GB2275374A

GB2275374A - Cable distribution apparatus

Info

Publication number: GB2275374A
Application number: GB9303358A
Authority: GB
Inventors: Raymond Charles Foss
Original assignee: Bowthorpe PLC
Current assignee: Bowthorpe PLC
Priority date: 1993-02-19
Filing date: 1993-02-19
Publication date: 1994-08-24
Anticipated expiration: 2013-02-19
Also published as: GB9303358D0; GB2275374B

Abstract

A cable distribution apparatus comprises a closure having a base 10 formed with ports 16 for the entry of cables and a tubular cover 30 for fitting to the base. A cylindrical cable distribution tap 40 is mounted co-axially inside the cover 30 with its terminals directed towards the cable entry ports 16. The tap 40 is supported by the cables 43, 44 or by a support member extending to a central, unused entry part of the base 10. A coax cable is split and impedance matched within the tap 40, for TV signals. <IMAGE>

Description

Cable Distribution Apparatus This invention relates to an apparatus for distributing cables, and to a cable distribution tap therefor.

It is common to transmit television signals from a central relay unit to individual subscribers via cables. These cables are of the so-called co-axial type comprising an inner conductor and a cylindrical outer conductor extending coaxially with the inner. The outer conductor acts as an electrical shield for the inner. The cables feeding from the central relay unit divide at various points, and distribute the television signals to different areas or subscribers. A socalled cable distribution tap has to be provided at each point at which the cable divides, These cable distribution taps maintain the characteristic impedance of the cables feeding into and out of the tap, regardless of how many cables are actually connected. Also the cable distribution taps provide an effective electrical shield around the inner conductor of the cable at the point of cable division.

Hitherto, cable distribution taps have comprised a rectangular box-shaped arrangement having a cable input at one end and a cable output the opposite end. Opposite sides of the cable distribution tap are provided with a plurality e.g. eight output terminals for connecting to distribution cables.

Typically these cable distribution taps are housed in rectangular water-proof closures, which may be mounted in chambers in underground cable ducts. The closures have to be made considerably larger than the cable distribution taps in order to accommodate the bending of cables between cable entry ports in the closure and the terminals.

Telephone signals are transmitted from an exchange to subscribers via a twisted pair of copper conductors. However, it. is becoming increasingly more popular to multiplex telephone signals and television signals along existing television distribution cables. A problem with this is that an increased number of cable distribution taps are required. These cable distribution taps each have to be mounted in large rectangular water-proof closures, but often there is insufficient room to mount extra closures in chambers in existing cable ducts. Furthermore, it is undesirable to have to construct large chambers at each point of cable division when installing new systems.

We have now devised a cable distribution apparatus which alleviates the above mentioned problems with the existing types of apparatus.

In accordance with this invention as seen from a first aspect there is provided a cable distribution apparatus comprising a closure having a base provided with a plurality of cable entry ports, a tubular cover for fitting to the base and a cable distribution tap mounted inside the cover and arranged such that its input and output terminals are directed towards said cable entry ports.

Thus, because the terminals are directed towards the cable entry ports of the closure, there is no need to provide a large closure to accommodate bending of the cables inside the closure. These smaller closures can be mounted in a smaller space than existing closures.

Preferably the cable distribution tap comprises a cylindrical casing mounted co-axially inside the cover.

Preferably the cable distribution is provided with its input and output terminals on a lower surface thereof.

Preferably the terminals are arranged on a line which extends concentrically with a line on which said cable entry ports are arranged.

The cable distribution tap may be mounted inside the cover by cables extending through said ports which connect to said terminals. Alternatively a support may be provided which extends between the base of the closure and the cable distribution tap.

Also in accordance with this invention as seen from a second aspect, there is provided a cable distribution tap comprising a cylindrical casing having a plurality of terminals for connecting to input and output cables disposed on one end of the casing.

The circular cable distribution taps can be mounted inside small tubular closures.

Preferably the terminals comprise co-axial terminals, which may be provided with means for locking a plug on the end of a cable to the cable distribution tap.

Preferably the cable distribution tap is arranged for connecting in series with a co-axial cable, a plurality of said terminals being arranged for outputting a portion of a signal carried by said co-axial cable.

Preferably the casing comprises an electrically conductive material which shields the internal components of the cable distribution tap.

Embodiments of this invention will now be described by way of example only, and with reference to the accompanying drawings in which: Figure 1 is a bottom view of an embodiment of cable distribution apparatus in accordance with this invention; Figure 2 is a longitudinal section through the cable distribution apparatus on the line II - II shown in Figure 1, when its cover is fitted.

Figure 3 is a longitudinal section through the cable distribution apparatus, on the line III - III shown in Figure 1, when its cover is removed.

