Closure Cap Attachment Ring Cam Shoulder Design
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Solution Overview
Problem
Existing closure cap designs for industrially sized containers face challenges in achieving secure snap-fit engagement without requiring excessive force, which can lead to breakage of tamper-evidencing features, especially when applied manually or with sub-optimally adjusted machinery.
Innovation Solution
The design incorporates an attachment ring with a cam surface and an upwardly facing shoulder featuring an inner, radially outwardly extending portion and an outer, upwardly extending lip, which engages with a complementary depending lip on the container closure lugs, enhancing resistance to forced withdrawal while reducing the radial extent of engagement, thus lowering the force required for snap-fit assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the radial extent of engagement between the upwardly facing shoulder on the attachment ring and the downwardly facing shoulders on the lug guide surfaces is increased to provide secure retention, then the pull-out resistance is improved, but the force required to press the attachment ring down between the lugs increases significantly
Solution Approach 1:
The upwardly facing shoulder is segmented into two functional portions: an inner radially outwardly extending portion that provides snap-fit retention with the downwardly facing shoulders, and an outer upwardly extending lip that engages with the complementary depending lip on the lugs. This segmentation allows each portion to contribute differently to the overall retention mechanism, reducing the force needed for assembly while maintaining secure retention.
Solution Approach 2:
The engagement mechanism is extended from a purely radial interaction to include an axial component through the upwardly extending lip that engages with the depending lip. This adds a vertical dimension to the retention mechanism, distributing the retention force across multiple dimensions and reducing the radial engagement requirements.
2Ease of operation
If a more easily deformable attachment ring is used to reduce the force required for assembly, then the ease of operation is improved, but the structural strength and retention security are reduced
Solution Approach 1:
The attachment ring's upwardly facing shoulder is divided into two portions with different functional requirements. The inner radially outwardly extending portion can be made more easily deformable to facilitate assembly, while the outer upwardly extending lip provides additional retention through engagement with the depending lip, compensating for the reduced deformability.
Solution Approach 2:
Different portions of the upwardly facing shoulder are designed with different structural characteristics. The inner portion is optimized for ease of deformation during assembly, while the outer lip portion is designed to provide strong retention engagement. This local differentiation allows each region to optimize its performance for its specific function.
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
This configuration provides a secure snap-fit retention with reduced assembly force and increased resistance to forced withdrawal, while maintaining compatibility with legacy plugs and ensuring easy recycling and tamper indication.
Implementation Method 1
the attachment ring comprising a) a cam surface configured to deflect the attachment ring radially inward upon engagement of the attachment ring with the container closure or closure plug
Implementation Method 2
The upwardly facing shoulder comprises an inner, radially outwardly extending portion and an outer, upwardly extending lip. This upstanding lip is therefore configured for engagement behind a complementary depending lip which may be provided on the downwardly facing shoulder of the container closure or closure plug lugs, so as to constrain inward deformation of the attachment ring upon attempted forced withdrawal from between the lugs.
Data Source
AI summary
A cap for a screw-threaded container closure or closure plug includes a cap top and an attachment ring. The attachment ring is securingly engageable with the container closure or closure plug. The attachment ring comprises a cam surface and an upwardly facing shoulder above the cam surface. The container closure or closure plug comprises a plurality of lugs engageable by a wrench or other drive tool. Each lug includes a radially inwardly facing guide surface comprising a downwardly and radially inwardly sloping portion and a downwardly facing shoulder extending radially outward below the downwardly and radially inwardly sloping portion. A secure and relatively easy engagement between the cap and container closure or closure plug is thereby obtainable.