GB2408393A - Microduct bundle. - Google Patents

Abstract

A sheathed microduct bundle (16) comprises a bundle of microducts (12) in fixed hexagonal formation in a sheath and an index (20) identifying the rotational orientation of the bundle. The idex may two adjacent microducts being connected together, a radially outermost one and a radially inwardly adjacent microduct. Indeed, it may comprise a single shared conduit (24), elongate in section.

Description

1 2 4 0 8 3 9 3 Microduct Bundle This invention relates to ducting for

optic fibre communications.

It is frequently now the case that new buildings require an infrastructure of ducting to receive optic fibres for communications purposes. Because optic fibres are relatively expensive, the relatively inexpensive ducting is installed without the fibres in place. When a specific requirement is realised, the fibres are blown down the relevant ducts to appear at their intended location. This presupposes that the ducking is fully mapped and labelled.

The ducting comprises microducts of a few millimetres diameter bundled with other microducts into a sheathed duct. The sheath can have various degrees of environmental protection. The sheathed ducts may themselves be contained in larger ducts, at least as the network approaches a central communications room, for

example.

Each microduct is capable of having optic fibres or other cables blown into them. When requirements change, existing cables or fibres can be withdrawn and upgraded or different fibres inserted in their place. At the end of each microduct a connector is needed to connect each microduct to a blowing machine. The connector needs to be of a type which has a gripping function, to securely locate on the end of the microduct, and a seal, to prevent escape of gas pressure in the microduct when the fibre is being blown into it. Such connectors exist and overlap the end of the microduct.

In a communications room of a large building, there may be hundreds of microducts. Managing those ducts is a problem. In a sheath, each microduct is usually colour coded and, being round, they form a hexagonal formation inside the sheath. That formation is consistent throughout the length of the sheath. However, if there are 19 or more microducts in a sheath, not all will be different colours. But since their position is consistent, identifying which duct is which is possible.

The problem arises, however, when the sheathing is stripped back to expose a reasonable length of microduct (usually perhaps about one metre length) that is sufficient to permit easy working with the microduct when connecting it to a blowing machine or to a junction box.

Under these circumstances it is more difficult to trace a microduct back to its original position in the sheath and 2 identification becomes a problem. In any event, managing a large number of stripped back microducts in a confined communications room is also a problem.

The solution is to provide a connector plug on the end of the sheath and in which connectors are already in place and so that the entire sheath and all its microducts can be connected en bloc to a blowing machine manifold or to a junction box patch system.

But how to connect such a plug to the end of a sheath is a difficulty, which it is an object of the present invention to overcome. Connection of the plug needs to be capable of being effected in the field, rather than in the factory. This is because the sheaths need to be cut to length once they are installed.

Therefore the system must be simple and straightforward to implement and must ensure that each connector location in the plug is occupied by the appropriate microduct so that identification is assured.

In accordance with the invention claimed in United Kingdom application number 0202253.1, from which this application has been divided, there is provided a connector plug for a sheathed bundle of microducts in a fixed polygonal formation, the plug comprising a cone sleeve and a divider guide body, wherein: the cone sleeve comprises a coned tubular element whose smaller end is formed into said polygonal shape to confine microducts inserted through the sleeve to the same polygonal formation they have in the bundle; and wherein the divider guide body comprises passages smoothly transitioning between a rear end and a front end of the body, the passages opening at the rear end of the body in said polygonal formation, and at the front end the passages open in a spaced relationship permitting connectors to overlap their ends; so that assembly of the connector on a bundle can be effected by: ë stripping back a sheath thereof to expose microducts; sliding on the cone sleeve over the exposed microducts to re-orientate the microducts into the same formation they have in the sheath; and pushing on the divider guide body so that the microducts enter the openings of the passages in the rear end of the body.

A connector plug constructed in this way therefore permits ready assembly in the field while at the same time ensuring that each microduct is led to a specific position in the plug so that each can be reliably identified and accurate connections to it can be made.

