Retractable Harvester Knife Assembly for Easier Cutter Maintenance

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Solution Overview

Problem

Existing cutter devices for agricultural harvesters are difficult to service, particularly in accessing and maintaining the knives due to their large and heavy sub-assemblies, which require strong frames and make manual handling cumbersome.

Innovation Solution

A cutter device design featuring a lightweight, compact sub-assembly that includes a bottom plate with integrated openings for knives, allowing easy access and maintenance, and a support frame with guide rails and a locking mechanism for smooth lateral movement, reducing the need for additional parts and minimizing dirt accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a traditional cutter device design is used with large and heavy sub-assemblies, then the structural strength and stability are improved, but the ease of maintenance and accessibility of knives deteriorates

Engineering Contradiction:
Improvestructural strengthVSAvoidease of maintenance
Core Design Contradiction:
StrengthVSEase of repair

Solution Approach 1:

The cutter device is divided into modular sub-assemblies (cutter head, rotor assembly, knife assembly) that can be independently accessed and maintained. The bottom plate with integrated openings allows direct access to knives without requiring disassembly of the entire cutter device, resolving the contradiction between structural integrity and maintenance accessibility.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The knife assembly is extracted as a separate, easily removable component from the main cutter structure. Knives can be individually accessed through openings in the bottom plate and removed for sharpening or replacement without affecting the overall structural strength of the cutter device.

Inventive Principle:
Principle #2Taking out (Extraction)

2Reliability

If a heavy sub-assembly is used to ensure structural strength, then the reliability is improved, but the ease of operation and manual handling deteriorates

Engineering Contradiction:
ImprovereliabilityVSAvoidease of manual handling
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The cutter device is segmented into lighter modular sub-assemblies that can be manually positioned and adjusted. The bottom plate with integrated knife openings allows operators to easily access and maintain knives without requiring heavy equipment or complex disassembly procedures, improving ease of operation while maintaining reliability through proper modular connections.

Inventive Principle:
Principle #1Segmentation

3Adaptability or versatility

If a complex sub-assembly with multiple parts is used, then the functional capability is improved, but the device complexity increases

Engineering Contradiction:
Improvefunctional capabilityVSAvoiddevice complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The bottom plate integrates multiple functions into a single component: it provides structural support, contains openings for knife access, and serves as a mounting surface for the knife assembly. This merging of functions reduces the number of separate parts and simplifies the overall device structure while maintaining full functional capability for cutting operations.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The bottom plate with integrated openings serves multiple purposes: structural support, maintenance access, and component mounting. This multi-functional design reduces device complexity by eliminating the need for separate access panels, mounting brackets, and support structures, while still providing all necessary functional capabilities.

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

4Adaptability or versatility

If additional parts and components are added to the sub-assembly, then the functional capability is improved, but the ease of manufacture and assembly deteriorates

Engineering Contradiction:
Improvefunctional capabilityVSAvoidease of assembly
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The bottom plate combines structural support, access features, and mounting functions into a single integrated component, reducing the total number of parts that need to be manufactured and assembled. This simplifies the manufacturing process and assembly procedures while maintaining all necessary functional capabilities for cutting and maintenance operations.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4385315B1Cutter device for an agricultural harvester
Publication Date: 2026.02.04 KUHN GELDROP
  • EP4385315B1 patent drawingFigure 1
  • EP4385315B1 patent drawingFigure 2
  • EP4385315B1 patent drawingFigure 3

AI summary

The present invention relates to a cutter device for an agricultural harvester, comprising a sub-assembly (300) including a retractable knife (56), the sub-assembly further including a bottom plate (60) located beneath a tine rotor (42), and the bottom plate (60) includes an opening (61) through which the knife (56) extends in a cutting position. The cutter device also comprises a support frame (305), a positioning device (70) mounted to the support frame (305), wherein the positioning device (70) is arranged to control movement of the knife (56), and a control mechanism (80) mounted to the support frame (305), wherein the control mechanism (80) is arranged to control movement of the positioning device (70). The sub-assembly is moveably mounted to the support frame (305) and is arranged to move relative to the support frame (305) in a lateral direction that is transverse to the forward moving direction independently from the positioning device (70).