Replaceable Toothbrush Head Snap Lock With Flexible Finger Engagement
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Solution Overview
Problem
Existing toothbrushes with replaceable heads suffer from complex designs prone to damage, low rigidity, and hygiene issues due to small details that trap toothpaste and bacteria, leading to reduced cleaning performance and accidental detachment.
Innovation Solution
A toothbrush design featuring a handle with a flexible and non-flexible finger segment for snap engagement, where the flexible portion can flex transversally to achieve strong locking without complex components, ensuring high rigidity and easy cleaning, with an inclined recess and protrusion for secure attachment and comfortable detachment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a snap locking mechanism with multiple flexible components is used to attach the brush head to the handle, then the attachment strength is improved, but the device complexity increases and the reliability decreases due to prone-to-damage small components
Solution Approach 1:
The snap locking mechanism is segmented into a finger portion integrated in the handle and a recess in the brush head, with the finger including a flexible portion and a non-flexible portion. This segmentation allows the mechanism to be simpler while maintaining attachment strength, as the flexible portion provides the necessary elasticity for engagement without requiring multiple separate flexible components.
Solution Approach 2:
The finger is merged as a single integral component with both flexible and non-flexible portions, eliminating the need for multiple separate flexible components. This merging reduces device complexity while maintaining the snap locking function, as the integrated finger provides both the flexible engagement element and the rigid structural support in one piece.
2Manufacturing precision
If small detailed components are used in the snap locking mechanism, then the attachment precision is improved, but hygiene conditions worsen due to toothpaste and bacteria accumulation in small details
Solution Approach 1:
The complex small detailed components are extracted and replaced with a simpler finger-recess interface. The snap locking mechanism uses the flexibility of the finger portion rather than multiple small flexible components, eliminating the small details that trap toothpaste and bacteria while maintaining precise engagement through the finger's elastic deformation and the recess geometry.
Solution Approach 2:
Instead of using multiple small flexible components that create small details, the design inverts the approach by using a single finger with a flexible portion that engages with a recess. This inversion eliminates the small trapping details while maintaining engagement precision through the finger's elastic behavior and the recess's geometric constraints.
3Ease of manufacture
If the brush head material is made deformable to enable snap locking engagement, then the ease of manufacture is improved, but the rigidity decreases leading to breakage or detachment during use
Solution Approach 1:
The brush head is designed with local quality differentiation: the recess area allows controlled deformation for snap locking engagement, while the rest of the brush head structure maintains high rigidity. The finger includes a flexible portion for engagement and a non-flexible portion for structural support, enabling the brush head to be deformable only where needed for assembly while remaining rigid during use.
Solution Approach 2:
The snap locking mechanism uses dynamic flexibility in the finger portion during assembly and disassembly, allowing the finger to elastically deform for engagement. Once engaged, the system transitions to a static locked state where the rigid non-flexible portion of the finger and the brush head structure provide stable connection, preventing breakage or detachment during use.
4Reliability
If the snap engagement interference is increased to prevent accidental detachment, then the reliability is improved, but the device complexity increases due to larger engagement features
Solution Approach 1:
The finger-recess engagement features asymmetric geometry optimized for snap locking: the finger has a specific cross-sectional shape that elastically deforms during engagement and locks into the recess with sufficient interference. The asymmetric design allows the engagement features to be simple in form while providing reliable anti-detachment through the elastic snap action and geometric interlocking, without requiring complex multi-component mechanisms.
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 design enhances reliability, reduces the risk of accidental detachment, and maintains high hygiene standards while ensuring effective cleaning performance with reduced material consumption and improved durability.
Implementation Method 1
the flexible portion can flex in a direction transversal to the longitudinal extension of the finger away from the bristle
Data Source
Figure 1~2
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Figure 5~6
AI summary
A toothbrush (10) includes a handle (12) forming a gripping portion (12a) of the toothbrush and a replaceable brush head (11) carrying a plurality of bristles (17), wherein the replaceable head (11) is connectable to the handle (12) in a detachable manner by means of a snap locking mechanism (13, 14), the snap locking mechanism including a finger (13) protruding from the handle (12) and a recess (14) formed in the brush head (11), wherein the finger (13) extends along a longitudinal direction (X). The finger (13) includes a flexible portion (13a) and a non-flexible portion (13b) that are configured to be at least partly received in the recess (14) when the brush head (11) is mounted on the handle (12); the non-flexible portion (13b) connects the flexible portion (13a) to the handle (12); the flexible portion (13a) is configured to elastically flex away from the bristles (17) with respect to the non-flexible portion (13b) in a direction transversal to the longitudinal direction (X) during the insertion of the finger (13) into the recess (14) along the longitudinal direction (X); the flexible finger portion (13a) is configured to flex due to the interaction with an inclined surface (18) formed in the recess (14) during insertion of the finger (13) into the recess (14) along the longitudinal direction (X); the flexible portion (13a) includes a protrusion (19) configured to snap into an engagement position with the recess (14) when the protrusion (19) slides beyond the inclined surface (18) inside the recess (14).