Grinding Device for Chopping Knives Reducing Facet Length

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Solution Overview

Problem

The existing grinding devices for chopping knives in agricultural harvesting machines increase the facet length of the cutting edges, leading to power loss, blockages, and the risk of fire due to increased friction and temperature, which affects the efficiency and safety of the chopping mechanism.

Innovation Solution

A grinding device that adjusts the grinding stone to grind open surfaces on the chopping knives radially inward, reducing the facet length, and includes actuators for precise control and processing of cutting edges and open areas, with a control unit to manage the grinding process and prevent blockages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the grinding device removes material radially from the chopper knives, then the cutting edges are sharpened, but the facet length of the facet surface increases

Engineering Contradiction:
Improvecutting edge sharpnessVSAvoidfacet length
Core Design Contradiction:
Manufacturing precisionVSLength of moving object

Solution Approach 1:

Instead of removing material radially from the outside of the chopper knives (conventional approach), the invention introduces a grinding device that grinds the facet surfaces from the inner side, working inward toward the cutting edge. This inverted grinding approach reduces the facet length while maintaining cutting edge sharpness, as the grinding stone removes material from the inner facet surface rather than adding to the outer radius.

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

Solution Approach 2:

The invention changes the grinding parameter from radial material removal to axial material removal. By orienting the grinding stone to grind the facet surfaces axially (reducing the length of the facet surface in the axial direction) rather than radially, the system achieves a shorter facet length while preserving the sharpness of the cutting edge through controlled material removal from the inner surface.

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If the facet length of the facet surface increases, then the cutting edges are maintained, but power loss increases

Engineering Contradiction:
Improvecutting edge qualityVSAvoidpower loss
Core Design Contradiction:
Manufacturing precisionVSLoss of energy

Solution Approach 1:

The invention inverts the conventional grinding approach by grinding from the inner side of the chopper knife toward the cutting edge, rather than from the outer side inward. This allows the facet surface length to be reduced while the cutting edge remains sharp and functional, thereby decreasing the surface area that causes power loss during operation.

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

Solution Approach 2:

By changing the grinding direction from radial to axial and controlling the amount of material removed from the inner facet surface, the invention optimizes the facet length parameter. This reduces the effective cutting surface area that contacts the crop, thereby reducing friction and power loss while maintaining adequate cutting edge performance.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the facet length of the facet surface increases, then the cutting edges are maintained, but the risk of blockages increases

Engineering Contradiction:
Improvecutting edge sharpnessVSAvoidblockage risk
Core Design Contradiction:
Manufacturing precisionVSReliability

Solution Approach 1:

The invention applies the inversion principle by grinding the facet surfaces from the inner side toward the cutting edge, which allows the facet length to be reduced without compromising cutting edge sharpness. A shorter facet length reduces the area where crop material could accumulate and cause blockages, thereby improving the reliability of the chopping mechanism.

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

Solution Approach 2:

The invention changes the grinding approach to reduce the axial length of the facet surface by removing material from the inner surface. This parameter change shortens the facet length, which directly reduces the risk of crop blockages while maintaining the cutting edge's ability to perform its function effectively.

Inventive Principle:
Principle #35Parameter changes

4Manufacturing precision

If the facet length of the facet surface increases, then the cutting edges are maintained, but friction increases

Engineering Contradiction:
Improvecutting edge performanceVSAvoidfriction
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The invention inverts the conventional grinding approach to grind from the inner side toward the cutting edge, enabling reduction of the facet surface length. This shorter facet length reduces the contact area between the cutting edges and the crop, thereby reducing friction and the associated harmful effects while preserving cutting edge performance.

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

Solution Approach 2:

The invention changes the grinding parameter to reduce the axial length of the facet surface by removing material from the inner surface. This parameter optimization shortens the facet length, which directly reduces the friction between the cutting edges and the processed material, thereby reducing energy loss and thermal effects.

Inventive Principle:
Principle #35Parameter changes

5Manufacturing precision

If the facet length of the facet surface increases, then the cutting edges are maintained, but temperatures on the blades and crop increase

Engineering Contradiction:
Improvecutting edge sharpnessVSAvoidblade and crop temperature
Core Design Contradiction:
Manufacturing precisionVSTemperature

Solution Approach 1:

The invention applies the inversion principle by grinding from the inner side toward the cutting edge, which allows reduction of the facet length without compromising cutting edge sharpness. A shorter facet length reduces the surface area generating friction heat during operation, thereby reducing the temperature of both the blades and the processed crop.

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

Solution Approach 2:

The invention changes the grinding approach to reduce the axial length of the facet surface by removing material from the inner surface. This parameter change shortens the facet length, which reduces the frictional heating during chopping operations, thereby maintaining lower temperatures for both the cutting edges and the processed material.

Inventive Principle:
Principle #35Parameter changes

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

The solution effectively reduces the facet length, minimizing power loss, friction, and the risk of fire, thereby enhancing the efficiency and safety of the chopping mechanism by creating defined open spaces that counteract blockages and maintain optimal operational conditions.

Implementation Method 1

material is removed radially from the chopper knives via the grinding device's grindstone

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 2

the grindstone can be adjusted to the chopping knives in the radial direction of the chopping drum in such a way that, viewed in the direction of rotation of the chopping drum, the free surfaces downstream of the cutting edges of the chopping knives can be ground and extend radially inwards

Methodology Applied
Scientific EffectGrinding: Abrasion

Data Source

PatentEP4427579A1Grinding device for cutter blades of a cutter, cutter and method for grinding the cutter blades of a cutter
Publication Date: 2024.09.11 CLAAS SAULGAU GMBH
  • EP4427579A1 patent drawingFigure 1~2
  • EP4427579A1 patent drawingFigure 3a~3c
  • EP4427579A1 patent drawingFigure 4

AI summary

Grinding device (3) for chopping knives (7) of a chopping unit (1) of an agricultural harvesting machine, comprising a grinding slide (10) which is displaceable along a housing-fixed guide (9) parallel to a rotational axis (6) of a chopping drum (2) of the chopping unit (1) carrying the chopping knives (7), which is rotatably mounted on a housing of the chopping unit (1), in the axial direction of the chopping drum (2), comprising a grinding stone assembly (12) mounted on the grinding slide (10) and comprising a grinding stone (11), which together with the grinding slide (10) is displaceable parallel to the rotational axis (6) of the chopping drum (2) in the axial direction of the same, wherein the grinding stone (11) is rotated about a rotational axis (13) of the grinding stone (11), which preferably extends parallel to the rotational axis (6) of the chopping drum (2) and thus in the axial direction of the chopping drum (2), is rotatably drivenand can be adjusted in the radial direction of the chopping drum (2) to the chopping knives (7) such that, viewed in the direction of rotation of the chopping drum, clearance surfaces downstream of the cutting edges of the chopping knives can be ground, extending radially inwards. Fig. 2,