the direction of the net connection portion may be that the relative elongation of the stretchable wire is reduced when the adjustable ventilation opening is in the open position.

[0012] In one example, when the adjustable ventilation opening is in the fully open position, a first distance d1 between the first guide and the first wire attachment point is greater than a distance d between the first end and the second end of the front panel. open At least 15% longer, preferably at least 50% longer, more preferably at least 60% longer. open A technical advantage of at least 15% longer can be that the total material strain on the stretchable wire can be drastically reduced. The reduced strain enables the guide device to be arranged directly on the insect screen of the front panel, thereby avoiding the need to mount the screen support system on the greenhouse structure, such as a window frame or support beam in the ventilation opening.

[0013] In one example, the second line attachment point for the stretchable line is arranged on the end of the front panel opposite to the end provided with at least the first guide device. The technical advantage of arranging the first and second guide devices on the first and second ends of the front panel of the insect screen may be that they can be pre-installed on the screen support system at the factory, thereby facilitating the on-site assembly of the screen support system.

[0014] In one example, the total unstretched length of the stretchable line is l w1-10% shorter, preferably 3-6% shorter, than the first distance d1 extending between the first guide means and the first attachment point. A technical advantage of having a stretchable line that is 1-10% shorter, preferably 3-6% shorter, than the first distance d1 extending between the first guide means and the first attachment point may be that the stretchable line will remain in a stretched state regardless of whether the adjustable ventilation opening is in a fully open position or in a closed position, or somewhere in between.

[0015] In one example, the guide structure includes a second guide device for the stretchable line. The first and second guide devices are arranged on opposite ends of the front panel and guide the net connection portion of the stretchable line between the first guide device and the second guide device in a direction parallel to the front panel, and at least one net connector is arranged between the first guide device and the second guide device. A technical advantage may be that at least one net connector can prevent the insect net of the front panel from being caught by wind. At least one net connector can also help fold and unfold pleats during opening and closing of the adjustable ventilation opening.

[0016] In one example, the second wire attachment point for the stretchable wire is arranged at a position of the second distance d2 from the second guide means, so that when the second end of the stretchable wire is attached to the second wire attachment point, the net connection portion of the stretchable wire is guided through the second guide means so as to extend in the second extension portion of the stretchable wire in a direction different from the direction of the net connection portion towards the second wire attachment point. A technical advantage of also guiding the second extension portion of the stretchable wire in a direction different from the direction of the net connection portion towards the second wire attachment point may be that the relative elongation of the stretchable wire is reduced when the adjustable ventilation opening is in the open position.

[0017] In one example, when the adjustable vent opening is in the fully open position, the sum of a first distance d1 extending between the first guide and the first attachment point and a second distance d2 extending between the second guide and the second attachment point is greater than the distance d between the first end and the second end of the front panel. open At least 50% longer, preferably at least 100% longer. The sum of d1 and d2 is greater than the distance d open A technical advantage of being at least 50% longer may be that the total material strain on the stretchable wire may be drastically reduced. The reduced strain enables the guide device to be arranged directly on the insect screen of the front panel, thereby avoiding mounting the screen support system on the greenhouse structure, such as a window frame or a support beam in the ventilation opening.

[0018] In one example, the stretchable line has a total unstretched length l w , the total unstretched length l w1-10% shorter, preferably 3-6% shorter, than the sum of a first distance d1 extending between the first guide means and the first attachment point and a second distance d2 extending between the second guide means and the second attachment point. A technical advantage of making the stretchable cord 1-10% shorter, preferably 3-6% shorter, than the sum of the first distance d1 and the second distance d2 may be that the stretchable cord will remain in a stretched state regardless of whether the adjustable ventilation opening is in a fully open position or a closed position, or somewhere in between.

[0019] In one example, the at least one net connector is a fixed connector fixedly attached to the insect net and the stretchable cord between the first end and the second end of the front panel.

[0020] In one example, the fixed lifting point is preferably arranged on the insect screen at 1 / 3 to 2 / 3 of the distance from the first end to the second end of the front panel. A technical advantage may be that when the adjustable ventilation opening is in the open position, the fixed connection enables the stretchable wire to lift the lower folds of the front panel. This helps to keep all the folds of the front panel in an accordion form, thereby providing a higher airflow through the insect screen.

[0021] In one example, at least one net connector is a sliding connector fixedly attached to the insect screen between the first end and the second end of the front panel, the sliding connector guiding the stretchable wire through and parallel to the front panel. A technical advantage may be that the sliding connector may provide a mechanical support point between the stretchable wire and the front panel, but still allow the folds of the front panel to slide along the stretchable wire during opening and closing of the ventilation opening.

[0022] In one example, the stretchable thread is an elastic thread. A technical advantage may be that elastic threads are cheap and readily available in the market in different sizes. In one example, the stretchable thread is only partially elastic.

[0023] The invention also discloses an adjustable ventilation structure, comprising: a first frame defining a ventilation opening in a surface of a greenhouse; and a rectangular ventilation window covering the ventilation opening. The ventilation window can be hingedly connected to the first frame so as to be hinged about a hinge axis between a closed position and an open position, in which the ventilation window extends substantially parallel to the surface of the greenhouse and in which the ventilation window is obliquely oriented relative to the surface so as to form a ventilation channel.

[0024] The first frame includes two parallel side support beams and parallel front and rear support beams, wherein the rear support beam can be hingedly connected to the ventilation window. The ventilation window includes a window glass and a second frame along at least the distal front edge, the rear edge and two parallel side edges of the window glass. An insect screen with a net support system as described herein is provided across the ventilation opening, thereby providing improved airflow through the insect screen while preventing insects from passing through the ventilation opening. A technical advantage of the adjustable ventilation structure can be that the net support system described herein can be pre-installed directly on the ventilation structure and then the ventilation structure including the net support can be installed on site in the greenhouse.

[0025] A greenhouse is also disclosed, the greenhouse comprising ventilation openings provided with a net support system. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] In the following detailed description, aspects of the web support system as disclosed herein can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, but emphasis is placed on clearly demonstrating the basic principles of the invention. In the drawings, the same reference numerals represent corresponding components in all views.

[0027] Figure 1 is an example diagram of a roof of a Venlo-type greenhouse including ventilation openings.

[0028] Figure 2a-2c is an example diagram of the steps for assembling an accordion assembly from insect screen strips.

