Brush head manufacturing methods

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Solution Overview

Problem

Existing toothbrush brush heads often experience loose retention rings and bristle tufts, leading to suboptimal bristle positioning and increased manufacturing time and cost, especially under dynamic conditions of power toothbrush operation.

Innovation Solution

A method involving the insertion of bristle tufts into retention rings, securing them with a heat-formed proximal head portion, and embedding both within an elastomeric matrix, utilizing layers with different elastic modulus values to enhance retention and flexibility.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If bristle tufts are inserted into retention rings and cooled to fix them in place, then the bristle tufts are retained within the brush head, but the retention rings become loose and separate under dynamic conditions

Engineering Contradiction:

Improveretention ring securityVSAvoidbristle tuft positioning

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent uses a two-material composite system: a rigid thermoplastic retention ring provides structural support and initial securing, while a flexible elastomeric matrix material (such as silicone rubber or thermoplastic elastomer) embeds the retention ring and bristle tufts. This composite approach allows the rigid component to maintain positioning while the flexible matrix absorbs dynamic stresses, preventing loosening and separation under operational conditions.

Inventive Principle:

Principle #40Composite materials

2Reliability

If the brush head material is cooled to fix bristle tufts in place, then the tufts are secured, but the manufacturing process becomes time-consuming

Engineering Contradiction:

Improvebristle tuft fixationVSAvoidmanufacturing cycle time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent utilizes the phase transition properties of thermoplastic materials. The retention ring is formed from thermoplastic material that can be molded at elevated temperatures and then cooled to lock the bristle tufts in place. This phase change from molten to solid state provides rapid fixation without requiring extended cooling periods, significantly reducing manufacturing cycle time while ensuring secure tuft retention.

Inventive Principle:

Principle #36Phase transitions

3Ease of manufacture

If retention rings are made with hollow circular shape, then they are easy to manufacture, but they do not provide firm security for bristle tufts

Engineering Contradiction:

Improveretention ring fabricationVSAvoidbristle tuft positioning accuracy

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent applies local quality by varying the cross-sectional geometry of the retention ring along its circumference. While the overall ring maintains a simple circular shape for ease of manufacturing, specific localized regions incorporate non-circular cross-sections (such as oval, triangular, or irregular shapes) that provide enhanced grip and positioning accuracy for the bristle tufts. This selective geometric modification maintains manufacturing simplicity while improving precision where needed.

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 approach results in a cost-effective and efficient production of brush heads with securely retained bristle tufts, improving cleaning efficacy and durability, suitable for both manual and power toothbrushes.

Implementation Method 1

applying heat to each bristle tuft proximal end at a temperature sufficient to at least partially melt the bristle tuft proximal end

Methodology Applied

Scientific EffectHeating: Heating

Implementation Method 2

applying heat to each bristle tuft proximal end at a temperature sufficient to at least partially melt the bristle tuft proximal end and create a proximal head portion

Methodology Applied

Scientific EffectMelting: Melting

Implementation Method 3

injecting the thermoplastic elastomer into the space to create an elastomeric matrix that at least partially encompasses the platen and the proximal head portions

Methodology Applied

Scientific EffectInjection: Injector

Data Source

PatentUS10477959B2Brush head manufacturing methods

Publication Date: 2019.11.19 KONINKLIJKE PHILIPS NV

AI summary

A method (200) for manufacturing a brush head (100). The method includes the steps of providing a plurality of polypropylene bristle tuft retention rings (50), and inserting a respective nylon bristle tuft (21) into each of the bristle tuft retention rings. Heat is applied to each bristle tuft proximal end (23) at a temperature sufficient to at least partially melt the bristle tuft proximal end and create a proximal head portion (26). The platen (42) of the brush head is positioned in relation to the retaining rings (50) and proximal head portions (26) to define a space (92) in relation to the proximal head portions for injection of a thermoplastic elastomer, and the thermoplastic elastomer is injected into the space to create an elastomeric matrix (30) that at least partially encompasses the neck and the proximal head portions.