LDPE Closure Assembly With Rotational Locking and Thin-Wall Strength
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Solution Overview
Problem
Existing closure assemblies are unsatisfactory due to their large diameter and requirement for hard plastic materials, which are not preferred by recycling technologies, and they lack flexibility in material choice, especially for containers made from low-density polyethylene (LDPE).
Innovation Solution
A closure assembly design featuring a cap body with outwardly protruding longitudinal ribs and grooves, along with axial and rotational locking formations, allowing for a reduced wall thickness and robust structure, enabling use of LDPE and facilitating easy opening and reclosing with minimal material usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If hard plastic materials (HDPE, PP) are used for closure assemblies, then structural integrity and manufacturing precision are improved, but adaptability to recycling demands and ease of manufacture with softer plastics deteriorate
Solution Approach 1:
The patent changes the material parameter from hard plastics (HDPE, PP) to softer plastics (LDPE, LLDPE), enabling compatibility with recycling demands while maintaining functional integrity through optimized design of locking formations and frangible connections that work effectively with the softer material properties
2Manufacturing precision
If additional assembly steps are added to produce closure assemblies, then manufacturing precision and reliability are improved, but device complexity and productivity deteriorate
Solution Approach 1:
The patent merges the cap body and plug into a single integrally molded component, eliminating the need for separate assembly steps to connect these parts. The frangible peripheral connection is built-in during molding, allowing the assembly to be produced in one injection molding cycle without additional assembly operations
3Volume of moving object
If the tubular neck diameter is reduced, then volume and material usage are improved, but manufacturing precision and reliability deteriorate
Solution Approach 1:
The patent applies local quality by concentrating structural strength at critical locations (locking formations, frangible connection, seal portion) while maintaining a small overall diameter. The longitudinal ribs provide localized reinforcement that enables reliable function in a compact geometry
Data Source
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AI summary
A closure assembly has a monolithic plastic fitment with a base portion and a tubular neck extending from the base portion for dispensing of product from a container body. A plug is connected via a frangible peripheral connection to the top end of the neck so as to close the product passage. The closure assembly further has a plastic cap body with a skirt portion defining an open-ends bore, which is mounted over the tubular neck and the plug. The skirt portion has a longitudinal rib. The plug has an outwardly projecting tab received in a longitudinal groove to provide a rotational locking and axial locking formations, distinct from the tab and groove, lock the plug and cap body in axial directions.