EP2317033A1

EP2317033A1 - An element for screening fences and a method for realisation thereof

Info

Publication number: EP2317033A1
Application number: EP10188739A
Authority: EP
Inventors: Pierluigi Maggioni; Paolo Molteni
Original assignee: Tenax SpA
Current assignee: Tenax SpA
Priority date: 2009-10-27
Filing date: 2010-10-25
Publication date: 2011-05-04
Also published as: CN102052000A; ITMI20091866A1; IT1397173B1

Abstract

A method for realising a screening fence element provided with a tape body (2) having a plurality of first through-openings (3), and further comprising a plurality of covering elements (4), each of which is coupled to the tape (2) at a corresponding opening (3) of the through-openings and is mobile between a first operating position in which it at least partly covers the corresponding opening (3) and a second operating position in which it covers the corresponding opening (3) to a lesser degree with respect to the first operating position; the method comprising stages of extruding, by means of an extruding head (9), the tape body (2) made of a plastic material along an extrusion direction (MD) and realising a plurality of through-cuts (5) for defining the first openings (3) and the covering elements (4).

Description

The present invention concerns an element for a screening fence.
The invention further relates to a method for realising screening fence elements. In particular the device is applicable in the realising of screening fences in all situations in which an area is to be fenced with a complete or partial prevention of a view of the area delimited by the fence.
In the prior art it is usual to predispose a delimiting fence around an area, for example a work-site, which offers a practically-complete covering of the view, which is destined to prevent outsiders from viewing whatever is inside the delimited area.
The solutions available on the market for this type of application have necessarily to surrender to compromise in relation to two aspects which are in contrast with one another: the screening capacity and the lightness of the product, together with the ability to offer a resistance to wind which is as low as possible.
Screening solutions in which the percentage of screening is 100% or nearly so are constituted by panels, either continuous or beams of wood, metal or plastic material textile netting, with a warp or weft which leave no space between the elements constituting the material. Other known solutions offering a partial screening are constituted by netting made of a plastic material with meshes that can be more or less tight according to needs.
As mentioned above, the two types of products have positive characteristics which are in contrast to one another; the first provide a total screening but are very sturdy and heavy to set up on-site; the others give excellent manageability, set-up and costs, but their true screening capacity is moot.
Other systems are realised by a netting coupled with material or panels which give a better concealment from sight; this solution requires the use and acquisition of two different products for obtaining a specific aim, beyond the difficulty of uniting the two products to form one final product. This latter solution is typical of characteristic zones where it is necessary to signal, in a typically orange colour, the presence of a worksite, while it is also required to prevent outsiders from observing the inside of the work-site.
Document CH963931 describes realising a modular screening structure, particularly suited to delimiting areas where a road accident has occurred, such that the area can be hidden from general view. Each of the modules of the screening barrier exhibits a support structure provided with a base and a plurality of vertical uprights which delimit a support frame on which a predetermined number of flexible sheets provided with respective semicircular openings is mounted, which sheets exhibit respective semi-circular openings defining tabs that are openable by the action of the wind.
The main aim of the present invention is to obviate the problems encountered in the prior art. An aim of the present invention is therefore to provide an element for screening fences which is able to provide a high screening capacity and at the same time a lower resistance to wind.
A further aim of the present invention is to provide an element for screening fences which offers complete coverage.
A further aim of the invention is to make available an element for screening fences which is light, easy to handle and to apply.
A further aim of the present invention is to make available an element for a screening fence which exhibits easiness of setting up and which is economical. A further aim of the present invention is to provide an element for screening fences which does not require a reinforcing structure in order to resist the action of the wind.
A still further aim of the invention is to provide a method for realising elements for screening fences which is simple, rapid and easy to industrialise.
A further aim is to make available a production method which makes the handling of the product before use easier and simpler.
These aims and others besides are substantially attained by an element for screening fences and a method for realisation thereof, in accordance with what is expressed in one or more of the accompanying claims, taken alone or in combination.
The invention further relates to an element of one or more of the accompanying claims, in which a tape body is provided with a plurality of additional second through-openings that are without covering elements.
The invention further relates to an element of one or more of the accompanying claims, wherein the covering elements are defined by means of the same cutting operation which defines the corresponding opening.
The invention further relates to an element of one or more of the accompanying claims, wherein the covering elements cover corresponding openings more in a second operating position than in a first operating position.
The invention further relates to an element of one or more of the accompanying claims, wherein the covering elements are displaceable between a plurality of distinct operating positions.
The invention further relates to an element of one of more of the accompanying claims, wherein each covering element exhibits a connecting portion with the tape body and in which the cuts are larger in size than the corresponding and contiguous connecting portion.
The following is a detailed description, by way of non-limiting example, of a preferred embodiment of an element for screening fences and a method for realisation thereof, wherein:

