RELATED APPLICATION

This application claims priority fom Australian Patent Application No.

2010900177, filed on 18 January 2010, the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to ^' a method and apparatus for identifying cables and/or. owners of cables, particularly electrical power cables, and thereby providing a deterrent to theft of such cables.

BACKGROUND

In more recent times, electrical power cables have become desirable targets for thieves on account of the substantial quantity of copper or other metal in such cables. This metal represents significant value, even when sold as scrap metal. As electrical power cables are commonly deployed in remote areas, theft becomes even more attractive. The problem of copper cable theft has become widespread in numerous countries and regions, including South Africa, Russia, South America and the United Kingdom. Existing methods of marking cables for identification purposes comprises the incorporation of identification markings on the exterior surfaces of the cables, which are easily removable.

For these and other reasons, a need exists for improved methods and apparatuses that assist in preventing, reducing or deterring theft of such cables. Another need exists for identifying such cables and/or owners of such cables, particularly when the cables have been illegally removed from overhead and underground installations and are on- sold. 46

- 2 - SUMMARY

An aspect of the present invention provides an elongated carrier comprising a plurality of discrete indicia dispersed in or on the elongated carrier, each of the indicia comprising identification data unreadable by a naked human eye, and a machine- readable identification marker applied substantially homogeneously to the elongated carrier.

Another aspect of the present invention provides a method for producing a polymer monofilament. The method comprises the steps of: combining polymer granules, a plurality of discrete indicia comprising identification data unreadable by a naked human eye, and at least one machine-readable identification marker to produce a master batch; and extruding the master batch to produce the polymer monofilament.

Another aspect of the present invention provides a method for identifying a cable or an owner of a cable having an elongated filament integrated therewith. The method comprises the steps of: detecting presence of a machine-readable identification marker applied substantially homogeneously to the elongated; upon detecting presence of the machine-readable identification marker, locating at least one discrete identification indicia dispersed in or on the elongated filament; and retrieving data from the at least one discrete identification indicia and processing the data to identify the cable or an owner of the cable.

BRIEF DESCRIPTION OF THE DRAWINGS

A small number of embodiments of the present invention are described hereinafter, by way of example only, with reference to the accompanying drawings in which:

Figure 1 is a cross-sectional longitudinal view of an elongated carrier in accordance with an embodiment of the present invention;

Figure 2 is a photograph taken under magnification by an optical microscope of a DataDot polymer microdot; and

Figure 3 is a magnified image of a Holomatrix metallic microdot. DETAILED DESCRIPTION

Embodiments of the present invention provide methods and apparatuses for identifying cables and or owners of cables, thereby providing a deterrent to theft of such cables.

Although certain embodiments are described hereinafter with specific reference to electrical power cables, the present invention is not intended to be limited in this manner. For example, embodiments of the present invention may be useful for other types of cable, including electrical communications cables, wire and rope. Furthermore, embodiments of the present invention may be practised with products other than cables, which may not necessarily exhibit an elongated form. For example, embodiments of the present invention may be incorporated into products such as paper, fibre glass, carbon fibre, textiles (as a . thread), polymer sheets, concrete, and various other composite materials, building materials, objects and labels.

Embodiments of the present invention comprise an elongated carrier or strip that may be integrated with a cable for the purpose of identifying the cable or an owner of the cable. For example, the elongated carrier may be wound together with the cores of an electrical cable, as described in South African Patent Application No. 2009705638, filed in the name of Holomatrix (Pty) Limited on 14 August 2009, the disclosure of which is incorporated herein by reference.

Figure 1 shows an elongated carrier or substrate 110 that comprises a plurality of discrete indicia 120 dispersed in or on the elongated carrier 110. The elongated carrier is long and thin (i.e., long in relation to its width) and embodiments thereof are thus string-like or strand-like in appearance. In certain embodiments, the elongated carrier is flexible, but may alternatively be rigid.

In certain embodiments, the elongated carrier 110 comprises an extruded polymer monofilament, such as is used for high quality fishing lines. Examples of suitable polymer materials for production of the polymer monofilament include: polypropolene, polyethylene (PE), high-density polyethylene (HDPE), polyehylene terephthalate (PET), nylon and other polymers. However, those skilled in the art will appreciate that other suitable materials may alternatively be practised. A typical size of an extruded polymer monofilament as used an embodiment of the present invention is about 0.6mm. Suitable sizes for the extruded polymer monofilament include diameters in the range of 0.1mm to 3.0mm. However, extruded polymer monofilaments of diameters outside this range may also be practised.

