Self-Supporting Drop Cable Assembly for Aerial Spans
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Solution Overview
Problem
Aerial fiber optic cables used in 'fiber-to-the-home' applications face mechanical stresses such as wind and ice loading, which can cause breakage, and existing solutions require additional messenger cables or lashing, increasing installation costs and complexity.
Innovation Solution
A self-supporting fiber optic cable assembly is designed with an outer sheath that includes embedded strength members, allowing the drop cable to be reinforced and installed without messengers or lashing, using a drop cable with embedded strength members and a sheath that provides additional tensile strength to handle ice and wind loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a metallic messenger conductor is included in the cable to provide high strength, then the cable can resist wind and ice loading, but the cable structure becomes more complex and installation costs increase
Solution Approach 1:
The patent combines the drop cable and messenger cable into a single integrated assembly. The outer sheath encloses both the drop cable containing its strength members and the separate messenger cable, creating a unified structure that provides both functions without requiring separate installation processes or additional lashing hardware.
Solution Approach 2:
The outer sheath serves multiple functions: it protects the drop cable, encloses the messenger cable, provides additional strength, and enables direct attachment to utility poles. This multi-functional design eliminates the need for separate messenger cable installation and lashing operations, reducing overall system complexity.
2Strength
If a separate messenger cable is lashed to the drop cable to support ice loading, then the cable can handle mechanical stresses, but installation complexity and costs increase due to additional lashing requirements
Solution Approach 1:
The patent merges the drop cable and messenger cable into a single pre-assembled unit where the messenger cable is positioned within the outer sheath alongside the drop cable. This integrated construction eliminates the need for field lashing operations, as the cables are already mechanically coupled during manufacturing.
Solution Approach 2:
The messenger cable and drop cable are pre-positioned and secured within the outer sheath during the manufacturing process, before installation at the utility pole. This preliminary arrangement of strength members and cable positioning simplifies the installation process by eliminating complex field lashing operations.
3Strength
If the drop cable is made of high strength to resist mechanical stresses, then the cable does not break under tension, but the cable becomes more rigid and difficult to install
Solution Approach 1:
The patent applies different structural characteristics to different parts of the cable system. The strength members provide localized tensile strength where needed to resist pole attachment stresses, while the polymeric jacket and inner cable structures maintain flexibility for easy handling and installation. This localized application of strength properties allows the cable to be both strong and flexible.
Data Source
AI summary
A drop cable assembly has a drop cable and an outer sheath formed around the drop cable that encloses and reinforces the drop cable. The drop cable is accommodated within a cavity of the outer sheath and includes strength members.