Double-Walled Container Pinched-Off Bottom Recess Design
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Solution Overview
Problem
Double-walled containers that rely on the own weight of the content medium for dispensing face issues with air leakage through the ambient air introduction hole, leading to insufficient volume reduction of the inner layer body, especially when the outer layer body is squeezed, resulting in difficulty in dispensing the content medium.
Innovation Solution
A double-walled container design featuring a pinched-off portion with a straight slit and a substantially cross-shaped recess at the bottom, reinforced by ribs and bitten portions, which minimizes air leakage and ensures effective volume reduction of the inner layer body during dispensing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the outer layer body is squeezed to dispense content medium, then dispensing speed is improved, but air leakage from the ambient air introduction hole increases causing the inner layer body to fail volume reduction
Solution Approach 1:
The bottom wall is segmented into multiple functional zones: a first bottom surface for normal dispensing, a second bottom surface with the ambient air introduction hole positioned away from the center, and a third bottom surface with a reinforcement rib. This segmentation allows different regions to serve different functions - the offset hole position reduces air leakage during squeezing while the reinforcement rib maintains structural integrity, enabling both fast dispensing and effective volume reduction.
Solution Approach 2:
The ambient air introduction hole is positioned offset from the center of the bottom wall, changing its spatial dimension relative to the conventional centered position. This offset positioning creates an asymmetric air flow pattern during squeezing that reduces direct air leakage into the inner layer body, allowing the inner layer to undergo proper volume reduction even during rapid dispensing.
2Ease of manufacture
If the ambient air introduction hole is positioned at the center of the bottom wall, then manufacturing is simplified, but air leakage increases when the outer layer body is squeezed
Solution Approach 1:
The ambient air introduction hole is positioned offset from the center of the bottom wall in the radial direction, creating an asymmetric configuration that reduces air leakage during squeezing operations. This offset positioning changes the spatial relationship between the hole and the inner layer body, allowing air to be introduced more effectively without causing excessive leakage that would prevent volume reduction.
3Ease of manufacture
If the inner layer body thickness varies, then manufacturing is easier, but some portions collapse preferentially leaving narrow passages
Solution Approach 1:
The bottom wall is segmented into multiple zones with different functional characteristics. The first bottom surface provides a larger area for uniform air distribution, the second bottom surface positions the air introduction hole optimally, and the third bottom surface includes a reinforcement rib to prevent localized collapse. This segmentation compensates for thickness variations in the inner layer body, ensuring all portions undergo uniform volume reduction and maintaining adequate passage width for content medium flow.
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 allows for smooth dispensing of the content medium by its own weight and through squeezing of the outer layer body, maintaining efficient volume reduction of the inner layer body without the need for an ambient air introduction valve, thus avoiding cost increases and ensuring the container is empty before use.
Implementation Method 1
an inner layer body that is accommodated inside the outer layer body and that is deformable to undergo volume reduction
Implementation Method 2
the outer layer body is provided with an ambient air introduction hole that communicates between the outer layer body and the inner layer body
Implementation Method 3
mainly utilizing the own weight of the content medium
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
Provided is a double-walled container (1) including: an outer layer body (10); an inner layer body (20), which is provided in a pinched-off portion and which passes through the outer layer body (10). The pinched-off portion is formed in a bottom due to pinch-off using a splittable mold in blow molding. The bottom is provided, on an inner side in a radial direction of an outer edge portion (11a) thereof, which serves as a ground-contacting surface, with a substantially cross-shaped recess (11b), which is concave toward a mouth. The recess (11b) is configured by a first-direction recess portion (17a), which extends along an extending direction of the slit (14), and a second-direction recess portion (17b), which intersects with the first-direction recess portion (17a). The slit (14) is provided in a region in which the first-direction recess portion (17a) and the second-direction recess portion (17b) intersect with each other.