Folded-Back Container Body Notches to Prevent Flat-Section Buckling

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Solution Overview

Problem

Containers with a trapezoid-shaped cross section and bottom experience buckling during the folding back of one end portion due to high compressive forces, which is not addressed by existing manufacturing methods.

Innovation Solution

The implementation of triangularly-shaped notches at the lower ends of the flat sections, with increasing depth towards the center, to reduce compressive forces during folding, thereby preventing buckling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If one end portion of the cylindrical body is folded back inwardly to form the container, then the container structure is formed, but buckling occurs in the folded-back portion of the flat section

Engineering Contradiction:
Improvefolding back processVSAvoidbuckling of flat section
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

Notches are formed at both end portions of the flat section before the folding back operation. This preliminary action creates stress relief zones that prevent buckling during the subsequent folding process, allowing the flat section to be folded back cleanly without deformation

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The flat section is segmented by introducing notches at its end portions. These notches divide the continuous flat section into zones with different structural characteristics, allowing the folded-back portion to deform more uniformly and preventing buckling in the middle region

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3663216B1Body, container, and method for manufacturing container
Publication Date: 2026.04.01 TOKAN KOGYO CO LTD
  • EP3663216B1 patent drawingFigure 1
  • EP3663216B1 patent drawingFigure 2
  • EP3663216B1 patent drawingFigure 3

AI summary

A body portion (120A) that is a cylindrical body has one end portion, such as a lower end portion or the body portion (120A) or a first part (126) of a body portion (120), that is folded back inwardly. The body portion (120A) has at least one planar-shaped flat section, such as a second flat section (122) or a fourth flat section (124). A notch, such as a notch (K1) or a notch (K2), is provided at one end, such as a lower end, of the flat section. The one end portion includes a portion provided with the notch, such as by providing the notch (K1) or (K2) at a lower end of the lower end portion of the body portion (120A) or at a distal end of the first part (126A) of the body portion (120).