EP0039371B1 - Surveillance device for the field behind a security fence - Google Patents

Description

The invention relates to an after-field protection for a security fence as described in the preamble of claim 1.

According to the prior art, all physically evaluable detection options are used. The multitude of possibilities are detections, which do not work mechanically wired but in the area of the low to high frequency basis. All of these detections from sound to laser light can also be triggered by other events that are not caused by an intelligent perpetrator. The so-called filtering out of objects of smaller sizes than a human body can be described as questionable. In the past, a purely electro-mechanical system failed due to a whole series of problems that were technically impossible or realizable at the time.

In GB-PS-978 051 some theoretical possibilities have been shown, which however are not technically applicable. A resistance wire as the core of the wire for the braid was indicated, but not the problems with the temperature drift when used outdoors (day - night, summer - winter etc.). The problems of braid production, the many connections required in known production processes for braids and their tightness against water and earth moisture were also not solved and no ways of doing so were also shown.

From EP-A-0 004 048 an arrangement for post-field protection for a security fence made of security wire is known, where the security wire consists of a resistance wire, which is provided with a shield made of metal mesh and a plastic sheathing arranged above it.

Avoiding false alarms is a top priority for anyone concerned with security issues. Every false alarm seriously questions the suitability of a security system.

It is therefore the object of the invention to avoid false alarms which can be caused by temperature fluctuations.

• Fig. 1 zeigt einen Sicherheitsdraht, wie er für die Geflechtsmatten verwendet wird.
• Fig. 2 zeigt eine Schaltungsanordnung für den Sicherheitsdraht.
• Fig. 3 zeigt eine Brückenschaltung.
• Fig. 4 stellt einen Auslegeschalter dar.
• Fig. 5 zeigt die Form des Zaunes.
• Fig. 6 zeigt die Nachfeldsicherung.
• Fig. 7 stellt eine Geflechtsmatte dar.

The object is solved by the features of claim 1. The invention will now be explained with reference to the drawings.

• Fig. 1 shows a safety wire as it is used for the mesh mats.
• Fig. 2 shows a circuit arrangement for the safety wire.
• Fig. 3 shows a bridge circuit.
• Fig. 4 shows a delivery switch.
• Fig. 5 shows the shape of the fence.
• 6 shows the post-field protection.
• Fig. 7 shows a mesh mat.

A safety wire according to FIG. 1 is used for the production of a fence mesh. This safety wire contains in the core protected by a steel armor two resistance and two copper wires externally of the same dimension and nature, which is connected according to a circuit arrangement according to FIG. 2 to a bridge circuit suitable for safety purposes according to DE-OS-2 834 957 according to FIG. 3 . The two resistance wires A1 and A2 contained in the safety wire each represent a bridge branch of the bridge circuit. This automatically compensates for the change due to the outside temperature, since both bridge branches change at the same time and the bridge therefore always remains in balance. The two resistance wires are connected in opposite directions with the aid of the two copper wires B1 and B2 in accordance with the circuit arrangement with FIG. 2, so that a bridging attempt in any case immediately leads to an alarm.

To protect against climbing over the fence is in the upper third of the fence post E in Fig. 4, a spring-loaded switch A, B, C, D according to DE-OS-2 717 906, which triggers a magnetic switch D in the event of lateral or vertical loading. This release takes place with lever arm (arm) A over the tipping edge B and stylus with return spring C.

To protect against crawling under, the braid is buried (streams can also be protected) according to Fig. 5. The post-field protection required for objects of the highest security requirement (currently 5 m) is made with a braid made of the above-described security wire according to Fig. 6, which according to a special braiding process as well as all other fencing is braided in an endless process and therefore only has to be connected via a connection at the beginning and end of the respective mat.

This braid (Fig. 7) is angled from the outer fence A via a spring D against the point G, which can also be designed as a second fence. The pull rope or pull rod F is mechanically connected from the center of the braid E to the bracket C. As a result, in the event of vertical loading by a perpetrator, the boom switch B mounted in the post A is actuated and the alarm is triggered.

The entire system is simple, easy to manufacture and operate, and error-free with good workmanship.

Claims (4)

1. Secondary-field fuse designed to be used for a safety fence as a safety wire in endless braiding matting with said safety wire being comprised of a resistance wire which is enclosed by a metal braiding and a plastic sheathing being arranged above thereof and being comprised of a bridge circuit, which is suitable as alarm device, characterized by using a safety wire having one core and comprising two resistance wires (A1, A2) and two copper wires (B1, B2) of equal size and equal external quality to manufacture the endless braiding matting.

2. Secondary-field fuse pursuant to claim 1, characterized by the endless braiding made of safety wiring being spring-suspended from the external fence in oblique arrangement towards the inner section down to ground level.

3. Secondary-field fuse pursuant to claim 1 or 2, characterized by the alarm being triggered under vertical load being imposed on said oblique braiding via a traction rope or traction rod from said endless braiding matting via a bracket arm to a switch (bracket arm switch) being mounted in the upper top third of a fence post.

4. Secondary-field fuse pursuant to one or more claims of 1 to 3, characterized by the resistance wires (A1, A2) contained in said safety wire being connected via said copper wires (B1, B2) counterclockwise preferably to the bridge circuit considered suitable as alarm device.

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