Metal Child-Resistant Closure with Nested Axial Caps
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Child-resistant closures are costly and difficult for adults with reduced manual dexterity to open, and existing solutions with complex structures are expensive to fabricate, while metal-based materials pose challenges in creating complicated structures for packaging applications.
Innovation Solution
A child-resistant closure made from recyclable metal with coaxial and nested inner and outer caps that engage through angled or parallel knurls and notches, allowing for easy fabrication and operation with both axial and rotational forces, enabling easy opening for adults while maintaining child safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If child-resistant closure mechanisms are implemented, then child safety is improved, but ease of operation for adults with reduced manual dexterity deteriorates
Solution Approach 1:
The closure is divided into two functional segments: an inner cap that provides child-resistant threading engagement with the container, and an outer cap that provides easy-grip opening surfaces. The segments are axially movable relative to each other, allowing the outer cap to be pulled off without requiring complex manipulation, while the inner cap maintains secure engagement with the container neck.
Solution Approach 2:
The inner cap is nested within the outer cap, with the inner cap providing the child-resistant threading engagement and the outer cap providing easy-grip surfaces. This nested arrangement allows the outer cap to be simply pulled axially away from the inner cap for opening, while maintaining child safety through the inner cap's engagement with the container.
2Reliability
If complex convertible closure structures are used, then child safety with easy adult operation is achieved, but manufacturing cost and structural complexity increase
Solution Approach 1:
The closure is segmented into two simple axially-movable caps rather than a single complex convertible structure. The inner cap engages the container threads while the outer cap provides grip surfaces, and they move axially relative to each other. This segmentation achieves child safety and easy operation without requiring complex mechanical conversions or multiple positioning mechanisms.
Solution Approach 2:
Instead of using a single cap that converts between child-resistant and easy-open modes through complex mechanical transformations, the invention inverts the approach by using two simple caps that remain in fixed functional roles but move axially relative to each other. The outer cap is simply pulled off the inner cap, eliminating the need for complex conversion mechanisms.
3Ease of manufacture
If metal materials are used for closure fabrication, then environmental sustainability and manufacturing simplicity are improved, but ability to create complicated child-resistant structures deteriorates
Solution Approach 1:
The metal closure is segmented into two simple caps with basic geometric features (threads on the inner cap, grip surfaces on the outer cap). This segmentation allows each cap to be manufactured using simple metal forming processes without requiring complex molding or assembly steps, while still achieving the functional complexity needed for child safety and easy operation.
Solution Approach 2:
The invention changes the material parameter from plastic to metal, which simplifies manufacturing through metal forming processes. The structural complexity is reduced by using simple axially-movable caps rather than complex molded structures, demonstrating that metal can achieve the required functionality with simpler manufacturing processes.
Data Source
AI summary
A child resistant closure for use with a container having a threaded portion and an axis extending therethrough about which said closure is rotatable may be manufactured from a recyclable material such as tin plate metal or aluminum. The closure includes coaxial and nested inner and outer caps that are axially movable with respect to each other. An axial force causes notches in the outer cap to engage with knurls in the inner cap to transmit torque from the outer cap to the inner cap. Abutment surfaces on the notches interact with the knurls to cause the outer cap and the inner cap to move away from each other in the axial direction when axial force is removed. The knurls may to angled or straight with respect to the axis.