EP3541975B1 - Method for producing security structures in a surface element, and surface element - Google Patents

Description

The invention relates to a method for producing security structures in a surface element and surface element.

Such surface elements are generally used to ensure protection against burglary, theft and vandalism. In general, the security structures of the surface element protect against unauthorized access.

An example of such a surface element is a security packaging device, as in the WO 2012/080888 A1 is described. This security packing device essentially consists of a cover intended to protect an object, such as a suitcase or bag, against unauthorized tampering. The cover consists of a cut-resistant textile structure with integrated conductive thread layers. At least two electrically conductive layers are provided, which are separated by an insulating layer. If an attempt is made to cut open the conductive layers will be short-circuited by the impact of the object into the cover, causing an alarm to be triggered.

A major disadvantage of this arrangement is that it has a high weight due to its multi-layer structure.

From the DE 10 2014 115 437 A1 a method for producing security structures in a surface element is known. Using a warp knitting machine or Raschel machine, cut-resistant structures and/or threads forming sensor structures are worked into the planar element as security structures.

One advantage of this method is that with the warp knitting machine or the Raschel machine, both the cut-resistant structure and the sensor structure can be worked into the surface element.

If the planar element has both a cut-resistant structure and a sensor structure, the sensor structures are located on one side of the planar element and the cut-resistant structures are located on the other side of the planar element.

The disadvantage here is that the cut-resistant structures and the sensor structures have to be worked into the planar element in two different, separate machine passes, which undesirably increases the effort involved in producing the planar element.

The WO 03/077692 A1 relates to a sheet having at least two layers or at least two individual elements in different directions, where at least one individual element is a reinforced fiber, and where the individual elements are not woven but are connected indirectly by chemicals or the like.

The DE 10 2015 103 533 A1 relates to a method for producing security structures in a surface element. Using a warp knitting machine or Raschel machine, threads forming security structures are worked into the surface element, which threads also form cut-resistant structures and sensor structures.

The invention is based on the object of providing a method by means of which planar elements with a high, reliable protective function can be produced in an efficient manner while at the same time having a low intrinsic weight.

To solve this problem, the features of the independent claims are provided. Advantageous embodiments and expedient developments are described in the dependent claims.

The invention relates to a method for producing sensor structures and cut-resistant structures on a surface element using a warp knitting machine or Raschel machine. Sensor threads incorporated as a sensor structure and cut-resistant threads as a cut-resistant structure on the same side of the surface element. To produce the sensor structure and the cut-resistant structure, two stitch-forming guide bars are used, so that the sensor threads are connected to one another at their crossing areas by stitch formations with these guide bars. Blocking means are assigned to the laying rails in the areas of the cut-resistant structure, by means of which a mesh formation of the cut-resistant structure is prevented in their crossing areas.

A first advantage of the invention is that the cut-resistant structure and the sensor structure form different, separate structures. In this way, the sensor threads forming the sensor structures and the cut-resistant threads forming the cut-resistant structures can each be optimized separately with regard to their function.

The cut-resistant threads can be optimized in terms of their stability and cut resistance. Irrespective of this, the sensor threads can be optimized so that they can be used to generate easily detectable electrical signals that can be evaluated in a measuring device in order to be able to generate an alarm message or the like if the sensor threads are interrupted.

A further advantage of the invention is that by incorporating the sensor threads and the cut-resistant threads on one side of the surface element, the other side of this surface element remains free and is therefore readily available for other machining processes such as coatings.

Finally, an essential advantage of the invention is that the planar element with the cut-resistant structure and the sensor structure can be produced particularly quickly and efficiently. In particular, it is advantageous that the sensor threads and the cut-resistant threads are worked into the surface element in one operation.

With the incorporation of the cut-resistant structure and the sensor structure in the surface element, a high level of security against unauthorized tampering with this surface element is achieved.

The cut-resistant structure generally provides mechanical protection against the planar element being pierced by objects such as knives or similar sharp-edged objects. The cut-resistant structures are designed in such a way that at most only a local piercing into the planar element is possible, but not a large-area severing of the planar element. Furthermore, a puncture of the surface element with the sensor structure is detected, so that an alarm signal is then generated, for example, which reports the unauthorized intervention in the surface element.