figure 1 is a perspective view of an element for screening fences, in accordance with the present invention;
figure 2 is a perspective view of a detail of the element of figure 1, in which covering elements are arranged in a first operating position;
figure 3 is a second perspective view of a detail of the element of figure 1, in which covering elements are arranged in a second operating position;
figure 3 a is the same view as in figure 3, in relation to a first variant;
figure 3b is the same view as in figure 3, in relation to a second variant;
figure 4 is a perspective view of a further variant of an element for screening fences, with a different distribution of openings, in accordance with the present invention;
figure 5 is a schematic illustration of a machine and the relative production method of the element for screening fences of figure 1;
figure 6 is a detailed view of the element of figure 1;
figure 7 is a variant of the view of figure 6; and
figure 8 illustrates the stages of setting up the element 1 produced with the device of figure 5.

With reference to the figures, 1 denotes in its entirety an element for screening fences of the present invention. The element 1 comprises at least a tape-form body 2 provided at least with a plurality of first through-openings (visible in figure 3). The element 1 further comprises a plurality of covering elements 4, each of which is coupled to the tape body 2 at a corresponding opening 3 of the first through-openings 3.
Each covering element 4 is mobile at least between a first operating position (illustrated in detail in figure 2) in which it at least partially covers the corresponding opening 3 and a second operating position (illustrated in detail in figure 3) in which it is displaced with respect to the first operating position. In the invention, the covering elements 4 are displaceable from the first operating position to the second operating position by a gust of wind when the covering element 4 is set up on-site, such as to reduce the resistance of the covering element 1 to the wind. A greater thrust of the wind corresponds to a more greatly-displaced position of the covering elements 4, and a more exposed area of the openings 3, which leads to a lower wind-resistance of the fence. The covering elements 4 are afforded in the tape body 2, each by a through-cut 5 in the tape body 2 itself. The covering elements 4 defined thus consist in effect of mobile tabs made in a single piece with the tape body 2. In particular, the covering elements 4 are defined by the cut defining the corresponding opening 3. The covering elements 4 exhibit a connecting portion 6 with the body 2. The covering elements 4 are made in a single piece with the tape body 2.
The cuts 5 exhibit a greater extension than the connecting portion 6, such as to be able to define the covering elements 4. The extension of the cuts 5 is at least 1.5 times the extension of the corresponding connecting portions 6. The covering elements 4 exhibit substantially complementarily-shaped forms to the shapes of the corresponding openings 3 at which they are coupled to the tape body 2.
As can be seen in figure 2, the covering elements 4 in the first operating position substantially completely close the corresponding through-openings 3 at which they are coupled to the tape body 2. The covering elements 4 are substantially coplanar with the tape body 2 in the first operating position and are inclined in the second operating position with respect to the tape body 2. Of importance is the fact that in practice the covering elements 4 can be partially displaced with respect to the coplanar position with the tape body 2, for example due to the properties of the material the tape body 2 is made of.
The covering elements 4 reveal corresponding openings 3 more greatly in the first operating position than in the second operating position. The covering elements are displaceable among a plurality of distinct operating positions, not illustrated in detail in the figures.
In an alternative embodiment (not illustrated) the covering elements 4 could be made independently of the tape body 2 and be applied at the portion 6 to the tape body 2 at the first openings 3. This solution however leads to greater costs and production times with respect to the first above-illustrated solution.
The tape body 2 can be made of a plastic material, but could also be realised in other materials that are appropriate for the purpose. The openings 3 and the tilting covering elements 4 made in the tape body 2 facilitate external use of the fencing element 1 without its being necessary to provide a reinforcing structure in order for it to resist the action of the wind, as the covering elements 4 displace at the passage of the breeze, thus defining windows which can guarantee a lower resistance to the wind.
The tape body 2 can be provided with a plurality of additional second through-openings 7 (for example holes) which are not covered. The second through-openings 7 can be defined by small-diameter holes (such as not to allow vision of the delimited area) and can enable a further reduction in wind-resistance of the fencing element 1. The dimensions and shapes of the openings made in the tape body 2, as well as the weight of the body 2 itself can be varied such as to obtain a product having different characteristics and fields of application.
Of significance is the fact that the invention is very flexible and adaptable to the various needs. For example, the capacity of the covering elements 4 to bend under the thrust of the wind can be varied by changing the extension of the connecting portions 6, as the smaller the length of the connecting portion 6 the more easily the covering elements 4 can bend (as illustrated for example in the first variant of figure 3a in which the connecting portions 6 are shorter than those of figure 3). Also, the connecting portion 6 can be perforated in order to further reduce the thrust required for bending the covering elements 4.
