Ball-Spring Contact Ring Connector for Low-Force Lead Insertion

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Solution Overview

Problem

Conventional implantable electrical stimulation systems face challenges in efficiently and reliably connecting leads or lead extensions to control modules due to high insertion forces and frictional drag during insertion and withdrawal, which can lead to misalignment and damage.

Innovation Solution

The use of biased ball-spring type contacts in connector assemblies, featuring a contact ring with ball-spring assemblies that include a housing, a biasing member, and a conductive ball, which ensures concentric alignment and reduces friction by urging the ball outward for secure contact, thereby minimizing insertion forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If conventional connector designs are used, then electrical connection is achieved, but high insertion forces and frictional drag occur during insertion and withdrawal

Engineering Contradiction:
Improveinsertion forceVSAvoidconnection reliability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The connector employs dynamic ball-spring assemblies where balls are biased by springs to move between engaged and disengaged positions. This dynamic mechanism allows the connector to adapt during insertion and withdrawal, reducing frictional drag and insertion forces while maintaining reliable electrical connection through the flexible contact interface

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connector divides the contact interface into multiple independent ball-spring assemblies distributed around the contact ring. Each ball-spring assembly operates independently, allowing localized adaptation to insertion forces and reducing overall frictional drag compared to a rigid monolithic contact structure

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If conventional connector designs are used, then electrical connection is achieved, but misalignment and damage occur during insertion and withdrawal

Engineering Contradiction:
Improveinsertion easeVSAvoidmechanical durability
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The biased ball-spring assemblies provide dynamic compliance that absorbs insertion forces and accommodates misalignment. The balls can move independently within their spring bias, preventing stress concentration and mechanical damage while facilitating easy insertion without requiring precise alignment

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring-biased balls provide beforehand cushioning by being pre-loaded to deflect during insertion. This cushioning effect absorbs impact forces and reduces mechanical stress on the connector components, preventing damage during insertion and withdrawal operations

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

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 ball-spring assemblies provide stable, low-friction connections that facilitate easy insertion and withdrawal of leads or lead extensions, reducing mechanical stress and ensuring consistent electrical coupling within implantable electrical stimulation systems.

Implementation Method 1

a biasing member disposed within the ball-spring housing and configured to urge the ball outward towards the opening

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a conductive ball disposed at least partially within the ball-spring housing... ensuring consistent electrical coupling

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP3458154B1Connector assembly with contact rings comprising biased ball-spring contacts
Publication Date: 2025.11.12 BOSTON SCI NEUROMODULATION CORP
  • EP3458154B1 patent drawingFigure 1
  • EP3458154B1 patent drawingFigure 2
  • EP3458154B1 patent drawingFigure 3A~3B

AI summary

A connector assembly includes a connector housing having a longitudinal axis and a port for receiving a proximal end of a lead having terminals electrically insulated from one another. A lumen extends along the longitudinal axis of the connector housing. Contacts are disposed in the housing and are electrically insulated from one another. The contacts couple to the terminals when the proximal end of the lead is received within the lumen. Each contact (500) includes a contact ring and ball-spring assemblies (508) distributed around the contact ring. Each ball-spring assembly includes a housing coupled to the contact ring, a biasing member (514) disposed within the ball-spring housing and a conductive ball disposed at least partially within the ball-spring housing. The ball-spring housing defines an opening that is smaller than a diameter of the ball and the biasing member is configured to urge the ball towards the opening so that a portion of the ball extends out of the opening in the ball-spring housing.