NZ514880A

NZ514880A - Coupling apparatus and method

Info

Publication number: NZ514880A
Application number: NZ514880A
Authority: NZ
Inventors: Paul Anthony Brown; Brian Summerscales
Original assignee: Nor
Priority date: 1999-04-01
Filing date: 2000-03-29
Publication date: 2003-05-30
Also published as: JP2002541638A; CA2368443A1; HK1043484A1; GB2363529A; WO2000060701A1; GB0124697D0; AU3567000A; EP1173901A1

Abstract

The coupling apparatus is for fitting to a conductor or cable. In particular, it refers to high frequency coupling apparatus suitable for telecommunications signals propagated, at least in part, along conventional power distribution cables. Accordingly, in a first aspect, there is a coupling apparatus suitable for coupling with an electricity cable (2), where the cable includes an electrically insulated conducting member (1), where the coupling apparatus includes cable insulation penetration means (3) for penetrating the electricity cable to provide an electrical connection to the conducting member, the penetration means (3) being electrically connected to a coupling member (5) suitable for connection to a telecommunications signal source or receiver. In this way, a coupling member suitable for connection to a telecommunications signal source or receiver may be electrically connected to the conducting core of a power cable or other type of conductor.

Description

PCT/GBOO/OH96 1 COUPLING APPARATUS AND METHOD The preserv: invention relates to coupling apparatus for fitting to a conductor or cable. In particular, it 5 refers to high frequency coupling apparatus suitable for telecommunications signals propagated, at least in part, along conventional power distribution cables.

The transfer of communication signals along electricity 10 distributi m and/or transmission networks is a promising developmen: in the telecommunications industry. The communication signals may be transferred even whilst the power cabl ;s/conductors are energized.

Various technical aspects of systems whereby telecommunications signals can be conveyed along an electricity distribution and/or transmission network are disclosed :.n published patent applications of the present applicant. These applications include the following: 20 W094/09572, W095/29572, W095/29537, W096/07245, W098/19398. the disclosures of which are incorporated herein by reference.

WO 00/60701 PCT/GB00/01196 2 It is desi rable that the coupling of telecommunication signals or to power distribution and/or transmission networks he achieved in a safe, efficient and cost-effective way.

The presert invention aims to provide a method and apparatus ::or effectively coupling communication signals onto and iff an existing, possibly energized, mains electricity distribution and/or transmission network.

Accordinglr, in a first aspect, the present invention provides a coupling apparatus suitable for coupling with an electr. .city cable, where the cable includes an electricalLy insulated conducting member, where the coupling apparatus includes cable insulation penetration means for j enetrating the electricity cable to provide an electrical connection to the conducting member, the penetration means being electrically connected to a coupling member suitable for connection to a telecommunications signal source or receiver.

In this way, a coupling member suitable for connection to WO 00/60701 PCT/GB00/01196 3 a telecommunications signal source or receiver may be electrically connected to the conducting core of a power cable or otier type of conductor.

Thus the csupling device could be retro-fitted to an existing pokier distribution and/or transmission network. To minimize disruption to consumers' power supplies and to avoid t ime-consuming installation, preferably the coupling d«vice should be adapted to'be fitted to, for example, ar: insulated power cable without disconnecting that power cable from the power source, i.e. while the cable is "energized" or live.

The coupli lg member is electrically isolated at low frequencies (e.g. 50/60 Hz or possibly up to 100 or 200 Hz) from tie insulation penetration means using a low frequency jrotection means such as a high pass filter, for exampl; a suitable capacitor. Furthermore, the coupling iru mber may be electrically protected from the cable insulation protection means by, for example a fuse and/or trarsformer, e.g. a balun transformer. 4 The insula-:ion penetration means is adapted to pierce a sleeve of electrical insulation material around the power cable or conductor and hence come into and establish electrical contact with the electrical current carrying part of th« conductor. In this way, the coupling device is suitable for attachment to a power cable or conductor at many different places along the cable or conductor length.

