GB2186995A

GB2186995A - An improved optical fibre ribbon structure

Info

Publication number: GB2186995A
Application number: GB08703197A
Authority: GB
Inventors: David Turner Parr
Original assignee: BICC PLC
Current assignee: Balfour Beatty PLC
Priority date: 1986-02-14
Filing date: 1987-02-12
Publication date: 1987-08-26
Also published as: GB2186995B; GB8603706D0; GB8703197D0

Abstract

An optical fibre ribbon structure suitable for installation under carpets or other floor covering comprises a plurality of separately formed, elongate ribbon elements 1 arranged side by side in such a way that adjacent ribbon elements are detachably connected together throughout their lengths. Each ribbon element 1 comprises at least one tube 2 in the bore of which at least one optical fibre 6 is loosely housed and, integral with and extending alongside the tube, an elongate socket member 3 which, throughout its length, is of such a transverse cross-sectional shape and size that the tube of the adjacent ribbon element 1 is a snap and longitudinally sliding fit in the elongate socket member. Preferably, the or each tube 2 of each ribbon element 1 is of circular cross-section and the elongate socket member 3 of each ribbon element has a transverse cross-section of approximately C-shape. <IMAGE>

Description

SPECIFICATION An improved optical fibre ribbon structure This invention relates to optical fibre ribbon struc tures of the kind com prising a plurality of optical fibres extending side-by-side.

It is an object of the present invention to provide an improved optical fibre ribbon structure of the aforesaid kind which is especially, but not exclusively, suitable for installation under carpets or other floor covering.

According to the invention, the improved optical fibre ribbon structure comprises a plurality of separatelyformed, elongate ribbon elements arranged side-by-side in such a way that adjacent ribbon elements are detachably connected togetherthroug houttheir lengths, each ofwhich ribbon elements comprises at least one tube having loosely housed within its bore at least one optical fibre and, integral with an extending alongside the tube or one ofthe tubes, an elongate socket memberwhich,throughout its length, is of such a transverse crosssectional shape and size thatthe or a tube of the adjacent ribbon element is a snap and longitudinally sliding fittherein.

Byasnapand longitudinallyslidingfitismeanta fit in which separation of the elongate socket member and the tube in a direction transverse to their longitudinal axes is resisted and in which movementofthetube relativetothe elongate socket member in a direction lengthwise of their longitudinal axes is permitted.

Where two or more optical fibres are loosely housed within the bore of the or a tube of a ribbon element, they may be components of an optical fibre ribbon in which they extend side-by-side with their axes lying in a substantially common plane.

The or each tube, and hence the elongate socket member, of each ribbon element may be of any convenient cross-sectional shape but, preferably, the or each tube is of approximately circulartransverse cross-section and the elongate socket member has a transverse cross-section of approximately C-shape.

To provide for bending of the optical fibre ribbon structure about an axis normal to the longitudinal axes of the tubes and elongate socket members of the structure, the walls bounding the socket ofthe elongate socket member of each ribbon element preferably have extending transversely inwardly from theirfree edges a multiplicity of slots at longitudinally spaced positions along the length ofthe ribbon element. Preferably, the slots are uniformly spaced along the ribbon element and the width of each slot may decrease smoothly in a direction away from the free edge of the wall in which it is formed over at least a part of the length of the slot.

The snap and longitudinally sliding fit between the elongate socket member and one ribbon element and the or a tube of the adjacent ribbon element may be such thatthe ribbon elements can only be detachably connected together by a machine during assembly of the optical fibre ribbon structure orthe fit may be such that the ribbon elements may be detachably connected together and, when required, separated by hand.In the former case, where it is desired to extract any particular ribbon element from the ribbon structure, parts between slots in the upper wall of the elongate socket member in which the ora tube ofthe ribbon element to be extracted is siidably engaged are removed and parts between slots in the lowerwall of the elongate socket member of the ribbon elementwhich is to be extracted are removed to permitthe ribbon element to be extracted upwardly out of the ribbon structure; if desired, the ribbon elements bounding the ribbon element that has been extracted may be detachably connected together to reassemblethe ribbon structure at a position downstream from the position of extraction.

