Dielectric Inner Ferrule Ribs for Universal Shielded Cable Termination

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Solution Overview

Problem

Existing shielded cable termination methods require multiple ferrule sizes for different cable cross-sections, are not versatile, and involve costly manufacturing processes, with potential for electrical shorting and increased manufacturing time due to size differentiation and marking requirements.

Innovation Solution

A dielectric inner ferrule with longitudinal ribs and optional cut-outs, adaptable to various cable sizes, and a conductive outer ferrule, allowing for a universal assembly process that includes a termination ring for secure connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple ferrule sizes are used for different cable cross-sections, then cable termination accuracy is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvecable termination accuracyVSAvoidferrule assembly complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The inner ferrule is designed with a universal structure that can accommodate multiple cable cross-sections through the integration of longitudinal ribs and optional cut-outs. This single ferrule design replaces the need for multiple size-specific ferrules, reducing device complexity while maintaining accurate termination for various cable sizes.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The inner ferrule incorporates longitudinal ribs with varying radial lengths at different locations to adapt to different cable cross-sections. The ribs can be selectively removed or adjusted to match specific cable dimensions, providing localized adaptation while using a single ferrule design.

Inventive Principle:
Principle #3Local quality

2Manufacturing precision

If deep draw stamping or machining is used to manufacture ferrules, then manufacturing precision is improved, but manufacturing cost increases

Engineering Contradiction:
Improveferrule dimensional accuracyVSAvoidmanufacturing cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

The manufacturing process is replaced from mechanical methods (deep draw stamping or machining) to injection molding. The inner ferrule is formed by injecting dielectric material into a mold cavity, which automatically creates the longitudinal ribs and cut-outs. This substitution significantly reduces manufacturing cost while maintaining precision through mold-defined geometry.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If inner and outer ferrules are crimped together, then electrical connection reliability is improved, but the risk of electrical shorting increases due to inner ferrule rupture

Engineering Contradiction:
Improveelectrical connection reliabilityVSAvoidelectrical shorting risk
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The inner ferrule acts as a dielectric intermediary between the inner conductor and the conductive outer ferrule. This dielectric barrier prevents direct electrical contact between the inner conductor and outer ferrule, eliminating the risk of electrical shorting even if the inner ferrule ruptures during crimping. The outer ferrule crimps onto the outer conductor while the inner ferrule remains electrically isolated.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Ease of operation

If color coding markings are applied to distinguish ferrule sizes, then ease of operation is improved, but manufacturing time and cost increase

Engineering Contradiction:
Improveferrule identificationVSAvoidmanufacturing efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The inner ferrule incorporates asymmetric longitudinal ribs with different radial lengths that create visually distinct patterns on the ferrule surface. These asymmetric rib configurations provide inherent visual identification for different cable size adaptations without requiring additional color coding markings, thus maintaining manufacturing efficiency.

Inventive Principle:
Principle #4Asymmetry

Data Source

PatentEP4607707A1Ferrule for a shielded cable, terminal assembly and process of teminating a shielded cable
Publication Date: 2025.08.27 APTIV TECHNOLOGIES AG
  • EP4607707A1 patent drawingFigure 1~3
  • EP4607707A1 patent drawingFigure 4A~4D
  • EP4607707A1 patent drawingFigure 4E~6

AI summary

An inner ferrule (4) for a terminal assembly configured to terminate a shielded cable (2). The inner ferrule (4) is formed of a dielectric material. The inner ferrule (4) has a generally tubular shape. The inner ferrule (4) comprises a plurality of ribs extending longitudinally parallel to a longitudinal axis and radially inwardly, over a height, from the inner surface of the inner ferrule (4). Set of inner ferrules (4) comprising at least two inner ferrules (4) differing from the each other in the height of their respective ribs. A terminal assembly configured to terminate a shielded cable. A method of terminating a shielded cable.