It is also worthy of note that it is possible to vary the extension surface of each covering element 4 in order to vary the thrust necessary for bending the elements 4. The greater the extension of each covering element 4, the greater the overall thrust exerted by the wind on the element 4 will be.
Further, the shape of the covering elements 4 can be any, according to requirements (see for example the second variant of figure 3b).
It is also possible to vary the overall resistance of the element for screening fences by changing the overall number of covering elements 4 and corresponding openings 3 provided in the fencing element.
The invention further relates to a method for realising an element for screening fences comprising at least the stages of providing a tape body 2 and coupling a plurality of covering elements 4 to the tape body 2 at a plurality of first openings 3 of the tape body 2 such that the covering elements 4 are mobile at least between a first operating position in which they at least partially cover the corresponding first openings 3 and a second operating position which is displaced with respect to the first operating position. The stage of coupling a plurality of covering elements 4 to the tape body 2 is performed by realising the covering elements 4 directly on the tape body 2 by means of a stage of realising the through-cuts 5 of the tape body 2, such that the cuts define the first through-openings 3 and the covering elements 4 at the same time.
Observing figure 5 in particular, a schematic illustration of a machine for producing a screening fence element is provided, according to what has been described herein above.
In particular, the plastic material defining the whole structure of the screening fence element is brought to the molten stage and then extruded by means of an extruding head 9. Figure 5 schematically represents a linear extruding head 9 which shows the tape body 2 already in its flat form in output.
Alternatively rotary extruding heads can be used, giving a tubular product made of plastic which is then cut along the extruding direction and flattened such as to reach exactly the flat configuration illustrated in figure 5, immediately downstream of the extruding head.
In particular, the material exits the extruding head 9 along an extrusion direction denoted in the figures with the arrow MD.
The material used will usually be a thermoplastic polymer.
Preferably the polymer will be polyethylene and in general a high-density polyethylene, with an appropriate addition of colorants, for example in order to give it the typical orange colour used for work-site fencing, and for example with inclusion of further additives such as UV protection agents.
Note that the tape body 2 in exit from the extruding head can already be provided with the second openings 7.
Alternatively the second openings 7 can also be made after the extrusion stage, for example during the stage of realising the through-holes or also at different times, with separate devices.
In general, the second through-holes 7, typically though not necessarily circular-shaped (slightly irregular if realised during the extrusion stage with the material still in the plastic state) are used for guiding the tape body 2 in the movement along the extrusion direction MD.
In still other terms, the second through-holes 7 constitute the reference that guarantees the correct positioning of the tape body 2 during the stages of movement on the production machine.
On this subject, and merely by way of example, the second openings 7 can be arranged along a predetermined number of rows 13, 14 that are substantially parallel to the extrusion direction MD.
From the point of view of distribution, too, the through-holes 7 can be equidistanced or not, according to needs, without forsaking the inventive concept of the present invention.
A cutter 10 is located downstream of the extruding head 9, for realising the plurality of through-holes 5 which define the first openings 3 and the covering elements 4.
As can also be seen from figure 5, there exists a very precise arrangement relation of the covering elements 4 with respect to the extrusion direction MD. In general, in the cutting operation, covering elements 4 are defined which develop substantially entirely in a transversal direction TD with respect to the extrusion direction MD.
Looking in particular at figure 6, it can be seen how the covering element 4 exhibits a transversal prevalent development direction, which is substantially perpendicular to the extrusion direction MD.
In particular, the covering element illustrated in figure 6 is symmetrical with respect to the prevalent development direction 8.
Generally speaking, the covering element 4 is joined to the tape body 2 along at least the connecting portion 6 and at least a portion 4a of the covering element 4 develops in a direction TD which is transversal to the extrusion direction MD and external of the extension of the dimension 11 of the connecting portion 6 in the extrusion direction MD.
This situation is clearly illustrated in figure 7, where the extrusion direction MD and the transversal direction TV thereto have been indicated.
The covering element 4 represented exhibits a connecting portion 6 which is slightly inclined with respect to the extrusion direction MD and the dimension 11 has been illustrated with an area of grey background which the connecting portion identifies along the extrusion direction MD.
As can be seen, the covering element 4 is arranged at least partly externally of the dimension 11.
In general, the portion 4a external of the dimension 11 will be greater than the portion 4b internal of the dimension 11 and in general at least twice larger in terms of surface.
The foregoing determines in general terms that the connecting portion 6 is positioned during use superiorly of the furthest free portion of the covering element 4 which is thus maintained in a closed position by its own weight once the screening fence element is set up in working position.
In still other terms, it is extremely relevant that covering elements 4 can be realised which in the absence of wind are maintained in the closed position, or the substantially closed position, thanks to their own weight.