The present invention provides a microduct bundle comprising a bundle of microducts in fixed polygonal formation in a sheath and an index identifying the rotational orientation of the bundle.

Said index may comprise two adjacent microducts being connected together. Indeed, said two interconnected microducts may comprise a single shared conduit, elongate in section, whereby the key is shaped to permit insertion in said conduit with a specific orientation with respect thereto, a key tooth of the key being adapted to extend parallel the bundle outside of said polygonal formation and fit in said keyway of the sleeve. Such an arrangement ensures that it is only with . the index that the key can be associated. :

Preferably, said interconnected microducts are a. , radially outermost microduct of the bundle and a radially .

adjacent microduct. Said fixed polygonal formation is. . preferably hexagonal. . : Said index permits rotational orientation of the bundle. The connector plug therefore further comprises a key for said index and a keyway in said cone sleeve which both orientates the sleeve with respect to the index and the sleeve with respect to the body. Therefore, rotational orientation of the bundle with respect to the plug can be assured.

A method of joining a sheathed bundle of microducts as defined above to a connector plug as defined above comprises the steps of: ! a) stripping sheath from the end of the bundle to expose loose microducts; b) sliding on the cone sleeve over the exposed microducts to re-orientate the microducts into the same formation they have in the sheath; and c) pushing on the divider guide body so that the microducts enter the openings of the passages in the rear end of the body.

The rear end of the divider body preferably has points formed between the openings of the passages adapted to be inserted into the triangular gaps between adjacent microducts and to guide the microducts into their respective passages.

The divider body is preferably formed by layers, between adjacent ones of which said passages are formed.

Where the microduct bundle comprises seven or nineteen microducts in hexagonal formation, the divider body comprises four or six layers, respectively.

In each case, the middle two layers define between them passages that remain in a plane of intersection between the layers, which plane is parallel the axis of the coned sleeve. Outer layers outside said middle layers define, either with the middle layers or, in the case of a nineteen microduct bundle, with intermediate layers, inclined passages departing from said plane away from the rear end of the body.

In each case, with the exception of passages lying in a plane perpendicular said intersection plane, the passages on either side of said perpendicular plane depart from said plane away from the rear end of the body.

The passages preferably open into parallel, spaced ports at said front end of the body. Connectors may be captured in said ports, each comprising a sleeve fitting having a seal and a directional grip, whereby microducts can be inserted into the fitting and be sealed thereto by the seal, withdrawal thereof being prevented by said grip.

A face plate having apertures sized to receive microducts, but to prevent passage of the connectors, may be located in front of said front end, said apertures being positioned to coincide with said ports.

Preferably, the face plate is fixed to said front end, for example by screws.

The body and sleeve are preferably captured, once they have been assembled on the end of a bundle of microducts, between clamshell housing parts. Preferably, the housing parts are capable of ultrasonically being welded together and optionally to the body and/or sleeve.

Preferably, the clamshell housing extends beyond the coned sleeve so that it can overlap the end of the sheath on the microduct bundle. Preferably, a ring end cap is snapped into engagement with the clamshell housing, and is adapted to lock around the housing around the sheath of the microduct bundle and press a ring seal in the end cap between the housing and sheath.

The coned sleeve is preferably substantially circular at its widest end and of corresponding diameter to the sheath on the bundle of microducts. In this event, when assembly is commenced, the sheath of the microduct bundle is stripped back only so far as to permit the sleeve to abut the sheath end with a relief gap between the sleeve and the body when the body is fully inserted onto the microducts so that the microducts are all received within their connectors in their ports and the clamshell housing is located about the body and sleeve.

Where the index comprises said joined microducts having a shared conduit, the passage for said index is correspondingly elongate in section and is formed between middle layers. Said index passage therefore lies in said intersection plane.

