GB2470584A

GB2470584A - Cable end unit

Info

Publication number: GB2470584A
Application number: GB0909135A
Authority: GB
Inventors: Kevin Arthur Hancock
Original assignee: CONNECTIX Ltd
Current assignee: CONNECTIX Ltd
Priority date: 2009-05-28
Filing date: 2009-05-28
Publication date: 2010-12-01
Anticipated expiration: 2029-05-28
Also published as: GB0909135D0; GB2470584B

Abstract

An end unit to assist the pulling through a duct of a cable 10 having a pre-fitted termination 11 has a body in the form of a sleeve 17 and a cylindrical housing 25 rotatably mounted on the sleeve. The housing is arranged to receive the termination on the cable. A gripping arrangement 38, 47 is provided on the sleeve to grip the cable at a location spaced back along the cable from the termination. The housing has an end cap 31 releasably attached to the housing end 27 remote from the sleeve and the end cap has an opening 35 to allow the connection of a pull-cord thereto, for pulling the cable through the duct. Alternatively, the end unit may be combined with a co-operating locking member adapted to receive a connector for the termination, or with a joiner to connect with a like end unit.

Description

CABLE END UNIT

This invention relates to an end unit suitable for mounting on the end of a pre-terminated cable and adapted to protect the cable and termination during installation.

This invention has been developed principally for use on fibre optic cables, and therefore will be described herein with particular emphasis on this application. It is envisaged, however, that the end unit may be used for many other cable types but especially those for digital signals such as CAT5E cables.

With advances in technology, fibre optic cables are increasingly being used in favour of copper wires for the transmission of communications signals.

Rather than using electronic pulses to transmit information down copper wires, fibre optic cables use light pulses to transmit information down the fibres. The installation of a fibre optic network in a building is more difficult than with copper wires since fibre optic cables are more prone to damage, especially when the cables are pulled along ducts, through openings and so on.

Existing methods of installation generally comprise using pulling equipment such as a pull-cord or line fastened to the end region of a cable with tie wraps, cable clamps or even just insulation tape wrapped round the cable and pull-cord or line. Pulling of the cable by the termination is likely to lead to damage to the termination or the ground optical face thereof. Airborne particles can contaminate optical end faces of terminations and lead to absorption of light. Moreover, if not removed, the particles can scratch cable connectors, again resulting in high losses. Due to the difficultly in protecting the terminations from inadvertent stress and other damage, cables are often installed prior to the attachment of the terminations to the ends thereof.

Connecting a termination on site is far more difficult and less reliable than undertaking this work in a factory. It may also be difficult due to lack of space at the location of the cable end. Furthermore, the pulling equipment needs to be removed from the cable once installed so that the cable connector can be inserted into a patch panel or similar port. This disconnection step of course increases likelihood of damage to the cable fibres or termination, if pre-fitted.

It is a principal aim of the present invention to provide an end unit for a cable having a pre-fitted termination, which unit facilitates pulling of the cable to be installed, protects the cable fibres and termination during installation and does not require complete removal prior to connection to a patch panel or other component.

According to this invention, there is provided an end unit for a cable having a pre-fitted termination, said end unit comprising a body defining a housing for the termination, gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination, and the body having connection means for a pull-cord, to allow the cable to be pulled by a pull-cord connected to the body.

It will be appreciated that a cable may be provided with an end unit at each end thereof. This is advantageous where bi-directional installation of the cable is required. In this arrangement, at least one end of the cable must not be fitted with a termination until the end unit has been assembled on to the cable. If the cable is to be pulled from both ends two such units may be installed on the cable, whereafter the terminations may be fitted, all in a factory environment.

Preferably, the body comprises a sleeve and a cylindrical housing which is rotatably mounted on the sleeve, the gripping means being provided on the sleeve. In this way, the sleeve and cylindrical housing can simply slide on to the cable from an un-terminated end thereof. The cylindrical housing is adapted to surround the cable termination and thus provide protection thereto.