The discrete indicia 120 may comprise microdots such as supplied by DataDot Technology (Australia) Pty Ltd of Suite 9, 19 Rodborough Road, Frenchs Forest NSW 2086, Australia (www.datadotdna.com/australia/dtal technology indetail dot.htm). Holomatrix (Pty) Limited of Suite B, 180 Mansfield Road, Berea, Durban 4001, South Africa, and JDS Uniphase Corporation, which provides ceramic microdot equivalents under the brand name "Charms™".

While metallic (e.g., nickel, gold, silver, metalised polymer) or ceramic microdots or indicia are preferred for heat and fire resistance reasons, polymeric and other types of indicia or microdots may alternatively be used. Ceramic microdots, as provided by JDS Umphase Corporation, exhibit good fire resistance but are relatively more costly than metallic microdots. For this reason, metallic microdots are generally preferred.

Microdots or similar identification indicia provide a convenient means of recording data for identification purposes. Such data may, for example, comprise a name, a logo, or a substantially unique serial or identification (ID) number. The data may, for example, be in the form of numbers, characters, graphics, barcodes, holograms, or a combination thereof. Metallic microdots are frequently produced in serial number batches. A batch of microdots having the same serial number could thus be used for producing a single section or length of the elongated carrier. The size, form factor, and durability of such microdots make them eminently suitable for incorporating in an extruded monofilament. Furthermore, the microdots can withstand temperatures in excess of 70 degrees Celsius for extended periods of time.

Typical microdot concentrations or distributions in an elongated carrier are in the range of 1 microdot/cm to 10 microdots/cm. However, those skilled in the art will appreciate that other concentrations or distributions outside this range may alternatively be practised. In one particular embodiment, the microdot distribution practised was 1-2 microdots/cm. Figure 2 shows a magnified image of a DataDot polymer microdot 210. As can be seen from Figure 2, the microdot 210 comprises a disc, laser-etched with multiple lines of code or text. In certain instances, a unique code may be used for each item the microdots are to be applied to and stored on a verification database. In other instances the microdot may simply carry an identifier of the item, or an owner of the item.

Figure 3 shows a magnified image of a Holomatrix metallic microdot 310. As can be seen from Figure 3, the microdot 310 comprises a disc, laser-etched with multiple lines of code or text. In certain instances, a unique code may be used for each item the microdots are to be applied to and stored on a verification database. In other instances the microdot may simply carry an identifier of the item, or an owner of the item.

Metallic microdots typically range in diameter from 0.05mm to 3.0mm. Microdots used in one specific embodiment had a nominal diameter of 0.3mm and were incorporated into a monofilament of diameter about 0.6mm.

On account of the size of the indicia or microdots, the identification data recorded thereon is generally not readable with the naked human eye. However, optical magnification to retrieve the identification data may be performed in numerous known ways. For example, optical magnification may be performed using a jewel's loop, a magnifying glass, a camera having a macro lens, a microscope (including disposable microscopes and LCD microscopes). Alternatively, and particularly in the case of barcodes and holographic data, a laser beam may be used to read or project the data off the identification indicia or microdots. Optical character recognition and other known machine reading techniques may be practised to automate or partially automate retrieval of the data and consequent identification. The elongated carrier 110 preferably further comprises at least one machine- readable identification marker which may be applied substantially homogeneously to the elongated carrier. Detection of such a machine-readable identification marker enables simplified preliminary identification of a marked cable, without the need for locating and/or retrieving an identification indicia or microdot from the cable. Retrieval of a microdot may, in some instances, require removal using an acid such as hydrochloric acid (HO).

One such identification marker comprises a luminescent marker selected from a group or set of luminescent markers. When activated, the selected luminescent marker is adapted to emit a spectral response that is unique relative to spectral responses emitted by other luminescent markers in the group. The identification marker may be invisible to the naked human eye. The spectral response emitted by the identification marker may also be invisible to the naked human eye.

