Spliced Optical Fibre Protection for Blown Microduct Cable Assembly
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Solution Overview
Problem
Existing pre-terminated optical fibre cable assemblies face challenges in efficiently manufacturing and installing spliced joints that are small enough and robust enough to be installed by blowing methods, requiring complex constructions and additional protective sleeves.
Innovation Solution
A method of assembling a pre-terminated optical fibre cable assembly with a spliced joint encased in a protective body, allowing for efficient manufacturing and installation through ducts, using a protective body with streamlined ends and a diameter similar to or smaller than the ferrule sub-assembly, and a kit of parts including a connector body for completion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a spliced joint is made between optical fibres in a pre-terminated cable assembly, then the cable can be manufactured efficiently with pre-assembled connectors, but the spliced joint requires additional protective sleeves and complex constructions to be small enough for blowing installation
Solution Approach 1:
The patent merges the spliced joint protection function with the existing cable sheath structure by creating a protective body that is integrated into the cable assembly. The protective body is formed by moulding material that encapsulates the spliced joint and bonds to the sheath, eliminating the need for separate protective sleeves and reducing overall structural complexity while maintaining blowing installation compatibility.
Solution Approach 2:
The protective body serves multiple functions simultaneously: it protects the spliced joint from damage, provides structural support, maintains cable flexibility, and enables blowing installation. This multi-functional design eliminates the need for separate protective components, reducing device complexity while preserving manufacturing efficiency benefits.
2Volume of moving object
If the protective body diameter is reduced to enable blowing installation through micro-ducts, then the cable assembly becomes compact and installable by blowing, but the protective capability and structural support may be compromised
Solution Approach 1:
The protective body is constructed from composite materials including moulding material that bonds to the cable sheath, providing both structural strength and protection. The composite structure allows the protective body to maintain adequate strength and protective capability while achieving the reduced diameter necessary for blowing installation through micro-ducts.
Solution Approach 2:
The protective body provides localized protection at the spliced joint region with optimized material distribution. The moulding material is applied specifically where protection is needed, creating a compact structure with concentrated protective properties that maintains strength while minimizing overall volume for blowing installation compatibility.
3Productivity
If pre-terminated cable assemblies are manufactured in high volume, then costs and lead time are reduced, but specialist skills and equipment are still required for spliced joint protection
Solution Approach 1:
The protective body is formed and bonded to the sheath as a preliminary action during the cable assembly manufacturing process, before final cable completion. This preliminary protection step is integrated into the manufacturing workflow, allowing high-volume production without requiring separate specialist intervention for spliced joint protection, thereby reducing skill requirements while maintaining productivity.
Data Source
AI summary
A protective body 800 is provided to protect a spliced joint (912) between two optical fibres. The protective body is small, robust and streamlined so that the cable including the spliced joint can be installed in a microduct, for example by blowing. A pre-terminated cable assembly (1000, 1200) comprises a length of cable (1110, 1210) in which one or more optical fibres (306) are embedded in a coated fibre bundle. An extruded sheath (324) covers the coated fibre bundle. A ferrule sub-assembly (1124a, 1224a) is pre-arranged on a leading end of the cable. After passing through a duct, the sub-assembly (1124a, 1224a) becomes part of a pluggable connector (500). For the manufacture of such cable assemblies, a supply (1152) of pre-terminated fibre “tails” is made. These tails are then spliced to the ends of a longer cable, to form the cable complete assembly of desired length.