The invention is further described, hereinafter, by way of example, with reference to the accompanying drawings, in which: Figure la and b are an end view of a bundle of microducts in accordance with the present invention in hexagonal formation and a perspective view of the bundle of microducts in the initial stages of assembly of a plug connector; Figure 2 is an exploded view of the guide body, some connectors, and an end face plate of the connector; and ..': Figures 3a to f are perspective views similar to Figure lb showing further stages of assembly of the plug connector.

In the drawings, a microduct bundle 10 comprises 19 microducts 12 formed into an hexagonal configuration.

Throughout their length, the microducts 12 are sheathed with a protective sheath 14 and in such a way that the relative orientation of each microduct 12 remains the same along the entire length of the sheath 14. The microducts 12 are colour coded, but not necessarily all with different colours. Consequently, some of the microducts 12 can only be distinguished from the others by virtue of their position in the hexagonal formation 16. However, since an hexagonal formation is rotationally symmetrical about its axis 18, an index 20 is provided. In this example, the index 20 comprises a lobed conduit 24 which effectively occupies the position of two microducts 12. Thus the duct 22 has a single elongate conduit 24. As illustrated, the index 20 is arranged at the outside of the bundle in a radial orientation. The reasons for this are explained below.

The use to which the sheath 14 of microducts 12 is put is to provide routes for optic fibres in a building when specific communication requirements are identified.

The ducting is therefore laid in a building as it is constructed with numerous sheathed cables 14 being distributed to various points of the building, but all terminating back in a communications room. However, until a particular communications requirement is identified for any particular area of a building, no further infrastructure is required. When it is desired to provide optic fibre communication to a particular area in a building, the appropriate cable 14 is identified that leads to the area in question. It is then necessary to terminate the microconduit up which it is desired to feed an optic fibre with a connector that permits connection to a blowing machine (not shown). A connector 26 is shown in Figure 2, but no further detail is given of this conventional device other than that it comprises a sleeve incorporating a seal and gripping means so that when a microduct is inserted in the connector 26, a seal is effected between the connector and microduct and the gripping means grips the microduct to prevent its withdrawal from the connector. When the connector is then also connected to the manifold of a blowing machine, an optic fibre can be fed into the microduct until appears at its destination.

When a microduct is identified in a sheath 14 as requiring optic fibre insertion, the present invention suggests terminating the entire sheath with a plug connector 100 that terminates each microduct 12 with a connector 26 and enabling the entire plug to be inserted in a manifold of a blowing machine and one which can select which microduct it shall feed with an optic fibre.

The cable bundle 14 is shown in the drawings with 19 microducts 12 (or 17 if the index 20 is excluded), but smaller bundles of 7 microducts are also possible with a smaller cable and still having an hexagonal formation.

Obviously, other formations are also possible with any number of microducts.

When the cable 14 that requires a plug 100 has been identified, its sheath is stripped back a specific length as described further below, in the example illustrated, this is 180mm. A key 30 is first inserted into the index duct 20 and the bundle of microfibres 12 are collected together in a roughly circular formation. A cone sleeve 33 is then inserted over the end of the bundle so that the key 30, which has a key 32 that is positioned outside the index 20 when the key body 34 is inserted in the conduit 24 of the key 20.

The coned sleeve 32 has an enlarged end 36 and an hexagonal end section 38. A keyway 40 is formed down one side of the sleeve 32. If the sleeve 32 is able to slide all the way to the sheath 14, over the key 32, then two facts can be deduced from this. Firstly, that the microducts passing through the hexagonal end 38 of the coned sleeve 32 will have the same disposition with respect to one another as they have in the sheath 14.

The second is that the keyway 40 is aligned with the index 20, which is therefore positioned appropriately for insertion in the plug 100.

The plug 100 further comprises a guide body 40 which is shown exploded in Figure 2. The guide body 40 comprises a number of layers 42a,b,c and 44a, b,c. When assembled together, the layers 42, 44 form passages 46 between a front face 48 and a rear face 50 of the guide body 40.