In some ir stances, it might not be desirable for the electronic components to be attached to the cable at all times. Accordingly, in a second aspect, the present invention jrovides a coupling device including a clamp and a clanp head. The clamp includes the insulation penetration means and means for fitting the insulation penetration means to the cable. The clamp head includes a coupling member suitable for connection to a telecommunications signal source or receiver. The coupling member is preferably protected by low frequency protection means such as a high pass filter, for example a suitable capacitor. Furthermore, the coupling member may be ele :trically protected from the cable insulation WO 00/60701 PCT/GB00/01196 penetratic 1 means by, for example, a fuse and/or balun transformer.

In a preferred embodiment of the present invention, one 5 end of the primary winding and/or one end of the secondary binding of the transformer is/are electrically bonded to an earth potential. Furthermore, in another preferred embodiment, one end of both the primary and secondary windings of the transformer are electrically 10 bonded to the same earth potential.

In another preferred embodiment of the present invention, the cable insulation means includes a spike. Additionally or alternatively, this spike may be rigid.

Additiona .ly or alternatively, the spike may be electrica. .ly conducting. Additionally or alternatively, there may be a plurality of spikes, preferably spaced 0.5 - 1.5cm aoart, most preferably around 1cm apart.

Preferably, the present invention includes clamping means for urging the penetration means into the cable the clamping neans may include a screw operated compression 6 member.

Preferably the present invention includes a housing which, in ase, fits around the cable.

In another preferred embodiment of the present invention, the coupling apparatus includes a two part housing, the first part containing the coupling member and the second part containing the penetration means wherein the two 10 parts are releasably joined together. Preferably, the clamping :neans is included in the second part of the housing.

Preferable, the cable insulation penetration means and 15 the coupling member are electrically connected via a conductinj spring.

Embodiments of the present invention will now be described with reference to the accompanying drawings in 20 which Figure 1 is a schematic diagram of a coupling device WO 00/60701 PCT/GBOO/Ol 196 7 according to a first embodiment in which the main internal components are illustrated.

Figure 2 i.; an exploded schematic diagram of a coupling 5 device according to the first embodiment, showing the device in .ts two main component pieces. > Figure 3 is an exploded schematic diagram of a coupling device according to the first embodiment, corresponding 10 to a section viewed in a plane which is perpendicular to the axis o: the cable at the line marked "X-X" in Figure 2.

Figure 4 Is a schematic diagram of a coupling device 15 according to a second embodiment in which the main internal components are illustrated.

Figure 5 js an exploded schematic diagram of a coupling device according to the second embodiment, showing the 20 device in its three main component pieces.

Figure 6a is a side view of a coupling device according 8 to a further embodiment of the present invention; Figure 6b .s an end view of the device of Figure 6a; Figure 7a is a side view of a further embodiment of a coupling device according to the present invention; and Figure 7b Is an end view of the device of Figure 7a.

Figures 1, 2 and 3 show a coupling device according to the first smbodiment of the present invention. The unit consists of two parts 21 and 22, constructed in part using a strong, non-conducting material, which are clamped tightly together using, for example, two screws 15 7. The device is preferably clamped across an insulated power cab:.e 2. The outline of the unit is preferably shaped to fit an insulated cable 2 between the two parts of the coupling device 21 and 22. For example, the outline o:.; the coupling device is concave, as shown in 20 Figure 3. The insulation penetration means preferably includes a rigid conducting spike 3. This spike protrudes a pre-set distance into the concave outline of WO 00/60701 PCT/GB00/01196 9 the unit. The insulation 8 ' is pierced and electrical contact is uade between the rigid conducting spike 3 and the metallic power conductor 1 as the clamping screws 7 are tightered.

The rigid cmducting spike 3 is electrically connected to a circuit 4, schematically shown in Figure 1. This circuit preferentially includes one or more protection devices su>:h as a fuse and a balun transformer. _The circuit further includes a low frequency protection device suet as a high pass filter for the high frequency communication signals, for example a suitable capacitor. The circuit is provided with a coupling member such as a communications signal input/output port, typically a coaxial, mbalanced, high frequency, standard BNC connector !> well known in the art. Preferably, a safety earth is attached via 6 in Figure 1. Additionally or alternatively an isolation capacitor may be included on the "braid'' side of the coaxial connector 5 in order to isolate it from the mains electricity supply in the event of a fault WO 00/60701 PCT/GBOO/Ol 196 In this first embodiment, the circuit 4 is entirely contained within the insulating casing of the device. Therefore, during installation of the coupling device, no ^live' conducting elements are exposed, either on the 5 cable or cn the device itself.

