Toothbrush Bristle Rib Form-Fitting Retention

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Solution Overview

Problem

The existing technologies for toothbrush bristles face limitations in achieving an optimized cleaning effect due to restricted material choices for the ribs and matrix, which must form a strong connection to prevent the rib from detaching, limiting the selection and combination options and thus the cleaning performance.

Innovation Solution

A monofilament design where the rib is securely held within the matrix through a form-fitting connection, which can also include integral or non-positive bonding, allowing for the use of different plastic materials for the rib and matrix, enabling improved material selection and adaptation for enhanced cleaning properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the rib and matrix are made of different plastic materials to optimize cleaning effect, then the cleaning performance is improved, but the material selection is restricted because the two materials must form a strong connection to prevent rib detachment

Engineering Contradiction:
Improvematerial selection freedomVSAvoidrib retention in matrix
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The rib is designed with a predetermined geometric shape featuring a radially outwardly tapering cross-section and undercuts at the radially inner end. This preliminary geometric configuration enables form-fitting retention within the matrix before any bonding occurs, ensuring the rib remains securely positioned during use while allowing diverse material selections for both rib and matrix.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If a strong connection between rib and matrix is ensured through material bonding, then the rib retention is improved, but the choice of plastic materials is severely restricted

Engineering Contradiction:
Improverib retention in matrixVSAvoidmaterial selection freedom
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The connection between rib and matrix is segmented into two independent components: (1) a form-fitting mechanical connection achieved through the rib's geometric shape with undercuts and tapering, and (2) an optional bonding layer. This segmentation allows the mechanical retention to function independently of material compatibility, freeing material selection while still providing reliable rib retention.

Inventive Principle:
Principle #1Segmentation

3Reliability

If the rib has a radially outwardly tapering cross section with undercuts to improve form fit, then the retention is improved, but the manufacturing complexity increases

Engineering Contradiction:
Improverib retention in matrixVSAvoidrib geometry complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The rib cross-section is designed with a radially outwardly tapering profile and strategic undercuts at the radially inner end. These geometric parameter changes create effective form-fitting retention within the matrix. The tapering angle and undercut dimensions are optimized to achieve sufficient retention while remaining compatible with standard extrusion manufacturing processes.

Inventive Principle:
Principle #35Parameter changes

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 allows for a secure and adaptable bristle structure that enhances the cleaning effect by enabling the use of various plastic materials, improving the retention and performance of the bristles, thereby optimizing the cleaning efficiency of the toothbrush.

Implementation Method 1

the rib is held in a form-fitting manner in a first area of the matrix

Methodology Applied
Scientific EffectForm-fitting connection: Mechanical Fastener

Implementation Method 2

the materials and the parameters during the extrusion of the monofilament are selected in such a way that the rib is also welded to the first area of the matrix in addition to the form fit

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 3

it can also be provided that the rib is glued to the first area of the matrix in addition to the positive fit

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP2934234B1Plastics monofilament and toothbrush bristle produced from a corresponding monofilament
Publication Date: 2016.06.15 PEDEX & CO GMBH
  • EP2934234B1 patent drawingFigure 1
  • EP2934234B1 patent drawingFigure 2
  • EP2934234B1 patent drawingFigure 3

AI summary

The invention concerns a plastics monofilament comprising a matrix which consists at least in a first region of a first plastics material, and at least one rib which extends in the longitudinal direction of the monofilament, consists of a second plastics material, and is held in formfitting manner in the first region of the matrix.