GB2421640A

GB2421640A - Blown optical fibre multi tube terminal connector.

Info

Publication number: GB2421640A
Application number: GB0428047A
Authority: GB
Inventors: John Kerry; Robert William Prentice; Scott James Harvey
Original assignee: Brand Rex Ltd
Current assignee: Leviton Manufacturing UK Ltd
Priority date: 2004-12-22
Filing date: 2004-12-22
Publication date: 2006-06-28
Anticipated expiration: 2024-12-22
Also published as: GB2421640B; GB2421640B8; WO2006067409A1; GB0428047D0; GB2421640A8

Abstract

Lengths of cables of tubes (1,1' fig 2) are connected together via a pair of connectors 2,2', each made up of two parts, one part formed as a gland slip ring 4 and gland body 5 for receiving and clamping onto a cable of tubes (1,1' fig 2), and the second part formed as an alignment device 6, seal 7 and tube seat 8 for receiving the tubes in a splayed orientation. The tubes (1,1' fig 2) are also connected by a connecting part 3 made of a seal 9 and seal retainer plate 10, and a connector locking ring 11. The gland body 5 clamps onto a cable (1,1' fig 2) via the gland slip ring 4. Tubes are then fed from the cable (1,1' fig 2), through the alignment device 6 and tube seat 8 to form a male plug with the connecting part 3.

Description

I U 2 2 242 1 640

ONOPTICAL FIBRE MULTI-TUBE TERMINAL CONNECTOR

This invention relates to connectors and specifically to terminal connectors for tubes for carrying optical fibre.

Fibre optic cables are used in the communications industry for transmitting information by light through the individual fibres. During installation, in a method known as the blown fibre method, the fibres or cabled fibres are blown along lengths of tube. Bundles of blown fibre tubes can be arranged in a cable or outer duct.

This technique is described in EP0408266A2 (BICc & Corning) and EP0345043 (British Telecommunications).

Tubes to carry optical fibres normally need to be connected, e.g. to further lengths of fibre optic tubes, or to a terminal device.

The connection of two lengths of tubes in a cable via an inline joint is currently achieved by individual inline connectors of a type made by John Guest Connectors Ltd as described in W003/023466A2 (Pirelli) . The cable has a protective sheath which is stripped to expose the bare tubes, and using individual tube connectors to connect individual tubes to each other in a suitable housing. Such joints can be permanent or re-enterable A permanent joint involves Placing a permanent closure around the joint, sealing the joint to the cable and thereby forming a Watertight seal for the cable interstices. A re-enterable joint may be used where glands seal the cable to the joint and the housing has a re-usable seal. The sealing of the cable to the joint can be via a mechanical means or simple heat shrink.

Whichever method isud it is sometimes important to Y'h(1U\ U Hi ij 2 seal the joints against the ingress of moisture.

Furthermore when Using a blown fibre method it is necessary to seal against high installation blowing pressures (up to lObar) and burst pressures (typically installation pressure multiplied by 2.5, i.e. 25bar) The current method of joining is time consuming and tedious due to the requirem to join each tube fldividual1y.

Accordingly the present invention provides a blown optical fibre multitube terminal connector comprising at least a first part arranged to receive and clamp onto a cable of tubes in an initially closely packed state, and a second part arranged to receive tubes in a splayed state wherein the tubes terminate in the second part at a Spaced relationship where the spacing is greater than the spacing at the initially closely packed state, the arrangement being such that provision is made so as to connect the connector to a further element.

Reference will now be made to embodiments of the invention by way of example to the accompanying drawings.

Figure i i5 a perspective view of a pair of fully assembled blown optical fibre multi-tube connectors.

Figure 2 is a Partially expanded perspective view of a pair of blown Optical fibre multi-tube connectors Figure 3 is a perspective view of all components of a pair of blown optical fibre multi-tube connectors.

Figure 4 and Figure 4a are a longitudi cross section of a pair of blown optical fibre multi-tube 3)(,I\ IH 7 24:i 3 connectors along the line A-A of Figure 1, including the path of a single tube through the connector.

Figure 4b is a formulaic representation of the displacement of the tube from its original position and for the subsequent distance between the beginning and end of the bend in the connector Figure 5 is a longitudinal cross section of a connecting part formed into an elbow' configuration.

Figure 1 shows a pair of connectors, comprising a first part arranged to receive and clamp onto a cable of tubes, a second part to receive splayed tubes, and a connecting part and connector locking ring to allow for connection to a further element.

Figure 2 shows a length of cable i terminating in connector 2, and a second length of cable i' terminating in connector 2'. Connecting part 3 links the two connectors thereby joining the cables. Connecting ring 11 (covering connecting part 3) maintains the connection.

Figure 3 illustrates the separated components of the connector, and the connecting part. The first part comprises gland slip ring 4 and gland body 5, and the second part comprises alignment device 6, sealing means 7, and tube seating body 8. The connecting part 3 includes sealing means 9 and sealing retaining plate 10.

Connector locking ring ii maintains the connection of the connector to a further element.

The gland body 5 is clamped onto a cable of tubes by means of gland slip ring 4. The separated tubes then pass through the alignment device 6 7&z\ IIS III 21 12 4 a ld 4 The Separated tubes then pass through channels in the tube seating body 8. The channels of the tube seating body 8 decrease in diameter at a point such that a shoulder is formed on which the terminal ends of the tubes sit.

The tube seating body 8 forms a multiple male plug interface with the connecting part 3. This arrangement ensures that each tube is connected sealingly to the next inline tube via tube seating body 8 and connecting part 3. Sealing means 7 is provided between the alignment device 6 and tube seating body 8, and sealing means 9 and seal retaining plate 10 are provided between the tube seating body 8 and the connecting part 3. Sealing means 7 and 9 could comprise, for example, multiple 1Q1 rings.