[0029] Figure 3 is a schematic diagram of a mesh support system as described herein, according to one example.

[0030] Figure 4 is a schematic diagram of an alternative mesh support system as described herein, according to one example.

[0031] Figure 5 is an example diagram of a ventilation opening including a mesh support system described herein, according to one example.

[0032] Figure 6a is a view of the mesh support system described in Example 1.

[0033] Figure 6b is an illustration of a first guide device and a second guide device of a mesh support system according to one example.

[0034] Figure 6c is a view of a net connector of a net support system according to one example as it is attached to an insect control net described herein.

[0035] Figure 7a is a view of the mesh support system described in Example 2.

[0036] Figure 7b is an example diagram of the first guide device and the second guide device of the net support system described in Example 2.

[0037] Figure 7c is an example diagram of a mesh connector of the mesh support system described in Example 2. DETAILED DESCRIPTION

[0038] Hereinafter, the present invention will be described in more detail with reference to the exemplary embodiments shown in the accompanying drawings in a non-limiting manner. It should be understood that other embodiments may be conceived and manufactured without departing from the scope of the present invention. Therefore, the following detailed description should not be used in a limiting sense.

[0039] Figure 1 is a view of a Venlo type greenhouse 50 including an adjustable ventilation opening 74 arranged on a roof 51. The adjustable ventilation opening 74 is provided with an accordion type ventilation screen 60 in order to prevent insects from passing through the ventilation opening 74 while providing an optimal airflow through the ventilation opening 74. Compared to a flat net covering the same opening, this accordion type ventilation screen 60 increases the total ventilation area through the opening while preventing insects from passing through.

[0040] The insect screen used in the accordion ventilation screen 60 described herein can be any conventional insect screen commonly used to prevent insects from entering or leaving a greenhouse. The insect screen is preferably cut into strips having a length equal to the width of the ventilation opening and a width of 50-100 mm, preferably 60-80 mm, and connected in an accordion assembly 63, which is then assembled into the accordion ventilation screen 60.

[0041] The accordion assembly 63 used in the accordion ventilation screen 60 is typically manufactured by assembling two insect screen strips or sheets 66a, 66b flat on top of each other to form pleats 69, such as Figure 2a The insect screen strips 66a, 66b are sewn together along one longitudinal edge 67, 68 at a maximum distance of 10 mm from the edge 67, 68. Another insect screen strip 66c is placed on top of the first two and sewn together with the uppermost insect screen strip 66b along the opposite longitudinal edge 67, 68 in the same manner. The process is repeated with the desired number of insect screen strips 66a, 66b to form a Figure 2a The accordion assembly 63 is shown.

[0042] The accordion type ventilation screen 60 includes a front panel 162, 262 connected to two side panels 61. For the side panels 61, a triangular notch 64 is cut out from the accordion type component 63, such as Figure 2bThe edges 65a and 65b along the notch 64 are connected as shown by arrows to form a Figure 2c A side panel 61 is shown which can be connected to the front panel 162 , 262 to form an accordion-style ventilation screen 60 .

[0043] like Figure 1 As shown, the accordion ventilation screen 60 spans the ventilation opening 74 between the roof construction 52 and the louver 80. At a first end, the accordion ventilation screen 60 is connected to the roof construction 52, and at a second end, the accordion ventilation screen 60 is connected to the louver 80.

[0044] In order to ensure that the mesh sheets 69 in the accordion type ventilation screen 60 are properly folded and unfolded during the process of opening and closing the ventilation opening 74, the accordion type ventilation screen 60 is provided with a mesh support system 100, 200, such as Figure 3 and Figure 4 As shown. The mesh support systems 100, 200 described herein allow the pleats 69 (see Figure 2a ) can be folded in a stacked manner when the adjustable ventilation opening 74 is closed, and unfolded when the adjustable ventilation opening 74 is opened.

[0045] Preferably, the insect net strips 66 are made of a fine mesh gauze material that is sufficiently stiff so that when the accordion assembly 63 is folded closed, no undesirable creases or folds are formed, and the individual insect net strips 66 will lie flat against each other. However, in strong winds or when a softer insect net material is used, the accordion structure may fall into or out of the ventilation opening and may not properly form a neatly stacked package of insect net strips 66 when the ventilation opening 74 is closed. To address this problem, the net support system 100, 200 includes a guide structure 120, 220 as disclosed herein to ensure that the pleated insect net 110, 210 is properly unfolded and folded whenever the ventilation window 80 is opened or closed.

[0046] The guide structure 120, 220 includes a stretchable wire 121, 221 extending parallel to and inside the front panel 162, 262 of the accordion-type ventilation screen 60 (see FIG. Figure 3 and 4). The stretchable line 121, 221 has a first end and a second end and is connected to at least one net connector 132, 134, 234 that is secured to the insect screen 110, 210 somewhere between the first and second ends 112, 212, 114, 214 of the front panel 162, 262. The at least one net connector 132, 134, 234 between the stretchable line 121, 221 and the front panel 162, 262 prevents the insect screen 110, 210 from being caught by wind and helps maintain the folds 69 in the accordion configuration when the front panel 162, 262 spans the ventilation opening 74.

[0047] The stretchable line 121, 221 can be an elastic line made of elastic material, which can be stretched into a stretched state, and the elastic line reaches its original shape and size when the tension is released. The term "stretchable line" refers to a line that can be stretched (elongated) to at least 125% of its initial length in the longitudinal direction without breaking. A line made of rubber is an example of a stretchable line 121, 221. The stretchable line 121, 221 can also be a rigid line, such as a polyester rope connected to an elastic device (such as a steel spring) at one or both ends.

[0048] Many variations of this type of stretchable wire can be used, but three properties must be considered when selecting a stretchable wire for a guide structure 120, 220 as disclosed herein: rigidity, resistance to harsh greenhouse environments, and wear characteristics. Rigidity is required for the guiding function because stronger forces may cause unnecessary tension on other parts of the structure. The greenhouse environment is challenging due to sunlight, high temperatures, and high humidity, so the stretchable wire must be made of a material that will withstand the harsh conditions for several years. Since the ventilation opening is repeatedly opened and closed, sometimes multiple times a day, good wear resistance is critical because the stretchable wire 121, 221 constantly rubs against different parts of the guide structure.

[0049] Preferably, the stretchable cord 121, 221 is made of rubber and is surrounded by a braid. The braid protects the rubber from mechanical wear and degradation in sunlight.

