Retractable Fibre Optic Cable With Polypropylene Lining
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Solution Overview
Problem
Conventional pullback cables have limited fibre unit length that can be withdrawn in one section, restricting the distance a fibre unit can be rerouted to customer premises, requiring multiple stages of withdrawal and repositioning, which hampers the efficiency of fibre optic installations.
Innovation Solution
The development of a fibre optic cable with retractable fibre units featuring a polyethylene sheath and a lining of a different polymer, such as polypropylene, allows for longer fibre unit lengths to be withdrawn without fusing during the manufacturing process, enabling extended distances to be covered in a single installation step by reducing friction and maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional pullback cable with polyethylene lining is used, then fibre units can be easily manufactured and installed, but the fibre unit length that can be withdrawn in one section is limited to a few tens of metres
Solution Approach 1:
The patent changes the material parameter of the tube lining from polyethylene to polypropylene, which has different friction characteristics. This parameter change enables longer fibre units (up to 200 meters) to be withdrawn without excessive pulling force, resolving the contradiction between increasing fibre unit length and maintaining installation simplicity.
Solution Approach 2:
The patent uses a composite structure combining polypropylene lining material with the extruded polymer tube, creating a multi-material system that optimizes both the structural integrity and the friction characteristics needed for long-distance fibre withdrawal without increasing installation complexity.
2Productivity
If fibre unit length is increased to cover longer distances, then fewer installation stages are needed, but the risk of fibre units fusing during manufacturing increases
Solution Approach 1:
The patent changes the chemical composition parameter of the tube lining from polyethylene to polypropylene, which has different thermal and friction properties. This prevents the fibre units from fusing during the extrusion process while enabling longer fibre unit lengths, thus maintaining reliability while improving productivity.
Solution Approach 2:
The polypropylene lining acts as an intermediary layer between the fibre units and the extrusion process. It provides sufficient friction resistance to prevent fusion during manufacturing while allowing easy withdrawal of long fibre units during installation, thus mediating between the conflicting requirements of manufacturing reliability and installation efficiency.
3Ease of operation
If multiple stages of fibre withdrawal are performed to reach distant premises, then the fibre unit length can be managed within limits, but the installation time and cost increase
Solution Approach 1:
The patent changes the friction parameter of the tube lining by using polypropylene instead of polyethylene. This enables a single-stage withdrawal of fibre units up to 200 meters long, eliminating the need for multiple installation stages and significantly reducing installation time while maintaining operational simplicity.
Solution Approach 2:
The patent enables continuous withdrawal of long fibre units in a single operation rather than requiring discontinuous multi-stage installation. This continuity of useful action reduces the number of installation steps and time required, directly addressing the contradiction between installation simplicity and installation time.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution enables reliable withdrawal of fibre units up to 200 meters without excessive pulling force, reducing the need for multiple stages and enhancing the efficiency and cost-effectiveness of fibre optic installations by allowing longer distances to be covered in a single step.
Implementation Method 1
the extruded polymer tube of the fibre optic cable has a lining made from a different polymer to the sheath of the fibre units, such as the tube having a lining made from polypropylene and the fibre units having sheaths made from polyethylene, which reduces friction between the tube and the fibre units
Data Source
AI summary
A fibre optic cable (500, 700) comprises retractable fibre units (502) extending in parallel with one another within an extruded polymer tube (504). The fibre units are free to slide in the tube such that a selected fibre unit (702a) can be accessed and re-directed by forming an opening in a wall of the tube (504) and withdrawing the selected fibre unit through the opening (710). Each fibre unit comprises two or more optical fibres (506) embedded in a solid resin material (520) to form a coated fibre bundle and an extruded polymer sheath (524). The fibre optic cable is manufactured by feeding the fibre units through an extrusion head (602) by which the extruded tube (504) is formed. The sheath (524) of each fibre unit is primarily polyethylene. A lining (510) of the extruded polymer tube is formed by polymer other than polyethylene, for example polypropylene.