Areas of application of the planar element according to the invention are, for example, tarpaulins for trucks or tents. Another area of application is the wrapping of objects such as suitcases, bags or the like with the surface element according to the invention.

Depending on the application, the planar element can be a textile planar element, in particular a knitted fabric or a woven fabric or a fleece, or a film consisting of plastic or paper.

Advantageously, the sensor threads used are threads which are formed of an electrically conductive material at least on their outer lateral surface.

Since the outer lateral surfaces of the sensor threads consist of electrically conductive materials, sensor threads are conductively connected to one another in crossing areas in which they are in mechanical contact with one another. This creates a two-dimensional structure of conductively connected sensor threads that preferably extends over the entire surface element and enables interruptions to be detected at any point on the surface element, as a result of which interventions in the surface element can be detected with a high level of detection reliability.

According to an advantageous embodiment, the electrically conductive material consists of a metallic material.

In general, the conductive materials can also be formed from carbon fibers and the like.

Particularly advantageously, silver-coated polyamide threads can be used as sensor threads, which are very flexible and pliable and can therefore be easily processed in the warp knitting machine or Raschel machine.

The functional principle of the sensor structure is to apply a defined electrical signal to the sensor threads, in particular by applying a defined voltage. This electrical signal defines an expectation for the error-free state in which all sensor threads are intact. This expectation is checked with the measuring device, in particular by a resistance measurement and/or a high-frequency propagation time measurement and/or possibly also by a current or voltage measurement. If a sensor thread is severed by an object being pushed in, the electrical signal changes, i.e. it deviates from what is expected. This deviation is recorded by the measuring device, whereby an alarm signal or the like is generated in order to signal the intervention.

So that the cut-resistant threads do not impair these measurements with the conductive structure of the sensor threads, cut-resistant threads are used which are formed from an electrically insulating material at least on their outer surface.

This is necessary because the incorporation of the sensor structures and the cut-resistant structures on the same side of the planar element can inevitably cause the sensor threads and cut-resistant threads to cross over.

A cut-resistant thread expediently has a core that is encased in an electrically insulating structure, the electrically insulating structure consisting of a plastic.

The casing can be formed by a coating. In general, the sheathing can also be formed by winding thread-like elements around the core.

In general, the cut-resistant threads are made of a stable, tear-resistant material such as stainless steel, a plastic or a stone fiber.

According to the invention, two guide bars of the warp knitting machine or Raschel machine are used to produce the sensor structure and the cut-resistant structure, with sensor threads and cut-resistant threads being guided in each guide bar.

In this case, sensor threads and cut-resistant threads are guided in an alternating sequence in predetermined hole grids of the laying bar in each laying bar.

These two guide bars are supplemented by another guide bar, which is used to tie off the sensor threads and the cut-resistant threads. With a warp knitting machine or Raschel machine designed in this way, the sensor threads and cut-resistant threads can be worked into the same side of the planar element in just one operation.

Wave-shaped arrangements of the sensor threads and cut-resistant threads are also advantageously generated on the surface element by movements of the laying rails.

A two-dimensional, networked sensor structure is thus created with the sensor threads guided over the two laying rails. A two-dimensional, cross-linked cut-resistant structure is created with the cut-resistant threads guided over the two guide rails.

Depending on the specification of the movement profile of the guide rails, different waveforms of the sensor threads or sensor structures can be generated, such as sinusoidal or zigzag structures.

According to the invention, two stitch-forming laying bars are used to produce the sensor structures and the cut-resistant structures, so that with these laying bars

Sensor threads are connected to each other at their crossing areas by mesh formations.

Since it has been shown that a mere overlapping of sensor threads is not sufficient for a sufficiently conductive connection, the mesh formation of two crossing sensor threads creates a particularly close contact between two sensor threads that extends in several dimensions, creating a reproducible, well conductive connection of the sensor threads becomes. Since the cut-resistant threads are also guided over the same laying rails, a stitch-forming connection would also be created for them. Due to their high stability and tear resistance, however, no stitch formation is possible for them.