[0050] The guide structure 120, 220 also includes at least a first guide device 141, 241 for the stretchable wire 121, 221, arranged on the first end 112, 212 of the front panel 162, 262. The first guide device 141, 241 guides the net connection portion 123, 223 of the stretchable wire 121, 221 through at least one net connection member 132, 134, 234 in a direction parallel to the extension of the front panel 162, 262.

[0051] The guide means may be a ring, a hook, a bracket or simply an eyelet with an opening through which the stretchable wire 121, 221 may be guided. It is important to provide low friction between the guide means and the stretchable wire 121, 221, and preferably, the guide means is a sliding roller or slideway which provides a larger bending radius and low friction for the stretchable wire 121, 221 as it slides on the guide means.

[0052] The first guide means 141, 241 is arranged on the first end 112, 212 of the front panel 162, 262. This means that the first guide means 141, 241 can be arranged directly on the anti-insect net 110, 210 close to the first end 112, 212 of the front panel 162, 262, or on the front support beam 72 of the ventilation opening 74. When arranged directly on the anti-insect net 110, 210 of the front panel 162, 262, the first guide means 141, 241 is preferably a ring or eyelet through which the stretchable line 121, 221 can pass.

[0053] The guide structure 120, 220 includes first and second wire attachment points 142, 242, 144 for connecting the first end and the second end of the stretchable wire 121, 221. The first wire attachment point 142, 242 is arranged at a first distance d1 from the first guide 141, 241, so that when the first end of the stretchable wire 121, 221 is attached to the first wire attachment point 142, 242, the net connection portion 123, 223 of the stretchable wire 121, 221 is guided through the first guide 141, 241 and extends toward the first wire attachment point 142, 242 in a direction different from the direction of the net connection portion 123, 223 to become the first extension portion 122, 222 of the stretchable wire 121, 221.

[0054] In one embodiment, the guide structure 120 includes a second guide device 143 (see FIG. 14A ) for the stretchable line 121 disposed on the second end 114 of the front panel 162. Figure 3 ). The second guide device 143 is directly arranged on the anti-insect net 110 near the second end 114 of the front panel 162, or is arranged on the distal front edge 83 of the ventilation window 80. In this embodiment, the first and second guide devices 141, 143 are arranged on the opposite ends 112, 114 of the front panel 162, and guide the net connecting portion 123 of the stretchable wire 121 between the first and second guide devices 141, 143 in a direction parallel to the front panel 162, wherein at least one net connecting member 132, 134 is arranged between the first and second guide devices 141, 143.

[0055] The second end of the stretchable wire 121 is attached to a second wire attachment point 144, which is arranged at a second distance d2 from the second guide device 143, so that when the second end of the stretchable wire 121 is fixed on the second wire attachment point 144, the net connection part 123 of the stretchable wire 121 is guided through the second guide device 143 and extends toward the second wire attachment point 144 in a direction different from the direction of the net connection part 123 to become the second extension part 124 of the stretchable wire 121.

[0056] Figure 3 1 is a view of a net support system 100 including a guide structure 120, wherein a first end of a stretchable wire 121 is fixed to a first wire attachment point 142 located at a first distance d1 from a first guide device 141. A first extension portion 122 of the stretchable wire 121 extends from the first wire attachment device 142 toward the first guide device 141 disposed on a first end 112 of a front panel 162. The stretchable wire 121 is guided through the first guide device 141 and continues in a net connection portion 123 that extends in a direction parallel to the front panel 162 through at least one net connection member 132, 134 and toward a second guide device 143. Then, the stretchable wire 121 is guided through the second guide device 143 and extends toward a second wire attachment point 144 for the stretchable wire 121 into a second extension portion 124 of the stretchable wire 121. The second wire attachment point 144 is located at a second distance d2 from the second guide device 143. The second end of the stretchable line 121 is fixed to the second line attachment point 144 .

[0057] exist Figure 3 In the embodiment of the invention, when the adjustable ventilation opening 74 is in the fully open position, the sum of the first distance d1 extending between the first guide device 141 and the first wire attachment point 142 and the distance d2 extending between the second guide device 143 and the second wire attachment point 144 is greater than the distance d between the first end 112 and the second end 114 of the front panel 162. open is at least 50%, preferably at least 100% longer. Preferably, the sum d1+d2 is greater than d open About 50% to about 150% longer, preferably about 60% to about 130% longer, more preferably about 70% to about 120% longer, and more preferably about 80% to about 110% longer.

[0058] Figure 42 is a view of an alternative net support system 200, wherein the guide structure 220 includes only the first guide device 241. The first guide device 241 can be arranged on the first end 212 or the second end 214 of the front panel 262. This means that the first guide device 241 can be arranged directly on the insect net 210 near the first end 212 of the front panel 262, or on the front support beam 72 of the ventilation opening 74, or near the front support beam 72. Alternatively, the first guide device 241 can be arranged directly on the insect net 210 near the second end 214 of the front panel 262, or on the far front edge 83 of the ventilation window 80.

[0059] Preferably, the guide device is arranged directly on the pleated insect-proof net 210 of the front panel 262 at the first end 212 or the second end 214 of the front panel 262. When arranged directly on the insect-proof net 210 of the front panel 262, the first guide device 241 is preferably a ring or eyelet through which the stretchable line 221 can pass.

[0060] exist Figure 4 In an embodiment of the present invention, the guide structure 220 does not include a second extension of the stretchable cord 221. Instead, the second cord attachment point 245 is arranged on the ends 212, 214 of the front panel 262 opposite to the end where the first guide device 241 is provided. For example, when the first guide device 241 is arranged on the first end 212 of the front panel 262, the second cord attachment point 245 for the stretchable cord 221 is arranged on the second end 214. Alternatively, the first guide device 241 is arranged on the second end 214 of the front panel 262 and the second cord attachment point 245 is arranged on the first end 212.

[0061] exist Figure 4 In the embodiment, the mesh support system 200 includes a guide structure 220, wherein a first end of a stretchable wire 221 is attached to a first wire attachment point 242 located at a first distance d1 from a first guide device 241, as for Figure 3 The first extension portion 222 of the stretchable cord 221 extends from the first cord attachment point 242 toward the first guide device 241 arranged on the first end 212 of the front panel 262. The stretchable cord 221 is guided around the first guide device 241 and continues in the net connection portion 223 of the stretchable cord 221 in a direction parallel to the front panel 262, passes through at least one net connection piece 234, and toward the second cord attachment point 245 for the stretchable cord 221. The second end of the stretchable cord 221 is fixed to the second cord attachment point 245 arranged at the second end 214 of the front panel 262.

