Articulating Earplug Stem with Locking Protrusion

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Solution Overview

Problem

Conventional earplugs face challenges in balancing sound attenuation and comfort due to rigid stems that hinder natural ear curvature conformity and complex, costly assembly processes, whether integrally formed or separately assembled.

Innovation Solution

A hearing protection device featuring a stem with a protrusion and articulation point that locks into a sound attenuating element's cavity, allowing for a friction/snap-fit attachment without adhesives, providing sufficient rigidity for insertion while remaining pliable to conform to the ear's shape.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the stem is made rigid to facilitate assembly and insertion, then assembly ease and insertion effectiveness are improved, but comfort and ability to conform to ear curvature deteriorate

Engineering Contradiction:
Improveinsertion effectivenessVSAvoidconformity to ear curvature
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The stem is segmented into multiple portions with different rigidity characteristics. The first portion (proximal to sound attenuating element) has greater rigidity for effective insertion, while the second portion (distal portion) has lesser rigidity to conform to ear curvature. This segmentation resolves the contradiction by distributing different mechanical properties to different functional zones of the same component.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the stem are assigned different local qualities in terms of rigidity. The proximal portion maintains higher rigidity for insertion effectiveness, while the distal portion has reduced rigidity for comfort and conformability. This local differentiation allows each section to optimize its function without compromising the other.

Inventive Principle:
Principle #3Local quality

2Ease of manufacture

If the stem and sound attenuating element are formed separately and bonded together, then manufacturing flexibility is improved, but assembly complexity and cost increase

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidassembly complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The stem and sound attenuating element are merged into a single integral structure formed from a single piece of material. This eliminates the need for separate bonding operations, adhesives, or multi-step assembly processes, thereby reducing assembly complexity and cost while maintaining manufacturing flexibility. The integral formation resolves the contradiction by combining two components into one without sacrificing the benefits of separate functional design.

Inventive Principle:
Principle #5Merging (Combining)

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 comfortable, effective sound attenuation with easy insertion and reduced manufacturing costs by using a stem that is rigid enough for depth insertion but flexible to follow the ear's contours, and allows for assembly without adhesives or bonding.

Implementation Method 1

The protrusion is disposed in locking engagement within the cavity to releasably attach the stem to the sound attenuating element

Methodology Applied
Scientific EffectFriction engagement: Friction

Implementation Method 2

the stem is configured to at least partially articulate about the articulation point

Methodology Applied
Scientific EffectArticulation: Hinge

Data Source

PatentEP2073770B1Earplug with articulating stem and locking feature
Publication Date: 2012.11.21 3M INNOVATIVE PROPERTIES CO
  • EP2073770B1 patent drawingFigure 1~2
  • EP2073770B1 patent drawingFigure 3~5
  • EP2073770B1 patent drawingFigure 6~10

AI summary

A hearing protection device is provided including a stem, a protrusion formed on the stem, an articulation point formed on the stem, and a sound attenuating element including a cavity, where the protrusion is disposed in locking engagement within the cavity to releasably attach the stem to the sound attenuating element, and where the stem is configured to at least partially articulate about the articulation point.