Folded-Bottom Bag Forming with Multi-Station Paper Sealing

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Solution Overview

Problem

Existing methods for producing bags from paper or low-plastic paper composite materials struggle with thermal welding limitations, making it difficult to create a liquid-tight bottom without using high plastic content.

Innovation Solution

A device with multiple folding stations and clamping devices forms a hose section into a bag with a closed bottom by folding and adhesive bonding, using pure paper or low-plastic content materials, ensuring a dense and stable bottom through multiple folds and adhesive application.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If thermal welding is used to close the bag end, then the bag is sealed and liquid-tight, but pure paper or low-plastic materials cannot be welded

Engineering Contradiction:
Improveliquid-tight sealVSAvoidmaterial compatibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the thermal welding system with a mechanical folding and clamping system. Multiple folding stations with clamping devices create sequential folds that are mechanically secured, eliminating the need for thermal welding while achieving liquid-tight seals with pure paper or low-plastic materials.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the sealing mechanism from thermal (heat-based) to mechanical (force-based). By using clamping devices that apply mechanical pressure to create and secure folds, the system adapts to materials that cannot withstand or respond to thermal welding, thereby expanding material compatibility.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If a single fold is made at the bottom, then the bag structure is simple, but the bottom area lacks sufficient stability and density

Engineering Contradiction:
Improvebottom stabilityVSAvoidnumber of folds
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The patent divides the bottom formation process into multiple discrete folding stages. Each folding station creates a separate fold sequence, with clamping devices securing each fold individually. This segmentation allows the bottom to achieve enhanced stability through cumulative layering while maintaining systematic control over the folding process.

Inventive Principle:
Principle #1Segmentation

3Manufacturing precision

If multiple folding stations are used to create a dense bottom, then the bottom area achieves sufficient stability, but the device complexity increases

Engineering Contradiction:
Improvebottom densityVSAvoidnumber of folding stations
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent combines multiple folding operations into a continuous sequential process. The folding stations are arranged in series along the conveying path, allowing multiple folds to be created in one continuous operation rather than requiring separate processing steps. This merging approach achieves high bottom density while minimizing overall device complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent utilizes the spatial dimension along the conveying direction to arrange folding stations sequentially. By distributing folding stations along the length of the conveyor path rather than stacking them vertically or horizontally, the system achieves multiple folds without proportionally increasing device footprint or operational complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

Data Source

PatentEP4674608A2Apparatus for forming bags having a folded bottom
Publication Date: 2026.01.07 WEBER VERPACKUNGEN FRIEDRICH WEBER NACHF GMBH & CO
  • EP4674608A2 patent drawingFigure 1

AI summary

The invention relates to a device for producing bags with a folded bottom section from a flat, open-ended section of tubing, comprising at least two folding stations, each comprising a folding drum with at least one axially extended clamping device arranged on/in or below the drum surface, having two clamping jaws, and a knife shaft radially spaced from the folding drum, with at least one axially extended folding knife, wherein, during rotation of the folding drum and knife shaft, a folding knife can be immersed at least partially in a gap between the clamping jaws, a feeding device with which a section of tubing can be fed in a conveying plane to the folding drum of a first folding station substantially tangentially to the drum surface of the folding drum, and a transfer device between folding stations adjacent in the conveying direction.with which the hose section can be transferred tangentially to the drum surfaces between the folding drums of the adjacent folding stations, a depositing station after the last folding station in the conveying direction, into which the hose section can be deposited, wherein with each folding station a leading area of ​​a hose section conveyable by the folding station can be folded around a fold line onto the hose section, so that a hose section conveyed by all folding stations has a closed bottom after the last folding station, with a number of folds corresponding to the number of folding stations.