Integrally Molded Waterproof Seal for Portable Devices

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Solution Overview

Problem

Existing portable devices for wireless communication, such as electronic keys, require a screw-fastened O-ring seal to prevent water ingress, which complicates the waterproofing mechanism and increases the need for a fastening structure.

Innovation Solution

A waterproof portable device design featuring a battery lid with integrally molded silicone rubber, where the rubber is elastically deformed to create a liquid-tight seal without the need for screws, using hooks and catches to secure the lid in place, eliminating the requirement for a screw-fastened structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an O-ring seal is used with screw fastening to prevent water ingress, then waterproofing reliability is improved, but device complexity increases due to the fastening structure

Engineering Contradiction:
Improvewaterproofing reliabilityVSAvoidfastening structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the sealing function and fastening function into a single integrated structure. The O-ring seal is molded directly onto the battery lid, eliminating the need for separate screw fasteners. The compression of the O-ring against the case body simultaneously achieves both sealing and mechanical attachment, thereby reducing device complexity while maintaining waterproofing reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the screw fastening component from the sealing mechanism, replacing it with an integrated O-ring structure that provides both sealing and attachment functions. This extraction simplifies the overall structure by removing unnecessary fastening parts while maintaining the essential waterproofing function.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If an O-ring seal is compressed to maintain waterproofing, then sealing effectiveness is improved, but the structure requires additional fastening components

Engineering Contradiction:
Improvesealing effectivenessVSAvoidfastening components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent merges the sealing function and fastening function into a single integrated structure. The O-ring seal is molded directly onto the battery lid, eliminating the need for separate screw fasteners. The compression of the O-ring against the case body simultaneously achieves both sealing and mechanical attachment, thereby reducing device complexity while maintaining waterproofing reliability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If a screw-fastened waterproof structure is used, then liquid-tight sealing is achieved, but device size increases

Engineering Contradiction:
Improveliquid-tight sealingVSAvoiddevice size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent combines the sealing function and fastening function into a single integrated structure. The O-ring seal is molded directly onto the battery lid, eliminating the need for separate screw fasteners. The compression of the O-ring against the case body simultaneously achieves both sealing and mechanical attachment, thereby reducing device complexity while maintaining waterproofing reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses a flexible O-ring seal made of elastomeric material that can be compressed to form a liquid-tight barrier. This flexible sealing approach eliminates the need for rigid screw fasteners and complex sealing mechanisms, thereby reducing overall device size while maintaining effective waterproofing.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If a complex fastening structure is used for waterproofing, then sealing reliability is improved, but ease of manufacture decreases

Engineering Contradiction:
Improvesealing reliabilityVSAvoidmanufacturing simplicity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent combines the sealing function and fastening function into a single integrated structure. The O-ring seal is molded directly onto the battery lid, eliminating the need for separate screw fasteners. The compression of the O-ring against the case body simultaneously achieves both sealing and mechanical attachment, thereby reducing device complexity while maintaining waterproofing reliability.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent uses composite construction by molding the O-ring seal from elastomeric material directly onto the battery lid body. This integration of different materials and functions into a single component simplifies the manufacturing process while maintaining reliable sealing performance.

Inventive Principle:
Principle #40Composite materials

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 design provides a simplified, screw-less waterproofing mechanism that maintains a liquid-tight seal, reduces the size of the device, and facilitates easy battery replacement while ensuring effective prevention of water ingress.

Implementation Method 1

where the rubber is elastically deformed to create a liquid-tight seal

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

the compression of the O-ring produce a repulsive force that urges the case and battery lid away from each other

Methodology Applied
Scientific EffectCompression: Compression

Data Source

PatentEP2405407B1Portable device having a simple waterproof structure
Publication Date: 2017.08.09 KK TOKAI RIKA DENKI SEISAKUSHO
  • EP2405407B1 patent drawingFigure 1~2
  • EP2405407B1 patent drawingFigure 3~4
  • EP2405407B1 patent drawingFigure 5~6

AI summary

A portable device (2), which performs wireless communication with a communication peer, includes a battery (9), which powers an electronic component (5), and a case, which accommodates the electronic component (5) and battery (9). The case (6) includes a battery compartment (11) having an opening. An elastic waterproof seal (26) surrounds the opening. A battery lid (7), which covers the opening, is formed integrally with the waterproof seal (26) and coupled to the case (6) in a direction perpendicular to a radial direction of the waterproof seal. A rim around the opening of the battery compartment pushes the waterproof seal when coupling the battery lid to the case thereby elastically deforming the waterproof seal in an inward radial direction. The waterproof seal, when elastically deformed, keeps the battery lid coupled to the case and seals the battery lid and case in a liquid-tight state.