Locator Pin Header Assembly for Implantable Medical Device Sealing

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Solution Overview

Problem

Traditional methods for manufacturing header assemblies for implantable medical devices, such as IPGs, often result in liquid plastic resin leaking into electrical contacts and seals, leading to rejection of the entire device if the resin leaks or the molding process fails.

Innovation Solution

A header assembly and method that involves positioning electrical contact rings and seals within a pre-molded plastic header using locator pins inserted through axially arranged holes to interface with grooves on the rings and seals, ensuring proper retention and sealing, with features like canted coil springs and annular grooves for secure engagement.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If over-molding with liquid plastic resin is used to fix electrical contacts and seals, then the components are encapsulated and held in place, but the liquid resin may leak into the electrical contacts and seals causing device rejection

Engineering Contradiction:

Improvedevice acceptance rateVSAvoidresin leakage

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent divides the header assembly into separate components: a pre-formed header body, electrical contacts, seals, and locator pins. The electrical contacts and seals are positioned and secured with locator pins before the over-molding process, separating the positioning function from the encapsulation function to prevent resin interference with component placement and avoid leakage into sensitive areas.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent performs preliminary positioning and securing of electrical contacts and seals using locator pins inserted through axially arranged holes in the header body before the over-molding process. This preliminary action ensures components are firmly in place and properly oriented before resin is applied, preventing resin from displacing or contaminating the components.

Inventive Principle:

Principle #10Preliminary action

2Manufacturing precision

If locator pins are inserted through axially arranged holes to secure electrical contacts and seals, then component positioning precision is improved, but the device complexity increases

Engineering Contradiction:

Improvecomponent positioning accuracyVSAvoidassembly structure complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The locator pins serve multiple functions: they position the electrical contacts and seals axially, provide alignment references during assembly, and act as locators during the over-molding process. The axially arranged holes in the header body serve as both positioning features and guides for pin insertion, reducing the need for separate positioning and guiding features.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The locator pins act as intermediary elements between the header body and the electrical contacts/seals. Rather than directly molding the components into the header body, the pins provide a mechanical interface that transfers positioning information and secures components during assembly and molding, simplifying the overall manufacturing process.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Object-affected harmful factors

If pre-molded plastic header is used instead of over-molding the entire assembly, then resin leakage is prevented, but the manufacturing process complexity increases

Engineering Contradiction:

Improveresin leakageVSAvoidmanufacturing process simplicity

Core Design Contradiction:

Object-affected harmful factorsVSEase of manufacture

Solution Approach 1:

The patent segments the manufacturing process into distinct stages: first forming the header body as a pre-molded component with axially arranged holes, then separately positioning electrical contacts and seals with locator pins, and finally applying over-mold resin to encapsulate only the necessary areas. This segmentation allows the header body to be pre-formed without resin leakage issues while maintaining manufacturing efficiency.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The header body is pre-molded with axially arranged holes and basic structural features before component assembly. This preliminary action creates a ready-to-receive header that guides component placement and reduces the complexity of the subsequent assembly and molding operations, as the positioning features are already built into the header body.

Inventive Principle:

Principle #10Preliminary action

Data Source

PatentUS8690609B2Method, apparatus and system for positioning and holding electrical contacts, seals and related components

Publication Date: 2014.04.08 BAL SEAL ENG CO INC

AI summary

A header assembly and method to incorporate electrical contacts and seals into a header are described. The header and method include properly positioning a stack of electrical contact housings and seals or seal assemblies in the header and maintaining the electrical contact housings and the seals in the header with pins inserted in the header from outside the header through axially arranged holes in the header to interface corresponding grooves of the electrical contact housings.