Dirt or dust is a major cause of scratches on cable terminations and so, to protect the cable termination from such damage, the body preferably has an end cap which is releasably attached to the free end of the housing remote from the gripping means. With the end cap connected, the cable termination is enclosed within a protective environment away from airborne particles and is shielded from physical damage.

The free end of the housing may be internally threaded in which case the end cap should have an external thread inter-engageable with the internal thread of the housing. The end cap can be removed simply by unscrewing from the housing, but when attached, the end cap and cylindrical housing are together rotatable relative to the sleeve and a termination enclosed within the housing.

In a preferred embodiment, the connection means comprises a bore extending transversely through the end cap to allow the connection thereto of a pull-cord for pulling the cable. To further facilitate the pulling of an attached cable along a duct or though an opening, the end cap is preferably bullet shaped.

The gripping means provided on the sleeve preferably comprises a cable gland having a plurality of fingers arranged to surround a cable extending through the sleeve, and a compression member screw-threaded to the sleeve to urge the fingers on to the cable so as thereby to grip the cable. In this arrangement, the end unit must be suitably mounted on the cable with the end cap connected, before the compression member is screwed to the gripping means. This ensures that the cable is gripped at the correct location relative to the cable termination.

Twisting forces on a optical cable can cause stress on the fibres. It is therefore important that twisting forces on the cable and termination are minimised, if not totally avoided. Preferably, the forward end of the sleeve within the housing is profiled to receive and hold a pre-fitted cable termination so as to prevent rotation of the termination with respect to the sleeve. In this way, the cable is securely held at the termination end by the sleeve and at a location remote from the termination by the gripping means.

Once the cable has been installed, the end unit must remain on the cable as the termination will prevent the removal thereof, but it will be appreciated that the end cap must be removed from the end unit to access the cable termination, to make a connection to a suitable connector. The end unit may then be used to lock the termination to that connector.

Accordingly, this invention extends to an end unit as described above in combination of with a locking member adapted to receive a connector for a termination on the cable, the housing being engageable with the locking member to retain the cable termination to the connector. In a case where the end of the housing remote from the gripping means is internally threaded, the locking member may have an external thread with which the internal thread of the housing is engageable.

In one embodiment, the connector comprises a patch panel connector and the locking member is profiled to receive fasteners for securing the locking member and the patch panel connector to a patch panel. In another embodiment, the locking member is provided at one end of a break-out connector housing, the connector being received within the locking member and having a plurality of individual separate conductors connected thereto for coupling to the conductors of the cable when the housing thereof is locked to the locking member.

This invention further extends to an end unit as described above in combination of with a joiner adapted to receive a cable connector having aligned sockets for end-to-end connection of cable terminations of a pair of cables, the joiner being profiled for inter-engagement with the housing of the end unit and with the housing of a second like end unit provided on the end of a second cable pre-fitted with a termination. The respective ends of the housings remote from the gripping means of both the first and second end units may be internally threaded, in which case the joiner should have external threads with which the internal threads of the housings are engageable.

The end unit of this invention is configured to allow easy installation of fibre optic cables. The end unit protects the cable termination from dirt and minimises stress on the cable fibres. The cable can be installed by pulling on the end unit rather than directly on the fibres or on the termination. The end unit is adapted for connection to a modified patch panel or other connector following installation of the cable.

This invention extends to the combination of an end unit and a locking member for co-operation with the end unit, the end unit being arranged for mounting on a cable having a pre-fitted termination and comprising a body defining a housing for the termination and gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination and the locking member being adapted to receive a connector for the termination on the cable, the housing of the end unit being engageable with the locking member to retain the cable termination to the connector.

The invention further extends to the combination of an end unit and a joiner for co-operation with the end unit, the end unit being arranged for mounting on a cable having a pre-fitted termination and comprising a body defining a housing for the termination and gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination, and the joiner being adapted to receive a termination coupler having aligned sockets for end-to-end connection of cable terminations of a pair of cables, the joiner being profiled for inter-engagement with the housing of the end unit and with the housing of a second like end unit provided on the end of a second cable also pre-fitted with a termination.

