Dual-Motion Toothbrush Drivetrain for Uniform Oral Cleaning
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Solution Overview
Problem
Current powered personal care devices, such as electric toothbrushes, are optimized for specific areas of the mouth and struggle to achieve uniform cleaning performance across all target areas due to conflicting requirements and user handling variability.
Innovation Solution
The implementation of a drivetrain assembly that generates both a sweeping motion and a power tapping motion, where the cleaning elements move in a first direction about a central axis and in a second direction perpendicular to the cleaning unit platen, with different frequencies and phase shifts to optimize cleaning performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single sweeping motion is used for cleaning all areas of the mouth, then the device structure remains simple, but cleaning performance becomes non-optimal at certain target areas due to conflicting requirements
Solution Approach 1:
The patent combines sweeping motion and tapping motion into a single integrated drivetrain assembly. The motor generates rotational motion that is transmitted through a shaft to produce both the sweeping movement (rotation about central axis) and the tapping movement (reciprocating motion perpendicular to the platen), merging multiple cleaning functions into one unified structure.
Solution Approach 2:
The drivetrain assembly dynamically generates two different types of motion (sweeping and tapping) from a single motor source. The system transitions between different motion patterns by controlling the motor's rotational characteristics, allowing the cleaning elements to adapt their movement pattern based on the desired cleaning action without requiring separate mechanical systems.
2Manufacturing precision
If the cleaning elements move only in a sweeping motion about a central axis, then the drivetrain is simpler, but the device cannot achieve proper cleaning performance at all target areas including interproximal and gumline areas
Solution Approach 1:
The patent adds a second dimension of motion to the traditional sweeping movement. While the sweeping motion provides rotational cleaning about the central axis, the tapping motion adds reciprocating movement perpendicular to the platen surface, creating a two-dimensional cleaning pattern that enhances access to difficult-to-reach areas like gumlines and interproximal spaces.
3Manufacturing precision
If sweeping and tapping motions operate at the same frequency and in-phase, then the control system is simpler, but cleaning performance is not optimized for different target areas
Solution Approach 1:
The controller varies operational parameters including frequency and phase relationship between sweeping and tapping motions. By adjusting these parameters dynamically, the system optimizes cleaning performance for different target areas - for example, using different frequency combinations for gumline areas versus occlusal surfaces, and adjusting phase relationships to enhance mechanical action on plaque and stain.
Data Source
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AI summary
A personal care device including a body portion; a cleaning unit having a set of cleaning elements, the set of cleaning elements extending in an axis of alignment; a controller and an actuator assembly arranged to be driven by the controller. The actuator assembly includes an actuator configured to generate first and second periodic movements, wherein the first and second periodic movements operate at different frequencies or out-of-phase with each other. The first periodic movement causes the cleaning elements to move in a first direction about a central axis of the personal care device or along a line that is tangential to a platen of the cleaning unit. The second periodic movement causes the cleaning elements to move in a second direction that is different than the first direction, wherein the second direction is normal to the platen of the cleaning unit.