Polymeric Closure Rotation-Inhibiting Projections
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Solution Overview
Problem
Existing polymeric closures for pressurized containers, such as carbonated soft drinks, face challenges in controlling the unthreading speed due to distortion risks and inadequate resistance, with larger speed bumps potentially damaging the closure or container and smaller ones providing insufficient drag, leading to unthreading that is too fast.
Innovation Solution
A polymeric closure design featuring a polymeric annular skirt with internal thread formations and rotation-inhibiting projections, such as a 'C'-shaped or projection-valley configuration, that contacts the container's external thread to provide controlled resistance during unthreading, while a tamper-evident band is detachably connected via a frangible connection to indicate opening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If larger speed bumps are used to control unthreading speed, then the drag on the finish thread is increased and unthreading speed is reduced, but the closure or container may get distorted during application or removal
Solution Approach 1:
The speed bump is divided into multiple smaller projections (first projection, second projection, third projection) spaced around the interior surface of the annular skirt portion. This segmentation provides distributed drag points that control unthreading speed without concentrating excessive force at a single location, thereby preventing distortion while maintaining speed control.
Solution Approach 2:
The projections are designed with specific local geometries (rounded tops, spaced valleys) that create localized contact points with the finish thread. This local quality optimization allows each projection to engage the thread at controlled intervals, providing sufficient drag to slow unthreading while distributing the mechanical stress to avoid distortion.
2Stability of the object's composition
If smaller speed bumps are used to avoid distortion, then the drag on the finish thread is lessened and unthreading becomes faster than desired
Solution Approach 1:
Multiple smaller projections are arranged circumferentially around the annular skirt portion. While each individual projection is smaller and causes less localized stress, the cumulative effect of multiple projections engaging the finish thread simultaneously provides sufficient total drag to control unthreading speed without causing distortion at any single point.
Solution Approach 2:
The drag effect of multiple smaller projections is combined to achieve the total resistance needed for controlled unthreading. By merging the contributions of several projections spaced around the circumference, the closure achieves adequate speed control without the distortion risks associated with a single large speed bump.
3Speed
If existing larger speed bumps are used, then unthreading speed is controlled, but material may flash onto the container finish that affects closure release from mold
Solution Approach 1:
The projections are designed to provide partial engagement with the finish thread rather than full continuous contact. This partial action approach creates sufficient drag to control unthreading speed while avoiding excessive material displacement that would cause flashing onto the container finish and interfere with mold release.
4Speed
If larger speed bumps are used, then drag on finish thread is increased, but torque requirements increase and more material is used
Solution Approach 1:
The total drag force is segmented across multiple smaller projections rather than concentrated in one large speed bump. This distribution reduces the torque required at any single engagement point while maintaining adequate overall resistance to control unthreading speed, thereby reducing total material requirements.
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 closure effectively slows down unthreading, reduces the risk of damage, and maintains consistent performance across various conditions, ensuring controlled unthreading without excessive speed or distortion, while using less material and reducing torque requirements.
Implementation Method 1
The at least one rotation-inhibiting projection is located to contact the external thread formation of the container... effectively slows down unthreading, reduces the risk of damage, and maintains consistent performance
Data Source
AI summary
A closure includes first and second closure portions. The first closure portion includes a polymeric top wall portion and an annular skirt portion. The skirt portion includes exterior and interior surfaces. The interior surface includes an internal thread formation for mating engagement with an external thread formation of a container and at least one rotation-inhibiting projection. The rotation-inhibiting projection is located to contact the external thread formation. The rotation-inhibiting projection is in the general shape of the letter “C” prior to engagement with the external thread formation of the container. The second closure portion includes a polymeric tamper-evident band.