Such luminescent markers include luminescent or fluorescent dyes that glow when activated or illuminated with light of a particular wavelength or frequency. The marker dye may be selected to glow with a colour that maximizes contrast visible to the human eye relative to the colouring of the particles themselves. Examples of such marker dyes include, but are not limited to the following families of optical brighters: UV-Tex and Tinopal (Manufactured by Ciba), Blankophor (manufactured by Bayer), Leucophor (manufactured by Clariant), and Photine (manufactured by Hickson and Welch), and various materials supplied by DayGlo Color Corporation. The luminescent marker may comprise a spectroscopic marker powder such as

DatatraceDNA powders, which are available from DataTraceDNA Pty Ltd of Suite 9, 19 Rodborough Road, Frenchs Forest NSW 2086, Australia. The DatatraceDNA powders include inorganic ceramic materials that can be individually identified or traced via their spectroscopic signature using a highly sensitive digital electronic scanner (e.g., the DatatraceDNA PI Reader and other readers available from DataTraceDNA Pty Ltd). The DatatraceDNA powders comprise a micro- or nanoparticulate spectroscopic marker material and/or a master batch comprising a micro- or nanoparticulate spectroscopic marker material. A particular spectroscopic marker used in embodiments of the present invention is DATATRACE code #12 powder. The DatatraceDNA powders typically operate in a concentration range of 5ppm to 4%. Concentrations of the DatatraceDNA in a polymer monofilament may, for example, be in the range 0.01 to 0.0001

Another identification marker practised in embodiments of the present invention comprises a colour incorporated into the elongated carrier. Colours may be selected from a colour code or library, for example, based on the conventional resistor colour code, which is available at: http://linm.softpedia.com/progScreenshots/Resistor- Color-Code-Calculator-Screenshot-13039.html. A selected colour may be incorporated into the elongated carrier by adding the colour material to a master batch prior to extrusion of the elongated carrier. Multiple monofilaments of different colours may be produced and combined to form a polyfilament having a greater colour coded identification space.

A limited number of luminescent, spectroscopic, and colour identification markers are described hereinbefore. However, those skilled in the art will appreciate that numerous other identification markers may alternatively be used to practise emrx)diments of the present invention. Furthermore, those skilled in the art will appreciate that multiple identification markers may be incorporated in a single elongated carrier, thus extending the identification code space.

The ability to substantially instantly interrogate the elongated carrier using one or more identification markers as described hereinbefore (e.g., a luminescent marker and/or a colour marker) provides a convenient means to rapidly check whether a cable has been stolen (and from whom). If presence of an identification marker indicates the cable is marked, the relevant data can then be retrieved from the indicia or microdots. A new reader currently under development (the DatatraceDNA CBDR-1 reader) identifies or reads both luminescent markers and colour markers, thus providing a compounded and much larger identification code space. More sophisticated versions of the reader apparatus can also provide additional information, including: date and time, GPS co-ordinates, photographic images, number of reads, etc. Such information is useful for providing evidence when a stolen cable is identified.

A polymer monofilament in accordance with an embodiment of the present invention may be produced by combining suitable polymer granules, a plurality of the discrete identification indicia (e.g., microdots), and at least one machine-readable identification marker to produce a master batch. The master batch is then extruded at a desired diameter to produce the polymer monofilament. The polymer granules may be coated with an adhesion promoter to aid adhesion of the indicia to the polymer granules.

In another embodiment, a polymer monofilament may be produced by combining suitable polymer granules and a plurality of the discrete identification indicia (e.g., microdots) to produce a master batch.

In another embodiment, suitable polymer granules may be combined with one of a plurality of discrete identification indicia (e.g., microdots) and at least one machine- readable identification marker to produce an intermediate master batch. The remaining component may be added to the intermediate master batch and extruded to produce the polymer monofilament.

The term 'master batch ¹ is generally used to denote a concentrate of some type, typically a colorant or a process aid, which may subsequently be diluted or 'let down' to create a final polymer material, which is then subjected to extrusion or moulding.

Information concerning cables and ownership thereof may be stored in a cable database and made available to relevant parties such as authorities (e.g, police departments, regional councils and electricity utilities) and recycling facilities.

The foregoing description provides exemplary embodiments only, and is not intended to limit the scope, applicability or configurations of the invention. Rather, the description of the exemplary embodiments provides those skilled in the art with enabling descriptions for implementing an embodiment of the invention. Various changes may be made in the function and arrangement of elements without departing from the spirit and scope of the invention as set forth in the claims hereinafter.