Interdental Brush Filament Geometry for Cleaning
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Solution Overview
Problem
Conventional interdental brushes with circular cross-section filaments have limited cleaning effectiveness and reachability to minute portions due to low filament density and friction, causing filaments to detach during use.
Innovation Solution
The interdental brush features filaments with a polygonal cross-section, specifically an equilateral triangle or rhombus shape, arranged spirally between twisted wires, enhancing filament retention and cleaning efficacy by concentrating brushing pressure on acute corners.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If filaments with circular cross section are used, then the brush structure is simple and easy to manufacture, but the filling density is limited and spaces are formed between filaments and wires
Solution Approach 1:
The patent changes the geometric parameter of the filament cross-section from circular to polygonal (triangle, quadrangle, pentagon, or hexagon). This parameter change eliminates the inherent spaces between circular filaments, achieving dense packing with 100% filling density when the filaments are arranged between twisted wires, while maintaining manufacturing simplicity.
2Device complexity
If filaments with circular cross section are used, then the structure is simple, but friction force is limited and filaments come off during cleaning
Solution Approach 1:
The patent changes the cross-sectional shape parameter from circular to polygonal, which fundamentally alters the contact mechanics. The polygonal shape creates larger contact areas and higher friction forces between adjacent filaments and between filaments and wires, significantly improving filament retention during cleaning operations without increasing structural complexity.
3Ease of operation
If filaments with circular cross section are used, then the tips contact interdental portions, but reachability to minute portions is limited
Solution Approach 1:
The patent applies local quality by creating acute corner portions at specific locations on the filament cross-section. These acute corners are strategically positioned to contact and clean minute interdental portions such as interdental corners, while the rest of the filament maintains its cleaning function. This local geometric modification enhances reachability without compromising overall cleaning effectiveness.
4Volume of moving object
If thin filaments are used to achieve reachability to minute portions, then reachability improves, but resistant strength is weak and cleaning effectivity degrades
Solution Approach 1:
The patent changes the cross-sectional shape from circular to polygonal, which fundamentally alters the strength characteristics. The polygonal shape with acute corners provides both the reachability needed for minute portions and the structural strength required for effective cleaning, eliminating the need to compromise between these two requirements.
Data Source
Figure 1
Figure 2(a)~2(d)
Figure 3(a)~3(b)
AI summary
Provided is an interdental brush having a wire and filaments arranged therein by folding the wire and disposing the filaments between the wire and then twisting the wire. The interdental brush has improved filament retention and improved cleaning effectivity and reachability to minute portions. Each of filaments 3 has a polygonal cross section whose at least one corner portion has an interior angle 31 as acute as 30 to 75 degrees. Specifically, an angle ¸3 of the acute corner portion 31 is set at 1.2 to 3 times a twisting angle ¸4 of the wire. The filaments each have two or more such acute corner portions, and two or more rows of such filaments are disposed and laminated between the wire in a densely arranged manner.