Conical Bristle Tufts for Toothbrush Head
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Solution Overview
Problem
Conventional toothbrushes with flat bristle trims are ineffective in conforming to tooth curvature, penetrating interproximal areas, and retaining dentifrice, leading to reduced cleaning efficiency and discomfort during brushing due to gaps between bristles and tuft holes.
Innovation Solution
The design features a handle with a head containing four conical tufts of bristles, where each tuft has an inner surface defining a cavity with a transverse cross-sectional area that increases with distance from the front surface, and annular top surfaces inclined relative to the front surface, enhancing bristle packing and retention of dentifrice.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional flat bristle trim is used, then manufacturing is simple, but cleaning effectiveness on curved tooth surfaces is poor
Solution Approach 1:
The patent applies curvature by transitioning from flat bristle trims to conical tufts with curved bristle arrangements. Each tuft has a conical shape with bristles radiating from a central axis, allowing the bristle surface to conform to the curvature of tooth surfaces. This spherical/conical geometry enables better contact with curved tooth surfaces while maintaining cleaning effectiveness.
Solution Approach 2:
The bristle assembly is segmented into multiple conical tufts rather than a single flat trim. Each tuft operates independently to contact different areas of the teeth, allowing the segmented conical structures to collectively cover curved surfaces more effectively than a continuous flat trim.
2Reliability
If conventional circular tuft holes are used, then manufacturing is easy, but packing factor is low due to gaps between bristles
Solution Approach 1:
The patent replaces symmetric circular tuft holes with asymmetric conical tuft structures. The conical tufts have a triangular cross-section that fits more efficiently into the head structure, eliminating gaps between adjacent tufts and achieving a packing factor approaching 100%. This asymmetric conical geometry optimizes space utilization while maintaining manufacturability.
Solution Approach 2:
Each tuft is designed with locally optimized conical geometry tailored to its specific position in the head. The tufts near the periphery have different orientations and angles compared to central tufts, allowing each local region to achieve optimal packing and contact with tooth surfaces.
3Adaptability or versatility
If conventional flat bristle trim is used, then structure is simple, but ability to penetrate interproximal areas is limited
Solution Approach 1:
The conical tuft configuration with radially arranged bristles creates a three-dimensional structure that can penetrate into interproximal areas between teeth. The curved conical shape allows the tufts to reach into gaps and contours that flat trims cannot access, improving adaptability to complex oral geometries.
Solution Approach 2:
The conical tufts are designed to flex and adapt dynamically during brushing. The inclined top surfaces and conical geometry allow the tufts to deform and reorient themselves to access tight interproximal spaces, providing dynamic adaptability rather than a fixed rigid structure.
4Reliability
If conventional flat bristle trim is used, then dentifrice application is simple, but dentifrice retention is poor as it slips through bristles
Solution Approach 1:
The conical tuft structure with curved bristle walls creates a cup-like cavity that traps and retains dentifrice. The inclined top surfaces of the conical tufts form a reservoir that holds dentifrice against the bristles, preventing it from slipping away during brushing and improving retention.
Solution Approach 2:
The bristle walls of each conical tuft are designed with specific local properties including inclined top surfaces at optimized angles. These locally tailored geometric features create effective dentifrice retention zones within each tuft, maximizing the holding capacity for cleaning agents.
Data Source
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Figure 1A
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AI summary
An oral care implement that includes a conical tuft of bristles. In one embodiment, the invention is an oral care implement that includes a handle and a head coupled to the handle, the head having a front surface. A plurality of tooth cleaning elements extend from the front surface of the head. The plurality of tooth cleaning elements include a conical tuft that has a bristle wall having an inner surface defining a cavity, the cavity having a transverse cross-sectional area that increases with distance from the front surface of the head. Furthermore, in some embodiments the bristle wall terminates in an annular top surface that is inclined relative to the front surface of the head. In some embodiments, the head includes more than one of the conical tufts, such as two of the conical tufts or four of the conical tufts.