Electric Toothbrush Coupling Sleeve Anti-Twist Design
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Solution Overview
Problem
Existing electric toothbrush designs face challenges in achieving a secure and optimal coupling between the handle and brush attachment parts, which affects the transmission of mechanical movement and compatibility with new and old models, potentially leading to functional impairment or damage.
Innovation Solution
The design incorporates a coupling sleeve with a circular segment-shaped wall thickening and axial grooves or ridges on the brush attachment part, and a corresponding coupling pin with a circular segment-shaped recess and axial comb on the handle part, creating a form-fitting connection that enhances anti-twist protection and prevents incompatible attachments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a simple coupling means is used between handle and brush attachment, then device complexity is reduced, but coupling security and anti-twist protection deteriorate
Solution Approach 1:
The coupling means employs asymmetric geometric features including a circular segment-shaped wall thickening on the coupling sleeve and a corresponding circular segment-shaped recess on the coupling pin. These asymmetric shapes provide directional engagement that prevents twisting while maintaining relatively simple construction. The asymmetric design ensures that the brush attachment can only be coupled in the correct orientation, thereby preventing rotational misalignment without requiring complex locking mechanisms.
Solution Approach 2:
The coupling means incorporates localized geometric features such as axial grooves or ridges on the coupling sleeve and corresponding axial combs on the coupling pin. These local quality enhancements are concentrated at specific engagement points rather than distributing complexity throughout the entire coupling structure. The local features provide enhanced anti-twist protection and coupling security only where needed, maintaining overall simplicity of the coupling system.
2Adaptability or versatility
If new brush attachments are made compatible with old handles, then adaptability is improved, but functional impairment risk increases due to incompatible old brushes on new handles
Solution Approach 1:
The coupling means uses asymmetric geometric features that create a form-fitting connection between new brush attachments and new handles, preventing incompatible old brush attachments from being coupled. The circular segment-shaped wall thickening and corresponding recess, combined with axial grooves or ridges and axial combs, create a geometric interface that is incompatible with older brush attachment designs. This asymmetric design ensures that only brush attachments specifically designed for the new coupling system can be properly coupled, eliminating the risk of functional impairment from incompatible attachments.
3Reliability
If a form-fitting connection with axial grooves or ridges is implemented, then anti-twist protection is improved, but manufacturing precision requirements increase
Solution Approach 1:
The anti-twist protection is achieved through localized axial grooves or ridges on the coupling sleeve and corresponding axial combs on the coupling pin, rather than requiring high precision throughout the entire coupling geometry. These local features are concentrated at specific engagement points where they are most effective at preventing rotation. The localized approach allows for relatively relaxed manufacturing tolerances in non-critical areas while maintaining sufficient precision only where the axial grooves, ridges, and combs engage, thereby reducing overall manufacturing precision requirements.
Data Source
Figure 1
Figure 2a~2b
Figure 3a~4b
AI summary
The invention relates to an attachment brush part (5) for attachment to the handle part of an electric toothbrush. Said attachment brush part (5) contains a brush head (7) and a coupling sleeve (20), the brush head (7) and the coupling sleeve (20) being interconnected via a tubular neck (6). The hollow space inside the coupling sleeve (20) has a circular base cross-section. The coupling sleeve (20) further has a circular segment-shaped wall portion (21) which is thicker than the circular base cross-section and which has an inner, planar axial surface forming a cross-sectional narrowing. The planar axial surface (26) has an axial groove (22).