Further, and as will be clarified herein below, this orientation is also extremely advantageous in the stage of packing the roll 15 constituted by the tape body 2 wound about an axis 12.
A different orientation of the covering elements 4 from the one illustrated in figure 5, i.e. a configuration of the covering elements 4 in such a way as to present a prevalent axis of development parallel to the extrusion direction MD would lead to the opening of the tabs themselves if the tape body 2 were rolled; this would lead to problems in correcting predisposition and positioning of the roll 15 itself.
Note also how the connecting portion 6 extends generally substantially parallel to the extrusion direction MD (see figure 6) or in any case is slightly inclined with respect thereto (see figure 7).
In general, the angle of inclination with respect to the extrusion direction MD will less than 30% and preferably less than 15°.
A further important characteristic is the presence of the cuts 5 having an extension (perimeter) of at least 2.5 times, and usually at least 3 times the extension of the connecting portion 6.
Because of the plastic material used (thermoplastic polymer, in particular polyethylene) it is necessary to give the covering element particular geometric characteristics such as to enable them to be opened in the presence of wind.
The extension of the perimeter is one of the characteristics to be taken account of. The present of a semi-circular opening or in any case an opening having a perimeter which is at least 2.5 times the length of the connecting portion determines a not-easy opening of the openings 3 and a good level of resistance even in the presence of wind.
Obviously the maximum distance of the cut with respect to the connecting portion 6 is also of considerable importance.
In fact, the dynamic pressure exerted by the wind generates a torque about the hinge defined by the connecting portion 6.
It is clear that the zones of areas further from the connecting portion 6 are those which, given a same dynamic pressure, develop a greater torque.
Further, the length 1 of the connecting portion 6 determines an effective resistance to the opening of the covering element 4.
In other terms, at least a zone of the cut 5 defining the covering element 4 must exhibit a distance d from the connecting portion which is greater than 1/2 and in particular at least 0.81.
Preferably this distance d will be at least 1 (see once more figures 6 and 7). Obviously also the surface or area of the covering element 4 has an importance to the ability thereof to open in the presence of wind of the other tabs.
The covering element must in general define an area of surface which is at least 1.5 times the length predefined by the connecting portion 6 squared. In other words, the ratio must be at least A>1.5·1².
Looking once more at figure 5, in the production process the tape body 2 is cooled and thus can be wound in a roll 15 about a winding axis 12 up to the desired dimensions of the roll 15.
At this point a transversal cut is made and a new roll is commenced.
Thus the fencing element in the final realisation thereof is constituted exclusively by a sheet made of an extruded plastic material wound in a roll and exhibiting cuts 5 on its surface.
In general, in terms of weight per unit of length, it is more than 200 grams per square metre and in particular more than 650 grams per square metre in order to guarantee minimum resistance performance levels in the face of atmospheric agents once set up in the worksite.
The procedure for setting up the fencing element comprises predisposing the roll 15, still wound up, and then constraining a most-external first portion 16 of the tape body 2 to a first support 17, for example by means of constraining elements 18 such as strings or bands passing through the first or second openings 3, 7. As can be seen in figure 8, the roll 15 is unwound about the winding axis such as to be able to fence-in a predetermined area 19.
A further portion 20 of the tape body is constrained to a further support 21 and the stages are gradually repeated up until they completely conceal the area 19 of interest.
Note in particular that by its nature the tape body can be positioned following any path and in particular areas that are not flat and/straight.
Obviously the length L of the roll will be a number of times the height H thereof.
In general the length L of the roll will be at least 10 times the height H, in particular it will be between 20 and 70 times the height H of the roll.
Purely by way of non-limiting example, the height of the tape body 2 can be comprised between 1 and 2 metres, while the lengths can be any as the length coincides with the extrusion direction.
Standard lengths will generally be comprised between 30 and 50 metres.
The present invention provides important advantages. Firstly, the above-described element enables problems encountered in the prior art to be solved. In particular, a screening fence element of the invention is able to provide high screening capacity while at the same time offering only a low resistance to wind. In particular, a fencing element of the invention does not require a reinforcing structure for resisting the action of the wind. An element of the invention can offer a complete coverage of the delimited area and is light, easy to handle and to apply. A fencing realised as in the invention is economical and is very easy to set up in the worksite.
With the present invention a fenced perimeter can be completely screened with a much lighter product that is easier to handle with respect to wooden panels or aluminium alloy panels of known type. The fencing element of the element, for example orange in colour, can be used to delimit work-site areas where the complete screening of the working area is required.
The device of the invention is also simple and economical to realise, and the method for realising the screening fence elements of the invention is simple, rapid and economical.

