Push-to-fit Earplug with Cavity Array for Reduced Insertion Force

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Solution Overview

Problem

Existing hearing protection devices, such as push-to-fit earplugs, face challenges in reducing the insertion force and equilibrium force exerted on the ear canal, which can lead to discomfort and difficulty in insertion.

Innovation Solution

The earplug design incorporates an array of cavities in the tip region spaced around the longitudinal axis, allowing the sound attenuating body to compress and collapse into a collapsible volume, reducing the insertion force and equilibrium force, and featuring a flange with geometric features for improved insertion and comfort.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the sound attenuating body is made solid without cavities, then the sound attenuation performance is improved, but the insertion force and equilibrium force increase causing discomfort

Engineering Contradiction:
Improvesound attenuation performanceVSAvoidinsertion force and equilibrium force
Core Design Contradiction:
Object-affected harmful factorsVSForce

Solution Approach 1:

The sound attenuating body incorporates an array of cavities creating a porous internal structure that reduces material density while maintaining sound attenuation performance. The cavities allow the material to compress more easily during insertion and reduce the equilibrium force exerted on the ear canal, solving the contradiction between sound attenuation and insertion comfort.

Inventive Principle:
Principle #31Porous materials

2Strength

If the earplug is made with a stiff structure, then the structural integrity and durability are improved, but the ease of insertion is reduced due to higher insertion force

Engineering Contradiction:
Improvestructural integrityVSAvoidease of insertion
Core Design Contradiction:
StrengthVSEase of operation

Solution Approach 1:

The earplug is segmented into distinct regions: a stiff stem portion for structural integrity and a sound attenuating body with cavities for ease of insertion. The cavities create a collapsible volume that allows the sound attenuating body to compress during insertion while the stem maintains its stiffness for durability and handling.

Inventive Principle:
Principle #1Segmentation

3Ease of operation

If the earplug material is made highly compressible, then the ease of insertion is improved, but the sound attenuation performance deteriorates

Engineering Contradiction:
Improveease of insertionVSAvoidsound attenuation performance
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The earplug employs local quality by creating cavities specifically in the sound attenuating body portion while maintaining the stem's solid structure. This localized modification allows the sound attenuating body to be highly compressible for easy insertion while the overall device maintains sufficient sound attenuation performance through the strategic placement and configuration of cavities.

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 design facilitates easy and comfortable insertion while maintaining effective sound attenuation, with a reduced equilibrium force that enhances user experience and durability.

Implementation Method 1

The array of cavities provides a collapsible volume. The tip region comprises a cavity area (Ac), a material area (Am) and an area aspect ratio (Ac/Am) at a plane intersecting the array of cavities transverse to the longitudinal axis

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

push-to-fit type earplugs may include a compressible attenuating portion... The attenuating portion compresses as it is accommodated in the ear canal

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3145461B1Push-to-fit earplug having an array of cavities
Publication Date: 2024.09.11 3M INNOVATIVE PROPERTIES CO
  • EP3145461B1 patent drawingFigure 1~2
  • EP3145461B1 patent drawingFigure 3~4b
  • EP3145461B1 patent drawingFigure 5~6a

AI summary

The present description provides an earplug. One exemplary earplug (100) described herein includes a stem (110) and a sound attenuating body (120) attached to the stem. The sound attenuating body includes a leading end (121), a base end(102), a tip region (123) positioned rearward of the leading end, and a longitudinal axis (10) extending between the leading end and the base end. An array of cavities(60) is positioned within the tip region and spaced around the longitudinal axis and provides a collapsible volume.