Non-Circular Filament Tuft for Oral Care Stiffness

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Solution Overview

Problem

Conventional oral care implement tufts, particularly those with tapered filaments, struggle to effectively penetrate interdental spaces due to low bending stiffness and have a short lifespan, failing to adequately remove plaque and debris from hard-to-reach areas like the gingival margin and interproximal regions.

Innovation Solution

The oral care implement features a tuft with a plurality of substantially cylindrical filaments having non-circular cross-sectional areas, arranged to create a scaled-up version of their individual shapes, providing increased bending stiffness and longer lifespan, and incorporating end-rounded tips for gentle cleaning, along with specific geometries like squares, rectangles, and grooves for enhanced plaque removal.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If tapered filaments are used, then the filaments can flex easily to adapt to tooth surfaces, but the bending stiffness is reduced and they wear away quickly

Engineering Contradiction:
Improveflexibility to adapt to tooth surfacesVSAvoidbending stiffness and lifespan
Core Design Contradiction:
Adaptability or versatilityVSStrength

Solution Approach 1:

The patent applies asymmetry by using non-circular cross-sectional filaments (e.g., triangular, rectangular, or oval cross-sections) instead of symmetric circular filaments. This asymmetric geometry provides different stiffness characteristics in different directions, allowing the filaments to maintain higher overall bending stiffness while still adapting to tooth surfaces through controlled flexion in specific directions.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the geometric parameters of the filaments by using non-circular cross-sections with varying dimensions (e.g., different width and height in rectangular cross-sections). This parameter change allows optimization of the stiffness-to-flexibility ratio, providing both the needed bending stiffness for durability and the flexibility for adapting to oral cavity contours.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If conventional cylindrical filaments are used, then the tuft structure is simple, but the cleaning efficiency in hard-to-reach areas like interdental spaces is insufficient

Engineering Contradiction:
Improvetuft structure simplicityVSAvoidcleaning efficiency in interdental spaces
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent uses non-circular cross-sectional filaments that create tufts with asymmetric outer lateral surfaces. This asymmetry allows the tuft to conform better to the irregular geometry of interdental spaces and gingival margins, improving access to hard-to-reach areas while maintaining relatively simple manufacturing processes.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent designs the tuft geometry to provide uniform cleaning effectiveness across different brushing directions and locations. The non-circular cross-section ensures that the filament distribution and contact pressure are optimized for various orientations, making the tuft equally effective whether brushing buccal, lingual, or interproximal surfaces.

Inventive Principle:
Principle #12Equipotentiality

3Object-affected harmful factors

If end-rounded filament tips are used, then gum injury is avoided, but the ability to penetrate and clean interdental spaces is reduced

Engineering Contradiction:
Improvegum injury preventionVSAvoidpenetration ability into interdental spaces
Core Design Contradiction:
Object-affected harmful factorsVSProductivity

Solution Approach 1:

The patent employs a composite approach by combining end-rounded tips with non-circular cross-sectional bodies. The rounded tips provide gentle contact with gum tissue to prevent injury, while the non-circular main body maintains the structural integrity and penetration capability needed to reach into interdental spaces effectively.

Inventive Principle:
Principle #40Composite materials

Data Source

PatentEP2918191B1Head for an oral care implement
Publication Date: 2024.01.24 PROCTER & GAMBLE CO
  • EP2918191B1 patent drawingFigure 1
  • EP2918191B1 patent drawingFigure 2~4
  • EP2918191B1 patent drawingFigure 5

AI summary

A head for an oral care implement comprises a mounting surface and at least one tuft mounted on the mounting surface. The tuft has a longitudinal axis and a cross-sectional area extending in a plane that is perpendicular to the longitudinal axis. The tuft comprises a plurality of substantially cylindrical filaments. Each filament has a longitudinal axis and a cross-sectional area extending in a plane that is perpendicular to the longitudinal axis. The cross-sectional area of each filament has a substantially non-circular shape. The plurality of filaments is arranged in a manner that the cross-sectional area of the tuft has a scaled up shape with respect to the shape of the cross-sectional area of each filament.