By way of example only, one specific embodiment of cable end unit of this invention and three combinations thereof will now be described in detail, reference being made to the accompanying drawings in which:-Figure 1 is an isometric exploded view of the embodiment of an end unit having an end cap; Figure 2 is an isometric assembled view of the end unit of Figure 1; Figure 3 is an axial sectional view through the end unit of Figure 1; Figure 4 is an isometric exploded view of the end unit in combination with a patch panel connector; Figure 5 is an isometric view of the end unit and patch panel connector of Figure 4; Figure 6 is an axial sectional view through the end unit and patch panel connector of Figure 5; Figure 7 is an isometric view of the end unit in combination with, but separated, from a break-out connector; Figure 8 is a view similar to that of Figure 7 but with the end unit coupled to the break-out connector; Figure 9 is an isometric view of the end unit in combination with, but separated from, a cable joiner connector; and Figure 10 is a view similar to that of Figure 9 but with the end units coupled together by the cable joiner.

Referring initially to Figure 1 there are shown the components making up the end unit, adapted to house a pre-terminated cable end which, in this case, comprises a fibre optic cable 10 having a pre-fitted MPO connector 11. The connector 11 has a substantially rectangular casing 12 and a ferrule 13 having two guide-pin holes 14, adapted for mating with another MPO connector, having a ferrule end face provided with corresponding guide-pins, and typically provided on a patch panel. The details of the MPO connector form no part of this invention and will not be discussed further, here.

The end unit comprises a tubular support 17 having a bore within which the cable 10 is received. The forward end 18 of the support has an external flange 19 with a groove 20 extending diametrically thereacross and within which the casing 12 of the connector 11 is located, so as to prevent rotation of the cable 10 with respect to the support 17. As shown in Figure 3, the rearward end 21 of the support 17 is provided with an internal thread 22.

Rotatably mounted on the external surface of the support 17 is a rotatable portion, comprising a cylindrical housing member 25 and end cap 31, as shown in more detail in Figure 3. The housing member 25 has a tapered profile at the rearward end 26 which provides an opening sufficiently large to enable the housing member 25 to be located around the support 17, but small enough to prevent the flange 19 from passing therethrough. The forward end 27 of housing member 25 has an internal thread 28 to which is screwed an end cap 31 by way of an externally threaded boss 32 at the rearward end 33 of the end cap 31, so as to restrain the housing member 25 adjacent the flange 19 at the forward end 18 of the support 17. The arrangement of the housing member and end cap 31 ensures that the cable connector 11 is enclosed within the rotatable portion to protect the connector. The forward end 34 of the end cap 31 is substantially bullet shaped and is provided with a bore 35 extending transversely therethrough for tying a pull-cord (not shown) thereto, for pulling the cable through a duct or other passage where it is to be installed.

The end unit further includes a gripper arranged to grip the cable 10 at a location spaced from the connector 11, the gripper comprising a cable gland 38 and a compression member 47 through both of which the cable 10 extends.

The cable gland 38 has an external thread 39 at the forward end 40 which is screwed into the internal thread 22 at the rearward end 21 of the support 17.

The gland 38 has a further external thread 42 and a plurality of fingers 43 extending rearwardly therefrom, to surround the cable 10. The compression member 47 has an internal thread 48 for engaging the external thread 42 of the cable gland 38 and a taper section which bears on the fingers 43, so that the fingers are urged on to the cable on tightening of the compression member. A hexagonal section 44 is moulded between the screw threads 39 and 42 to facilitate connection of the cable gland 38 to the support 17 and tightening of compression member 47 during assembly. A strain-relief extends rearwardly from the taper section of the compression member.

The cable may have connectors 11 at both ends thereof. During the initial set up of an end unit to a cable 10, at least one end of the cable 10 must not be fitted with a connector 11, to enable the components of the end unit to be located on the cable. If required, two such end units may be provided on a cable, one for each end respectively, whereafter the connector is fitted to the cable end. The end cap 31 is screwed to the housing member 25 once the connector 11 has been located in the groove 20 of the support 17, and then the gland 38 is tightened onto the cable. Figure 2 shows the assembled end unit ready for the tying of a pull cord (not shown) through the bore 35 in the end cap 31, to enable pulling of the cable through a duct, passageway or the like. With -10-the cable held securely by the gripper and the connector in the groove 20 of the support 17, the housing member 25 and end cap 31 are freely rotatable about the cable 10. In this arrangement, the cable 10 and connector 11 are isolated from twisting forces. The guiding of the cable 10 through a passage is facilitated.

