EP0392827A2
Expired / Lapsed
EP
⏱️ 0.0 years remaining
Optical cable
Assignee: Balfour Beatty PLC
•
Filing: 1990-04-11
•
Granted: —
•
Expires: 2010-04-11
Abstract
Abstract In a slotted core optical cable in which each slot contains stacked optical fibre ribbons, the cost of the cable can be reduced and cooling of the slotted core during manufacture of the cable is facilitated as compared with an optical cable in which the slots of the slotted core are all of the same depth by forming the circumferentially spaced slots into two groups, the slots of each group being of the same depth as one another and the depth of each of the slots 3 of one group being greater than the depth of each of the slots 4 of the other group, and by arranging for each slot 3 to be disposed between two slots 4. The number of optical fibre ribbons 5 stacked in each of the slots 3 is greater than the number of optical fibre ribbons stacked in each of the slots 4. Approximately the same number of optical fibre ribbons can be accommodated in slots of a core of smaller diameter than hitherto achieved.
Inventors
- 👤 Stephen Thomas Spedding
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-11-01 12:27
CPC Classifications
G; G02; G02B; G02B6/00; G02B6/44; G02B6/4401; G02B6/4407; G02B6/4408; G02B6/4403
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
233 words
An optical cable comprising a central flexible elongate member (1) of plastics material having in its outer surface a plurality of circumferentially spaced slots which extend lengthwise of the member, each of which slots is of substantially uniform width throughout its depth and is so disposed within the central member that a plane substantially midway between and parallel to the side walls of the slot extends substantially radially of the longitudinal axis of the central member, a plurality of optical fibre ribbons stacked one on top of another in at least some of the slots and, surrounding the central member, an overall outer protective sheath (6), wherein the circumferentially spaced slots comprise two groups of slots (3,4), the slots of each group being of substantially the same depth as one another and the depth of each of the slots (3) of one group being substantially greater than the depth of each of the slots (4) of the other group and each slot of one of said groups being disposed between two slots of the other of said groups, and wherein each of said slots has a plurality of optical fibre ribbons (5) stacked one on top of another in the slot, the number of optical fibre ribbons in each of the slots of greater depth being substantially greater than the number of optical fibre ribbons in each of the slots of smaller depth.
Claim 2
Dependent Claim
233 words
An optical cable comprising a central flexible elongate member (1) of plastics material having in its outer surface a plurality of circumferentially spaced slots which extend lengthwise of the member, each of which slots is of substantially uniform width throughout its depth and is so disposed within the central member that a plane substantially midway between and parallel to the side walls of the slot extends substantially radially of the longitudinal axis of the central member, a plurality of optical fibre ribbons stacked one on top of another in at least some of the slots and, surrounding the central member, an overall outer protective sheath (6), wherein the circumferentially spaced slots comprise two groups of slots (3,4), the slots of each group being of substantially the same depth as one another and the depth of each of the slots (3) of one group being substantially greater than the depth of each of the slots (4) of the other group and each slot of one of said groups being disposed between two slots of the other of said groups, and wherein each of said slots has a plurality of optical fibre ribbons (5) stacked one on top of another in the slot, the number of optical fibre ribbons in each of the slots of greater depth being substantially greater than the number of optical fibre ribbons in each of the slots of smaller depth.
Claim 3
Dependent Claim
29 words
An optical cable as claimed in Claim 1, wherein the depth of the slots (3) of greater depth is approximately twice that of the slots (4) of smaller depth.
Claim 4
Dependent Claim
31 words
An optical cable as claimed in Claim 1 or 2, wherein each of the circumferentially spaced slots (3,4) follows a helical path around the longitudinal axis of the central member (1).
Claim 5
Dependent Claim
42 words
An optical cable as claimed in any one of the preceding Claims, wherein the central member has encapsulated within the plastics material of the member a central flexible elongate reinforcing element (2) of a metallic or non-metallic material of high tensile strength.
Claim 6
Dependent Claim
21 words
An optical cable as claimed in Claim 4, wherein the central flexible elongate reinforcing element (2) is of an aromatic polyamide.
Claim 7
Dependent Claim
29 words
An optical cable as claimed in Claim 4 or 5, wherein the central flexible elongate reinforcing element (2) comprises a plurality of elongate elements stranded or otherwise assembled together.
Claim 8
Dependent Claim
40 words
An optical cable as claimed in any one of the preceding Claims, wherein the overall outer protective sheath (6) is of composite form comprising an inner sheath (7) of plastics material and an oversheath (8) of termite-resistant or flame-retardant material.
Claim 9
Dependent Claim
28 words
An optical cable as claimed in any one of the preceding Claims, wherein a circumferentially continuous moisture barrier of metal or metal alloy underlies the overall protective sheath.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
Maintenance schedule is calculated for granted US utility patents.