Fiber Optic Cable Boot Design for Stress Relief
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Solution Overview
Problem
Fiber optic cables face stress concentrations and bending issues due to the rapid transition from rigid connector bodies to less rigid cables, which can lead to improper functioning when radial loads are applied.
Innovation Solution
A fiber optic assembly design that includes a fiber optic cable with aramid fibers between the cable jacket and the optical fibers, a connector body with a back-end portion for the optical fibers, and a tube that prevents boot material from entering the space between the cable jacket end and the connector body, all of which are over-molded with a boot to provide strain relief.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a rigid connector body is used to withstand forces during handling and use, then the connector can maintain structural strength, but the rapid transition from high stiffness to low stiffness creates stress concentrations where the cable meets the connector body
Solution Approach 1:
The boot is designed with non-uniform thickness, being thicker at the front end and progressively thinner toward the rear end. This local variation in geometry creates a gradual transition in stiffness properties at the cable-connector interface, reducing stress concentrations while maintaining overall structural strength.
Solution Approach 2:
The boot is formed from a elastomeric material that is softer and more flexible than the rigid connector body. This material combination creates a compliant transition zone that absorbs stress and prevents sharp stiffness changes at the interface between the rigid connector and flexible cable.
2Stress or pressure
If a flexible strain-relieving boot is added to provide stiffness transition, then stress concentrations are reduced, but the manufacturing process becomes more complex requiring multiple components
Solution Approach 1:
The boot integrates multiple functions into a single component: it provides strain relief, creates stiffness transition, protects the cable-connector interface, and serves as a structural support element. This consolidation reduces the number of separate parts while maintaining all necessary functions.
Solution Approach 2:
The boot serves multiple purposes simultaneously: it acts as a strain-relief mechanism, a stiffness transition element, a protective covering, and a structural support. This multi-functionality reduces the need for additional separate components.
3Stability of the object's composition
If traditional boot designs are used without discontinuities, then the boot provides uniform coverage, but the rear segment lacks sufficient flexibility to properly relieve strain
Solution Approach 1:
The boot incorporates discontinuities (such as slots, gaps, or reduced thickness regions) at specific locations to create zones of controlled flexibility. These local modifications allow the boot to adapt and flex where needed while maintaining overall structural integrity and coverage.
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
The design effectively manages stress transitions between the connector and the cable, preventing excessive bending and ensuring proper functioning under radial loads without the need for crimping or heat shrink tubes, thus simplifying the manufacturing process and reducing costs.
Implementation Method 1
The boot provides a transition in stiffness between the fiber optic connector and the cable
Implementation Method 2
aramid fibers between the cable jacket and the at least one optical fiber
Data Source
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AI summary
Fiber optic cable assemblies are provided that comprise a fiber optic cable, a fiber optic connector installed on at least one of the fiber optic cable, and a boot that is molded over portions of the fiber optic connector and fiber optic cable. A tube is used to prevent material of the boot from entering space that exists between a connector body of the fiber optic connector and an end of a jacket of the fiber optic cable. Methods of forming the fiber optic cable assemblies are also disclosed.