Interdental Cleaning Tool Recess Geometry to Prevent Peeling

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Solution Overview

Problem

Existing interdental cleaning tools face issues with the flexible cleaning portion being easily peeled due to recesses left by hold pins during insert molding, leading to potential peeling and re-peeling, which can catch teeth or dental calculus.

Innovation Solution

The interdental cleaning tool features recesses on the core base portion shaped obliquely, with dimensions controlled to minimize peeling, and a distance between recesses adjusted to ensure neat cutting and minimize peeling, preventing further catching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If hold pins are used to fix the base portion during insert molding, then the flexible portion can be formed uniformly on the core base portion, but recesses are left in the flexible cleaning portion which can catch teeth or dental calculus and cause peeling

Engineering Contradiction:
Improveuniformity of flexible portion formationVSAvoidtooth or dental calculus being caught by recesses
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The invention changes the geometric parameters of the recesses by controlling their depth and shape. Specifically, the recesses are designed with a depth of 0.05mm or less and an oblique shape that reduces the exposed core base portion to 0.22mm or less in the longitudinal direction. This parameter optimization prevents teeth and calculus from being caught while maintaining the structural integrity provided by hold pins during molding

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If recesses are left in the flexible cleaning portion, then the molding process is simplified, but the recesses become origins of peeling when teeth or calculus are caught

Engineering Contradiction:
Improvesimplicity of molding processVSAvoidpeeling resistance of flexible cleaning portion
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention optimizes the depth parameter of recesses to 0.05mm or less, which is shallow enough to prevent peeling propagation while still allowing the insert molding process to proceed efficiently. This parameter change maintains manufacturing simplicity while dramatically improving reliability by preventing the recesses from becoming peeling origins

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The recesses are designed with an oblique asymmetric shape rather than symmetric circular or square forms. This asymmetric geometry reduces the exposed core base portion to 0.22mm or less in the longitudinal direction and creates a tapered profile that prevents calculus accumulation and reduces stress concentration that would initiate peeling

Inventive Principle:
Principle #4Asymmetry

3Stability of the object's composition

If the flexible cleaning portion is peeled once, then the peeled portion bulges at the end part which may cause further catching and re-peeling

Engineering Contradiction:
Improveintegrity of flexible cleaning portionVSAvoidend part catching tooth or calculus again
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The invention takes preliminary anti-action by designing the recesses with oblique shapes and controlled depths before any peeling can occur. The oblique geometry creates a gradual transition that prevents the formation of bulging ends during peeling, and the limited exposed core base portion (0.22mm or less) ensures that even if peeling occurs, the peeled portion cannot catch teeth or calculus again

Inventive Principle:
Principle #9Preliminary anti-action

Data Source

PatentEP3903635B1Interdental cleaning tool
Publication Date: 2026.01.28 SUNSTAR INC
  • EP3903635B1 patent drawingFigure 1
  • EP3903635B1 patent drawingFigure 2
  • EP3903635B1 patent drawingFigure 3

AI summary

Provided is an interdental cleaning tool which prevents, when cleaning between teeth, a flexible cleaning portion from being easily peeled due to a tooth or dental calculus being caught by recesses that are left as marks of hold pins during insert molding, and which prevents, even if such peeling does occur, a large amount of peeling and re-peeling from an end part of a peeled portion. A flexible cleaning portion (21) includes a core covering portion (21a) that covers a core base (12), and a plurality of recesses (21c) that are formed due to hold pins during insert molding. The recesses (21c) are formed along a longitudinal direction of the core base portion (12). A core base exposed portion of each recess (21c) has a shape elongated in an oblique direction that intersects both the longitudinal direction and a lateral direction orthogonal to the longitudinal direction, and, at a position where a dimension of the core base exposed portion in the longitudinal direction is maximum, the maximum dimension is 0.25 mm or less.