Compressible Foam Ring Seal for Movable Keys

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Solution Overview

Problem

Existing methods for protecting electronic devices with movable keys from water and dust infiltration require multiple operations, specialized tools, and a waiting time for glue to harden, and are not adaptable to various shapes and dimensions of keys.

Innovation Solution

A foam ring with adhesive pads that can be mounted directly around the contact axis of movable keys without glue or tools, providing a waterproof and dustproof seal that adapts to different shapes and dimensions, and is compressible to ensure a secure fit.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a silicone part with adhesive bead is used to protect against water and dust infiltration, then protection reliability is improved, but installation complexity and time loss increase due to multiple operations and glue hardening waiting time

Engineering Contradiction:
Improveprotection against water and dust infiltrationVSAvoidinstallation complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the adhesive function and sealing function into a single integrated foam ring component. The foam ring includes adhesive layers on both its inner and outer surfaces, eliminating the need for separate adhesive beads and silicone parts. This merging reduces the number of installation steps from multiple operations (depositing adhesive, installing silicone part, assembling movable key) to a single snap-fit operation, thereby reducing installation complexity while maintaining protection reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adhesive layers are pre-applied to the foam ring during manufacturing, so that when the foam ring is installed around the movable key, the adhesive is already in position and does not require hardening time. The inner adhesive layer is pre-positioned to bond with the movable key, and the outer adhesive layer is pre-positioned to bond with the housing, eliminating the waiting time for glue hardening that plagues traditional methods.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a silicone part with specific shape is used to match the movable key dimensions, then protection reliability is improved, but adaptability decreases as each key requires a custom-shaped silicone part

Engineering Contradiction:
Improveprotection against water and dust infiltrationVSAvoidadaptability to various key shapes and dimensions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The foam ring's dimensions and shape are made adjustable through compression. The foam material allows the ring to be compressed radially inward, enabling a single standard-sized foam ring to adapt to multiple different key sizes and shapes. When compressed, the foam ring conforms to the specific dimensions of each movable key, providing reliable sealing without requiring custom-shaped silicone parts for each key variant. This parameter change (compressibility) provides both reliability and adaptability.

Inventive Principle:
Principle #35Parameter changes

3Strength

If traditional adhesive methods are used, then strong bonding is achieved, but installation time increases due to glue hardening waiting time

Engineering Contradiction:
Improvebonding strengthVSAvoidglue hardening waiting time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent replaces the chemical bonding mechanism (adhesive hardening) with a mechanical bonding mechanism (snap-fit compression). The foam ring is compressed radially inward during installation, causing the adhesive layers to press firmly against the movable key and housing surfaces. This mechanical compression provides immediate bonding strength without requiring the adhesive to undergo a chemical hardening process, thereby eliminating the waiting time while maintaining strong bonding.

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

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 allows for quick and tool-free installation, providing a high level of protection (IP67) against dust and water, with the foam ring maintaining its seal even under repeated use and varying pressures, and can be mass-produced for efficient deployment.

Implementation Method 1

a first adhesive patch comprising two adhesive faces, one able to be fixed on an upper face of the foam ring, the other able to be fixed under the bearing surface of the movable key, and a second adhesive pad comprising two adhesive faces, one able to be fixed on a lower face of the foam ring, the other adapted to be fixed on a housing of the electronic device

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Implementation Method 2

a foam ring made of a closed-cell foam, this foam ring being able to be mounted around the contact axis of the movable key

Methodology Applied
Scientific EffectClosed-cell foam structure: Foam

Implementation Method 3

the foam ring allows the device to be adapted to numerous shapes and dimensions of reception housings and/or mobile keys

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP3026686B1Device for protection against the infiltration of water and dust in an electronic apparatus and method for manufacturing such a device
Publication Date: 2017.05.24 AIRBUS DEFENCE & SPACE SAS
  • EP3026686B1 patent drawingFigure 1A~1C
  • EP3026686B1 patent drawingFigure 2A~3
  • EP3026686B1 patent drawingFigure 2B~2C

AI summary

The invention relates to a protective device (20) against the infiltration of water and dust into an electronic device equipped with at least one movable key (130), said movable key having a bearing surface (130b) and a contact axis (130a). The protective device (20) comprises: - a foam ring (21) made of closed-cell foam, this foam ring being adapted to be mounted around the contact axis (130a) of the movable key, - a first adhesive pad (22) having two adhesive faces, one adapted to be fixed to an upper face (21a) of the foam ring, the other adapted to be fixed under the bearing surface (130b) of the movable key, and - a second adhesive pad (23) having two adhesive faces, one adapted to be fixed to an underside (21b) of the foam ring, the other adapted to be fixed to a housing (14) of the electronic device.