Foamable Earplug With Integrated Core And Expanded Outer Layer

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Solution Overview

Problem

Existing push-in earplugs are costly and pose manufacturing challenges due to complex assembly requirements, necessitating a more efficient and cost-effective method for producing hearing protection devices with sound attenuating properties.

Innovation Solution

A foamable article comprising an elongate core with a thermoplastic outer layer containing unactivated expandable sphere and chemical foaming agents, which expands to form a sound attenuating portion and stem, thermally bonded to the core without additional adhesives, allowing direct insertion into the ear canal without compressing the sound attenuating portion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If push-in earplugs are manufactured with separate stiff and attenuating portions, then ease of insertion and hygiene are improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improveease of insertionVSAvoidmanufacturing complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent combines the stiff portion and sound attenuating portion into a single integrated earplug body made from one continuous thermoplastic material. This merging eliminates the need for separate manufacturing and assembly of distinct components, thereby reducing manufacturing complexity while maintaining the push-in insertion mechanism that provides ease of operation and hygiene

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If push-in earplugs are manufactured with separate stiff and attenuating portions, then ease of insertion and hygiene are improved, but manufacturing cost increases

Engineering Contradiction:
Improveease of insertionVSAvoidmanufacturing cost
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The patent combines the stiff portion and sound attenuating portion into a single integrated earplug body made from one continuous thermoplastic material. This merging eliminates the need for separate manufacturing and assembly of distinct components, thereby reducing manufacturing cost while maintaining the push-in insertion mechanism that provides ease of operation and hygiene

Inventive Principle:
Principle #5Merging (Combining)

3Ease of operation

If the outer layer is made soft for comfort, then comfort and sound attenuation are improved, but structural stiffness decreases

Engineering Contradiction:
ImprovecomfortVSAvoidstructural stiffness
Core Design Contradiction:
Ease of operationVSStrength

Solution Approach 1:

The patent creates local quality differentiation within a single material structure by controlling the density distribution of the thermoplastic material. The耳塞体 exhibits varying density zones where certain regions provide stiffness for structural support while other regions provide softness for comfort and sound attenuation, achieving both requirements without needing separate materials

Inventive Principle:
Principle #3Local quality

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 enables efficient, cost-effective manufacturing of earplugs with improved hygiene by eliminating the need for compressing the sound attenuating portion, providing effective sound attenuation and comfort through a stiff core and soft outer layer, while reducing manufacturing complexity and costs.

Implementation Method 1

The second material includes an unactivated expandable sphere foaming agent and an unactivated chemical foaming agent. The unactivated foaming agents may be activated to increase the volume of the outer layer.

Methodology Applied
Scientific EffectFoaming: Foam

Implementation Method 2

an outer layer including a thermoplastic second material and covering at least a portion of the outer major surface of the elongate core

Methodology Applied
Scientific EffectThermal bonding: Heating

Data Source

PatentEP2872551B1Foamable article
Publication Date: 2017.08.09 3M INNOVATIVE PROPERTIES CO
  • EP2872551B1 patent drawingFigure 1~3D
  • EP2872551B1 patent drawingFigure 4~6B
  • EP2872551B1 patent drawingFigure 7A~7B

AI summary

A foamable article is disclosed. The article includes a substrate and an outer layer covering at least a portion of the substrate and including an unactivated expandable sphere foaming agent and an unactivated chemical foaming agent. The unactivated foaming agents may be activated to increase the volume of the outer layer.