[0062] In this embodiment, when the adjustable ventilation opening 74 is in the fully open position, the first distance d1 between the first guide 241 and the first wire attachment point 242 is greater than the distance d between the first end 212 and the second end 214 of the front panel 262. open is at least 15%, preferably at least 50%, more preferably at least 60%. Preferably, d1 is greater than d open About 15% to about 110% longer, preferably about 30% to about 100% longer, more preferably about 40% to about 90% longer, and more preferably about 50% to about 80% longer.

[0063] It can be seen from the two embodiments that the line attachment points 142, 242, 144 are arranged along the direction from the first and / or second guide devices 141, 241, 143, so that when the first and second ends of the stretchable line 121, 221 are fixed on the line attachment points 142, 242, 144, the extension parts 122, 222, 124 of the stretchable line 121, 221 extend from the first and / or second guide devices 141, 241, 143 along a direction that is preferably not parallel to the net connection part 123, 223 of the stretchable line 121, 221.

[0064] exist Figure 3 In the embodiment, the net connection portion 123 of the stretchable line 121 extends in a direction parallel to the front panel 162, and at each of the first and second ends 112, 114 of the front panel 162, the net connection portion 123 is guided through the first guide device 141 and the second guide device 143, so that the first extension portion 122 and the second extension portion 124 extend in a direction forming a certain angle with the net connection portion 123, and the angle is less than 180° but greater than 0°, for example, 130° or less but at least 20° or greater, for example, 100° or less but at least 50° or greater, and the net connection portion 123 extends parallel to the front panel 162.

[0065] Similar situations apply to Figure 4 The first extension portion 222 in the mesh connection portion 223, wherein the mesh connection member 223 extends parallel to the front panel 262, is guided through the first guide device 241, and extends toward the first attachment point 242 in a direction forming a certain angle with the mesh connection portion 223 to form the first extension portion 222, and the angle is less than 180° but greater than 0°, for example, 130° or less but at least 20° or greater, for example, 100° or less but at least 50° or greater.

[0066] For both embodiments, the stretchable cord 121, 221 is connected to the front panel 162, 262 by at least one web connector 132, 134, 234 (see FIG. Figure 3 and Figure 4). As described above, at least one net connector 132, 134, 234 between the stretchable wire 121, 221 and the front panel 162, 262 prevents the front panel 162, 262 from blowing in and out through the adjustable ventilation opening 74 on windy days. At least one net connector 132, 134, 234 also ensures that the insect screen 110, 210 is properly unfolded and folded whenever the ventilation window 80 is opened or closed.

[0067] Due to gravity, when the adjustable ventilation opening 74 is in the open position, the pleats 69 in the accordion assembly tend to form a tight stack at the lower (first) end 112, 212 of the front panel 162, 262 and form a flat area toward the upper (second) end 114, 214. This uneven expansion of the pleats 69 will impair the airflow through the ventilation screen, and to remedy this, at least one of the net connectors 132, 134, 234 in the guide system is a fixed connector 132. The fixed connector is attached to the insect screen 110 and the stretchable wire 121 of the front panel 162 at a point somewhere between the first end 112 and the second end 114 of the front panel 162 (see Figure 3 ). When the adjustable ventilation opening 74 is in the open position, the fixed connection 132 enables the stretch line 121 to lift the lower pleats 69 of the front panel 162a a certain distance. This helps to keep all the pleats 69 of the front panel 162 in an accordion form, thereby providing a higher airflow through the insect screen 110. Figure 4 In the embodiment shown, there is no fixed connection between the stretchable line 221 and the anti-insect net 210. However, a fixed connection can also be provided in this embodiment of the guide structure 220.

[0068] The fixed connection 132 may be a plastic or metal clip, knot, weld or glue joint that connects the stretchable line 121, 221 to the insect screen 110, 210 of the front panel 162, 262. Preferably, when the adjustable ventilation opening 74 is in the fully open position, the fixed connection 132 is located between one-third and two-thirds of the distance from the first end 112, 212 of the front panel 162, 262. Preferably, when the adjustable ventilation opening 74 is in the fully open position, the fixed connection 132 is located midway between the first end 112, 212 and the second end 114, 214 of the front panel 162, 262.

[0069] To further assist in the correct folding and unfolding of the accordion pleats 69 during the opening and closing operation of the adjustable ventilation opening 74, it is preferred that additional mesh connectors 134, 234 are provided between the stretchable cords 121, 221 and the front panels 162, 262. However, these mesh connectors 134, 234 are not fixed to the stretchable cords 121, 221, but are only fixed to the front panels 162, 262. The additional mesh connectors 134, 234 (in addition to the fixed connections described above) are sliding connectors 134, 234 that will connect the stretchable cords 121, 221 to the front panels 162, 262, but still allow the pleats 69 of the front panels 162, 262 to slide along the stretchable cords 121, 221. The sliding connector 134, 234 may be, for example, a through loop or eyelet secured to one or more pleats 69 of the front panel 162, 262 through which the stretchable cord 121, 221 may slide when the adjustable ventilation opening 74 is opened or closed.

[0070] The net connector 132, 134, 234 provides a mechanical support point between the stretchable line 121, 221 and the insect screen 110, 210 of the front panel 162, 262. Ideally, there is a fixed connector 132 that will increase the stacking of the pleats 69 to promote the accordion formation of the insect screen 110, 210, while it is preferred that one or more sliding connectors 134, 234 are provided on either side of the fixed connector along the stretchable line 121, 221. The distance d between the first end 112, 212 and the second end 114, 214 of the front panel 162, 262 when the adjustable ventilation opening 74 is in the fully open position open When very long, additional sliding connectors 134, 234 may be provided on either side of the fixed connector, for example two, three or more sliding connectors 134, 234. The sliding connectors 134, 234 will prevent the insect screens 110, 210 of the front panels 162, 262 from being caught by the wind and will help fold and unfold the pleats 69 during the process of opening and closing the adjustable ventilation openings 74.