The connecting part 3 links one connector to another, or to a device, and connector locking ring 11 maintains the connection.

Figure 4 shows the route of a single tube through the connector. As illustrated in Figure 4 and in detail in Figure 4a, the tube forms an 5' bend as it passes through the gland body S and alignment device 6. All tubes except the central tube assume an S' bend, thus ensuring that the end of a tube is parallel to the same tube when in the bundle clamped by cable gripping gland 4.

Figure 4b provides a formulaic representation of shape required to be formed by the tube to allow an optical fibre to be installed by the blown fibre method.

The formula provides the displacement of the tube from its original position, and the subsequent distance between the beginning and end of the bend in the GU\ IS UI 21 2 O4a tIcd 5 connector using the centre line of the tube as a reference point.

The connecting part 3 may be formed in a particular configurat to provide a certain function. Figure 5 shows the connecting part formed into an elbow. This configurati can be used when it is necessary to change the direction of the optical fibre cables, for example, to turn a corner. To prevent tube kink or tube collapse, a minimum bend radius must be maintained for multi-tube cables on changing direction. The minimum bend radius for multi-tube cables is approximately ten times the diameter of the cable, e.g. a multi-tube cable comprising seven 5mm tubes and having an overall diameter of 20mm should not be subjected to a bend radius of less than 200mm.

However, by stripping the sheath from the cable and essentially treating each single 5mm tube as a separate entity, the minimum bend radius is reduced to 50mm. The elbow contains pre-configured routes for the tubes at the correct radii, and provides a patch tube interface which allows a fibre optic multi-tube gland and multi-tube cable to be connected to either end. Therefore the space required to achieve the 90 bend is reduced compared with bending the cable as a whole.

It may be Possible for substitution of the connecting part 3 to occur after installation of the tubes and prior to blown installation of the fibre.

The connecting part 3 and the tube seating body 8 may also be formed so as to provide a keyway.

It is known from WQO3/023466A2 (Pirelli) to have a carbon loaded radially inner surface to blown fibre tubes. This is to dissipate static charges.

I II 21 2 iId 6 However, when such tubes are so provided in cables to be Connected as in the present invention, the inner conducting surface of adjacent Connected lengths of tube can be used to Convey electrical signals from one tube length to another or from one tube length to a terminal device. The invention thus enables multiple conductor provision For such an arrangement the tube seating body 8 and connecting part 3 require mutually conductive surfaces which can be provided on the shoulders of tube seating body 8 and connecting part 3 so that a conductive path is maintained through the connector. This could be achieved, for example, by introducing a carbon lining during manufacturing, or by application of a conductive paste to the connector components during assembly.

* . S.. * S..

* S * I * * I S. I S * * S S S I * S *. S I I S.. S * . I

Claims

Th( I \ III 21 204 7 Claims 1. A blown optical fibre multi-tube terminal

connector comprising at least a first part arranged to receive and clamp onto a cable of tubes in an initially closely packed state, and a second part arranged to receive tubes in splayed state wherein the tubes terminate in the second part at a spaced relationship where the spacing is greater than the spacing at the initially closely packed state, the arrangement being such that provision is made so as to connect the connector to a further element.
2. A blown optical fibre multi-tube terminal connector as claimed in claim 1 wherein the provision so as to connect the connector to a further element is made by a connecting part with axially aligned sealing provided between the second part and connecting part and between the connecting part and the further element, the arrangement being such that provision is made so as to maintain said connector, connecting part, and further element in Position relative to one another.
3. A blown optical fibre multi-tube terminal connector as claimed in claim 2 wherein the provision so as to maintain the connector, connecting part and further element in Position relative to one another is made by a connector locking ring.
4. A blown optical fibre multi-tube terminal connector as claimed in claims 2 or 3 wherein a pair of connectors are linked by a connecting part.

* * tis * * * * S I * S * * * * Ste **. * ** * S * * S S * * S S
5. I S S - (I\ I I 2 4 flk'd 8 5. A blown optical fibre multi-tube terminal connector as claimed in claim 4 wherein the connecting part is shaped such that the tubes in the initially closely packed state received by one first part are axially misaligned, preferably at right angles, to the corresponding tubes in the other first part.
6. A blown optical fibre multi-tube terminal connector as claimed in any of the Preceding claims wherein the tubes form an S' bend, the shape of the bend being determined by the formulae: f = 2 (cd - (Ed cosa)) + c wherecoforf Ed and g 2cd sina R=cd Where d = tube diameter and E = optimum blowing parameter
7. A blown optical fibre multi-tube terminal connector as claimed in any one of the Preceding claims wherein the tubes terminate in a flat plane.
8. A blown Optical fibre multi-tube terminal connector as claimed in any one of claims 1 to 6 wherein the centres of the tubes terminate in a curved plane.
9. A blown Optical fibre multi-tube terminal connector as claimed in any one of the Preceding claims wherein the ends of the tubes are spaced radially from an axial centre of the connector.
10. A blown Optical fibre multi-tube terminal connector as claimed in any one of claims 2 to 9 wherein the * . S. * *I.

* 0 * S S S * * I I * ** *.. I S. I * * * I I I * . S 5. 5 5 5 *05 S * S I IL\ r U 2 9 connecting part and the second part are arranged so as to provide a keyway.
11. A blown optical fibre multi-tube terminal connector as claimed in any one of the preceding claims wherein a conductive path is maintained through the connector
12. A blown optical fibre multi-tube terminal connector substantially as herein described, with reference to the accompanying drawings.

* * S.. * S..

* . S S * * S * S S * *. S.. * a. S * * * S 0 * S S * ** S S a "0 5 * S