In Figure 3a, the layers 42, 44 are shown assembled, with the exception of top layer 42c when assembled, a series of openings are defined in the rear face 48, as well as a series of points 52 the openings are not easily visible in the drawings but are defined by the points and also by the openings of the passages 46 that are formed by mating grooves on the facing sides of respective layers.

When the bundle of microducts 12 is offered to the rear face 48 of a guide block 40, the points 52 fit into the triangular spaces 56 (see Figure la) between adjacent microducts. These points then guide each microduct into its respective opening and passage 46 when each enters its respective passage, the guide body 40 is further pressed onto the ends of the microducts 12 so that the ducts progress along their respective passage. At the same time the sleeve 32 is manoeuvred back until its rear end 36 abuts the sheathing 14.

With reference to Figure 2, as well as forming the passages 46, the layers 42, 44 also form ports 58 adapted to receive connectors 26. Each port has one connector 26 and these are kept in place by an end face plate 60 secured to the front of the guide body 40, for example by screws. The face plate 60 has apertures 62 corresponding to the openings of the ports 58. However, these apertures 62 are of smaller diameter than the connectors 26, which are thereby locked in position. However, the apertures 62 are sufficiently large to accommodate microducts inserted from the other side, for example from a blowing machine.

The front ends of the layers 42 are stepped so as to form slots 64 in the face 48, which again serve to facilitate insertion of the microducts into the rear face 48. However, the slot 64a between the two middle layers 42a, 44a also has the function of permitting entry of the key 30. This measure ensures that the guide body 50 is correctly in orientated with respect to the bundle of microducts 12 and the cone sleeve 33. Furthermore, the Ace. . passage 46a adapted to receive the index 20 is shaped accordingly. Likewise, is the port 58a and also the corresponding aperture 62a. Indeed, when the key 30 reaches the aperture 62a, it can be withdrawn therefrom so that use can be made of the index conduit 24.

Figure 3b shows three microconduits 12a lying in their respective passages 46 (bear in mind that layer 40c is not shown in Figure 3b). The microconduits 12a are shown inserted in connectors 26. In this view, the front end of the guide block 40 including the ports 48 is missing. However, in Figure 3c, not only is the guide body 40 complete with regard to its layers, it is also shown with its front end in place and also the end face 60. In addition, a lower clam shell housing 70 is shown positioned around the guide body 40 and capturing a front edge 41 thereof. It also encloses its rear face 48 and has a half tubular extension 71 that is arranged to enclose the cone sleeve 33 as well as a part of the sheath 14 of the microduct bundle. In Figure ad a corresponding top clam shell 72 is shown fitted and this is welded to the lower half 70 by ultrasonic welding, and optionally also to the body 40 and connector sleeve 33.

Rings 74 are formed on the end of the extension 71, and these are adapted to be engaged by an end ring cap 76 (see Figure 3f) which incorporates catches to lock onto the rings 44, but more importantly contain an 'O' ring seal that provides a seal between the sheath 14 and the clam shell housing 70, 72. Beet - - e e - . . - e..

Claims (6)

1. A sheathed microduct bundle comprising a bundle of microducts in fixed polygonal formation in a sheath and an index identifying the rotational orientation of the bundle.

2. A bundle as claimed in claim 19, in which said fixed polygonal formation is hexagonal.

3. A bundle as claimed in claim 2, in which said index comprises two adjacent microducts being connected together.

4. A bundle as claimed in claim 3, in which said .

interconnected microducts are a radially outermost.

microduct of the bundle and a radially inwardly adjacent microduct. .

5. A bundle as claimed in claim 3 or 4, in which said two interconnected microducts comprise a single. ..

shared conduit, elongate in section. . :.

6. A bundle of microducts, substantially as hereinbefore described with reference to Figure la of the accompanying drawings.