Forage Harvester Knife Sharpening Using Inductive and Optical Sensing

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Solution Overview

Problem

Existing forage harvesters rely solely on inductive detection of chopping blade wear for determining the need for resharpening, which can lead to suboptimal chopping due to other influencing factors.

Innovation Solution

A self-propelled forage harvester that combines inductive detection of blade wear with optical sensor-based analysis of the harvested material stream to determine the necessity of sharpening the chopping knives, using a knife sharpening device and an adjustment device to ensure optimal chopping quality.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If inductive detection of blade wear is used to determine sharpening necessity, then the sharpening process can be automated, but the determination accuracy deteriorates because other influencing factors on chopping quality are not considered

Engineering Contradiction:
Improveautomation of sharpening processVSAvoiddetermination accuracy of sharpening necessity
Core Design Contradiction:
Extent of automationVSMeasurement precision

Solution Approach 1:

The patent combines multiple detection methods (inductive sensors for blade wear, optical sensors for crop quality) into a unified control system that integrates data from both sources to determine sharpening necessity, thereby maintaining automation while improving determination accuracy

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The system implements feedback control by continuously monitoring both blade wear conditions and crop chopping quality, using this information to dynamically adjust sharpening decisions and optimize the sharpening process

Inventive Principle:
Principle #23Feedback

2Measurement precision

If optical sensor device is added to monitor crop quality, then the determination of sharpening necessity is improved, but the device complexity increases

Engineering Contradiction:
Improvedetermination accuracy of sharpening necessityVSAvoidsensor system complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The control device serves multiple functions: it processes data from inductive sensors, analyzes optical sensor data for crop quality assessment, and determines sharpening decisions, thereby managing complexity through functional integration

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

Solution Approach 2:

The control device acts as an intermediary that processes and integrates information from multiple sensor sources, translating raw sensor data into actionable sharpening decisions without requiring direct complex interaction between sensors

Inventive Principle:
Principle #24Intermediary (Mediator)

3Adaptability or versatility

If knife sharpening device with movable grinding wheel is used, then all chopping knives can be sharpened, but the device complexity increases

Engineering Contradiction:
Improvecapability to sharpen all chopping knivesVSAvoidsharpening device complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The grinding wheel is designed to be movable along the chopping drum, allowing it to dynamically position itself to sharpen different knives on the rotating drum, providing universal sharpening capability through dynamic positioning rather than fixed multiple grinding points

Inventive Principle:
Principle #15Dynamics

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

Ensures that chopping knives are sharpened only as often and as intensively as necessary, maintaining optimal chopping quality by integrating sensor-based information and image analysis to adjust the sharpening process.

Implementation Method 1

an inductive detection device for monitoring the wear of the chopping knives

Methodology Applied
Scientific EffectInductive detection: Electromagnetic Induction

Implementation Method 2

an optical sensor device for recording image sequences of the crop passing through the discharge spout

Methodology Applied
Scientific EffectOptical detection: Reflection

Data Source

PatentEP4646913A1Forage harvester with inductive detection device and optical sensor device
Publication Date: 2025.11.12 CLAAS SELBSTFAHRENDE ERNTEMASCHINEN GMBH
  • EP4646913A1 patent drawingFigure 1
  • EP4646913A1 patent drawingFigure 2
  • EP4646913A1 patent drawing

AI summary

The present invention relates to an agricultural machine (1) designed as a self-propelled forage harvester (2) for picking up, processing, and conveying harvested crops. This forage harvester (2) has a chopping unit (6) for shredding the harvested crop, wherein the chopping unit (6) comprises a drum housing (21, 22) in which a chopping drum (7) and several chopping knives (8) are arranged, these chopping knives (8) being detachably, and in particular replaceably, attached to the chopping drum (7). Furthermore, the forage harvester (2) comprises an inductive detection arrangement (25) for detecting the condition of the chopping unit (6) and a sensor device (51) arranged on the discharge spout (15) for optically detecting the shredded crop.The present invention is based on the general idea that, depending on the sensor-determined chopping quality of the harvested material stream and the sensor-detected wear condition of the chopping knives (8), it is determined whether a grinding of the chopping knives (8) by means of a knife grinding device (17) is necessary.