Claims

A method for realising an element for screening fences, comprising at least a tape body (2) provided with at least a plurality of first through-openings (3) and a plurality of covering elements (4), each of which is coupled to the tape body (2) at a corresponding opening (3) of the through-openings (3) and is mobile at least between a first operating position in which it at least partially covers the corresponding opening (3) of the first through-openings (3) and a second operating position in which it is displaced with respect to the first position and in which it covers the corresponding opening (3) less than in the first operating position, the method comprising following stages:
extruding the tape body (2) made of plastic material along an extrusion direction (MD), by means of an extruding head (9);

realising a plurality of through-cuts (5) for defining the first openings (3) and the covering elements (4).
The method of the preceding claim, wherein the covering element (4) is joined to the tape body along at least a connecting portion (6), the stage of realising the through-cuts (5) determining at least a portion (4a) of the covering element (4) which portion (4a) develops in a transversal direction (TD) to the extrusion direction (MD) and externally of a dimension (11) of the connecting portion (6) in the extrusion direction (MD).
The method of one of the preceding claims, wherein the stage of realising the cuts (5) defines a connecting portion (6) which extends substantially parallel to the extrusion direction (MD).
The method of one or the preceding claims, wherein the stage of realising the cut defines a cut (5) having an extension which is at least 2.5 times, and in particular at least 3 times greater than an extension of the connecting portion (6).
The method of one or more of the preceding claims, wherein the stage of realising a plurality of cuts defines a covering element (4) which develops substantially entirely in a transversal direction (TD) with respect to the extrusion direction (MD) and externally of the dimension (11) of the connecting portion (6) in the extrusion direction (MD).
The method of one or more of the preceding claims, wherein the stage of realising the cuts defines a connecting portion (6) exhibiting a predefined length (1), the covering element (4) having a surface area which is at least 1.5 times the predefined length (1) of the connecting portion squared: A≥1.5·1²
The method of one or more of the preceding claims, wherein the connecting portion exhibits a predefined length (1), at least a zone (22) of the cut (5) defining the covering element (4) having a distance (d) from the connecting portion which is greater than ½*1 and in particular which is at least 0.8*1 and still more in particular is 1.
The method of any one of the preceding claims, wherein the covering element (4) exhibits a transversal prevalent development direction (8), in particular substantially perpendicular to the extrusion direction (MD).
The method of any one of the preceding claims, comprising following stages:
perforating the tape body in order to fashion a plurality of second through-openings (7); and

