Thermoplastic Container Bottom with Radial Ribs and Shoulder
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Solution Overview
Problem
Container bottoms made of thermoplastic materials, such as PET, face challenges in withstanding hydrostatic pressure and internal overpressure due to their lightweight design, leading to deformation and swiveling issues when filled with liquids.
Innovation Solution
Incorporating a shoulder connecting zone between the body and the bottom, combined with radial ribs that extend beyond the shoulder, enhances the rigidity and prevents deformation and swiveling by distributing pressure evenly and preventing accordion-like movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the bottom height is reduced to lighten the container, then the weight decreases, but the resistance to internal overpressure decreases
Solution Approach 1:
The bottom is segmented into multiple functional zones: an annular seat zone for stability, a central vault for volume, and radial ribs for structural reinforcement. This segmentation allows each zone to perform its specific function optimally while using minimal material overall.
Solution Approach 2:
Material thickness and structural reinforcement are concentrated locally where needed - specifically in the radial ribs that extend from the seat into the vault, and in the annular seat zone itself. The rest of the bottom uses thinner material, achieving weight reduction without compromising overall strength.
2Weight of moving object
If the bottom is made lighter with reduced material, then the weight decreases, but the bottom deforms under hydrostatic pressure
Solution Approach 1:
The bottom structure is divided into discrete rib elements spaced radially around the vault. These segmented ribs provide localized support against hydrostatic pressure, preventing general deformation while using less material than a continuous thick bottom would require.
Solution Approach 2:
The reinforcement strategy moves from a two-dimensional flat bottom to a three-dimensional structured bottom with radial ribs extending vertically into the vault. This adds a vertical dimension to the reinforcement, creating a more rigid structure that resists pressure-induced deformation more effectively.
3Strength
If conventional reinforced bottoms are used, then the resistance to overpressure improves, but the container exhibits swiveling behavior on flat surfaces
Solution Approach 1:
The radial ribs are distributed asymmetrically in a star pattern rather than uniformly, creating an uneven weight distribution that provides a stable base. This asymmetric arrangement with the annular seat creates a low center of gravity and wide base of support, preventing swiveling while maintaining structural integrity.
Solution Approach 2:
The bottom features a curved vault with a dome-shaped central recess, creating a spherical cap geometry. This curved structure naturally distributes stresses more evenly and provides a stable, flat seating surface that resists tipping and swiveling on horizontal surfaces.
Data Source
Figure 1A~1C
Figure 1D~2
Figure 3~4
AI summary
The invention relates to a container made of thermoplastic material, comprising a body that extends between a neck and a base that is able to withstand, without significantly deforming, a hydrostatic pressure caused by the column of a liquid contained in said container, said column of liquid being increased by a pressure not exceeding 2x105 Pa, said base comprising main ribs (70) in the form of grooves that are open towards the outside and extend approximately radially, passing through an annular zone that forms an approximately flat seat (50) by way of which said base (30) can rest in a stable manner on a flat support, said main ribs (70) extending upwards on a wall (80) connecting the base to the body of the container. The container has a shoulder (90) that forms a joining zone between said connecting wall (80) and said body of the container, and said main ribs (70) extend upwards beyond said shoulder (90).