Figures 4 md 5 illustrate a coupling device according to a second e:ibodiment of the present invention. The device is constructed in part using a strong, non-conducting 10 material jnd is made up of three main parts 51, 52 and 53. Main parts 51 and 52 are shaped, for example in a concave sense, so that an insulated cable 31 may fit between ttem in a similar sense to the first embodiment, shown in Figure 3. Parts 51 and 52 may be clamped 15 tightly together using a single screw 40. A rigid conducting spike 34, similar to a spike 3 in the first embodiment, protrudes a pre-set distance into the concave outline o:: part 52. The insulation 42 is pierced and electrical contact is made between the rigid conducting 20 spike 34 and the -metallic power conductor 32 as the clamping screw 40 is tightened.

WO 00/60701 PCT/GB00/01196 11 The rigid conducting spike may be electrically connected to a fuse carrier and link 36 via a conducting spring 35 when the clamp 33, made up using main parts 51 and 52, is attached tc< a clamp head 37 (or 53) via screws 41. The clamp head contains a circuit 36, preferentially including protection devices such as a fuse and a balun transformer. The circuit further includes a low frequency protection device such as a high pass filter for high frequency communication signals and is similar to the ci rcuit 4 described in outline in the first embodiment of the invention. The circuit 3 6 is provided with a coupling member such as a communications signal input/outpit port, typically a coaxial, unbalanced, high frequency, standard BNC connector 38 well known in the art. Preferably, a safety earth is attached via 39.

The second embodiment of the present invention allows the clamp head 53 to be easily removed from the cable clamp 51 and 52 whilst, if desired, leaving the cable clamp 51 and 52 stiLI attached to the cable. The cable clamp may then be covered using a fascia plate. This removes the need to place an insulating sleeve over the puncture hole WO 00/60701 PCT/GB00/01196 12 in the cabLe insulation if it is required to remove the coupling device from the cable at some later date.

The embodi nent of the invention shown in Figures 6a and 5 6b consists principally of a first part 60 of the coupling unit and a saddle 61. As will be seen, the saddle 61 sits on top of the coupling unit part 60. The saddle may, for example, be made of steel and may be around 20 c 30 x 3mm in size including a tapped hole for 10 receipt of a screw 62, with for example a 5mm thread.

In use, ths unit 60 is placed against an insulated cable 63 to a CDnductor of which contact is required to be made. Initially, the saddle lies-against or adjacent the 15 top of the part 60 as shown in Figure 6a. The contacts (not showr) project against the cable 63.

One or moie cable ties 64 (in this embodiment, two ties are used): ecure the unit 60 against the cable 63. In 20 this embociment each of the cable ties 64 is located on a respective side of the screw 62 and also serve to hold the saddle against the unit 60. As will be seen more WO 00/60701 PCT/GB00/01196 13 clearly in Figure 6b, the eye 65 of each cable tie abuts against a square edge 66 of the saddle 61. By contrast, the edge ( 7 of the saddle 61 over which the elongate portion of the cable tie 64 lies is rounded so as to 5 relieve the stress on the cable tie. Also optionally provided are locating notches in the saddle 61 (not shown) whi :h serve to locate the elongate portion of the cable ties 64. In some embodiments, the rounded edges mentioned previously may only be provided in the locating 10 notches.

Once the rable ties have been tightened as much as possible b i hand in the conventional manner, the machine screw 62 nay then be operated (in this case turned 15 clockwise) so that its end moves against the top of the unit 60 an! forces the saddle 61 away from the unit 60.

This acticn serves to drive the electrical connection spikes through the installation cable 63. As will be apparent to the skilled person, means other than the 20 screw 62 miy be provided to perform this same function.

