Folding Unit Vacuum Control for High-Speed Tissue Transfer

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Solution Overview

Problem

High-speed paper product folding machines face challenges in ensuring correct material transfer from one folding cylinder to another, limiting production speed and leading to defects due to inadequate vacuum systems.

Innovation Solution

A cross-wise folding unit with adjacent parallel channels and sequential valves that regulate vacuum flow to maintain paper segments securely during cutting and folding, using high and low vacuum arcs to ensure precise transfer and minimize deformations.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If high-speed operation is implemented, then productivity increases, but material transfer reliability deteriorates causing defects

Engineering Contradiction:
Improveproduction speedVSAvoidmaterial transfer reliability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The vacuum system dynamically adjusts suction levels through sequential valves that control different vacuum levels at different rotational positions. The system transitions from a static vacuum level to a dynamic one that varies throughout the folding cycle, enabling high-speed operation while maintaining reliable material transfer through optimized suction profiles at each stage.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention changes the vacuum parameter from a single constant level to multiple variable levels controlled by sequential valves. By adjusting vacuum pressure dynamically during the folding cycle and using different vacuum levels for different functional zones, the system achieves both high productivity and reliable material transfer without defects.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If vacuum suction is increased to prevent defects, then material transfer reliability improves, but device complexity increases due to additional vacuum control systems

Engineering Contradiction:
Improvematerial transfer reliabilityVSAvoidvacuum system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The folding cylinder surface is segmented into multiple functional zones (holding zone, transfer zone, release zone) with dedicated vacuum control for each. Sequential valves are positioned at different angular locations to control vacuum levels in each zone independently, allowing precise control of material transfer while managing system complexity through modular zoned control.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The vacuum system employs periodic action through sequentially activated valves that open and close at specific rotational positions of the folding cylinder. This periodic control pattern creates the necessary vacuum profiles at the right moments in the folding cycle, achieving reliable material transfer through rhythmic, timed vacuum application rather than continuous complex control.

Inventive Principle:
Principle #19Periodic action

3Manufacturing precision

If sequential valves are added to control vacuum levels, then manufacturing precision improves, but device complexity increases

Engineering Contradiction:
Improvefolding line precisionVSAvoidvalve system complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The sequential valves are positioned upstream at the axial ends of the folding cylinder to control vacuum levels before the material reaches critical folding zones. This preliminary action allows the system to prepare and control material holding and transfer conditions in advance, achieving precise folding lines by controlling vacuum conditions beforehand rather than reacting during the folding process.

Inventive Principle:
Principle #10Preliminary action

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

Enables increased production speed while maintaining high product quality by preventing defects and reducing waste through controlled vacuum suction, allowing for seamless paper transfer between folding cylinders.

Implementation Method 1

a vacuum system... holes or slots along the periphery of the folding cylinders, which are connected to a vacuum source

Methodology Applied
Scientific EffectVacuum suction: Suction

Data Source

PatentEP3055241B1Folding unit for tissue products and method for folding sheet-like products
Publication Date: 2019.12.18 RENT
  • EP3055241B1 patent drawingFigure 1
  • EP3055241B1 patent drawingFigure 2~7
  • EP3055241B1 patent drawingFigure 8~9

AI summary

The present invention refers to a folding unit of a high-speed folding machine, for folding sheet-like products (S) made of tissue paper or the like. Such a unit comprises a first folding cylinder (3) with pneumatic means (5, 6, 5', 6') adapted to promote an orderly and precise release of the material in the folding step even at high speed.