Dynamic Coil Connector for Implantable Medical Devices
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Solution Overview
Problem
Current implantable medical device connectors require high insertion force and tight tolerances, making them difficult to connect and disconnect, especially for complex applications with multiple leads, which poses a challenge for servicing or replacing implanted pulse generators.
Innovation Solution
A low-insertion force electrical connector design that allows coil contacts to move in multiple degrees of freedom without pre-canting, featuring a housing with inner and outer coils that can be radially compressed and expanded, accommodating variations in contact rings and reducing the need for tight tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If traditional electrical connectors are used with pre-canted coil springs, then reliable electrical contact is achieved, but high insertion force and tight tolerances are required
Solution Approach 1:
The coil spring is designed to be dynamic rather than pre-canted, allowing it to flex and adapt during insertion. The spring can compress axially and expand radially to accommodate misalignment and reduce insertion force while maintaining reliable contact.
Solution Approach 2:
The spring geometry is changed from pre-canted to a standard helical configuration, and the material properties are optimized to allow greater flexibility. This changes the mechanical parameters of the contact mechanism to reduce insertion force while maintaining contact reliability.
2Reliability
If traditional electrical connectors with pre-canted coil springs are used, then electrical contact is established, but tight tolerances between contact rings and springs are required
Solution Approach 1:
The dynamic spring design allows for movement and adjustment during assembly, compensating for manufacturing variations. The spring can flex to accommodate tolerance variations in contact ring positioning, eliminating the need for tight manufacturing tolerances.
Solution Approach 2:
The connector is designed with modular components that can be independently manufactured and assembled. The spring and contact rings are separate elements that work together through controlled flexibility rather than precise fit-up, reducing the need for tight tolerances.
3Reliability
If traditional electrical connectors are used, then connection is achieved, but difficulty in disconnection and servicing occurs
Solution Approach 1:
The spring is pre-loaded in a controlled manner during manufacturing to provide consistent contact force without creating excessive retention force. This preliminary setup allows for reliable connection while enabling easier disconnection when needed for servicing.
Solution Approach 2:
The dynamic spring mechanism allows for controlled disengagement by applying force in the insertion direction, which compresses the spring and releases the contact. This makes disconnection easier while maintaining reliable connection during normal operation.
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
Enables easier and more reliable connection and disconnection of implantable medical device leads with reduced risk of damage, allowing for wider tolerances and improved flexibility in connector assembly, facilitating maintenance and replacement of pulse generators.
Implementation Method 1
The outer coil is radially expanded within the recess in response to engagement with contact rings on the implantable medical device
Implementation Method 2
The coil spring exerts a constant force in a loading direction approximately normal to the centerline of the coiled spring in response to a deflection of the coil spring along the loading direction
Data Source
AI summary
A low-insertion force electrical connector for implantable medical devices includes a housing with a pair of opposing sidewalls each with center openings oriented generally concentrically around a center axis. An inner coil is located in a recess with a coil axis generally co-linear with the center axis of the center openings. The inner coil includes an outer diameter less than a recess diameter, and an inner diameter greater than a center opening diameter. An outer coil is threaded onto the inner coil. The outer coil has an outer diameter less than the recess diameter, and an inner diameter less than the center opening diameter. The outer coil is radially expanded within the recess in response to engagement with contact rings on the implantable medical device, such that the outer diameter of the outer coil is at least equal to the recess diameter.