Brush Head Section Over-Molding for Anchor-Free Cleaning Elements

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Solution Overview

Problem

Existing methods for producing brush heads for oral care devices, particularly powered toothbrushes, require high material costs and are not adaptable for both manual and electric devices using anchor-free or hot tufting methods.

Innovation Solution

A method involving injection molding of a first thermoplastic insert and over-molding with a softer second thermoplastic material to create a cleaning element carrier, allowing for secure anchoring of cleaning elements without the need for anchors, suitable for both manual and electric toothbrushes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If anchor-free or hot tufting methods are used for powered toothbrushes, then hygiene and bristle pattern variability are improved, but material requirements and costs increase

Engineering Contradiction:
ImprovehygieneVSAvoidmaterial requirements
Core Design Contradiction:
Object-affected harmful factorsVSQuantity of substance

Solution Approach 1:

The invention divides the brush head into modular components: a reusable insert containing the driving system and coupling elements, and a disposable brush head portion with cleaning elements. This segmentation allows the expensive anchor-free mounting system to be used only in the durable insert, while the disposable portion uses simpler, less material-intensive attachment methods.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the material parameter by using a thermoplastic material for the insert that can be molded to create integrated anchoring structures. The thermoplastic material allows for heat-based anchoring of cleaning elements directly into the insert, providing secure attachment without requiring additional anchor components or excessive materials.

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If anchor-free or hot tufting methods are used for powered toothbrushes, then hygiene and bristle pattern variability are improved, but manufacturing complexity increases

Engineering Contradiction:
ImprovehygieneVSAvoidmanufacturing complexity
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The invention merges multiple functions into the insert: the driving system, the coupling mechanism, and the anchoring structure for cleaning elements are all integrated into a single thermoplastic molded component. This consolidation simplifies manufacturing by reducing the number of separate parts and assembly steps required.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insert is designed as a universal component that can be used with different brush head configurations and cleaning element arrangements. The standardized insert design allows the same anchor-free mounting technology to serve multiple product variants, reducing overall manufacturing complexity across the product line.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Quantity of substance

If traditional anchor tufting methods are used, then material usage is reduced, but bristle pattern precision and hygiene are compromised

Engineering Contradiction:
Improvematerial usageVSAvoidbristle pattern precision
Core Design Contradiction:
Quantity of substanceVSManufacturing precision

Solution Approach 1:

The invention replaces the mechanical anchor system with a thermal bonding system. The thermoplastic insert is heated during molding to melt and bond cleaning elements directly into place, eliminating the need for separate anchor wires or mechanical fastening components, thus reducing material usage while maintaining precision.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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 method reduces material costs and increases versatility by enabling the production of brush heads with a secure, hygienic, and anchor-free mounting system for both manual and electric toothbrushes, ensuring high precision and ease of cleaning.

Implementation Method 1

injecting a first thermoplastic material into an insert-forming mold cavity to form an insert

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 2

injecting a second thermoplastic material into said over-molding mold cavity so that the part of the insert and the part of the at least one cleaning element which are located inside said over-molding mold cavity are over-molded by the second thermoplastic material

Methodology Applied
Scientific EffectInjection molding:

Implementation Method 3

the insert has a section behind which the cleaning element carrier can engage

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2599403B1Method and device for producing a brush head section for an oral care device and brush head section produced by said method and/or said device
Publication Date: 2019.10.02 BRAUN GMBH
  • EP2599403B1 patent drawingFigure 1
  • EP2599403B1 patent drawingFigure 2A~2B
  • EP2599403B1 patent drawingFigure 3

AI summary

A method for producing a brush head section for an oral care device has the following steps: injecting a first thermoplastic material into an insert-forming mold cavity to form an insert; transferring said insert into an over-molding mold cavity, wherein the insert is arranged partially inside and partially outside of said over-molding mold cavity; arranging one end of at least one cleaning element in said over-molding mold cavity; injecting a second thermoplastic material into said over-molding mold cavity so that the part of the insert and the part of the at least one cleaning element which are located inside said over-molding mold cavity are over-molded by the second thermoplastic material, which second thermoplastic material thereby forms a cleaning element carrier, and wherein the hardness of the second thermoplastic material is smaller than the hardness of the first thermoplastic material; and ejecting the resulting brush head section from said over-molding mold cavity.