Fiber Optic Cable Sub-Assembly Collar Strain Relief
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Solution Overview
Problem
Conventional fiber optic cable configurations face challenges in strain relief and electrical isolation, leading to potential deformation, attenuation, and electrical interference due to axial loads and the presence of conductive metal strength members.
Innovation Solution
A fiber optic cable sub-assembly is created using a collar with an inner conductive portion attached to the metal strength members and an outer dielectric portion, providing strain relief and electrical isolation by crimping the inner portion to the strength members and seating it within a dielectric outer portion, which is attached to a connector housing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional fiber optic cable configurations use metal strength members for strain relief, then cable strength and structural stability are improved, but electrical interference occurs and electrical isolation is compromised
Solution Approach 1:
The collar is divided into two distinct portions: an inner conductive portion that contacts the metal strength members for mechanical support, and an outer dielectric portion that provides electrical isolation. This segmentation allows the single collar structure to simultaneously provide both strength reinforcement and electrical interference prevention.
Solution Approach 2:
The collar combines two different materials with complementary properties: a conductive material (such as metal) for the inner portion that interfaces with strength members, and a dielectric material (such as plastic or rubber) for the outer portion that prevents electrical interference. This composite structure resolves the contradiction between needing electrical conductivity for mechanical attachment and electrical isolation for interference prevention.
2Stability of the object's composition
If axial loads are applied to preserve excess optical fiber length, then fiber positioning is maintained, but deformation occurs leading to tension and potential attenuation
Solution Approach 1:
The collar structure is designed beforehand to absorb and distribute axial loads through its crimped configuration, preventing these loads from being transmitted to the optical fibers. The collar acts as a cushioning element that protects the fibers from deformation and tension before harmful forces can affect them.
Solution Approach 2:
The collar serves as an intermediary element between the metal strength members and the optical fibers. It receives axial loads from the strength members and distributes them in a manner that prevents direct transmission of deforming forces to the fibers, thereby maintaining fiber positioning stability while protecting transmission reliability.
3Ease of manufacture
If a simple single-material collar is used for strain relief, then manufacturing complexity is reduced, but electrical isolation capability is insufficient
Solution Approach 1:
The collar is segmented into inner and outer portions with different material properties, allowing each portion to perform its specific function while being manufactured as an integrated component through processes like co-molding or overmolding.
Solution Approach 2:
The collar uses composite materials combining conductive and dielectric properties in a single integrated component, achieving both mechanical attachment and electrical isolation functions without requiring separate parts, thus maintaining manufacturing simplicity while adding electrical isolation capability.
Data Source
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AI summary
Fiber optic cable sub-assemblies comprise a fiber optic cable including at least one optical fiber (201), a cable jacket that houses the optical fiber and at least one strength member (207). The fiber optic cable sub-assembly further comprises a collar (301) including an inner portion (303) seated within a cavity of an outer portion (311), wherein the inner portion is attached to an end portion of the strength member of the cable, and the optical fiber extends through the collar to protrude from an outer axial end of the collar. Methods of assembling a fiber optic cable sub-assembly include providing a cable having a strength member along with a collar having an inner portion and an outer portion, attaching the inner portion to an end portion of the strength member so the optical fiber extends from an outer axial end of the collar along with methods for making cable assemblies.