Therefore, according to the invention, blocking means are assigned to the laying rails in the areas of the cut-resistant structure, by means of which a mesh formation of the cut-resistant structure is prevented in their crossing areas.

It is thereby achieved that, despite the guidance of the sensor threads and the cut-resistant structures over the same two laying rails, stitches are formed for their connection only for the sensor threads, but not for the cut-resistant threads.

Figur 1:

Schematische Darstellung eines Ausführungsbeispiels des erfindungsgemäßen Flächenelements mit einer Sensorstruktur und einer Schnittfeststruktur.

Figur 2:

Detaildarstellung einer Ausführungsform des Flächenelements mit einer Sensorstruktur und Schnittfeststruktur.

Figur 3:

Schematische Darstellung von Legeschienen einer Vlies-Raschelmaschine zur Herstellung einer Sensorstruktur und einer Schnittfeststruktur auf einem Flächenelement.

Figur 4:

Detaildarstellung einer Legeschiene der Anordnung gemäß Figur 3.

The invention is explained below with reference to the drawings. Show it:

Figure 1:

Schematic representation of an embodiment of the planar element according to the invention with a sensor structure and a cut-resistant structure.

Figure 2:

Detailed representation of an embodiment of the surface element with a sensor structure and a cut-resistant structure.

Figure 3:

Schematic representation of laying rails of a non-woven Raschel machine for the production of a sensor structure and a cut-resistant structure on a surface element.

Figure 4:

Detailed view of a laying bar according to the arrangement figure 3 .

figure 1 shows schematically an embodiment of the planar element 1 according to the invention with a sensor structure and a cut-resistant structure, which are incorporated on the same side of the planar element 1.

The surface element 1 consists of a knitted fabric, woven fabric, fleece or the like.

The sensor structure consists of sensor threads 2a, 2b, which consist of an electrically conductive material at least on their outer surface. In the present case, the sensor threads 2a, 2b are formed by silver-coated polyamide threads.

The cut-resistant structure consists of cut-resistant threads 3a, 3b, which consist of a tear-resistant material. The outer lateral surfaces of the cut-resistant threads 3a, 3b consist of an electrically non-conductive material. In the present case, the cut-resistant structures are made of stainless steel threads that are coated with a plastic layer.

The sensor threads 2a, 2b and the cut-resistant threads 3a, 3b are worked into the planar element 1 using a warp knitting machine or a Raschel machine. In the present case, a fleece Raschel machine is used.

How figure 1 shows, the sensor threads 2a, 2b run wavy along the surface element 1, the wavy shape of both sensor threads 2a, 2b having the same geometries, but offset from one another. In crossing areas 4, the sensor threads 2a, 2b are superimposed. As a result, a two-dimensional networked structure extending over the entire surface element 1 is obtained.

Since the sensor threads 2a, 2b are electrically conductive on their outer lateral surfaces and two sensor threads 2a, 2b are in constant contact in the crossing areas 4, a coherent, electrically conductive network extending over the entire surface element 1 is formed with the sensor threads 2a, 2b. A measuring device, not shown, is connected to this network, with which the electrical resistance is measured. As long as there is no interruption in a sensor filament 2a, 2b, the resistance corresponds to a predetermined desired value. If a sensor thread 2a, 2b is punctured locally by a knife or the like, the electrical resistance changes. The measuring device registers the change in resistance and then generates an alarm message.

How figure 1 furthermore shows, the cut-resistant threads 3a, 3b, like the sensor threads 2a, 2b, run in a wavy manner, the wavy shapes of the cut-resistant threads 3a, 3b corresponding to the wavy shapes, but running offset to them. The cut-resistant threads 3a, 3b also form a two-dimensional network structure extending over the surface element 1, with adjacent cut-resistant threads 3a, 3b being superimposed locally in crossing areas 5. Since the cut-resistant threads 3a, 3b are tear-resistant, it is possible to pierce the surface element 1 locally with a knife or the like. However, the offset structure of the cut-resistant threads 3a, 3b prevents the surface element 1 from being cut open over a large area.

