Round Baler Wrapping Rollers for Controlled Bale Film Tension

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Solution Overview

Problem

Conventional agricultural round balers require complex and costly mechanisms to tension wrapping material around bales, which can lead to material tearing or slowing down the bale rotation, causing wear and inefficiency.

Innovation Solution

The baler employs a tensioning device with two rotatable rollers that actively drive the wrapping material, moving in opposite directions at different circumferential speeds to induce tension, eliminating the need for sensitive adjustments and ensuring efficient wrapping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a brake acts directly on the supply roll to create tension in the wrapping material, then the wrapping material is tensioned during wrapping, but the brake requires very sensitive adjustment to prevent material tearing and avoid slowing down the bale rotation

Engineering Contradiction:
Improvetension in wrapping materialVSAvoidcontrol process complexity
Core Design Contradiction:
ForceVSDevice complexity

Solution Approach 1:

Instead of using a brake to create friction and tension the wrapping material, the invention uses a tensioning roller that rotates in the opposite direction to the supply roll. This inversion of the braking approach allows tension to be created through controlled reverse rotation rather than friction, eliminating the need for sensitive brake adjustment while maintaining reliable tensioning throughout the wrapping process

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The invention replaces the friction-based brake system with a mechanically-driven tensioning roller system. The tensioning roller is rotated by a drive mechanism (such as a motor or cam) that directly controls its rotation speed and direction, substituting the indirect friction-based tensioning with direct mechanical control. This eliminates the sensitivity issues inherent in brake-based systems

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

2Force

If the brake is set excessively strong to ensure sufficient tension, then the wrapping material is well tensioned, but the wrapping material slows down the rotating round bale, almost bringing it to a complete stop

Engineering Contradiction:
Improvetension in wrapping materialVSAvoidbale rotation speed
Core Design Contradiction:
ForceVSSpeed

Solution Approach 1:

The tensioning roller rotates in the opposite direction to the bale rotation, creating tension through this counter-rotation rather than through friction resistance. This allows the bale to maintain its rotation speed while the wrapping material is still effectively tensioned, as the tensioning effect comes from the relative motion between the two rotating surfaces rather than from braking force

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The brake system that caused speed reduction is replaced with a mechanically-driven tensioning roller. The drive mechanism controlling the tensioning roller can independently regulate its rotation speed, ensuring that tension is applied to the wrapping material without creating excessive resistance that would slow down the bale rotation

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

3Force

If a brake-based tensioning system is used, then tension can be created in the wrapping material, but costly components and sensitive control processes are required for implementation

Engineering Contradiction:
Improvetension in wrapping materialVSAvoidmanufacturing cost
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The complex brake-based control system is replaced with a simpler mechanically-driven tensioning roller. The tensioning roller can be driven by standard agricultural machinery components such as motors, hydraulic actuators, or cam mechanisms that are already present in round balers, eliminating the need for specialized brake control systems and reducing manufacturing costs

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

Solution Approach 2:

The tensioning roller system can be integrated with the existing drive train of the round baler, using the same power source that drives the bale rotation. This self-service approach eliminates the need for separate control systems and additional costly components, as the existing mechanical infrastructure of the baler is utilized to provide the tensioning function

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 design allows for reliable and economical wrapping by precisely controlling tension, reducing material waste and maintaining bale integrity without complex components or slowdowns.

Implementation Method 1

The tension rollers can be actively driven during the wrapping of a pressed round bale, in such a way that the tension rollers move towards each other in opposite directions of rotation at a relative circumferential speed

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4677993A1Agricultural round baler
Publication Date: 2026.01.14 USINES CLAAS FRANCE SAS
  • EP4677993A1 patent drawingFigure 1A~1B
  • EP4677993A1 patent drawingFigure 2
  • EP4677993A1 patent drawingFigure 3

AI summary

The present invention relates to an agricultural round baler (1) with a device (7) for receiving crops from an agricultural area, a baling chamber (5), and a pressing element (6) circumferentially delimiting the baling chamber (5) for compressing the received crops into a round bale (B), as well as a device (9) for wrapping a compressed round bale (B) with wrapping material (H) supplied via a supply roll (V). The wrapping device (9) comprises a tensioning device (11) for tensioning the wrapping material (H) during the wrapping of a compressed round bale (B). The round baler (1) is characterized in that the tensioning device (11) comprises two rotatable tension rollers (12, 12.1, 12.2), wherein the wrapping material (H) is guided between the tension rollers (12, 12.1, 12.2), wherein the tension rollers (12, 12.1, 12.2) are actively driven during the wrapping of a pressed round bale (B) in such a way that the tension rollers (12, 12.1, 12.2) move with a relative circumferential speed (U, UR1) towards each other in opposite directions of rotation (D, D1, D2).