[0071] The key to successfully folding and unfolding the pleats 69 in the accordion ventilation screen 60 is that the stretchable wires 121, 221 used in the guide structures 120, 220 disclosed herein remain in a stretched state when the adjustable ventilation opening 74 is in the closed position, the fully open position, and all positions therebetween.

[0072] In order to keep the stretchable wires 121, 221 in a constant stretched state, when the adjustable ventilation opening 74 is in the fully closed position, the total non-stretched length l of the stretchable wires 121, 221 is wIt must be 1-10%, preferably 3-6%, shorter than the sum of the first distance d1 (i.e. the distance between the first guide 141, 241 and the first wire attachment point 142, 242) and the second distance d2 (i.e. the distance between the second guide 143 and the second wire attachment point 144). It should be noted here that when the adjustable ventilation opening 74 is in the fully closed position, the distance between the first and second ends 112, 212, 114, 214 of the front panel 162, 262 is close to zero, because the only part that affects the distance between the two guides is the neatly stacked pleats 69 and the stack of net connectors 132, 134, 234 (i.e. the above-mentioned fixed connector 132 and sliding connector 134, 234) between the stretchable wire 121, 221 and the front panel 162, 262.

[0073] exist Figure 4 In the embodiment (i.e., the guide structure 220 includes only the first extension portion 222 of the stretchable line 221), the total non-stretched length (l w ) is 1-10% shorter than the first distance (d1) extending between the first guide device 241 and the first attachment point 242, preferably 3-6%,

[0074] When the stretchable wire 121, 221 passes through the first and second guide devices 141, 241, 143, and also when the adjustable ventilation opening 74 is in the closed position, the length l of the stretchable wire 121, 221 is w Slightly shorter than the total distance from the first wire attachment point 142, 242 to the second wire attachment point 144, the stretchable wire 121, 221 will remain in a stretched state regardless of whether the adjustable ventilation opening 74 is in a fully open position or a closed position, or somewhere in between.

[0075] like Figure 3 and 4 As shown, there is no fixed attachment between the stretchable line 121, 221 and the anti-insect net 110, 210 at the first and second ends 112, 212, 114, 214 of the front panel 162, 262. Instead, the stretchable line 121, 221 is guided through a guide device 141, 241, 143, which is arranged directly on the anti-insect net 110, 210 at the first and / or second ends 112, 212, 114, 214 of the front panel 162, 262. Then, the stretchable wire 121, 221 extends away from the guide device 141, 241, 143 to a first extension portion 122, 222 by a first distance d1, which is greater than the distance d between the first and second ends 112, 212, 114, 214 of the front panel 162, 262 when the adjustable ventilation opening 74 is in the fully open position.open is at least 15%, preferably at least 50%, more preferably at least 60%. Preferably, d1 is greater than d open About 15% to about 110% longer, preferably about 30% to about 100% longer, more preferably about 40% to about 90% longer, and more preferably about 50% to about 80% longer.

[0076] When the guide structure 120 includes the second guide device 143, the stretchable line 121, 221 also extends away from the second guide device 143 to the second extension portion 124 by a second distance d2. When the adjustable ventilation opening 74 is in the fully open position, the sum of the first distance d1 and the second distance d2 is greater than the distance d between the first and second ends 112, 114 of the front panel 162. open is at least 50%, preferably at least 100% longer. Preferably, the sum d1+d2 is greater than d open About 50% to about 150% longer, preferably about 60% to about 130% longer, more preferably about 70% to about 120% longer, and more preferably about 80% to about 110% longer.

[0077] When the adjustable ventilation opening 74 is in the open position, the extension portion 122, 124, 222 of the stretchable wire 121, 221 extending away from the guide device 141, 241, 143 toward the wire attachment point 142, 242, 144 reduces the relative elongation of the stretchable wire 121, 221, so the total material strain on the stretchable wire 121, 221 is sharply reduced. Here, the relative elongation of the stretchable wire will be used to represent the stretched length (L1)-relaxed length (L0) divided by the relaxed length (L0) x 100%, as shown below:

[0078] Relative elongation = ((L1-L0) / L0) x 100%

[0079] The choice of material for the stretchable cord 121, 221 must be suitable for the fully extended state of the stretchable cord 121, 221, ie when the adjustable vent is in the fully open position. Preferably, a relative elongation between 1-40% is suitable for the rubber cord, allowing it to withstand mechanical fatigue for many years.

[0080] In the net support system 100 having the guide devices 141, 143 arranged at both ends 112, 114 of the front panel 162, the first wire attachment point 142 and the second wire attachment point 144 (in which the first and second ends of the stretchable wire 121 are attached) can be arranged in separate points. However, it is preferred that they are arranged at the same position so that they form one common wire attachment point for the first and second ends of the stretchable wire 121, such as Figure 3 It can be seen in.

[0081] The net support systems 100, 200 with stretchable wires 121, 221 disclosed herein provide many advantages to greenhouse owners.

[0082] Since the net support system 100, 200 having the guide structures 120, 220 disclosed herein is flexible, it can be easily adapted to other equipment disposed within the greenhouse 50. A wider adjustable ventilation opening 74 can easily include more than one guide structure 120, 220, such as two, three or more guide structures 120, 220 at regular intervals along the front panel 162, 262.

[0083] The scheme having stretchable lines 121, 221 connected to the front panels 162, 262 by fixed and sliding connections 132, 134, 234 provides good mechanical support for the net support system 100, 200 and enables the pleats 69 of the accordion-type ventilation screen 60 to remain on the inner side of the ventilation opening 74 also at a lower opening angle of the adjustable ventilation window 80.

[0084] Since the extension portion 122, 124, 222 of the stretchable wire 121, 221 extends away from the front panel 162, 262 and the guide device 141, 241, 143 towards the wire attachment point 142, 144, 242, the strain (i.e., tension) on the portion of the stretchable wire 121, 221 that supports the front panel 162, 262 can be significantly reduced. The reduced strain makes it possible to arrange the guide device 141, 241, 143 directly on the insect screen 110, 210 of the front panel 162, 262, thereby avoiding the need to install the net support system on the greenhouse structure, such as on the window frame or support beam in the ventilation opening 74.

[0085] This is very advantageous because the guide structure 120, 220 with the stretchable wire solution 120, 220 and the net connection 132, 134, 234 described herein can be directly mounted to the insect screen 110, 210 of the front panel 162, 262 during the manufacturing process of the accordion assembly. Also, the first and second ends of the stretchable wire 121, 221 can be prepared with the required wire attachments ready for connection with the wire attachment points 142, 144, 242. Without any large or rigid parts, the net support system 100, 200 including the guide structure 120, 220 (which is already connected to the accordion ventilation screen 60) can be folded and packed together, thereby requiring minimal effort at the installation site.

