Brush Head Assembly Bristle Retention and Flexibility

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Solution Overview

Problem

Existing brush head assemblies face challenges in retaining bristles securely while maintaining flexibility and conforming to the complex topography of teeth and gums, and in effectively transmitting lateral forces for efficient plaque removal.

Innovation Solution

The brush head assembly features bristle tufts retained within a sandwich of flexible material between two layers of stiffer material, or using shear-thickening material, which allows for improved retention and adaptation to tooth and gum surfaces while transmitting lateral forces effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If anchor-free tufting of bristles is used, then flexibility of bristles is improved, but bristle retention and positioning stability deteriorate

Engineering Contradiction:
Improveflexibility of bristlesVSAvoidbristle retention
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The brush head is divided into multiple tuft retention elements, each independently holding a bristle tuft. This segmentation allows each tuft to flex independently while being securely retained, resolving the contradiction between flexibility and retention.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Tuft retention elements act as intermediary components between the bristle tufts and the brush head body. These elements provide secure anchoring while allowing controlled movement, enabling both retention and flexibility simultaneously.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If longer bristles are used, then ability to splay over tooth topography is improved, but brush head bulkiness and manoeuvrability deteriorate

Engineering Contradiction:
Improveability to splay over topographyVSAvoidbrush head bulkiness
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The brush head is segmented into multiple tuft retention elements distributed across the brush head surface. This allows longer bristles to be accommodated in a compact arrangement, maintaining splaying ability while reducing overall bulkiness.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of extending bristle length in one dimension which increases bulk, the tuft retention elements are arranged in a two-dimensional pattern on the brush head surface, allowing long bristles to splay outwards without increasing brush head length.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If elastomer material is used in brush head, then conformity to tooth surface is improved, but lateral force transmission deteriorates

Engineering Contradiction:
Improveconformity to tooth surfaceVSAvoidlateral force transmission
Core Design Contradiction:
Adaptability or versatilityVSForce

Solution Approach 1:

The brush head uses a composite structure combining elastomer material for conformity with rigid tuft retention elements for force transmission. This composite approach allows the elastomer to conform to tooth surfaces while the rigid retention elements transmit lateral forces effectively to the bristles.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

Different parts of the brush head have different material properties: the elastomer provides local conformity to tooth surfaces, while the rigid tuft retention elements provide local strength for force transmission. This local differentiation resolves the contradiction between conformity and force transmission.

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

This design enhances bristle retention, improves conformity to oral topography, and ensures effective plaque removal by maintaining flexibility and stiffness as needed, leading to improved oral care performance.

Implementation Method 1

a flexible matrix, at least partially comprised of a shear-thickening material for coupling the plurality of bristle tufts to the hard platen

Methodology Applied
Scientific EffectShear-thickening: Shear Thickening

Data Source

PatentEP3294091B1Brush head assembly
Publication Date: 2022.04.06 KONINKLIJKE PHILIPS NV
  • EP3294091B1 patent drawingFigure 1
  • EP3294091B1 patent drawingFigure 2A~2B
  • EP3294091B1 patent drawingFigure 3A~3B

AI summary

A brush head assembly (100) comprising a sandwich assembly (200) comprising a flexible matrix (30") positioned between two layers of stiff or stiffer material (220), a plurality of bristle tufts (21), each of which comprises a plurality of bristle strands, each bristle tuft having a proximal end (23) and a free end (25), a bristle tuft retention element (250) for each bristle tuft (21), the bristle tuft retention elements (250) connecting the proximal end of the bristle tufts (21) to the sandwich assembly.