Preferably, the or each tube and the elongate socket member of each separately formed ribbon element is of plastics material, e.g. polyethylene poly propylene or nylon.

Preferably, in each ribbon elementthe elongate socket member and the adjacenttube,and wherethe ribbon element includes two or more tubes adjacent tubes, are joined throughout their lengths by along itudinally continuous neck. To provide when required for ready separation of the elongate socket member and theadjacenttube, or of adjacenttubes, preferably the or each neck of the ribbon element has in its outer surface and extending throughout its length at least one continuous or discontinuous line ofweakness.

Preferably, also, in orderthatthe or each tube of each ribbon element can be readily opened to provide access to the or any optical fibre within the tu be, the tube has in its outer surface and extending throughout its length at least one continuous or discontinuous line of weakness. For example, the or each tube of each ribbon element may have two con tinuous or discontinuous lines ofweakness at diametrically opposed portions in the outer surface of the tube along which the tube can be separated into two parts.

The invention also includes, for use in the improved optical fibre ribbon structure as hereinbefore described, a ribbon element comprising at least one tube having loosely housed within its bore at least one optical fibre and, integral with and extending alongside the tube or one of the tubes, an elongate socket memberwhich, throughout its length, is of such a transverse cross-sectional shape and size that the or a tube of a ribbon element of similar construction can be a snap and longitudinally sliding fit therein.

The invention isfurther illustrated by a description, by way of example, of a preferred optical fibre ribbon structure with reference to the accompanying drawings, in which Figure lisa fragmental transverse cross-sectional view of the preferred optical fibre ribbon structure.

Figure 2 is a fragmental plan view of one ribbon element of the optical fibre ribbon structure shown in Figure 1, and Figures 3 and 4 are transverse cross-sectional views of two alternative forms of ribbon element for use in an optical fibre ribbon structure.

Referring to Figures 1 and 2,the preferred optical fibre ribbon structure comprises a plurality of separ atelyformed, elongate ribbon elements 1 arranged side-by-side in such a waythatadjacent ribbon elements are detachably connected togetherthroughouttheir lengths as will be described. Each ribbon element 1 comprises of a tube 2 of plastics material and an elongate socket member3 of plastics material which extend side-by-side and are joined throughout their lengths by a neck 4. An optical fibre 6 is loosely housed in the bore ofthe tube 2. As will be seen,the tube is approximately circular transverse crosssection and the elongate socket member 3 has a transverse cross-section of approximately C-shape.

Adjacent ribbon elements 1 are detachably connec tedtogetherthroughouttheir lengths by virtue of the factthatthetube2 of one ribbon element is a snap and longitudinally sliding fit in the elongate socket member 3 of the adjacent ribbon element To provide for bending of the optical fibre ribbon structure about an axis normal to the longitudinal axes ofthetubes 2 and elongate socket members 3 of the structure, the walls bounding the socket of the elongate socket member of each ribbon element 1 have extending transversely inwardly from their free edges a multiplicity of slots 7 at longitudinally spaced positions along the length ofthe ribbon element.

When it is desired to extract any particular ribbon element 1 from the ribbon structure, parts between several neighbouring slots 7 in the upper wall ofthe elongate socket member 3 in which the tube 2 ofthe ribbon element to be extracted is slidablyengaged are removed and parts between neighbouring slots7 in the lowerwall of the elongate socket member 3 of the ribbon element 1 which is to be extracted are removed to permit the ribbon element to be extracted upwardly out of the ribbon structure. If desired, the ribbon elements 1 bounding the ribbon element that has been extracted may be detachably connected together to reassemble the ribbon structure ata position downstream from the position of extraction.

The alternative form of ribbon element 11 shown in Figure 3 for use in an optical fibre ribbon structure comprises two tubes 12 of plastics material extending side-by-side and, extending alongside one of the tubes, an elongate socket member 13 of plastics material, the elongate socket member and the adja centtubebeingjoinedthroughouttheir lengthsbya longitudinally continous neck 14 and the adjacent tubes being joined throughout their lengths by a longitudinally continuous neck 15. Each tube 12 has an optical fibre ribbon 16 loosely housed in its bore.

