Biaxial Stiffness Earplug Stem with Adhesive Alignment Cavity

Solution Overview

Problem

Existing earplugs often face a trade-off between sound attenuation and comfort, with dense earplugs providing effective sound blocking but being uncomfortable, and less dense ones being difficult to insert and insert safely, while also risking deep insertion if the stem is stiff.

Innovation Solution

An earplug design featuring a tip with a rearward recessed cavity and a stem with biaxial stiffness, where the stem's elongate portion is easier to grip and insert laterally but bends safely to prevent deep insertion, combined with a member that aligns and adheres to the tip's surface for enhanced stability and sound sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the earplug tip is made very dense to attenuate a large amount of sound, then sound attenuation is improved, but comfort deteriorates

Engineering Contradiction:

Improvesound attenuationVSAvoidcomfort

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The earplug employs different foam densities in different regions: a denser forward portion for sound attenuation and a less dense rearward portion for comfort and ease of insertion. This local variation in density allows each region to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The earplug uses a composite foam structure with varying density zones within the same material body. The forward portion has higher density for blocking sound, while the rearward portion has lower density for comfort, creating a functionally optimized composite structure.

Inventive Principle:

Principle #40Composite materials

2Ease of operation

If the earplug is made less dense to improve comfort, then comfort is improved, but sound attenuation deteriorates

Engineering Contradiction:

ImprovecomfortVSAvoidsound attenuation

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The earplug employs different foam densities in different regions: a denser forward portion for sound attenuation and a less dense rearward portion for comfort and ease of insertion. This local variation in density allows each region to optimize its function without compromising the other.

Inventive Principle:

Principle #3Local quality

3Ease of operation

If the stem is made relatively stiff to facilitate easy insertion, then ease of operation is improved, but safety deteriorates due to risk of deep insertion

Engineering Contradiction:

Improveease of insertionVSAvoiddeep insertion risk

Core Design Contradiction:

Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The stem's stiffness parameter is made anisotropic: stiff in the lateral direction for easy insertion and bending, but flexible in the axial direction to prevent deep insertion. This parameter change allows the stem to provide both ease of operation and safety.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The stem uses a composite structure with different material properties in different directions, combining lateral stiffness for handling with axial flexibility for safety, creating a functionally optimized anisotropic structure.

Inventive Principle:

Principle #40Composite materials

4Reliability

If the earplug tip is made very dense to attenuate a large amount of sound, then sound attenuation is improved, but ease of insertion deteriorates

Engineering Contradiction:

Improvesound attenuationVSAvoidease of insertion

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The earplug employs different foam densities in different regions: a denser forward portion for sound attenuation and a less dense rearward portion for comfort and ease of insertion. This local variation in density allows each region to optimize its function without compromising the other.

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 allows for effective sound attenuation while ensuring user comfort and safety by facilitating easy insertion and reducing the risk of deep insertion, with the biaxial stiffness and adhesive alignment providing structural stability and acoustic sealing.

Implementation Method 1

a member, disposed at a forward end of the elongate portion and configured to be insertable into the cavity, wherein the member includes a surface to be adhered to an interior facing surface of the cavity

Methodology Applied

Scientific EffectAdhesion: Adhesive

Implementation Method 2

a stem, including a user graspable elongate portion configured with a stiffness in a first direction that is greater than a stiffness in a second direction, which is transverse to the first direction

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS8656927B2Earplug

Publication Date: 2014.02.25 3M INNOVATIVE PROPERTIES CO

AI summary

An earplug is provided and includes a tip for use in forward and lateral sealing, which is formed to define a rearward recessed cavity, and a stem. The stem includes a user graspable elongate portion configured with a stiffness in a first direction that is greater than a stiffness in a second direction, which is transverse to the first direction, and a member, disposed at a forward end of the elongate portion and configured to be insertable into the cavity, the member including a surface to be adhered to an interior facing surface of the cavity and on which a channel is defined to allow for outflow from the cavity, and the member being formed with a shape to complement that of the cavity to axially and circumferentially align the tip and the stem.