It will be appreciated that the end unit (except for the end cap 31) remains on the cable once the cable has been pulled to its final location. This may be used to serve as a locking arrangement to hold the pre-fitted MPO connector 11 to a corresponding MPO socket 50 (or bulkhead coupler) provided in a patch panel, as shown in Figures 4 to 6. For this purpose, an externally threaded locking member 51 is secured to the patch panel with the MPO socket 50 disposed within the locking member 51.

The locking member 51 has a body 52 defining a rectangular opening 53 in which is received the socket 50 and a flange 54 for securing the member to a patch panel. Screws (not shown) extend through holes 55 in a pair of opposed lugs 56 projecting laterally from the socket to be threaded into the patch panel thereby clamping the flange 54 of the locking member between the lugs and the panel. The body 52 is externally threaded with the same thread as the internal thread of the housing member 25.

In use, following the positioning of the cable end adjacent the MPO connector, the end cap 31 is removed from the end unit housing to expose the MPO connector 11. The MPO connector is pushed into the socket 50 and then the housing member 25 is screwed on to the body 52 of the locking member 51, so holding the MPO connector to the patch panel and restraining the MPO connector against accidental removal.

Referring now to Figures 7 and 8, there is shown an end unit 60 corresponding to that described above with reference to Figures 1 to 3. As such, that end unit will not be described in detail here. The end unit is shown fitted to a fibre optic cable 10 having (for example) twelve separate fibres (not shown) contained within the outer sheath of the cable. The break-out unit 61 comprises a cylindrical outer housing 62 carrying at one end a locking member 63 corresponding to locking member 51 of the arrangement shown in Figures 4 to 6. The flange of that locking member 63 is bonded to the housing 62 and an MPO socket 65 is secured to that flange by a pair of screws 64. Within the housing, twelve separate fibres 66 are fitted to the connector 65 such that each of those fibres will make optical connection with a corresponding fibre of the cable 10 to which the end unit 60 has been fitted. At the opposite end of the housing 62, there is an end fitting incorporating a sealing gland for the twelve separate fibres.

The arrangement shown in Figures 7 and 8 is used in much the same way as has been described above with reference to Figures 4 to 6. Following the positioning of a cable as required, using a pull-line if necessary, the end cap 31 is removed from the end unit housing 25 to give access to the MPO connector 11. The connector is then fitted into the MPO socket and the housing 25 is threaded on to the external threads of the locking member 63 50 securing together the end unit 60 and the housing 62 of the break-out unit 61.

Once completed, the end unit and break-out unit are securely interconnected -12 -with the internal fibres of cable 10 connected to the separate fibres 66 of the break-out unit.

In Figures 9 and 10 there is shown a pair of end units 70 and 71 each of which corresponds to the end unit described above with reference to Figures 1 to 3. Each end unit 70 and 71 is mounted on the end of a respective cable 72 and 73 having a pre-fitted MPO connector, only one of which is visible in Figure 9. The MPO connectors of the cables 72 and 73 are joined together by means of a joiner 74 comprising a bulkhead coupler 75 mounted within a joining member 76 which generally corresponds to a pair of locking members 51 as described with reference to Figures 4 to 6, arranged back-to-back but actually formed in one piece with a single centrally-disposed flange 77. The bulkhead coupler 75 is secured to the flange 77 by a pair of screws 78 extending through holes in lugs forming a part of the bulkhead coupler housing.

In use, the joiner 74 is used much as has been described above with reference to Figures 4 to 6. Following the appropriate positioning of each cable 72 and 73, the respective end caps are removed from the end units 70,71 and the two MPO connectors are fitted into the bulkhead coupler 75 from opposite ends thereof such that the fibres of the cables 72,73 are in optical communication. The assembly is completed by threading the housings 25 of the two end units to the external threads of the joining member 76 so securely connecting together the two cables.

