Child-Resistant Closure with Flexible Ratchet Fingers
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Solution Overview
Problem
Child-resistant packages with blow-molded neck finishes face challenges in maintaining tight manufacturing tolerances and ensuring effective operation over a substantial angle of rotation, as existing designs are optimized for injection molded necks and struggle with tolerance variations.
Innovation Solution
A child-resistant package with a blow-molded neck finish featuring an arcuate part-circumferential ledge and angularly spaced ratchet teeth, combined with a dual-wall closure having internal and external skirts with flexible resilient ratchet fingers and a seal element, accommodating tolerance variations while maintaining a seal and child-resistance capability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a blow-molded neck finish is used, then manufacturing cost and ease of manufacture are improved, but manufacturing precision and tolerance control deteriorate
Solution Approach 1:
The patent changes the geometric parameters of the ratchet teeth and fingers to accommodate broader tolerance ranges. By designing the ratchet teeth with specific angular spacing and the fingers with corresponding dimensional tolerances, the system maintains functionality despite the reduced precision inherent in blow-molded neck finishes.
Solution Approach 2:
The patent introduces flexible resilient ratchet fingers that can dynamically adapt to variations in neck finish geometry. The flexibility of the fingers allows them to engage with ratchet teeth even when dimensional tolerances are broad, providing a dynamic adjustment mechanism that compensates for manufacturing variations.
2Ease of manufacture
If broad tolerance ranges are accepted in blow-molded neck finishes, then ease of manufacture is improved, but the reliability of child-resistance mechanism deteriorates
Solution Approach 1:
The patent adjusts the geometric parameters of the engagement mechanism to ensure reliable operation across broad tolerance ranges. The angular spacing of ratchet teeth and the corresponding finger dimensions are designed to maintain proper engagement despite variations in neck finish dimensions.
Solution Approach 2:
The flexible resilient fingers provide dynamic adaptation to tolerance variations, maintaining reliable engagement across a substantial angle of rotation. This dynamic capability ensures that the child-resistance mechanism remains reliable even when manufacturing tolerances are broad.
3Manufacturing precision
If the closure is designed for injection molded neck finishes, then manufacturing precision is improved, but adaptability to blow-molded neck finishes deteriorates
Solution Approach 1:
The patent designs a universal closure system that can accommodate both injection molded and blow-molded neck finishes. The ratchet tooth and flexible finger configuration provides multi-functionality, allowing the same closure design to work with different neck finish types and tolerance ranges.
Solution Approach 2:
The patent modifies the geometric parameters of the engagement mechanism to provide adaptability across different manufacturing methods. The angular spacing and dimensional tolerances are designed to accommodate the broader variations inherent in blow-molded neck finishes while maintaining compatibility with injection molded necks.
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 provides a reliable child-resistant closure that can accommodate broad tolerance variations in blow-molded neck finishes, ensuring effective sealing and child-resistance across a wide range of orientations, allowing for easy application and removal while maintaining operational integrity.
Implementation Method 1
at least one flexible resilient ratchet finger extending radially inwardly from the skirt at an angle to the skirt
Implementation Method 2
a seal element within the skirt for sealing engagement with the end of the container neck finish
Data Source
AI summary
A child-resistant package includes a plastic container having a blow-molded neck finish with an end, at least one external thread, an arcuate part-circumferential ledge adjacent to the neck finish and a plurality of angularly spaced ratchet teeth on the ledge. A closure has at least one skirt, at least one internal thread on the skirt, at least one flexible resilient ratchet finger extending radially inwardly from the skirt at an angle to the skirt, and a seal element within the skirt for sealing engagement with the end of the container neck finish. Threading of the closure onto the container neck finish brings the ratchet finger into engagement with the ratchet teeth. The array of ratchet teeth and the seal element are such as to accommodate tolerance variations in the blow-molded neck finish while maintaining a seal and child-resistance capability at the neck finish. In an exemplary embodiment of the disclosure, there are a pair of angularly spaced ratchet fingers on the skirt, with the array of ratchet teeth, the seal element and the angular spacing between the ratchet fingers accommodating tolerance variations in the blow-molded neck finish. The closure preferably is a dual-wall closure having an internal skirt with the internal thread and an external skirt with the ratchet fingers.