The second alternative form of ribbon element 21 shown in Figure 4for use in an optical fibre ribbon structure comprises a tube 22 of plastics material and an elongate socket member 23 of plastics material joined throughouttheir lengths by a longitudin allycontinuousneck24,an optical fibre 26 being loosely housed in the bore ofthetube. To providefor ready separation ofthe elongate socket member 23 and the adjacent tube 22, the neck 24 has in its outer surface and extending throughout its length a con tinuous line of weakness 29. In order that the tube 22 ofthe ribbon element 21 can be readily opened to provide access to the optical fibre 26 within thetube, the tube has in its outer surface and extending throughout its length two continuous lines of weakness 28 at diametrically opposed positions in the outersurface of the tube along which the tube can be separated into two parts.

Claims

1. An optical fibre ribbon structure comprising a plurality of separately formed, elongate ribbon elements arranged side-by-side in such a way that adjacent ribbon elements are detachably connected together throughout their lengths, each ofwhich ribbon elements comprises at least one tube having loosely housed within its bore at least one optical fibre and, integral with and extending alongside the tube or one of the tubes, an elongate socket member which, throughout its length, is of such a transverse cross-sectional shape and size that the or a tube of the adjacent ribbon element is a snap and longitudin ally siiding fit therein.

2. An optical fibre ribbon structure as claimed in Claim 1, wherein the or each tube of each ribbon element is of approximately circular transverse crosssection and the elongate socket member of each ribbon element has a transverse cross-section of approximately C-shape.

3. An optical fibre ribbon structure as claimed in Claim 1 or 2, wherein the walls bounding the socket ofthe elongate socket member of each ribbon element have extending transversely inwardly from theirfree edges a multiplicity of slots at longitudinally spaced positions along the length ofthe ribbon element.

4. An optical fibre ribbon structure as claimed in Claim 3, wherein the slots are uniformly spaced along the ribbon element and the width of each slot decreases smoothly in a direction away from the free edge of the wall in which it is formed over at least a part of the length of the slot.

5. An optical fibre ribbon structure as claimed in any one of the preceding Claims, wherein, in each ribbon element,the elongate socket member and the adjacenttube, and where the ribbon elementinclu- destwo or moretubes, adjacenttubes, are joined throughouttheir lengths by a longitudinallycontinous neck.

6. An optical fibre ribbon structure as claimed in ClaimS, wherein the or each neck of each ribbon element has in its outer surface and extending throughout its length at least one continuous or discontinuous line ofweakness.

7. An optical fibre ribbon structure as claimed in any one of the preceding Claims, wherein the or each tube of each ribbon element has in its outer surface and extending throughout its length at least one con tinuous or discontinuous line ofweakness.

8. An optical fibre ribbon structure as claimed in Claim 7, wherein the or each tube of each ribbon el ementhastwo continuous or discontinuous lines of weakness at diametrically opposed positions in the outer surface of the tube along which the tube can be separated into two parts.

9. An optical fibre ribbon structure as claimed in any one of the preceding Claims, wherein the or each tube and the elongate socket member of each separ atelyformed ribbon element is of plastics material.

10. An optical fibre ribbon structure as claimed in any one the preceding Claims, in which two or more optical fibres are loosely housed within the bore of the or a tube of a ribbon element, wherein said optical fibres are components of an optical fibre ribbon in whichthey extend side by side with their axes lying in an substantially common plane.

11. For use in an optical fibre ribbon structure as claimed in any one of the preceding Claims, an elongate ribbon element comprising at least one tube having loosely housed within its bore at least one optical fibre and, integral with and extending alongside the tube or one of the tubes, an elongate socket memberwhich,throughout its length, isofsucha transverse cross-sectional shape and sizethatthe or a tube of a ribbon of an elongate ribbon element of similar construction can be a snap and longitudinally sliding fit therein.

12. An optical fibre ribbon structure substantially as hereinbefore described with reference to and as shown in Figures 1 and 2 of the accompanying drawings.

13. For use in an optical fibre ribbon structure as claimed in any one of Claims 1 to 10, an elongate ribbon element substantially as hereinbefore described with reference to and as shown in Figure 2,4 or 5 of the accompanying drawings.