Chaff Cutter Blade Guide Surface for Low-Energy Crop Conveyance

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Solution Overview

Problem

Existing chopper blades for forage harvesters face challenges in optimally guiding and deflecting chopped crop, leading to inefficiencies in energy consumption and crop circulation within the chopper drum.

Innovation Solution

The chopper blade design features a guide surface with specific geometric parameters, including angled and curved sections, to optimize crop guidance and deflection, combined with a roll-profiled element and wear-resistant coatings to enhance durability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the guide surface begins at a larger distance from the transition edge, then there is more space for structural components, but the crop guidance and deflection efficiency deteriorates

Engineering Contradiction:
Improvecrop conveyance efficiencyVSAvoidenergy consumption for crop deflection
Core Design Contradiction:
ProductivityVSUse of energy by moving object

Solution Approach 1:

The patent optimizes the distance parameter between the guide surface beginning and the transition edge to be between 4 mm and 8 mm. This parameter optimization enables the guide surface to effectively guide and deflect chopped crop while minimizing the circulation area within the chopper drum, thereby reducing energy consumption in the conveying process without compromising structural integrity.

Inventive Principle:
Principle #35Parameter changes

2Ease of operation

If the guide surface has complex curved contours, then crop guidance is improved, but manufacturing complexity increases

Engineering Contradiction:
Improvecrop guidance qualityVSAvoidguide surface manufacturing
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The guide surface features a concavely curved contour with specific geometric parameters (radius of curvature between 21 mm and 25 mm, wrap angle between 29° and 33°) that optimize crop guidance. The curved design efficiently directs chopped crop while the well-defined geometric parameters enable precise manufacturing through standardized processes.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If the material guide element is positioned closer to the transition edge, then crop deflection is more effective, but wear on the base body increases

Engineering Contradiction:
Improvecrop deflection efficiencyVSAvoidbase body durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent applies a wear-resistant coating specifically to the material guide element and its guide surface, while the base body maintains its structural function. This localized protection strategy allows the guide element to be positioned optimally close to the transition edge (4-8 mm distance) for effective crop deflection, while the coating protects against wear at this high-stress location.

Inventive Principle:
Principle #3Local quality

4Use of energy by moving object

If the guide surface has larger curvature radii, then crop flow is smoother, but the guide element height increases

Engineering Contradiction:
Improveenergy for crop accelerationVSAvoidguide element height
Core Design Contradiction:
Use of energy by moving objectVSLength of stationary object

Solution Approach 1:

The patent specifies optimized geometric parameters for the guide surface curvature: radius of curvature between 21 mm and 25 mm for the second section, and wrap angles between 29° and 33°. These parameter optimizations create smooth crop flow that minimizes acceleration energy requirements while controlling the guide element height to remain within practical limits for chopper drum integration.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP4176706B1Cutter blade for a chaff cutter and method for producing the same
Publication Date: 2025.07.16 CLAAS SAULGAU GMBH
  • EP4176706B1 patent drawingFigure 1~2
  • EP4176706B1 patent drawingFigure 3~4
  • EP4176706B1 patent drawingFigure 5~6

AI summary

Chopping knife (10), comprising a base body (11) having a mounting section (12) for attaching it to a chopping drum and a cutting section (13) angled relative to the mounting section, and a material guide element (15) attached to the mounting section (12) for guiding chopped crop material, wherein a guide surface (16) of the material guide element (15) has a curved contour. A distance (a) between the beginning of the guide surface (16) of the material guide element (15) and a transition edge (14) between the mounting section (12) and the cutting section (13) of the base body (11) is between 4 mm and 8 mm. The guide surface (16) extends in a straight line in a first section (18) with a length (b) between 4 mm and 8 mm, wherein this first section (18) forms an angle (a) between 18° and 22° with the mounting section (12).The first section (18) transitions into a concave second section (19) with a radius of curvature (Rx) between 21 mm and 25 mm and a wrap angle (β) between 29° and 33°. The second section transitions into a concave third section (20) with a radius of curvature (Ry) between 18 mm and 22 mm and a wrap angle (y) between 24° and 28°. The third section transitions into a convex fourth section (21). The maximum height of the guide element is between 24 mm and 30 mm.