Bale Press Yarn Tension Control via Second Holder

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Solution Overview

Problem

Conventional bale presses face issues with yarn snapping or slipping due to high tension as the bale grows, leading to potential damage and reduced tensile strength, despite efforts to maintain yarn tension below its rated strength.

Innovation Solution

A bale press design incorporating a second holder that maintains contact between the yarn and a deflecting member even when the bale is not under pressure from the piston, using a movable member that presses the yarn against an abutment and releases to prevent violent hits, allowing the existing components to be repurposed without additional costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the yarn is held firmly by the clamping disk to maintain tension during bale formation, then the yarn can wrap around the growing bale, but the tension becomes too high and causes the yarn to snap or slip

Engineering Contradiction:
Improveyarn tensile strengthVSAvoidyarn continuity
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The holding function is segmented between two distinct holders: the first holder (clamping disk) that maintains tension during active bale formation, and the second holder that prevents excessive tension buildup by allowing controlled slack when the bale is not being pressed. This segmentation resolves the contradiction by distributing the holding function across different operational phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system transitions from a static holding arrangement to a dynamic one where the second holder can move between a clamping position (when bale pressure is applied) and a released position (when bale pressure is removed). This dynamic adjustment allows the yarn tension to adapt to changing operational conditions, preventing both snapping and slipping.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the yarn is allowed to lose contact with the deflecting member when the bale is not under pressure, then the system operates with fewer constraints, but the yarn hits violently against the deflecting member causing fibre damage and reduced tensile strength

Engineering Contradiction:
Improvesystem constraintsVSAvoidyarn tensile strength
Core Design Contradiction:
Device complexityVSStrength

Solution Approach 1:

The second holder is positioned to preliminarily guide and support the yarn before it reaches the deflecting member. By maintaining light contact or proximity during the initial phase of bale formation, the holder prevents the yarn from accumulating excessive slack that would lead to violent impact, thus preserving yarn strength without requiring complex constraint mechanisms.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The second holder acts as an intermediary element between the yarn supply and the deflecting member. It provides a buffer that absorbs sudden movements and prevents direct violent contact between the yarn and the deflecting member, thereby protecting the yarn fibres from damage while maintaining system simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If a second holder is added to maintain yarn contact with the deflecting member, then yarn damage is prevented, but the device complexity increases

Engineering Contradiction:
Improveyarn integrityVSAvoidknotter device structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The second holder is designed to perform multiple functions: it guides the yarn during initial bale formation, prevents excessive slack accumulation, maintains light contact to avoid violent impacts, and can be integrated with existing deflecting member structures. This multi-functionality justifies the added complexity by delivering multiple benefits from a single component.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The second holder is designed to operate automatically based on the bale formation cycle. When the piston applies pressure to the bale, the holder naturally assumes a clamping position; when pressure is removed, the holder automatically releases. This self-service operation eliminates the need for additional control mechanisms, reducing the effective complexity increase while maintaining yarn integrity.

Inventive Principle:
Principle #25Self-service

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

This solution reduces the risk of yarn snapping by maintaining yarn tension and preventing damage during bale formation, ensuring the yarn remains effective throughout the process without requiring extra components.

Implementation Method 1

a slot having two flanks between which the yarn is held by friction might be quite effective as said second holder

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP2564686B1Bale press
Publication Date: 2014.05.07 USINES CLAAS FRANCE SAS
  • EP2564686B1 patent drawingFigure 1
  • EP2564686B1 patent drawingFigure 2~4
  • EP2564686B1 patent drawingFigure 5~7

AI summary

A bale press comprises a pressing channel (1) in which a piston (2) is displaceable for forming a bale (4; 5) from crop material supplied to the pressing channel (1), a yarn supply (16), and a knotter device (6) arranged at a side of the pressing channel (1). The knotter device (6) comprises a first holder (8) for releasably holding an end portion of a yarn (9), a yarn deflecting member (11) and a knotter beak (20). The yarn (9) extends between the first holder (8) and the yarn supply (16) across the deflecting member (11) and a side (14) of the bale (5) facing away from the piston (2). The knotter beak (20) is arranged to tie a knot in a first stretch (10) of the yarn extending between the first holder (8) and the deflecting member (11). A second holder (22) is arranged to hold the yarn (9) at the deflecting member (11) at least in an initial phase of bale formation.