The cut-resistant threads 3a, 3b do overlap with the sensor threads 2a, 2b. However, since the cut-resistant threads 3a, 3b have non-conductive lateral surfaces, the electrical properties of the network structure formed by the sensor threads 2a, 2b are not influenced by the cut-resistant threads 3a, 3b.

figure 2 1 shows a section of a real structure of sensor threads 2a, 2b and cut-resistant threads 3a, 3b on a surface element 1. This structure is periodically continued over the entire surface of the surface element 1.

figure 3 shows an arrangement of laying bars 6, 8, 9 of the non-woven Raschel machine for producing the sensor threads 2a, 2b and cut-resistant threads 3a, 3b according to the embodiment according to FIG figures 1 or 2.

A first laying bar 6 is used to tie the sensor threads 2a, 2b and the cut-resistant threads 3a, 3b on the surface element 1. This laying bar 6 is fully drawn in such that threads 7 are guided through all the holes in the laying bar 6 in order to lay sensor threads 2a, 2b and cut-resistant threads 3a, 3b on the surface element 1 to bind.

Sensor threads 2a, 2b and cut-resistant threads 3a, 3b are guided in two further laying bars 8, 9, with sensor threads 2a, 2b being arranged there alternately in the laying bars 8, 9.

In the guide bar 8, the sensor threads 2a and cut-resistant threads 3b are guided in an alternating arrangement, with a number of N holes in the guide bar 8 being unoccupied between two adjacent sensor threads 2a and cut-resistant threads 3b.

Correspondingly, the sensor threads 2b and the cut-resistant threads 3b are guided in an alternating arrangement in the guide bar 9, with the same number N of holes in the guide bar 9 being unoccupied here between two adjacent sensor threads 2b and cut-resistant threads 3b.

The representation of figure 3 is purely schematic. In particular, the number of holes in the laying rails 6, 8, 9 can be considerably larger.

The sensor threads 2a, 2b and cut-resistant threads 3a, 3b are integrated into the surface element 1 with the laying rails 8, 9. By moving the laying rails 8, 9 in their longitudinal direction (indicated by the double arrows in figure 3 ) During the incorporation process, the wavy structures of the sensor threads 2a, 2b and cut-resistant threads 3a, 3b are generated.

Since the sensor threads 2a and cut-resistant threads 3b are arranged alternately on the guide bar 8 and, furthermore, the sensor threads 2b and cut-resistant threads 3b on the guide bar 9 are offset from the arrangement on the guide bar 8 and are also arranged alternately, the networked sensor structures with the sensor threads 2a, 2b and the crosslinked cut-resistant structures with the cut-resistant structures 3a, 3b, as in particular in figure 2 shown, preserved. Because of the operation of the laying rails 8, 9, the sensor threads 2a, 2b and the cut-resistant threads 3a, 3b are worked into the surface element 1 in one operation with the non-woven Raschel machine.

In the non-woven Raschel machine, according to the invention, stitch-forming laying bars 8, 9 are used, as is the case for the laying bar 8 in FIG figure 4 shown.

How out figure 4 As can be seen, the sensor threads 2a are guided with guide needles 10 provided in holes in the laying bar 8 to compound needles 11 arranged on the non-woven Raschel machine. While the guide bar 8 is moved in the plane of the drawing in the arrangement of FIG. 5, the compound needles move perpendicularly thereto.

With this arrangement, the sensor threads 2a, 2b are connected to one another in the crossing areas 4 by stitch formations effected with the compound needles 11. FIG. The mesh formation of the sensor threads 2a with the sensor threads 2b results in a close, stable physical contact in the crossing areas 4 established between the sensor threads 2a and 2b, whereby a good and stable conductive connection is established between these sensor threads 2a, 2b.

Since the cut-resistant threads 3a, 3b are not suitable for forming such mesh connections due to their high stability and therefore lack of flexibility, blocking means are provided on the laying rails 8, 9 in the areas of the cut-resistant threads 3a, 3b, which blocking means prevent the cut-resistant threads 3a, 3b prevent in the crossing areas 5.

In the present case, the blocking means are formed by small tubes 12, which deflect the cut-resistant threads 3a, 3b in such a way that they do not get into the area of the compound needles 11.

