Flexure Drivetrain Assembly for Toothbrush Power Tapping Motion
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Solution Overview
Problem
Current power toothbrush devices rely on a sweeping motion that has limitations in cleaning efficiency, particularly in removing residual plaque and cleaning gum pockets, and are heavily dependent on precise user position and pressure.
Innovation Solution
The development of improved drivetrain assemblies that generate a controllable power tapping motion, either alone or in combination with a sweeping motion, using flexures to constrain periodic linear movement and transmit it to the brush head, allowing bristles to move vertically parallel to their axis of alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If a sweeping motion is used to clean teeth, then the brush head can cover large surface areas, but cleaning efficiency in interproximal zones and gum pockets is insufficient
Solution Approach 1:
The patent transitions from a static sweeping motion to a dynamic tapping motion where the brush head moves vertically along its axis in periodic cycles. This dynamic motion allows bristles to penetrate deeper into gum pockets and interproximal zones, significantly improving cleaning efficiency in areas that were previously difficult to reach while maintaining broad coverage capability.
Solution Approach 2:
The patent implements periodic tapping motion where the brush head oscillates vertically along its axis in repeated cycles. This periodic action creates high-impact forces that effectively dislodge plaque and debris from hard-to-reach areas such as gum pockets and between teeth, while the rhythmic nature maintains continuous coverage of larger tooth surfaces.
2Force
If bristles are pressed heavily against teeth to improve cleaning, then plaque removal increases, but bristles become trapped and cleaning efficiency decreases
Solution Approach 1:
The patent employs dynamic tapping motion where the brush head moves vertically along its axis, creating periodic high-impact forces. This dynamic approach allows bristles to penetrate plaque deposits and gum pockets effectively without becoming trapped, as the vertical motion continuously resets the bristle position, maintaining cleaning efficiency even under heavy load conditions.
Solution Approach 2:
The tapping motion generates mechanical vibrations in the bristle assembly as the brush head oscillates vertically. These vibrations prevent bristles from becoming stuck in plaque or gum tissue by creating oscillating forces that continuously work loose debris, thereby maintaining high cleaning efficiency without requiring sustained heavy pressure that would trap the bristles.
3Productivity
If a vertical periodic motion parallel to bristle axis is generated, then cleaning efficiency in gum pockets improves, but device complexity increases
Solution Approach 1:
The patent designs the drivetrain assembly so that a single actuator performs multiple functions: it generates both the vertical tapping motion for deep cleaning and the rotational sweeping motion for broad coverage. This multi-functionality is achieved through a unified drivetrain architecture where the actuator can operate in different modes, reducing overall device complexity while maintaining high cleaning efficiency in gum pockets and interproximal zones.
Solution Approach 2:
The patent combines the tapping motion mechanism and sweeping motion mechanism into a single integrated drivetrain assembly. By merging these two functions into one actuator system rather than using separate mechanisms, the patent reduces component count and structural complexity while achieving both deep penetration cleaning and broad surface coverage simultaneously.
4Ease of manufacture
If current power toothbrush devices are designed for sweeping motion, then manufacturing is simplified, but they are heavily dependent on precise user position and pressure
Solution Approach 1:
The tapping motion mechanism automatically adjusts to varying user positions and pressures through its vertical oscillation along the brush head axis. The periodic motion self-regulates to maintain effective cleaning contact with teeth and gums regardless of slight variations in user holding position or applied pressure, reducing the need for precise user technique while maintaining cleaning effectiveness.
Solution Approach 2:
The patent changes the motion parameter from horizontal sweeping to vertical tapping along the bristle axis. This parameter change makes the cleaning action less sensitive to user position variations because the vertical oscillation occurs along the natural axis of the brush head, allowing the mechanism to adapt to different angles and pressures applied by the user while maintaining consistent cleaning performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The power tapping motion enhances cleaning efficiency by achieving deeper reach in gum pockets, higher peak forces for plaque and stain removal, preventing bristle pinning, and improving resilience to user variables, while also providing new experiential modes for consumers.
Implementation Method 1
The improved drivetrain assemblies further comprise parallel flexures configured to constrain the periodic linear movement
Data Source
AI summary
Drivetrain assemblies for personal care devices to generate controllable power tapping motion alone or with controllable sweeping motion. The drivetrain assemblies include a drivetrain shaft at least partially contained within a body portion. The drivetrain shaft is further configured to engage a brush head member. Some drivetrain assemblies include a single actuator for generating periodic linear movement, wherein the drivetrain shaft transmits the linear movement to the brush head member via a pivoting motion and/or a translational motion. Other drivetrain assemblies include the actuator for generating periodic linear movement and a motor on the drivetrain shaft to periodically rotate the shaft about a central axis. Still other drivetrain assemblies include a motor to rotate the drivetrain shaft about the central axis, an actuator to generate periodic linear movement, parallel flexible flexures to constrain the periodic linear movement, and parallel substantially rigid translation linkages to transmit the periodic linear movement.