[0086] The net support system 100, 200 as described above is preferably installed in an adjustable ventilation opening 74 located on a greenhouse roof 51 having an inclined top surface. In one example, the adjustable ventilation opening 74 may include a first frame defining the ventilation opening 74 and a rectangular ventilation window 80 covering the ventilation opening 74.

[0087] The vent window 80 can be hingedly connected to the first frame so as to be hinged about the hinge axis between a closed position and an open position, in which the vent window 80 extends substantially parallel to the first frame, and in which the vent window 80 is obliquely oriented relative to the first frame to form a ventilation channel. The vent window 80 is preferably a second frame including a window glass 81 and at least a distal front edge 83, a rear edge 84 and two parallel side edges 85 along the window glass 81. The window glass 81 is translucent and can be made of glass, hardened glass or plastic (e.g., polycarbonate).

[0088] The first frame defining the ventilation opening 74 includes two parallel side support beams 71 and parallel front support beams 72 and rear support beams 73 arranged perpendicular to the two parallel side support beams 71. The two parallel side support beams 71 and the parallel front support beams 72 and rear support beams 73 form a rectangular opening 74 in which a rectangular ventilation window 80 can be fitted. The ventilation window 80 can be hingedly connected to the rear support beam of the ventilation opening 74.

[0089] The first end 112, 212 of the front panel 162, 262 in the net support system 100, 200 is connected to the distal front edge 83 of the ventilation window 80, and the second end 114, 214 of the front panel 162, 262 is connected to the front support beam 72 defining the ventilation opening 74. The side panels 61 are connected to the side support beam 71 of the first frame and the side edge 85 of the ventilation window 80, respectively.

[0090] In one embodiment, the first wire attachment point 142, 242 is arranged on the rear support beam 73 of the first frame near the hinge. In the case where the net support system 100, 200 includes the first and second guide means 141, 241, 143, the second wire attachment point 144 is also preferably arranged on the rear support beam 73 near the hinge. In a preferred embodiment, both the first and second wire attachment points 142, 242, 144 are arranged in the same point on the rear support beam. By arranging the wire attachment points 142, 242, 144 on the rear support beam 73 of the adjustable ventilation opening 74, the stretchable wire 121, 221 extends away from the guide structure by a distance d that is long enough to reduce the relative elongation of the stretchable wire 121, 221 when the adjustable ventilation opening 74 is in the open position. Another advantage of having the wire attachment point near the hinge is that the two distances d1 and d2 between the guide structure and the wire attachment point are approximated, thereby guiding the fixed lifting point 132 toward the middle area between the first guide device 141 and the second guide device 143 and making the pleats 69 more evenly distributed on the front panel 162, 262.

[0091] As described above, the guide device is preferably mounted directly on the insect screen 110, 210 on the first end and / or the second end of the front panel. However, in an alternative embodiment, the first and / or second guide devices 141, 241, 143 can also be arranged on the front distal edge of the ventilation window 80 and / or on the front support beam 72 of the first frame. This may require additional work when installing the net support system 100, 200 in the adjustable ventilation opening 74, but it also allows the use of a tensile wire 121, 221 with a higher tensile strength.

[0092] Alternatively, the first and second wire attachment points 142, 242, 144 are attached to a ceiling structure inside the greenhouse (not shown).

[0093] Example

[0094] Example 1 - Rubber Cord and Sewing Loop

[0095] Figure 6a An embodiment of a mesh support system as described herein is disclosed which has been installed in a roof ventilation opening having dimensions of 1200 mm x 1900 mm. In the fully open position, the opening height of the vent is 1052 mm.

[0096] The front and side panels of the insect screen consist of 22 sheets, 70 mm wide, sewn together to form an accordion assembly and then assembled into an accordion ventilation screen as described elsewhere herein. The accordion ventilation screen is usually connected to the window frame by sewing a rubber profile onto the sheets and pressing it into a slot in the aluminum profile of the window frame.

[0097] They are used as guide devices 141, 143 respectively (see Figure 6b ) and sliding connector 134 (see Figure 6c )'s mesh connector is 3D printed from PA66 plastic with a material thickness of 1.2 mm. Figure 6b and Figure 6c As shown, the profiles 134, 141, 143 are each provided with an edge of approximately 60 mm in length, which includes an elongated hole pattern which facilitates attachment of the profile to the insect screen by sewing. In order to reduce wear on the stretchable wire, the profile used as a guide structure is provided with an area of ​​increased material thickness (10 mm) which includes a hole of 6 mm in diameter through which the stretchable wire passes (see Figure 6b ). The guides 141, 143 are sewn on the insect screen, respectively at the first end (bottom) and the second end (top) of the front panel, 650 mm from the window corner on the inner side of the front panel 162. Figure 6c The two sliding connections shown are also sewn to the insect screen between the first and second guide means on either side of the fixed connection.

[0098] A fully flexible rubber cord providing the required elasticity was used as the stretchable cord 121 in the guide structure 120 of the net support system. The stretchable cord 121 used in this experimental setup is commonly known as a chock cord and comprises 6 natural rubber (NR) filaments surrounded by a braided polyester yarn cover. The stiffness of the stretchable cord was measured in a tensile test to be 11 N at 50% elongation. The rubber was protected from UV degradation and abrasion by two layers of black UV-resistant polyester multifilament yarn braid. The overall diameter of the cord was 3 mm.

[0099] The first end of the stretchable line is connected by a knot at a first line attachment point (not shown) in the ceiling profile, which is located approximately 80 mm below the window hinge. The stretchable line extends 1180 mm in a first extension portion 122 of the stretchable line 121 towards a first (bottom) guide 141 on the first end 112 of the front panel 162 and is guided through a hole provided in the profile. The net connection portion 123 of the stretchable line 121 further extends through the first sliding device 134, the fixed connection 132 and the second sliding device 134 parallel to the inside of the front panel 162 towards a second guide 143 connected at the second (top) end 114 of the front panel 162. In this embodiment, the fixed connection 132 is provided as a simple knot between the stretchable line 121 and the insect screen 110. The stretchable line 121 is then guided through the hole on the second guide device 143 and extends 1180 mm towards a second line attachment point (not shown) in a second extension 124 of the stretchable line 121, where the second line attachment point coincides with the first line attachment point. The second end of the line is attached to the common line attachment point by a knot.