guiding the tape body (2) in the movement along the extrusion direction (MD), by using the reference determined by the second openings (7), in particular the second openings (7) being arranged along a predetermined number of rows (13, 14) which are substantially parallel to the extrusion direction (MD); and

in particular winding the tape body (2) in a roll about a winding axis (12) that is perpendicular to the extrusion direction in order to define a roll (15).
An element for screening fences comprising at least a tape body (2) provided at least with a plurality of first through-openings (3) and a plurality of covering elements (4), each of which is coupled to the tape body (2) at a corresponding opening (3) of the first through-openings (3) and is mobile at least between a first operating position in which it at least partially covers the corresponding opening (3) and a second operating position which is displaced with respect to the first position and in which it covers the corresponding opening (3) less than in the first operating position, the tape body exhibiting a height (H) along a transversal axis which is defined between two parallel opposite sides (22, 23) and a length (L) along a prevalent development axis (24), characterised in that the length (L) is at least 10 times greater than the height (H) and in particular it is comprised between 20 and, for example 70, times the height (H).
The element of the preceding claim, wherein the tape body (2) is entirely made of a plastic polymer being polyethylene and in particular high-density polyethylene, the tape body exhibiting a weight per unit of length which is greater than 200 grams per square metre and in particular is greater than 350 grams per square metre.
The element of claim 10 or 11, wherein the covering element (4) is joined to the tape body along at least a connecting portion (6), at least a portion (4a) of the covering element (4) developing in the height direction (H) of the tape body (2) externally of the dimension (11) of the connecting portion (6) in a direction of the length (1) thereof.
The element of any one of claims from 10 to 12, wherein the cut (5) has an extension of at least 2.5, and in particular at least 3 times the extension of the connecting portion (6), in particular the connecting portion exhibiting a predefined length (1) and at least a zone (22) of the cut (5), defining the covering element (4), exhibiting a distance (d) from the connecting portion (6) which is greater than ½*1, and in particular at least 0.8*1 and more in particular 1, the covering element (4) optionally defining a surface area (A) of at least 1.5 times the predefined length (1) of the connecting portion squared: A≥1.5·1²
The element of any one of claims from 10 to 13, wherein the covering element (4) exhibits a transversal prevalent development direction (8), and in particular perpendicular to the prevalent development direction (24) of the tape body (2), the covering element (4) optionally developing entirely in the direction of the height (H) and externally of the dimension (11) of the connecting portion (6) along the prevalent development axis.
A process for setting up an element for screening fences, as in any one of claims from 10 to 14, comprising stages of:
predisposing a roll (15) constituted by a tape body (2) wound in a roll;

constraining a first portion (16) of the tape body (2), which first portion (16) is most external of the roll, to a first support (17), for example by means of a constraining element (18) such as strings or bands passing through the first and/or second opening (3, 7);

unwinding the tape body from the roll (15) along the winding axis (12) in order

to fence off a predetermined area (19);

constraining at least a further portion (20) of the tape body (2) to a further support (21) for defining a perimeter positioning of the tape body (2) about the area (19) to be fenced off, with a non-flat progression and in particular a curved progression along the prevalent development direction (24) of the tape body.