Toothbrush Drive Coupling With Torque-Triggered Disengagement
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Solution Overview
Problem
Handheld drive systems in small electrical appliances like toothbrushes are prone to damage due to prolonged transmission of drive despite impediments, such as excessive torque, which can lead to damage of small and delicate components within the system.
Innovation Solution
A drive system with a coupling that includes resiliently deformable driving teeth, which automatically disengage the transmission between the drive shaft and the head when a threshold torque is exceeded, using a gear set with pegged gears and slender fingers to prevent damage to the components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the drive transmission continues despite an impediment to the motion of the head, then the motor can maintain continuous operation, but damage occurs to the drive system components (gears, cogs)
Solution Approach 1:
The driving teeth are designed to be resiliently deformable rather than rigid, allowing them to dynamically adapt to load conditions. When excessive torque is detected, the teeth deform and disengage automatically, protecting the system while allowing continuous operation after the impediment is removed.
Solution Approach 2:
The drive system includes self-protecting features through the resiliently deformable driving teeth that automatically disengage when threshold torque is exceeded, eliminating the need for external protection mechanisms or manual intervention to prevent component damage.
2Weight of moving object
If the components within the system are made as small and light as possible, then the device maintains handheld portability, but the strength and torque capacity of individual components (teeth on cogs, gears) is reduced
Solution Approach 1:
The driving teeth are designed with specific material properties and geometric parameters (resiliently deformable, wire diameter less than 1mm) that allow them to be both lightweight and sufficiently strong. The resilience parameter enables the small components to withstand operational loads while maintaining portability.
3Reliability
If the driving teeth are made resiliently deformable to prevent damage, then component protection is improved, but the complexity of the gear set increases
Solution Approach 1:
The driving teeth are implemented as thin, flexible wire structures (diameter less than 1mm) that provide the necessary resilience and deformability. This flexible structure achieves protection functionality without requiring complex mechanisms or multiple components.
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 solution effectively prevents damage to the drive system components by disengaging the drive transmission when excessive torque is applied, allowing the drive shaft to continue rotating while avoiding harm to the gears and motor, thus extending the life of the device.
Implementation Method 1
the at least one driving tooth being resiliently deformable in order to facilitate the disengagement of drive transmission wherein the at least one driving tooth comprises a resiliently deformable finger
Data Source
Figure 1
Figure 2~3
AI summary
This invention relates to a drive system which automatically disengages when a loading above a certain threshold limit is applied to the driven component, thus preventing damage to the drive system and foremost to the gearing between the drive system and the driven component when such a load is applied.