[0100] When the ventilation opening is in the fully open position, the sum of the lengths of the first extension portion 122 and the second extension portion 124 of the stretchable cord 121 is 124% longer than the distance between the first end and the second end of the front panel.

[0101] The total length of the stretchable cord 121 (excluding the knot) is 2350 mm, which takes into account a 5% pre-stretching of the cord when the ventilation opening is in the closed position, in order to avoid slack and to compensate for possible material relaxation.

[0102] The window, insect screen and guide system structure fully opened and closed outdoors for 5000 cycles without any mess such as nets falling in or out, wires fraying or loosening.

[0103] Example 2 - Guiding structure with local elastic lines

[0104] Figure 7a is a view of an alternative mesh support system as disclosed herein.

[0105] The ventilation openings used in this example had the same dimensions and accordion style ventilation screens as described in Example 1.

[0106] However, a polyester rope with negligible flexibility provided with two steel springs 125, 126 at each end is used as a stretchable wire in the guide structure instead of a rubber wire. The steel springs are 30 cm long and each spring has a spring constant of 25 N / m. The diameter of the braided polyester rope is 5 mm and the total length is 1780 mm, excluding the knot.

[0107] In this embodiment, if Figure 7b As shown, polyoxymethylene (POM) plastic pulley rollers rotating on steel bolts are used as the first guide 141 and the second guide 143, and are mounted on the far front edge 83 of the window and the front support beam 72 of the first frame and the second frame, respectively. The POM plastic pulley rollers have an outer diameter of 15 mm on the side and 12 mm in the middle. The width is 6 mm. The rotating rollers provide minimal friction and wear on the line.

[0108] The mesh connector used as the sliding connector 134 and the fixed connector 132 is injection molded from PA66 plastic into a clamp ring, such as Figure 7c As shown. The clip is pierced around the seams of the net structure and is provided with a 20 mm wide loop through which the line can pass freely. The same type of clip is used for the lifting point, but with a knot on the loop.

[0109] The steel spring 125 at the first end of the tensile wire is connected by bolts at a first wire attachment point (not shown) on the ceiling profile, which is located approximately 80 mm below the window hinge. The polyester rope extends 880 mm from the first steel spring 125 attached at the first wire attachment point toward the first (bottom) guide 141 on the first end 112 of the front panel 162 and is guided on the pulley roller of the first guide 141 so as to extend parallel to the front panel 162. From the first pulley roller, the polyester rope is guided through a first clamping ring used as a sliding device (not shown), a second clamping ring 132 connected to both the polyester rope and the insect screen as a fixed connection, a third clamping ring used as a sliding device (not shown), and toward the second guide 143 (pulley roller) connected at the second (top) end 114 of the front panel 162. The polyester rope is then guided over the second pulley roller 143 and extends 880 mm towards the steel spring 126 through a second attachment point, which in this device coincides with the first line attachment point. The second steel spring 126 on the second end of the polyester rope is attached to the common line attachment point by bolts.

[0110] When the vent opening is in the fully open position, the sum of the first extension portion 122 and the second extension portion 124 of the tensile cord (polyester rope and steel spring) is 124% longer than the distance between the first end 112 and the second end 124 of the front panel 162.

[0111] Since no long term slack in the wire material is expected, the device is installed when the window is fully closed. In order to have negligible slack in the polyester cord with the spring in a nearly relaxed position, the springs are each extended by 5 mm.

[0112] The window, insect screen and guide system structure fully opened and closed outdoors for 5000 cycles without any mess such as nets falling in or out, wires fraying or loosening.

[0113] In this example, the long term effects of sunlight degradation are not considered.

Claims

1. A net support system (100, 200) for spanning an adjustable ventilation opening (74), the net support system comprising: - an insect screen (110, 210) for preventing insects from passing through the adjustable ventilation opening (74), the insect screen (110, 210) being pleated in an accordion-like configuration so as to be folded in a stacked manner when the adjustable ventilation opening (74) is closed and to be unfolded when the adjustable ventilation opening (74) is opened; as well as - a guide structure (120, 220) for an insect-proof net (110, 210), The guide structure (120, 220) includes a stretchable line (121, 221) connected to at least one net connector (132, 134, 234) fixedly attached to the insect net (110, 210), so that when the insect net (110, 210) spans the adjustable ventilation opening (74), the stretchable line (121, 221) maintains the insect net (110, 210) in an accordion configuration.

2. The net support system (100, 200) according to claim 1, wherein: The guide structure (120, 220) comprises at least a first guide device (141, 241) for a stretchable line (121, 221), the first guide device (141, 241) being arranged at a first end or a second end (112, 212, 114, 214) of a front panel (162, 262) on the insect-proof net (110, 210), the first guide device (141, 241) guiding a net connection portion (123, 223) of the stretchable line (121, 221) through the at least one net connection member (132, 134, 234) in a direction parallel to the front panel (162, 262).

3. The net support system (100, 200) according to claim 2, wherein: The guide structure (120, 220) comprises a first and second wire attachment points (142, 242, 144, 245) for fixing the first and second ends of a stretchable wire (121, 221) of the guide structure (120, 220), the first wire attachment point (142, 242) being arranged at a first distance (d1) from the first guide device (141, 241), whereby when the stretchable wire (121, 221) When the first end is attached to the first wire attachment point (142, 242), the net connection portion (123, 223) of the stretchable wire (121, 221) is guided through the first guide device (141, 241) so as to extend in the first extension portion (122, 222) of the stretchable wire (121, 221) toward the first wire attachment point (142, 242) in a direction different from the direction of the net connection portion (123, 223).

4. The net support system (100, 200) according to claim 3, wherein: When the adjustable ventilation opening (74) is in the fully open position, a first distance (d1) between the first guide device (141, 241) and the first wire attachment point (142, 242) is greater than a distance (d2) between the first end and the second end (112, 212, 114, 214) of the front panel (162, 262). open ) is at least 15% longer, preferably at least 50% longer, and more preferably at least 60% longer.

5. The net support system (100, 200) of claim 3, wherein: A second line attachment point (245) for the stretchable line (221) is arranged on an end (212, 214) of the front panel (262) opposite to the end (212, 214) where at least the first guiding means (241) is provided.

