Cable Connector Ferrule Crimping to Prevent Slippage and RF Loss
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Solution Overview
Problem
Existing connectors face challenges in achieving a balance between mechanical holding force and electrical performance, particularly at high frequencies, due to demanding crimping forces and potential slippage of crimping ferrules, which can degrade signal transmission and compromise electrical continuity.
Innovation Solution
A connector sub-assembly with a ferrule design that includes through-openings and protrusions to provide axial and rotational abutments, allowing for secure crimping onto a cable's metal braid while minimizing slippage and maintaining electrical performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If demanding crimping forces are applied to secure the ferrule onto the cable, then mechanical holding force is improved, but electrical performance and signal transmission are degraded due to cable deformation
Solution Approach 1:
The patent introduces an intermediary component (ferrule or adapter) between the connector body and the cable. This intermediary absorbs the mechanical stress during crimping, allowing the connector to be securely attached without transmitting excessive deformation forces to the cable itself, thereby preserving electrical performance while achieving mechanical strength
Solution Approach 2:
The connector is divided into separate functional components: the connector body, the ferrule/adapter, and the cable. The crimping force is localized to the ferrule-cable interface rather than being distributed throughout the entire assembly, allowing precise control over where mechanical deformation occurs and minimizing impact on electrical properties
2Reliability
If the ferrule is crimped tightly onto the cable to prevent slippage, then mechanical retention is improved, but electrical impedance and signal transmission are degraded
Solution Approach 1:
The ferrule acts as an intermediary that provides a dedicated crimping surface, isolating the cable from direct contact with the connector body. This allows the cable to be crimped with controlled force to achieve retention without compromising the precise electrical impedance characteristics of the cable-connector interface
Solution Approach 2:
The crimping force is localized to specific regions of the ferrule and cable, rather than being applied uniformly. The ferrule design concentrates deformation in non-critical areas while preserving the electrical properties in critical regions, achieving local optimization of both mechanical retention and electrical impedance
3Reliability
If the ferrule is crimped loosely to preserve signal transmission, then electrical performance is improved, but mechanical retention is degraded due to risk of slippage
Solution Approach 1:
The ferrule serves as a mediator that decouples the mechanical retention function from the electrical transmission function. The ferrule-cable interface can be optimized for mechanical strength while the ferrule-connector interface maintains electrical performance, allowing independent optimization of both parameters
Solution Approach 2:
The patent adds dimensional complexity to the ferrule design, incorporating features such as flanges, ridges, or multi-layer structures. These additional dimensions provide multiple contact surfaces and retention mechanisms, enabling strong mechanical attachment without requiring excessive crimping force that would degrade signal transmission
4Reliability
If complex locking mechanisms with projections and precise alignment features are added to prevent slippage, then mechanical retention is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent extracts the complex locking mechanism from the main connector body and relocates it to the ferrule component. This separation allows the ferrule to be pre-assembled with its retention features, simplifying the final connector assembly process and reducing the need for precise alignment during manufacturing
Solution Approach 2:
The ferrule is prepared in advance with pre-formed retention features such as flanges, ridges, or integrated locking elements. This preliminary preparation eliminates the need for complex real-time alignment and adjustment during assembly, reducing manufacturing complexity while maintaining reliable mechanical retention
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 solution enhances mechanical retention and reduces slippage, ensuring reliable electrical connectivity without degrading signal transmission, especially for RF signals, by optimizing the crimping process and preventing cable deformation.
Implementation Method 1
a rear part comprising at least one crimping zone provided internally with at least one protrusion, a ferrule, intended to be crimped around the end of the metal braid stripped of the outer cable sheath
Implementation Method 2
comprising at least one through-opening configured to house the one or more protrusions, when the rear part of the shielding body is crimped, so as to form an axial abutment between the ferrule and the shielding body
Data Source
AI summary
Connector sub-assembly or connector for a cable with at least one insulated electrical wire, including a metal body housing at least one central contact connected to a cable wire and comprising a rear part for crimping around a ferrule for crimping onto the cable. The invention relates to a connector sub-assembly or connector, intended to be electrically connected to an electrical cable including at least one insulated wire including a core and an electrically insulating sheath, a metal braid encircling the at least one insulated wire, and an outer sheath made of electrically insulating material encircling the metal braid. The sub-assembly includes a ferrule crimped first to the metal braid of the cable in a configuration permitting rear axial abutment against the outer sheath of the cable.