Figures 7 i. and 7b show a further embodiment of the WO 00/60701 PCT/GBOO/01196 14 present imention which is similar to the embodiment of Figures 6a and 6b with the exception that the saddle is omitted. The cable tie locating notches may instead be formed dir »ctly in an upper edge 70 of the unit 71. Means are provided inside the unit 71 (not shown) for moving the tips of the electrical connection spikes in a direction away from the unit 71 so that, in use, the spikes extend further towards the cable 72. These means are operable by, in this example, rotation of a rod head 73 which i: located on the top surface of the unit 71. Naturally other means for operating the spike driving means will be apparent to the skilled person and may be used instead.

In use, the unit 71 is placed adjacent the cable 72 and the cable ;;ies 74 are tightened by hand as previously. The rod 73 (which may be made of nylon of, for example a millimetre diameter) is then operated (e.g. turned clockwise) bo drive the contact spike(s) out of the base of the cousler into the cable thereby tensioning the cable ties and piercing the cable insulation to make contact with the conductor.

WO 00/60701 PCT/GB00/01196 In either jf the embodiments of Figure 6 or Figure 7, or indeed in any of the embodiments described previously, the base 68, 78 of the unit 60, 71 may be shaped differently to that shown in the drawings. In a 5 preferred =mbodiment, the base 68, 78 may be shaped so as to conform more closely to the surface shape of the cable which, in this example, is roughly circular. This enables'tte unit 60, 71 to be more easily located against the cable, Each of the embodiments of the present invention described above may be self supporting in that they are supported only by the cable to which they are clamped. A further embodiment of the invention includes having one 15 or more li gs attached to the clamp devices. In this way, the clamf s themselves may be attached to a suitable surface.

Furthermore, the embodiments described above are also 20 suitable for coupling communications signals to/from cables wi ;h more than one conducting core. In this way, a range of, for example differential, phase to phase, WO 00/60701 PCT/GB00/01196 16 phase to neutral/earth, phase to earth, neutral to earth or polypha >e modes of high frequency signal coupling may be provide!.

As will be appreciated, the above embodiments are given by way of example only and modifications will be apparent to those scilled in the art. -04-2001 30914274.6(29-03-2000) - GB00/01196(29-03-2000) PCT/( CLMS 17

Claims

1. A ccupling apparatus suitable for coupling with an electricity cable, where the cable includes an electrically insulated conducting member, where the coupling apparatus includes cable insulation penetration means for penetrating the electricity cabl * to provide an electrical connection to the cond icting member, the penetration means being electrically connected to a coupling member suitable for connection to a telecommunications signal source or receiver and low frequency protection means for electrically isolating the coupling member at low frequencies from the insulation penetration means.

2. A coupling apparatus according to any one of the above claims including a clamp and a clamp head, where in the clamp includes the insulation penetration means and means for fitting the insulation penetration means to the cable, and the clamp head includes the coupling member. Printed;26-06-2001 AMENDED SHEET I >0914274.6(29-03-2000) - GB00/O1196(29-03-2000) PCT/< CLMS 18

3. A coupling apparatus according to claim 1 or claim 2 including a fuse and/or transformer by which the coup Ling member may be electrically protected from the -able insulation penetration means.

4. A co ipling apparatus according to claim 3 in which one <;nd of the primary winding and/or one end of the secondary winding of the transformer is/are electrically bonded to an earth potential.

5. A coupling according to claim 4 in which one end of both the primary and secondary windings of the trans former are electrically bonded to the same earth potential.

6. A coupling apparatus according to any one of the above claims wherein the cable insulation means includes a spike. 1. A coipling apparatus according to any one of the above claims including clamping means for urging the penetration means into the cable.

Printed:26-06-2001 AMENDED SHEET ,2- 20-04-20011 ie 0914274.6(29-03-2000) - GB00/01196(29-03-2000) PCT/( CLMS 19

8. A coupling apparatus according to any one of the above claims including a housing which, in use, fits around the cable.

9. A co ipling apparatus according to any one of the above claims wherein the cable insulation penetration means and the coupling member are electrically connected via a conducting spring. Printed:26-06-2001 AMENDED SHEET 3i