Rotating Knife Shaft Mechanism for Loosening Stuck Crop Cutters

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Solution Overview

Problem

Crop cutting devices in agricultural machines, such as balers, face issues with knives becoming stuck due to contamination, necessitating laborious and potentially damaging manual intervention to adjust cutting width, leading to downtime and safety risks.

Innovation Solution

A crop cutting device with a rotatable shaft and engaging means that allows knives to be pivoted between retracted and extended positions via rotational movement, eliminating the need for manual disassembly and impact, using positive locking to safely and quickly loosen stuck knives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of repair

If knives are manually loosened by removing the knife drawer and cleaning, then stuck knives can be freed, but significant labor and downtime are required

Engineering Contradiction:
Improveease of knife looseningVSAvoiddowntime
Core Design Contradiction:
Ease of repairVSLoss of time

Solution Approach 1:

The shaft is designed to automatically force stuck knives into retracted or extended positions through its rotational movement between first and second rotational positions. The engaging means on the shaft interact with engaging means on the knives to self-loosen them without manual intervention, eliminating the need for operator disassembly and cleaning work.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The shaft is configured to be selectively rotatable between a first rotational position (where knives are freely pivotable) and a second rotational position (where the shaft forces knives into specific positions to loosen stuck knives). This dynamic positioning allows the system to switch between normal operation and knife-loosening modes, reducing downtime without manual intervention.

Inventive Principle:
Principle #15Dynamics

2Ease of repair

If stuck knives are hammered into position, then knives can be loosened, but irreparable damage and bending occur

Engineering Contradiction:
Improveease of knife looseningVSAvoiddamage to knives
Core Design Contradiction:
Ease of repairVSObject-affected harmful factors

Solution Approach 1:

The shaft's rotational movement between first and second rotational positions automatically forces stuck knives into retracted or extended positions through controlled mechanical interaction via engaging means. This self-loosening mechanism eliminates the need for violent hammering that causes knife bending and irreparable damage.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The engaging means on the shaft are configured to engage with engaging means on the knives before any damaging force is applied. This preliminary engagement controls the force application, forcing knives into proper positions through controlled mechanical action rather than uncontrolled hammering, preventing damage and bending.

Inventive Principle:
Principle #9Preliminary anti-action

3Ease of repair

If stuck knives are hammered to loosen them, then knives can be freed, but operator safety is compromised

Engineering Contradiction:
Improveease of knife looseningVSAvoidoperator safety
Core Design Contradiction:
Ease of repairVSEase of operation

Solution Approach 1:

The shaft automatically forces stuck knives into retracted or extended positions through its rotational movement and engaging means interaction. This self-loosening process eliminates the need for operators to perform dangerous hammering operations, significantly improving operator safety.

Inventive Principle:
Principle #25Self-service

4Loss of time

If the shaft forces knives into retracted or extended positions via rotation, then stuck knives are loosened quickly, but additional engaging means are required

Engineering Contradiction:
ImprovedowntimeVSAvoidcomplexity of shaft mechanism
Core Design Contradiction:
Loss of timeVSDevice complexity

Solution Approach 1:

The shaft serves multiple functions: it supports the knives during normal operation, enables free pivoting between retracted and extended positions, and actively forces stuck knives into proper positions through rotational movement. The engaging means are integrated into this existing shaft structure, adding knife-loosening capability without requiring a completely separate mechanism, thus limiting the increase in device complexity.

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

Data Source

PatentEP4670490A1Crop cutting device
Publication Date: 2025.12.31 CNH IND BELGIUM NV
  • EP4670490A1 patent drawingFigure 1a~1b
  • EP4670490A1 patent drawingFigure 2~3
  • EP4670490A1 patent drawingFigure 4~6

AI summary

A crop cutting device (22) for an agricultural machine according to the present invention comprises a shaft (28) and a plurality of knives (26) pivotally mounted on the shaft (28) between a retracted position and an extended position. The shaft (28) comprises first engaging means (44a) and each knife (26) comprises second engaging means (38, 40), wherein the first and second engaging means (38, 40, 44a) are configured to engage with each other, when the shaft (28) is rotated to force at least one knife (26) into one of the retracted position and the extended position.