Mechanically-Driven Sonic Toothbrush Four-Bar Linkage
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Solution Overview
Problem
Current sonic toothbrush technologies face high production costs with electro-magnetic drivers and fail to achieve sonic speeds with mechanically-driven rotating systems.
Innovation Solution
A mechanically-driven sonic toothbrush system utilizing a continuously rotating DC or AC motor and a four bar linkage with an eccentric pin to convert rotation into sonic oscillation, incorporating balance weights to minimize vibration and noise, allowing for a wide range of output speeds from sub-sonic to sonic.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If electro-magnetic drivers are used to create oscillating toothbrush motion, then sonic oscillation is achieved, but production cost increases
Solution Approach 1:
The patent replaces electro-magnetic drivers with a mechanically-driven system consisting of a continuously rotating motor coupled to a four bar linkage mechanism. This mechanical substitution achieves the same oscillating motion function while reducing production costs associated with electro-magnetic components
Solution Approach 2:
The patent employs a four bar linkage mechanism that dynamically converts continuous rotation into oscillating motion. The linkage includes a coupler, rocker arm, and eccentric pin that work together to transform the rotational input from the motor into the desired oscillating output at the brush shaft, enabling sonic speeds through pure mechanical means
2Ease of manufacture
If mechanically-driven rotating systems are used to create oscillating motion, then production cost is reduced, but oscillation speed remains below sonic level
Solution Approach 1:
The four bar linkage mechanism is designed with specific geometric relationships between links that enable it to convert continuous rotation into high-frequency oscillating motion. By optimizing the linkage dimensions and eccentricity, the system achieves sonic oscillation speeds while maintaining mechanical simplicity and low production cost
Solution Approach 2:
The patent utilizes an eccentric pin with offset center that changes the kinematic parameters of the four bar linkage. This eccentricity parameter allows the mechanism to generate the necessary oscillation amplitude and frequency, enabling sonic speeds to be achieved through mechanical means rather than electro-magnetic drivers
3Device complexity
If continuously rotating motor is used to drive oscillating motion, then system simplicity is improved, but vibration and noise increase
Solution Approach 1:
The patent incorporates balance weights into the four bar linkage mechanism that counterbalance the inertial forces generated during oscillating motion. These counterweights reduce vibration and noise by offsetting the dynamic imbalances, allowing the simple mechanically-driven system to operate smoothly at sonic speeds
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 system achieves sonic-speed toothbrush output motion with low vibration and noise, reducing production costs while maintaining sonic efficiency, and can be tailored for various models by adjusting balance components.
Implementation Method 1
an electric motor, a brush shaft, and a drive assembly. The electric motor includes a drive shaft. When the electric motor is caused to operate, the drive shaft continuously rotates
Implementation Method 2
The four bar linkage includes a coupler and an eccentric pin. The eccentric pin has a rearward end shaft axially aligned with an axis of the drive shaft, and a mid-portion axially offset from the axis of the drive shaft. The rotation of the drive shaft causes the eccentric pin to rotate within the second end. The rotation of the eccentric pin causes the coupler to oscillate
Data Source
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AI summary
A sonic toothbrush system includes an electric motor, a brush shaft, and a drive assembly. The electric motor includes a drive shaft. When the electric motor is caused to operate, the drive shaft continuously rotates until the motor is caused to stop. The drive assembly is coupled between the drive shaft and the brush shaft. The drive assembly is configured to convert the rotation of the drive shaft into sonic oscillation of a toothbrush head supported on an end of the brush shaft.