Wave-Shaped Toothbrush Head With Variable Filament Cross-Section
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Solution Overview
Problem
Conventional toothbrushes with wave-shaped filament assemblies are inadequate for removing plaque and debris from gingival margins, interproximal areas, and other hard-to-reach regions in a sensitive and gentle manner, often providing an uncomfortable brushing sensation.
Innovation Solution
A head for an oral care implement featuring a continuous wave-shaped upper top cleaning surface with filaments of varying lengths, where longer filaments have a smaller cross-sectional area and higher flexibility, and shorter filaments have a higher bending stiffness, allowing for effective cleaning of both interdental spaces and flat tooth surfaces with a smooth transition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional wave-shaped filament assemblies are used, then cleaning of outer buccal face is adequate, but cleaning of interproximal and gingival marginal regions is insufficient
Solution Approach 1:
The patent applies local quality by varying the cross-sectional area of filaments based on their length. Longer filaments (extending beyond wave peaks) have smaller cross-sectional areas for flexibility and gentleness in hard-to-reach areas, while shorter filaments (at wave troughs) have larger cross-sectional areas for stiffer scrubbing action on accessible surfaces. This localized differentiation resolves the contradiction between effective cleaning in different regions and comfortable brushing sensation.
Solution Approach 2:
The patent changes physical parameters of the filaments - specifically cross-sectional area - as a function of filament length. This parameter change creates a gradient where longer filaments are thinner and more flexible, while shorter filaments are thicker and stiffer. This systematic parameter variation enables the brush head to simultaneously achieve penetration into tight spaces and effective plaque removal on flat surfaces, resolving the cleaning effectiveness vs. brushing sensation contradiction.
2Ease of manufacture
If filaments of uniform cross-sectional area are used, then manufacturing is simplified, but cleaning performance in varied oral regions is compromised
Solution Approach 1:
The patent implements local quality by assigning different cross-sectional areas to filaments based on their specific function and location. Filaments at wave peaks (longer length) have smaller cross-sectional areas for gentle penetration, while filaments at wave troughs (shorter length) have larger cross-sectional areas for vigorous scrubbing. This localized differentiation optimizes cleaning performance across varied oral regions while the systematic approach maintains reasonable manufacturing feasibility.
3Force
If longer filaments have larger cross-sectional area, then scrubbing power is increased, but flexibility and penetration into tight spaces is reduced
Solution Approach 1:
The patent applies local quality by matching filament properties to their functional requirements. Longer filaments that need to penetrate tight spaces have smaller cross-sectional areas for flexibility, while shorter filaments that contact flat surfaces have larger cross-sectional areas for scrubbing power. This localized property assignment resolves the contradiction between force and adaptability.
Solution Approach 2:
The patent changes the cross-sectional area parameter inversely with filament length. This parameter change creates an optimal balance where longer, thinner filaments provide flexibility for penetration, while shorter, thicker filaments provide scrubbing force. The systematic parameter variation resolves the contradiction between force and adaptability across different filament types.
Data Source
Figure 1
Figure 2~3
AI summary
A head for an oral care implement comprises at least a first row of tufts comprising a plurality of filaments having free ends and fixed ends being opposite the free ends and being fixed on a mounting surface of the head. The filaments of the at least first row of tufts extend from the mounting surface of the head in different length extensions thereby defining with the filaments' free ends an upper top cleaning surface in the form of a continuous wave-shape. Each filament has a longitudinal axis and a cross-sectional area extending in a plane that is perpendicular to the longitudinal axis. The filaments of the longest length extension have a cross-sectional area being smaller than the cross-sectional area of the filaments of the shortest length extension.