With the arrangements of Figures 7 and 8 and Figures 9 and 10, there is no need for the end units to be fitted with end caps. Such end caps may be required only when a cable is to be pulled using the end unit, in which case the -13-end cap provides a means for connection of the pull-line and also protects the termination within the housing. If there is no need for the cable to be pulled, no end cap need be fitted to the end unit and each end unit may serve merely to make secure and protect the connection of the MPO connector to a corresponding socket, provided as a part of a patch panel, a bulkhead, a break-out connector or a joiner, as described above, or indeed provided as a part of some other equipment.

Claims

-14 -CLAIMS1. An end unit for a cable having a pre-fitted termination, said end unit comprising a body defining a housing for the termination, gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination, and the body having connection means for a pull-cord, to allow the cable to be pulled by a pull-cord connected to the body.
2. An end unit as claimed in claim 1, wherein the body comprises a sleeve and a cylindrical housing rotatably mounted on the sleeve, the gripping means being provided on the sleeve.
3. An end unit as claimed in claim 1 or claim 2, wherein the body has an end cap which is releasably attached to the free end of the housing remote from the gripping means.
4. An end unit as claimed in 3, wherein the free end of the housing is internally threaded and the end cap has an external thread inter-engageable with the internal thread of the housing.
5. An end unit as claimed in claim 3 or claim 4, wherein the connection means comprises a bore extending transversely through the end cap to allow the connection thereto of a pull-cord for pulling the cable.
6. An end unit as claimed in any of claims 3 to 5, wherein the end cap is bullet shaped to facilitate the pulling of an attached cable.
7. An end unit as claimed in any of claims 2 to 6, wherein the gripping means comprises a cable gland having a plurality of fingers arranged to surround a cable extending through the sleeve, and a compression member -15-screw threaded to the sleeve to urge the fingers on to the cable so as thereby to grip the cable.
8. An end unit as claimed in any of claims 2 to 7, wherein the forward end of the sleeve within the housing is profiled to receive and hold a pre-fitted cable termination so as to prevent rotation of the termination with respect to the sleeve.
9. The combination of an end unit and a locking member for co-operation with the end unit, the end unit being arranged for mounting on a cable having a pre-fitted termination and comprising a body defining a housing for the termination and gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination and the locking member being adapted to receive a connector for the termination on the cable, the housing of the end unit being engageable with the locking member to retain the cable termination to the connector.
10. The combination as claimed in claim 9, wherein the end of the housing remote from the gripping means is internally threaded and the locking member has an external thread with which the internal thread of the housing is engageable.
11. The combination as claimed in claim 9 or claim 10, wherein the connector comprises a bulkhead coupler and the locking member is profiled to receive fasteners for securing the coupler to the locking member and to a patch panel.
12. The combination as claimed in claim 9 or claim 10, wherein the locking member is provided at one end of a break-out connector housing, the coupler -16-being received within the locking member and having a plurality of individual separate conductors connected thereto for coupling to the conductors of the cable when the housing thereof is locked to the locking member.
13. The combination of an end unit and a joiner for co-operation with the end unit, the end unit being arranged for mounting on a cable having a pre-fitted termination and comprising a body defining a housing for the termination and gripping means provided on the body to grip the cable at a location spaced back along the cable from the termination, and the joiner being adapted to receive a termination coupler having aligned sockets for end-to-end connection of cable terminations of a pair of cables, the joiner being profiled for inter-engagement with the housing of the end unit and with the housing of a second like end unit provided on the end of a second cable also pre-fitted with a termination.
14. The combination as claimed in claim 13 and in which the respective ends of the housings remote from the gripping means of both the first and second end units are internally threaded, wherein the joiner has external threads with which the internal threads of the housings are engageable.
15. An end unit as claimed in claim 1 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.
16. The combination of an end unit and a locking member or coupler as claimed in claim 9 or claim 13 and substantially as hereinbefore described with reference to and as illustrated in the accompanying drawings.