Three-Cable Port Grommet Washer Sealing
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Solution Overview
Problem
Current sealing solutions for multiport closures, such as elastomeric grommets, are inadequate for securely sealing and strain-relieving three fiber optic cables simultaneously, as they fail to prevent leakage under environmental pressures and allow cable contact, leading to potential damage and inefficiency.
Innovation Solution
A cable attachment assembly comprising an adapter body, a grommet device, and a grommet washer with a flat and raised region, where the grommet washer is sandwiched between the bolt portion and the grommet device, providing compressive force and preventing cable contact through offset support structures, made from low-friction thermoplastics and elastomeric materials.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single elastomeric grommet is used to seal multiple cables, then the device complexity is reduced, but the sealing reliability and cable protection deteriorate
Solution Approach 1:
The single grommet is segmented into multiple individual grommets, each dedicated to sealing a specific cable. This segmentation allows each grommet to provide focused sealing pressure on its corresponding cable, ensuring reliable sealing without requiring a complex multi-component assembly. The segmentation resolves the contradiction by maintaining simple installation procedures while achieving superior sealing reliability through dedicated sealing elements.
Solution Approach 2:
The grommet washer acts as an intermediary element between the compression bolt and the grommet-cable assembly. It distributes the compressive force uniformly across all grommets and cables, preventing direct contact and concentration of force. This intermediary mechanism enables reliable sealing and cable protection while maintaining a relatively simple overall structure, resolving the contradiction between device complexity and sealing reliability.
2Ease of operation
If cables are allowed to contact each other for ease of installation, then the ease of operation is improved, but cable damage risk increases
Solution Approach 1:
Each cable is assigned its own dedicated grommet and sealing space, physically separating cables from direct contact with each other. This segmentation prevents cable-on-cable damage while maintaining ease of installation, as each cable can be independently inserted and sealed without interfering with other cables. The segmentation resolves the contradiction by eliminating cable contact hazards while preserving installation simplicity.
Solution Approach 2:
The grommet washer serves as an intermediary that prevents direct cable-to-cable contact by maintaining proper spacing and alignment. It distributes compression forces uniformly and prevents cables from shifting into contact with each other during installation and operation. This intermediary function protects cables from damage while allowing straightforward installation procedures.
3Device complexity
If compression force is applied directly to the grommet without a washer, then the device complexity is reduced, but the grommet deformation and creep increase
Solution Approach 1:
The grommet washer is introduced as an intermediary element between the compression bolt and the grommet. It distributes the compressive force uniformly across the grommet and cable assembly, preventing localized over-compression and deformation. This intermediary mechanism maintains dimensional stability and prevents creep over time, while adding minimal complexity to the overall compression system. The washer resolves the contradiction by ensuring stable grommet performance without significantly increasing device complexity.
Solution Approach 2:
The grommet washer is designed as a thin, flexible yet structurally sound component that conforms to the grommet and cable assembly while distributing loads uniformly. Its thin-film structure allows it to adapt to the compression geometry without introducing significant complexity, while its material properties provide the necessary stability to prevent grommet deformation and creep over 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
Effectively seals and retains up to three optical cables, preventing contact between cables and ensuring reliable sealing and strain relief under environmental pressures, enhancing durability and reducing the risk of cable damage.
Implementation Method 1
a bolt portion compressively engages the grommet washer and is capable of selectively applying a compressive force upon the grommet device such that the grommet device engages the outer surface of the cable
Implementation Method 2
Currently there are a number of multiport closures that use elastomeric grommets around cables to water-proof against leakage up to a pressure
Data Source
AI summary
A cable attachment assembly for sealing and retaining three flat cables entering a telecommunications closure provides a grommet having three radially arrayed passageways and a grommet washer having a flat portion and a raised portion for simultaneously maintaining compressive force to the grommet and mitigating creep of the grommet during thermal cycling.