Reference List

(1)

surface element

(2a, 2b)

sensor thread

(3a, 3b)

cut-resistant thread

(4)

crossing area

(5)

crossing area

(6)

laying bar

(7)

thread

(8, 9)

laying bar

(10)

punch needle

(11)

slider needle

(12)

tube

Claims (13)

1. Method for producing sensor structures and cut-resistant structures on a flat element (1) by means of a warp knitting machine or double rib loom, where sensor threads (2a, 2b) as sensor structure and cut-resistant threads (3a, 3b) as cut-resistant structure are worked in on the same side of the flat element (1),
   characterised in that
   for producing the sensor structure and the cut-resistant structure two stitch-forming guide bars (8, 9) are used so that the sensor threads (2a, 2b) are connected together at their intersection areas (4) through stitch formations by these guide bars (8, 9), wherein blocking means by way of which stitch formation of the cut-resistant structure in the intersection areas (5) thereof is precluded are associated with the guide bars (8, 9) in the areas of the cut-resistant structure.
2. Method according to claim 1, characterised in that the sensor threads (2a, 2b) and the cut-resistant threads (3a, 3b) are worked into the flat element (1) in one work step.
3. Method according to one of claims 1 and 2, characterised in that threads which are formed at least at the outer circumferential surface thereof by an electrically conductive material are used as sensor threads (2a, 2b), wherein the electrically conductive material consists of, in particular, a metallic material.
4. Method according to any one of claims 1 to 3, characterised in that threads which are formed at least at the outer circumferential surface thereof by an electrically insulating material are used as cut-resistant threads (3a, 3b), wherein a cut-resistant thread (3a, 3b) comprises, in particular, a core sheathed by an electrically insulating structure.
5. Method according to claim 4, characterised in that the electrically insulating structure consists of a plastics material.
6. Method according to any one of claims 1 to 5, characterised in that for producing the sensor structure and the cut-resistant structure use is made of two guide bars (8, 9) of the warp knitting machine or double rib loom, wherein sensor threads (2a, 2b) and cut-resistant threads (3a, 3b) are guided in each guide bar (8, 9).
7. Method according to claim 6, characterised in that sensor threads (2a, 2b) and cut-resistant threads (3a, 3b) are guided in each guide bar (8, 9) in an alternating sequence in predetermined hole grids of the guide bar (8, 9).
8. Method according to one of claims 6 and 7, characterised in that wave-shaped arrangements of the sensor threads (2a, 2b) and cut-resistant threads (3a, 3b) are generated on the flat element (1) by movements of the guide bars (8, 9).
9. Method according to any one of claims 6 to 8, characterised in that a two-dimensional reticular sensor structure is produced by the sensor threads (2a, 2b) guided over the two guide bars (8, 9) and a two-dimensional reticular cut-resistant structure is produced by the cut-resistant threads (3a, 3b) guided over the two guide bars (8, 9).
10. Method according to any one of claims 1 to 5, characterised in that for producing the sensor structure and the cut-resistant structure four guide bars of the warp knitting machine or double rib loom are used, wherein sensor threads (2a, 2b) are guided in two guide bars and wherein cut-resistant threads (3a, 3b) are guided in two further guide bars.
11. Method according to any one of claims 6 to 10, characterised in that a further guide bar (6) is used for tying off the sensor threads (2a, 2b) and the cut-resistant structure on the flat element (1).
12. Method according to any one of claims 1 to 11, characterised in that a measuring device by means of which a change, which is produced by an interruption of a sensor thread (2a, 2b), in an electrical variable and/or a high-frequency transit time signature is detected is associated with the sensor structure.
13. Flat element (1) with a sensor structure and a cut-resistant structure, wherein sensor threads (2a, 2b) as sensor structure and cut-resistant threads (3a, 3b) as cut-resistant structure are worked in on the same side of the flat element (1) by means of a warp knitting machine or double rib loom, characterised in that the sensor threads (2a, 2b) are connected together at the intersection areas (4) thereof by stitch formations and a stitch formation of the cut-resistant structure was precluded in the intersection regions (5) thereof.

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