Figure 4 is a sectional view through the cable distribution apparatus, on the line IV - IV shown in Figure 3; Figure 5 is a longitudinal section through an alternative embodiment of cable distribution apparatus; Figure 6 is a sectional view through the cable distribution apparatus on the line V - V shown in Figure 5; and Figure 7 is a side view of a portion of the cable distribution apparatus of Figure 5.

Referring to Figures 1 to 4 of the drawings, there is shown a cable distribution apparatus having a closure which comprises a base 10 and a tubular cover 30, each of plastics material. The base 10 comprises a tubular portion 12 and an end wall 14, with a plurality of tubular projections e.g. 16 extending outwards from its end wall 14 and forming cable entry ports. The tubular portion 12 has a peripheral surface formed with a groove 20, an edge of the groove being formed by a ring 22 applied to the end of the tubular portion 12 of the base.

The peripheral surface of the tubular portion 12, within the groove 20, tapers in the axial direction and carries an O-ring 24. The tubular cover 30 is closed at one end and its other end is dimensioned as a sliding fit over the outside of the tubular portion 12, so as to seal the cover 30 to the base 10.

A co-axial tap 40 comprises a cylindrical casing having a cup-shaped base 41 and a circular lid 42. A plurality of terminals 43 to 46 are arranged in a concentric line on the upper surface of the lid 42. An inlet terminal 43 is arranged diametrically opposite an outlet terminal 44, so that in use the co-axial tap 40 can be connected in series with a cable feeding from a central relay unit or exchange. The terminals 45, 46 arranged between the input and output terminals are provided for distributing the input signal to individual subscribers. The terminals 43 to 46 each comprise an externally screw threaded collar and an insulated centre terminal or terminals.

The co-axial tap 40 is mounted co-axially inside the cover 30 at its end. The co-axial tap 40 is supported by a plurality of cables 53 to 56 connected to the respective terminals 42 to 46, which cables enter the closure through the cable entry ports 16. Heat-shrinkable sleeves 47 are recovered over the cables 53 to 56 and the cable entry ports 16 to form an effective seal there between. Alternatively, mechanical seals may be used, such as grommets, self-amalgamating tape or clamps. When the cover 30 is removed from the base 10, a spanner 48 may be used to connect or disconnect internally screw-threaded plugs e.g. 50 disposed on the ends of the cables 53 to 56 to the terminals 43 to 46.

Referring to Figures 5 to 7 there is shown an alternative embodiment of a cable distribution apparatus, and like parts are given like reference numerals. The co-axial tap 40 is supported by a pillar 51 which extends between the base 10 of the closure and the co-axial tap 40. The lower end of the pillar 51 is mounted to a metal bridge 52 which is push fitted into an unused central cable entry port 57 formed in the base 10. The upper end of the pillar is bolted to the Co- axial tap 40. The co-axial tap 40 shown in Figures 5 to 7 comprises a dish-shaped lid 58 and a base plate 60 which fits into the lid 58. An annular chamber 59 is formed inside the tap 40 which contains a printed circuit board (not shown) carrying conductive tracks and impedance matching components.

Claims

1) A cable distribution apparatus comprising a closure having a base provided with a plurality of cable entry ports, a tubular cover for fitting to the base and a cable distribution tap mounted inside the cover and arranged such that its input and output terminals are directed towards the cable entry ports.

2) A cable distribution apparatus as claimed in claim 1, in which the distribution tap comprises a cylindrical casing mounted co-axially inside the cover.

3) A cable distribution apparatus as claimed in claim 1 or 2, in which the terminals are arranged on a line which extends concentrically with a line on which said cable entry ports are arranged.

4) A cable distribution apparatus as claimed in any preceding claim, in which the cable distribution tap is arranged to be mounted inside the cover by cables connected to its terminals and which pass through said cable entry ports.

5) A cable distribution apparatus as claimed in any of claims 1 to 3, in which the cable distribution tap is mounted inside the cover by a support which extends between the base of the closure and the cable distribution tap.

6) A cable distribution apparatus as claimed in any preceding claim, in which the input and output terminals of the cable distribution tap and the cable entry ports extend axially with the cover.

7) A cable distribution apparatus substantially as herein described with reference to the accompanying drawings.

8) A cable distribution tap comprising a cylindrical casing having a plurality of terminals on one end for connecting to input and output cables.

9) A cable distribution tap as claimed in claim 8, comprising co-axial-type terminals.

10) A cable distribution tap as claimed in claim 9, in which each terminal comprises means for engaging with a plug on the end of a cable connected to the terminal.

11) A cable distribution tap as claimed in claims 9 or 10, in which the cable distribution tap is arranged for connecting in series with a co-axial cable, a plurality of the terminals being arranged for outputting a portion of a signal carried by the co-axial cable.

12) A cable distribution tap as claimed in any of claims 8 to 11 in which the casing comprising an electrically conductive material which shields its internal components.

13) A cable distribution tap substantially as herein described with reference to the accompanying drawings.