GB2300206A

GB2300206A - Electric fencing element for concertina fencing

Info

Publication number: GB2300206A
Application number: GB9608751A
Authority: GB
Inventors: Yvon Perrot; Roland Gauthier; Bruno Jacob
Original assignee: Societe dEetudes et de Realisation de Protection Electronique Informatique Electronique Securite Maritime SERPE IESM SA
Current assignee: Societe dEetudes et de Realisation de Protection Electronique Informatique Electronique Securite Maritime SERPE IESM SA
Priority date: 1995-04-27
Filing date: 1996-04-26
Publication date: 1996-10-30
Also published as: FR2733624A1; FR2733624B1; GB9608751D0

Abstract

An element (C) intended to form coils of a barbed concertina fence comprising: an inner electrical conductor (1), an insulating sheath (2) surrounding the conductor (1), metal wires (3a), which may be braided, forming a protective layer around the insulating sheath (2) and an outer casing (4). The outer casing (4) is formed from a strip and has punch-outs or cut-outs defining outwardly projecting fins intended to injure any person tampering with the element. The metal wires (3a) may be replaced by a longitudinally split metal casing with lips nipped or welded together. Two such elements can be interconnected physically and electrically by a connector device.

Description

ELEMENT FOR USE IN THE MANUFACTURE OF ELECTRIC FENCING AND CONCERTINA TYPE FENCING UTILIZING SUCH ELEMENTS The invention relates to an element for use in the manufacture of electric fencing. It also relates to any concertina type fencing utilizing such elements.

The advantages of such fences are well known. They usually have a fairly high deterrent effect. However, they are not always easy to install, and often fail to present a sufficient obstacle to the determined intruder, provided he takes certain precautions, even if the fencing is electrified.

Some such systems have already been described. For example, a British patent GB 2215923 published on 182.h October 1989 in the name of COCHRANE PRODUCTS LIMITED describes the use of a concertina which is actually made up of two concentric spirals, an "outer" spiral consisting of steel barbed wire, and an "inner" spiral consisting of an electrical conductor. These two spirals are interconnected by a series of connections which insulate them electrically.

While this construction allows great flexibility in installation, it is a relatively low deterrent to a determined intruder, as he can cut each of the spirals.

Another construction is described in the American patent US 4818972 of MAINIERO ET AL., granted on 4th April 1989. In its most elaborate version, this consists of a spiral in the form of an open-section tube externally provided with fins designed to ward off the intruder by posing a risk of injury and containing, in the axis of the tube, an electrical conductor insulated from the wall of the tube by a first layer of insulating material and by a second layer of a vibrationsensitive electrical coaxial cable. Such a combination does allow effective monitoring by any break or impact detector if the fence is breached but, as in the previous example, the size of the conductor means that it is not difficult enough to cut to provide a sufficient deterrent.

Further shortcomings include the mechanical properties of the assembly in terms of strength and stiffness, and also the difficulty of linking different coils of barbed wire together.

The object of the present invention is to remedy these shortcomings, and the invention relates to a new cable for electrified concertina fencing combining the properties of mechanical and electrical security while remaining easy to form into concertina type fencing.

More particularly it relates to an element for use in the manufacture of electric fencing consisting of an outer casing with an open round or rounded section bounding a cavity and made from a strip with punched or cut fins intended to injure intruders, characterised in that the said cavity contains an electrical conductor axially arranged in the cavity and a steel casing, the conductor being insulated from the said casing by an insulating sheath, the element being intended for form spiral coils.

The invention will be more easily understood from the descriptions which will now follow and from the attached drawings, in which: - Figure 1 is a view in elevation of a first embodiment of an element according to the invention, partly bared in order to assist the description; - Figure 2 is a section on AA in Figure 1; - Figure 3 shows a section of another embodiment of the invention; - Figures 4 and 5 illustrate schematically a concertina type fence made with elements according to the invention.

For greater clarity, the same elements carry the same reference numbers in the figures.

As shown in Figures 1 and 2, an element according to the invention which will be referred to as cable C in the remainder of the description and which is intended to form a concertina type fence is constituted by a central electrical conductor 1 surrounded by an insulating sheath 2. A metal casing 3, which in the example described consists of a braid 3a, surrounds the conductor 1 and its sheath 2, the whole assembly being contained in an outer casing 4. This outer casing 4is formed from a strip and has an open round-section cavity 5 containing the assembly 1, 2, 3 defined above. This casing 4 is provided over its entire length with punched cutouts forming fins 6 which are sharp-pointed enough to deter anyone contemplating an unauthorized breach.

Figure 3 illustrates schematically a second embodiment. The electrical conductor lis covered with its insulating sheath 2 whose metal casing 3 in this case takes the form of a long ltudlnally open tube 3b with lips 6a and 6b closed up for example by nipping or welding. As in the previous example, this assembly is inserted in the outer casing 4 as defined above. The combination, according to the invention, of the metal casing 3, the electrical conductor 1 and its sheath 2, regardless of whether it is in the form of a braid 3a or an open or welded tube 3b, is one of the essential character istics of the invention.Contrary to what happens in the state of the art, and particularly in the patent US 4818972 cited above, this braid 3a or tube 3b forming a metal casing 3 has the advantage of performing a dual function: on the one hand, it gives the assembly of the cable C increased mechanical strength while allowing flexibility, particularly to facilitate coiling, yet, on the other hand, it makes it more difficult for an intruder attempting to sever the assembly.

As shown in Figures 4 and 5, in one of its applications the cable according to the invention is coiled in spirals so that a plurality of such coils form a concertina type fence.

Only two coils n-l and n have been shown in Figure 4, but n may be any number. To provide good electrical and mechanical continuity between the different coils, they are joined together by means of a connection device 100 comprising a leading connector 10, a trailing connector 11 and a body 13 inside which an electrical connection is made between the two conductors concerned. This electrical connection is sealed with a seal (not visible in the figure), while the mechanical connection is made in a conventional manner at each of the connectors 10 and 11.

Whichever of the embodiments described above is adopted, any cutting of the electrical conductor 1 is easily detectable, enabling defensive measures to be triggered in the event of an attempted unauthorized breach of the fence.

Claims

CLAIMS:

1. Element for use in the manufacture of electric fencing consisting of an outer casing with an open round or rounded section bounding a cavity and made from a strip with punch-outs or cut-outs forming fins intended to injure intruders, characterized in that the cavity contains an electrical conductor axially arranged in the cavity and a metal casing, the conductor being insulated from the casing by an insulating sheath.

2. Element according to claim 1, characterized in that the metal casing is in the form of steel braid or wire reinforcement.

3. Element according to claim 1, characterized in that the metal casing is in the form of a longitudinally open tube with lips which are nipped together.

4. Element according to claim 1, characterised in that the metal casing is in the form of a longitudinally open tube with lips which are welded together.

5. Concertina type electric fencing utilizing elements according to any one of claims 1 to 4, characterized in that the fencing is constituted by a plurality of coiled elements which are electrically and mechanically connected to one another by one or more connection devices.

6. Concertina type electric fencing according to claim 5, characterised in that any unauthorized breach comprising cutting of the electrical conductor triggers defensive measures against such attempted unauthorized breach.