Curled Metal Closure Edge for Thin-Wall Pressure Resistance
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Solution Overview
Problem
Conventional crown caps require a minimum thickness of 0.16 mm to withstand pressures, leading to material inefficiency and sharp edges that pose handling risks, while thicker materials complicate production and increase costs.
Innovation Solution
A metal closure with a thickness range of 0.12 to 0.16 mm, featuring a curled edge and radial deformations, which allows for greater pressure resistance and safe handling without increasing production complexity or costs, achieved through a method involving curling and radial deformation of the cap's edge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of substance
If the thickness of the cap material is reduced below 0.16 mm, then material efficiency and production economy are improved, but the pressure resistance capability deteriorates
Solution Approach 1:
The invention applies curvature to the edge of the cap by forming a curled portion that extends radially outward and then curves back toward the center. This curved geometry distributes stress more effectively across the cap structure, enabling thinner materials (0.12-0.16 mm) to withstand typical carbonated beverage pressures without failing.
Solution Approach 2:
The invention adds a radial dimension to the cap edge by creating a curled portion that extends outward and then folds back. This transforms a simple planar edge into a three-dimensional structure with multiple layers, increasing structural strength without increasing the base material thickness, thus resolving the contradiction between material efficiency and pressure resistance.
2Strength
If the thickness of the cap material is increased above 0.16 mm, then pressure resistance is improved, but production complexity and costs increase
Solution Approach 1:
By forming the edge into a curled configuration rather than using thicker material, the invention achieves enhanced pressure resistance through geometric optimization. The curling process creates a multi-layered edge structure that distributes mechanical loads more effectively, providing the strength of thicker material with thinner, more economical stock.
Solution Approach 2:
The invention changes the geometric parameters of the cap edge by creating a curled portion with specific radial extension and folding characteristics. This parameter transformation converts a simple flat edge into a complex three-dimensional form that provides superior mechanical performance, allowing the use of thinner materials while maintaining or enhancing pressure resistance capabilities.
3Ease of manufacture
If conventional crown cap edges are used, then production simplicity is maintained, but safety deteriorates due to sharp edges causing injuries
Solution Approach 1:
The curled edge configuration inherently eliminates sharp corners by replacing them with smooth curved surfaces. The edge curls radially outward and then folds back, creating a rounded profile that is safe to handle. This geometric transformation maintains production simplicity while fundamentally improving safety by eliminating the harmful sharp edges present in conventional flat-cut caps.
Solution Approach 2:
The invention converts the potentially harmful sharp edge into a beneficial curled configuration. By curling the edge radially outward and then folding it back, the originally dangerous sharp perimeter is transformed into a safe, rounded profile that protects handlers while maintaining structural integrity. The harmful sharpness is converted into a protective curved geometry.
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 solution enables the production of caps that withstand typical pressures while being safer to handle and more economical, using less material and simplifying the production process.
Implementation Method 1
a sliding contact element, movable along the inner contact element, for following a peripheral area of an edge of the capsule, causing a rounding or folding of the edge
Data Source
Figure 1a~3
Figure 4
Figure 5~8
AI summary
Described is a metal closure for containers comprising a capsule (1) designed to be applied to an opening (10) of a container (11) and comprising a circular part (2) from which extends a perimeter edge (3). The perimeter of the edge (3) has a rounding or folding (4) obtained by curling (4) and has a series of deformations (5) made in a radial direction (R) towards the centre of the capsule (1) for forming the seal.