Asymmetric Child-Resistant Closure Teeth
Solution Overview
Problem
Existing child-resistant container closures require additional manipulation beyond rotation to open, which can be cumbersome for users with limited dexterity and may not effectively prevent children from opening the container.
Innovation Solution
A child-resistant container closure design featuring asymmetric teeth on both the cover and base caps, requiring a combination of downward force and rotation to loosen the base cap, with sloped sliding faces to ensure engagement and an audible clicking sound when opened without force, preventing accidental opening by children.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional manipulation (pushing/squeezing) is required to open the closure, then child resistance is improved, but ease of operation deteriorates
Solution Approach 1:
The teeth on the cover cap and base cap are designed with asymmetric geometry, where the sliding faces have specific slope angles that create different engagement characteristics for closing versus opening. This asymmetry allows the closure to be easily opened by users with limited dexterity while still requiring deliberate manipulation to prevent accidental opening by children.
Solution Approach 2:
The patent specifies precise angular parameters for the tooth faces (sliding face angle, closing face angle, opening face angle) to optimize the balance between child resistance and ease of operation. By carefully controlling these geometric parameters, the closure achieves reliable child protection while maintaining user-friendly operation.
2Reliability
If the closure requires combined rotational and pushing action to open, then security against accidental opening is improved, but device complexity increases
Solution Approach 1:
The closure employs a nested two-cap construction where the base cap threads onto the container neck and the cover cap captures the base cap. This nested arrangement integrates the child-resistant feature within the basic closure structure, achieving security without adding separate complex mechanisms.
Solution Approach 2:
The asymmetric tooth design creates inherent directional engagement where the sliding faces guide the opening motion. The specific angle relationships between tooth faces automatically provide the required combined rotational and pushing action, eliminating the need for additional mechanical complexity.
3Reliability
If the teeth are designed with sloped sliding faces for engagement, then reliability of tooth engagement is improved, but manufacturing precision requirements increase
Solution Approach 1:
The patent establishes specific angular ranges for the tooth faces (sliding face at approximately 6 degrees from horizontal, closing face at 20 degrees from vertical, opening face at 30 degrees from vertical) that optimize engagement reliability while remaining achievable through standard manufacturing processes.
Solution Approach 2:
The asymmetric tooth geometry with specifically angled faces creates a self-aligning engagement mechanism. The slope angles are designed to guide the teeth into proper engagement, reducing sensitivity to manufacturing variations and maintaining reliable engagement without requiring extremely tight tolerances.
Data Source
AI summary
A child-resistant container closure includes a base cap having a top, a skirt, and a plurality of asymmetric teeth recessed in the skirt below the top, and a cover cap having a top, a skirt, and a plurality of asymmetric downwardly extending teeth adjacent to the skirt, the teeth being adapted for asymmetric engagement with the base cap teeth, the skirt having a plurality of interspersed vertical legs each spaced apart from adjacent legs by vertical openings, the legs being joined at a bottom end of the skirt by a support ring, the base cap teeth each having a sloped sliding face to ensure that one of the cover cap teeth will drop into a notch between adjacent base cap teeth when the cover cap is rotated in one direction.