Polymeric Closure with Axial Columns for Impact Resistance
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Solution Overview
Problem
Molded polymeric closures for bottles lack efficient material usage, strength, and impact resistance, while also being difficult to manufacture without deformation during the molding process.
Innovation Solution
The closure design features an annular skirt with circumferentially spaced gripping knurls and axial columns, providing flexibility and energy absorption, along with reinforcing knurls on the top wall for enhanced stiffness and impact resistance, and gas-venting grooves for carbonated contents, facilitating high-speed manufacturing and efficient material use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If polymeric material is used to form molded closures, then the closures can be efficiently formed by compression molding or injection molding, but the closures lack sufficient strength and impact resistance, particularly against deformation during top-loading
Solution Approach 1:
The closure incorporates axial columns that concentrate polymeric material in specific vertical regions, creating localized zones of enhanced strength and rigidity. These columns provide structural support where needed during ejection and top-loading, while the remaining sidewall areas maintain flexibility for manufacturing. This non-uniform distribution of material optimizes both manufacturing efficiency and mechanical strength.
2Strength
If the closure sidewall is made thicker to improve strength and impact resistance, then deformation resistance improves, but material usage increases and manufacturing efficiency decreases
Solution Approach 1:
Rather than uniformly thickening the sidewall, the invention introduces axial columns that concentrate material vertically at specific circumferential positions. This creates localized structural reinforcement that provides deformation resistance during top-loading without requiring overall sidewall thickening, thus minimizing polymeric material usage while maintaining necessary strength.
Solution Approach 2:
The sidewall is segmented into distinct regions: axial columns providing structural support and the spaces between columns providing flexibility. This segmentation allows the closure to use material efficiently only where structural support is needed, rather than uniformly throughout the entire sidewall, reducing overall material consumption while maintaining strength.
3Ease of manufacture
If the closure is designed with uniform sidewall thickness for simplicity, then manufacturing is easier, but the closure lacks the flexibility needed for high-speed ejection without deformation
Solution Approach 1:
The closure features axial columns that create localized rigid regions for structural support during ejection, while the spaces between columns provide flexible regions that allow the sidewall to deform elastically during high-speed ejection. This local differentiation of properties enables both structural integrity and manufacturing flexibility without complicating the overall design.
4Strength
If reinforcing structures are added to improve impact resistance, then strength improves, but the closure becomes more complex and harder to manufacture at high speed
Solution Approach 1:
The reinforcement structure is segmented into discrete axial columns rather than continuous complex geometries. These columns are simple vertical features that can be efficiently formed during injection molding or compression molding, avoiding complex tooling requirements. The segmented approach provides impact resistance through distributed structural support while maintaining manufacturing simplicity for high-speed production.
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 design minimizes polymeric material usage, enhances impact resistance, and simplifies the manufacturing process, ensuring efficient production and performance, including improved ergonomics and resistance to deformation and doming.
Implementation Method 1
These relatively thick columns maintain a raised core temperature at the point in time that the closure is ejected from the molding process
Implementation Method 2
the thickened columns in the closure sidewall provide energy absorption features that carry the brunt of any impact load encountered during container drops
Implementation Method 3
the annular skirt portion of the closure cap defines a plurality of circumferentially spaced, vertically extending gripping knurls on the exterior surface of the skirt portion
Data Source
AI summary
A plastic closure formed from polymeric materials in accordance with the present invention is configured for enhanced performance, including enhanced strength and impact resistance. In one aspect of the present invention, the closure includes a top wall portion, and an annular, depending skirt portion which defines a plurality of circumferentially spaced, axial columns. Notably, in accordance with the illustrated embodiment, each of these axial columns is provided by a group of gripping knurls provided on the exterior of the skirt portion, with each group of the gripping knurls having relatively shallow valleys between adjacent ones of the knurls.