Push-to-fit Earplug Tip Cavity for Insertion Comfort

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Solution Overview

Problem

Existing hearing protection devices, such as push-to-fit earplugs, face challenges in ease of insertion and comfort, particularly for users with smaller ear canals, due to the lack of a mechanism that allows the sound-attenuating body to collapse and reduce the sensation of the core during insertion.

Innovation Solution

The introduction of a tip cavity in the earplug design, which provides a volume for the sound-attenuating body to collapse into, and a recessed core end within this cavity, along with a plurality of protrusions on the side wall, facilitates easier insertion and enhanced comfort by minimizing the feeling of the core during use.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sound-attenuating body is made with a stiff core and compressible material, then the earplug can be easily inserted into the ear canal, but the user may feel the core during insertion and experience discomfort

Engineering Contradiction:
Improveease of insertionVSAvoidsensation of core
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The core is recessed into the tip cavity, creating a nested configuration where the core is partially contained within the cavity space. This nesting arrangement allows the core to be present for structural support while being less perceptible to the user during insertion, as it is hidden within the cavity rather than protruding outward.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The tip cavity is created specifically at the distal tip portion of the sound-attenuating body, concentrating the cavity space where it is most needed for comfort during insertion. The cavity is located at the tip rather than distributed throughout the entire body, providing localized relief from core sensation at the critical insertion zone.

Inventive Principle:
Principle #3Local quality

2Ease of operation

If the sound-attenuating body is compressed to facilitate insertion, then the earplug can be quickly inserted, but the material may not have sufficient space to collapse and conform to the ear canal

Engineering Contradiction:
Improvequick insertionVSAvoidconformability to ear canal
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The tip cavity provides a dedicated nested space within the sound-attenuating body that allows the material to collapse inward during insertion. This internal cavity acts as a receiving chamber for the collapsing material, enabling the earplug to conform to the ear canal shape while maintaining the structural integrity provided by the core.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The sound-attenuating body is designed with dynamic collapse capability, where the material can transition from an expanded state during insertion to a collapsed state within the tip cavity. This dynamic behavior allows the earplug to adapt to the ear canal geometry, improving conformability while maintaining quick insertion through the compressed initial state.

Inventive Principle:
Principle #15Dynamics

3Strength

If the core extends to the tip of the sound-attenuating body, then the core provides full structural support, but the user will definitely feel the core during insertion and experience discomfort

Engineering Contradiction:
Improvestructural supportVSAvoidsensation of core
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The core is recessed into the tip cavity, creating a nested configuration where the core is partially contained within the cavity space. This nesting arrangement allows the core to be present for structural support while being less perceptible to the user during insertion, as it is hidden within the cavity rather than protruding outward.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The core is extracted from the tip portion of the sound-attenuating body and recessed into the tip cavity. This extraction removes the core from the position where it would be most perceptible to the user during insertion, while the core remains in place to provide structural support for the remaining portions of the earplug.

Inventive Principle:
Principle #2Taking out (Extraction)

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

This design enhances the ease of insertion and comfort for users by allowing the sound-attenuating body to collapse into the tip cavity, reducing the likelihood of feeling the core, thus improving the overall user experience and fit within the ear canal.

Implementation Method 1

covering at least a portion of a major outer surface of a core that comprises a first material with a second material that comprises an unactivated foaming agent

Methodology Applied
Scientific EffectFoaming: Foam

Data Source

PatentEP3675781B1Push-to-fit earplug with tip cavity
Publication Date: 2022.08.10 3M INNOVATIVE PROPERTIES CO
  • EP3675781B1 patent drawingFigure 1~2
  • EP3675781B1 patent drawingFigure 3~4
  • EP3675781B1 patent drawingFigure 5A~5C

AI summary

An earplug comprises a core and a sound-attenuating body attached to the core, the sound- attenuating body comprising a tip cavity extending proximally from the tip of the sound-attenuating body and comprising a distal opening. The tip cavity side wall includes a plurality of protrusions extending inwardly toward the longitudinal axis of the core. The plurality of protrusions may include from 2 to 12 protrusions. A method of making an earplug includes covering at least a portion of a core with a material including unactivated foaming agent; inserting an end of the core and at least a portion of the material into a mold cavity; and activating the foaming agent to create a sound-attenuating body. The sound- attenuating body has a base, tip, and tip cavity with a plurality of protrusions. The mold cavity may include a boss with a cup and plurality of cut-outs on the cup for forming the protrusions.