Self-Cleaning Row Unit Shearing Edges

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Solution Overview

Problem

Row crop harvesters are prone to jamming due to contaminants like plant shreds, corn kernels, dirt, and grass getting trapped between the spinning stalk rolls and the gearbox, leading to operational inefficiencies.

Innovation Solution

The design incorporates a gearbox with stationary tubes and counter-rotating helical protrusions on the stalk rolls, featuring shearing edges and longitudinal knives to effectively shear and eject contaminants, preventing them from wrapping around the stalk rolls and gearbox.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the stalk roll is positioned close to the gearbox to reduce contamination risk, then the gap for contaminant entry is reduced, but long fibrous plant material can still wrap around the stalk roll base and wedge into the gap

Engineering Contradiction:
Improvecontaminant entry into gearboxVSAvoidstalk roll operation continuity
Core Design Contradiction:
Object-affected harmful factorsVSReliability

Solution Approach 1:

The patent converts the harmful wrapping action of fibrous plant material into a beneficial shearing action by providing a shearing edge on the stalk roll that works with the gearbox shearing edge to cut contaminants before they can enter the gearbox, thus transforming the potential harm of material contact into a protective function

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The shearing edges act as an intermediary mechanism between the stalk roll and gearbox, creating a controlled interaction point that prevents direct contamination while managing the plant material through shearing rather than allowing it to wrap and wedge into the gap

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the stalk roll rotates at high speed (1000 rpm) to maintain productivity, then harvesting efficiency is maintained, but contaminants become more likely to become jammed between the spinning stalk roll and gearbox

Engineering Contradiction:
Improveharvesting speedVSAvoidcontaminant jamming
Core Design Contradiction:
ProductivityVSObject-affected harmful factors

Solution Approach 1:

The shearing edges perform preliminary action by cutting and removing contaminants before they can become jammed in the gearbox, proactively preventing the harmful effect rather than reacting to it after contamination occurs

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The high rotational speed that increases contamination risk is converted into a benefit by the shearing edges, which use the rotational motion to continuously present fresh cutting surfaces that effectively shear and eject contaminants at the same speed the stalk roll rotates

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

3Ease of operation

If the stalk roll is positioned away from the gearbox to reduce friction and wear, then operational smoothness improves, but the gap increases allowing grass, weeds, and broken stalks to become jammed

Engineering Contradiction:
Improvestalk roll rotation smoothnessVSAvoidplant material jamming
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The shearing edges serve as an intermediary protective feature that allows the stalk roll to be positioned optimally for smooth operation while preventing plant material from reaching the gearbox gap, mediating between the operational requirements and contamination prevention

Inventive Principle:
Principle #24Intermediary (Mediator)

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

This configuration significantly reduces the likelihood of contamination, ensuring continuous operation by clearing out debris and maintaining the integrity of the stalk rolls and gearbox, even at high rotational speeds.

Implementation Method 1

the first shearing edge is disposed to shear against a mating shearing edge on the first stalk roll and the second shearing edge is disposed to shear against a mating shearing edge on the second stalk roll

Methodology Applied
Scientific EffectShear stress: Shear Stress

Data Source

PatentEP2018801B1Self-cleaning row unit
Publication Date: 2010.09.29 DEERE & CO
  • EP2018801B1 patent drawingFigure 1
  • EP2018801B1 patent drawingFigure 2
  • EP2018801B1 patent drawingFigure 3

AI summary

A row unit (100) comprises a row unit gearbox (102) with two shearing edges (138) and two stalk rolls (114, 116) with corresponding shearing edges (140), wherein the stalk roll shearing edges (140) shear against the gearbox shearing edges (138) when the stalk rolls (114, 116) rotate during normal operation of the row unit (100), thereby chopping material that might otherwise be wrapped around the row unit gearbox (102) and be jammed between the stalk rolls (114, 116) and the gearbox (102).