Bottle Can Curl Geometry for Cap Sealing and Drinking Comfort
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Solution Overview
Problem
The existing curl portions in bottle-shaped can bodies are too large, leading to reduced pressure resistance after cap mounting and discomfort during drinking due to sharp edges.
Innovation Solution
A can body design with a curl portion featuring specific radii of curvature and shapes to ensure reliable cap sealing and minimize lip discomfort, including an inflection portion with a small radius of curvature between the outer periphery-side tubular and lower-side bent portions, and convex surfaces to prevent the curl end from biting into the mouth portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the radius of curvature of the lower end portion of the curl portion is increased to make the shape similar to a bottle mouth, then the ease of operation (drinking comfort) is improved, but the pressure resistance after cap mounting deteriorates
Solution Approach 1:
The patent applies local quality by creating different curvature radii at different locations of the curl portion. Specifically, the lower end portion has a smaller radius of curvature (R1: 0.5-1.5mm) to ensure pressure resistance, while the upper portion maintains a larger radius for drinking comfort. This localized differentiation allows each section to optimize its function without compromising the other.
2Strength
If the radius of curvature of the lower end portion of the curl portion is reduced to improve pressure resistance, then the strength is improved, but the ease of operation (drinking comfort) deteriorates due to sharp tips hitting lips
Solution Approach 1:
The patent implements local quality by assigning different functional characteristics to different sections of the curl portion. The lower end portion (where the cap mounts) has a small radius of curvature for structural strength, while the upper portion (contacting the user) has a larger radius for comfort. This spatial differentiation of properties resolves the contradiction between strength and comfort.
3Ease of operation
If a curl portion with large radius of curvature is formed to prevent lip discomfort, then the ease of operation is improved, but the reliability of cap mounting deteriorates due to insufficient rolling up of the skirt portion
Solution Approach 1:
The patent applies local quality by creating a specific geometric configuration where the lower end portion of the curl portion has a small radius of curvature (R1: 0.5-1.5mm) to provide adequate rolling surface for reliable cap mounting, while the upper portion maintains larger curvature for comfort. This localized structural differentiation ensures both mounting reliability and user comfort.
Data Source
AI summary
A can body has a curl portion to which a skirt portion of a cap is mounted. In the curl portion, an outer periphery upper-side bent portion that forms an outer peripheral portion of a folded-back top portion, an outer periphery-side tubular portion that extends downward in a can axis direction, an outer periphery lower-side bent portion that is bent inward in a radial direction, and a curl end portion that extends from an inner peripheral edge of the outer periphery lower-side bent portion are continuously formed. When a radius of curvature of an outer surface of the outer periphery upper-side bent portion is R5 (mm), a radius of curvature of an outer surface of the outer periphery lower-side bent portion is R6 (mm), and a radius of curvature of an outer surface of the inflection portion is R7 (mm), which is 0.05 to 0.2 mm, R7<R6<R5 is established.