Hybrid Core Cable Cover Assembly with Low Friction End Cores

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Solution Overview

Problem

Conventional cable closure assemblies face challenges with solid cores requiring strong axial pulling forces for removal, especially when dealing with elastomeric tubes having higher recovery forces, and often necessitate additional tooling and human effort due to high friction coefficients.

Innovation Solution

A hybrid core structure comprising a spirally wound central core and removable solid end cores with low friction coatings, allowing the elastomeric tube to be maintained in a radially expanded state with reduced axial pulling force requirements, utilizing a combination of a spirally wound ribbon central core and solid end cores with low friction films for easy deployment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional solid cores are used to support elastomeric tubes, then the tubes can be maintained in a radially expanded state, but strong axial pulling forces are required to remove the core

Engineering Contradiction:

Improveaxial pulling forceVSAvoidcore removal

Core Design Contradiction:

ForceVSEase of operation

Solution Approach 1:

The core structure is divided into two distinct segments: a solid end core for initial support and a spirally wound ribbon core for final deployment. This segmentation allows the solid core to be removed with minimal force while the spiral core provides the necessary support structure that can be easily unwound and discarded.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A low friction coating acts as an intermediary between the solid core and the elastomeric tube. This coating reduces the friction coefficient to 0.05 or less, serving as a mediator that allows the tube to be supported by the solid core during installation but easily released during removal, significantly reducing the axial pulling force required.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Strength

If elastomeric tubes with higher recovery forces are used, then thicker and more durable tubes can be deployed, but additional tooling and human effort are required to overcome high friction coefficients

Engineering Contradiction:

Improvetube durabilityVSAvoidtooling requirements

Core Design Contradiction:

StrengthVSDevice complexity

Solution Approach 1:

The invention replaces the need for complex mechanical leverage systems with a simple low friction coating. Instead of using additional tooling to overcome high friction, the solution substitutes a chemical/surface property modification (coating with coefficient of friction ≤ 0.05) that eliminates the need for mechanical advantage devices.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The friction coefficient parameter is changed from conventional values (typically 0.3-0.6) to a significantly lower value (≤ 0.05) through the application of a low friction coating. This parameter change allows thick, high-strength elastomeric tubes to be deployed without requiring additional tooling or excessive human effort.

Inventive Principle:

Principle #35Parameter changes

3Ease of operation

If conventional solid cores with high friction coefficients are used, then the elastomeric tube can be securely held, but molded tapered and textured profiles are required to enable deployment

Engineering Contradiction:

Improvetube deploymentVSAvoidcore manufacturing

Core Design Contradiction:

Ease of operationVSEase of manufacture

Solution Approach 1:

Instead of modifying the core geometry (tapered and textured profiles) to enable deployment, the invention inverts the approach by modifying the surface friction property. Rather than making the core shape complex to reduce friction, a low friction coating is applied to a simple cylindrical core, eliminating the need for complex manufacturing processes.

Inventive Principle:

Principle #13The other way round (Inversion)

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 hybrid core structure enables straightforward deployment of thicker elastomeric tubes with higher recovery forces, reducing the axial pulling force needed to remove the solid core, facilitating easier installation in confined spaces and allowing longer core lengths, thus overcoming the limitations of conventional solid core systems.

Implementation Method 1

Each solid core structure has a film disposed on at least an inner surface thereof having a coefficient of friction less than or equal to 0.05

Methodology Applied

Scientific EffectFriction: Friction

Implementation Method 2

The hybrid core structure includes a central core structure formed from a spirally wound separable ribbon that supports a central portion of the elastomeric tube in a radially expanded state

Methodology Applied

Scientific EffectElastic recovery: Elastic Recovery

Data Source

PatentUS10819097B2Cover assembly with hybrid core structure

Publication Date: 2020.10.27 3M INNOVATIVE PROPERTIES CO

AI summary

An assembly for covering at least a portion of a cable, such as an electric cable, comprises an elastomeric tube and a hybrid support core structure. The hybrid core structure includes a central core structure formed from a spirally wound separable ribbon that supports a central portion of the elastomeric tube in a radially expanded state, and first and second solid end core structures that support first and second end portions of the elastomeric tube in a radially expanded state. Each solid end core structure has a film disposed on at least an inner surface thereof having a coefficient of friction less than or equal to 0.05.