Flexible Lid With Interrupted Circular Weld Path

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Solution Overview

Problem

Existing flexible lids for containers with laminate structures, comprising aluminum and weldable plastic, often require additional weld paths to ensure satisfactory joining, which can lead to instability and heterogeneity, especially when stacked or subjected to heat, due to trapped air forming 'pillows' that cause production disruptions.

Innovation Solution

A multilayer flexible lid design with a central circular weld path featuring interruptions to allow air passage and a larger contiguous surface for uniform heat exposure, combined with an outer edge weld for enhanced joining, and optional non-circular shapes to mitigate edge effects.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a central weld area is made sufficiently large to ensure strong joining, then the welding strength is improved, but the heat load becomes too great causing homogeneous central area to overheat

Engineering Contradiction:
Improvewelding strengthVSAvoidheat load
Core Design Contradiction:
StrengthVSTemperature

Solution Approach 1:

The central weld area is segmented into a ring-shaped region with an interruption, dividing the continuous area into a controlled path that allows heat dissipation while maintaining sufficient welding surface area for strong joining

Inventive Principle:
Principle #1Segmentation

2Reliability

If a continuous circular weld path is used, then welding coverage is improved, but air becomes confined inside forming pillows that cause instability

Engineering Contradiction:
Improvewelding coverageVSAvoidlid stability
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The harmful element (air) is extracted from the confined space by introducing an interruption in the weld path, allowing air to escape and preventing pillow formation that would cause instability

Inventive Principle:
Principle #2Taking out (Extraction)

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 ensures strong and uniform welding without heat overload, preventing air confinement and maintaining stability, even when stacked, thereby improving production consistency and reducing the risk of lid instability.

Implementation Method 1

the first and the second main layer are welded to one another across a welding area

Methodology Applied
Scientific EffectWelding: Welding

Implementation Method 2

welded by for example inductive heating around an opening in the container

Methodology Applied
Scientific EffectInductive heating: Induction Heating

Data Source

PatentEP2909098B1Flexible lid
Publication Date: 2017.07.19 A&R CARTON AB LUND
  • EP2909098B1 patent drawingFigure 1

AI summary

The invention relates to a flexible lid for sealed closing of an opening in a container, the lid is a multilayer structure comprising a first and a second main layer, wherein at least the first main layer is a laminate structure comprising a layer of aluminum and an outer layer of a weldable plastic, wherein the outer weldable layer faces the second main layer. The invention is characterized in that the first and the second main layer are welded to one another across a welding area, wherein the weld area comprises a first part located in the center of the lid where the welding is arranged in a circular path, wherein the circular weld path has at least one interruption which allows communication between a volume inside the circular weld path and a volume outside the circular weld path.