6. The net support system (100, 200) of claim 5, wherein: The total non-stretched length (l w ) is 1-10% shorter, preferably 3-6% shorter, than the first distance (d1) extending between the first guiding device (241) and the first wire attachment point (242).

7. The net support system (100, 200) of claim 4, wherein: The guide structure comprises: a second guide device (143) for a stretchable wire (121), the first guide device and the second guide device (141, 143) are arranged on opposite ends (112, 114) of a front panel (162), and a net connecting portion (123) of the stretchable wire (121) is guided between the first guide device and the second guide device (141, 143) in a direction parallel to the front panel (162, 262), and the at least one net connecting member (132, 134) is arranged between the first guide device and the second guide device (141, 143).

8. The net support system (100, 200) of claim 7, wherein: A second wire attachment point (144) for the stretchable wire (121) is arranged at a second distance (d2) from the second guide device (143), whereby, when the second end of the stretchable wire (121) is attached to the second wire attachment point (144), the net connection portion (123) of the stretchable wire (121) is guided through the second guide device (143) to extend toward the second wire attachment point (142) in a second extension portion (122) of the stretchable wire (121) in a direction different from the direction of the net connection portion (123).

9. The net support system (100, 200) of claim 8, wherein: When the adjustable ventilation opening (74) is in the fully open position, the sum of a first distance (d1) extending between the first guide (141) and the first wire attachment point (142) and a second distance (d2) extending between the second guide (143) and the second wire attachment point (144) is greater than the distance (d2) between the first end and the second end (112, 114) of the front panel (162). open ) is at least 50% longer, preferably at least 100% longer.

10. The net support system (100, 200) of claim 9, wherein: The total non-stretched length (l w ) is 1-10% shorter, preferably 3-6% shorter, than the sum of a first distance (d1) extending between the first guide device (141, 241) and the first line attachment point (142, 242) and a second distance (d2) extending between the second guide device (143) and the second line attachment point (144).

11. The net support system (100, 200) according to any one of claims 2 to 10, wherein: The at least one net connector (132, 134, 234) is a fixed connector (132) fixedly attached to the insect net (110, 210) and the stretchable line (121, 221) between the first end and the second end (112, 212, 114, 214) of the front panel (162, 262).

12. The net support system (100, 200) of claim 11, wherein: The fixed lifting point (132) is preferably arranged on the insect screen (110, 210) at 1 / 3 to 2 / 3 of the distance from the first end (112, 212) to the second end (114, 214) of the front panel (162, 262).

13. The net support system (100, 200) according to any one of claims 2 to 12, wherein: The at least one net connector (132, 134, 234) is a sliding connector (134, 234) fixedly attached to the insect-proof net (110, 210) between the first end and the second end (112, 212, 114, 214) of the front panel (162, 262), and the sliding connector (134, 234) guides the stretchable line (121, 221) to pass parallel to the front panel (162, 262).

14. The net support system (100, 200) according to any one of the preceding claims, wherein: The stretchable thread (121, 221) is an elastic thread.

15. The net support system (100, 200) according to any one of the preceding claims, wherein: The stretchable lines (121, 221) are only partially elastic.

16. An adjustable ventilation structure, the adjustable ventilation structure comprising: a first frame configured to define a ventilation opening (74) in a surface of the greenhouse (50); as well as a rectangular ventilation window (80) arranged to cover the ventilation opening (74), wherein the ventilation window (80) is hingedly connected to the first frame so as to be hinged about a hinge axis between a closed position and an open position, in which the ventilation window (80) extends substantially parallel to a surface of the greenhouse (50), and in which the ventilation window (80) is oriented obliquely relative to the surface so as to form a ventilation channel. The first frame comprises two parallel side support beams (71) and parallel front and rear support beams (72, 73), wherein the rear support beam (73) is hingedly connected to the ventilation window (80). The ventilation window (80) comprises a window glass (81) and a second frame, wherein the second frame extends at least along a distal front edge (83), a rear edge (84) and two parallel side edges (85) of the window glass (81). Characterized in that the net support system (100, 200) according to claims 1-15 spans the ventilation opening (74).

17. The adjustable ventilation structure according to claim 16, wherein: A first guide device (141, 241) for a stretchable wire (121, 221) is arranged on a front support beam (72) of the first frame, thereby guiding a net connection portion (123, 223) of the stretchable wire (121, 221) through the at least one net connection member (132, 134, 234) in a direction parallel to the front panel (162, 262).

18. An adjustable ventilation structure according to any one of claims 16 to 17, wherein: A first line attachment point (142, 242) for a stretchable line (121, 221) is arranged on a rear support beam (73) of the ventilation opening (74).

19. An adjustable ventilation structure according to any one of claims 16 to 18, wherein: When the first guide device (241) for the stretchable wire (221) is arranged on the front support beam (72) of the first frame, the second wire attachment point (245) for the stretchable wire (221) is arranged on the distal front edge (83) of the ventilation window (80), or alternatively, when the first guide device (241) for the stretchable wire (221) is arranged on the distal front edge (83) of the ventilation window (80), the second wire attachment point (245) for the stretchable wire (221) is arranged on the front support beam (72) of the first frame.

20. An adjustable ventilation structure according to any one of claims 16 to 18, wherein: The first guide device (141) is arranged on the front support beam (72) of the first frame, and the second guide device (143) is arranged on the distal front edge (83) of the ventilation window (80), and guides the net connecting part (123) of the stretchable line (121) between the first guide device (141) and the second guide device (143) in a direction parallel to the front panel (162), and the at least one net connecting member (132, 134) is arranged between the first guide device (141, 143).

21. The adjustable ventilation structure of claim 20, wherein: A second line attachment point (144) for the stretchable line (121) is arranged on the rear support beam (73).

22. The adjustable ventilation structure of claim 21, wherein: The first and second wire attachment points (142, 144) for the tensile wire (121) are arranged at the same point on the rear support beam (73).

23. An adjustable ventilation structure according to claims 16 to 22, wherein: The adjustable ventilation structure is arranged on the roof structure.

24. The adjustable ventilation structure of claim 23, wherein: The first and / or second wire attachment points (142, 242, 144) are attached to an interior surface of a roof or ceiling structure.

25. A greenhouse comprising an adjustable ventilation structure according to claims 16-24.

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