Fastenerless Electronic Circuit Enclosure Assembly

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Solution Overview

Problem

The existing methods for assembling electrical devices, such as automotive radios and computers, rely heavily on threaded fasteners, which lead to inefficiencies in high-volume production due to long assembly cycles, risks of damage, and additional inventory and tooling requirements, as well as issues with electromagnetic interference and thermal management.

Innovation Solution

A 'fastenerless' assembly design using a compression-molded, three-dimensional case with a conductive sheet material and elastomeric framework for shielding and grounding, allowing for screwless assembly and reduced handling, fixtures, and labor requirements, while providing effective thermal management and electromagnetic shielding.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded fasteners are used to assemble electrical devices, then structural support and electromagnetic shielding are provided, but assembly cycle time increases and production efficiency decreases

Engineering Contradiction:
Improvestructural support and electromagnetic shieldingVSAvoidassembly cycle time
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The patent combines the electromagnetic shielding function and structural support function into a single integrated chassis component. The chassis is formed as one piece that simultaneously provides both EMI/RFI shielding and mechanical support for subassemblies, eliminating the need for separate fasteners and reducing assembly steps while maintaining both functions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts and eliminates the fastener component entirely from the assembly system. By designing the chassis with integrated mounting features and snap-fit mechanisms, the separate fastener element is removed, simplifying the assembly process and reducing production time while maintaining structural integrity.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If threaded fasteners are used, then subassemblies are securely retained, but the risk of damage from improper installation increases

Engineering Contradiction:
Improvesecure retention of subassembliesVSAvoiddamage from improper installation
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent employs self-aligning and self-retaining features built into the chassis design. The integrated chassis includes molded-in mounting structures that automatically align and secure subassemblies without requiring external fasteners, eliminating the risk of improper fastener installation while ensuring secure retention.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces the mechanical fastener system with an integrated snap-fit and molded-in retention system. This substitution eliminates threaded fasteners and their associated installation risks, using instead a built-in mechanical retention mechanism that is inherently safer and more reliable.

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

3Reliability

If fasteners and specialized tools are used for assembly, then subassemblies can be securely mounted, but inventory burden and tooling requirements increase

Engineering Contradiction:
Improvesecure mounting of subassembliesVSAvoidinventory and tooling requirements
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the mounting function directly into the chassis structure itself. The chassis is designed with integrated mounting features that eliminate the need for separate fasteners and specialized installation tools, reducing inventory requirements while maintaining secure mounting capability.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If self-tapping fasteners are used, then thread formation is simplified, but metal shavings are generated that can cause electrical failures

Engineering Contradiction:
Improvethread formation processVSAvoidmetal shavings causing electrical failures
Core Design Contradiction:
Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The patent extracts and eliminates the self-tapping fastener process entirely. By using an integrated chassis design with molded-in mounting features, the thread formation process is removed, preventing the generation of metal shavings that could cause electrical failures.

Inventive Principle:
Principle #2Taking out (Extraction)

5Strength

If multiple fasteners are used to secure the chassis, then structural integrity is maintained, but assembly time and labor costs increase

Engineering Contradiction:
Improvechassis structural integrityVSAvoidassembly time and labor costs
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent combines multiple fastening functions into a single integrated chassis component. The one-piece chassis design incorporates all structural integrity features and mounting capabilities within one component, eliminating the need for multiple fasteners and significantly reducing assembly time and labor costs.

Inventive Principle:
Principle #5Merging (Combining)

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

This design significantly reduces assembly time, labor, and inventory costs, enhances product quality, and simplifies the manufacturing process by eliminating the need for fasteners and specialized tools, while maintaining effective shielding and thermal management.

Implementation Method 1

a preform blank of conductive sheet material such as wire screen mesh or the like which defines upper, lower and a plurality of side wall portions

Methodology Applied
Scientific EffectElectromagnetic shielding: Faraday Cage

Implementation Method 2

A framework of resilient elastomeric material is insert molded to the preform blank to provide three-dimensional case details to accept one or more electronic devices

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2684435B1Flexible electronic circuit enclosure assembly
Publication Date: 2019.10.02 APTIV TECHNOLOGIES LTD
  • EP2684435B1 patent drawingFigure 1
  • EP2684435B1 patent drawingFigure 2
  • EP2684435B1 patent drawingFigure 3

AI summary

A flexible enclosure assembly for an electronic device for vehicular application is virtually "fastenerless" and includes a preform blank of conductive sheet material such as wire screen mesh or the like which defines upper, lower and a plurality of side wall portions flexibly interconnected by living hinges. A framework of resilient elastomeric material is insert molded to the preform blank to provide three-dimensional case details to accept one or more electronic devices such as circuit boards required for electrical control and display of vehicle based systems. The conductive sheet material is preferably a wire mesh which provides shielding from electrical anomalies and grounding of the circuit boards via exposed wire mesh pads and adjacent ground clips. Major components and subassemblies are self-fixturing during the final assembly process, eliminating the need for dedicated tools, fixtures and assembly equipment.