Maize Stalk Chopper Dual Knife Overlap Design

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Solution Overview

Problem

Existing stalk choppers for corn harvesters either fail to chop stalks sufficiently small or result in uneven distribution of chopped material on the field due to single knife designs or cutting patterns that lead to long, striped residues.

Innovation Solution

A stalk chopper with two knives that rotate about vertical axes and overlap in the discharge area of a corn harvester, with one knife rotating in the opposite direction to the other, allowing for simultaneous cutting and distribution of chopped material from different directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a single knife is used to chop stalks, then the device complexity is reduced, but the cutting quality deteriorates and streaking occurs

Engineering Contradiction:

Improvenumber of knivesVSAvoidcutting quality

Core Design Contradiction:

Device complexityVSManufacturing precision

Solution Approach 1:

The single knife is segmented into multiple knives (first knife and second knife) that rotate in opposite directions. This segmentation allows each knife to contribute to the cutting process from different directions, improving cutting quality and preventing streaking while maintaining manageable device complexity through a systematic multi-knife arrangement.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If stalks are chopped by a single knife in one direction, then the device complexity is reduced, but the chopped material is deposited in strips making even soil incorporation difficult

Engineering Contradiction:

Improveknife arrangementVSAvoideven distribution of chopped material

Core Design Contradiction:

Device complexityVSEase of operation

Solution Approach 1:

The second knife rotates in the opposite direction to the first knife, creating bidirectional cutting action. This inversion of rotation direction causes chopped material to be dispersed in multiple directions rather than deposited in single-direction strips, enabling even distribution across the field and facilitating uniform soil incorporation.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If intermeshing cutting rollers are used to chop stalks, then the device complexity is reduced, but the cut material becomes very long and difficult to rot

Engineering Contradiction:

Improvecutting mechanismVSAvoidlength of cut material

Core Design Contradiction:

Device complexityVSLength of moving object

Solution Approach 1:

The cutting action is segmented into multiple sequential cuts by the first and second knives rotating in opposite directions. This multi-stage segmentation of the cutting process reduces the length of individual cut pieces compared to single-pass cutting, thereby improving decomposition rates while maintaining a relatively simple cutting mechanism.

Inventive Principle:

Principle #1Segmentation

Data Source

PatentEP2965611B1Stalk chopper for a maize harvesting implement

Publication Date: 2017.09.20 MASCHFAB KEMPER

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Figure 2

AI summary

A stalk chopper (132) for mounting below a row unit (152) of a corn harvester (108) comprises a first blade (134) and a second blade (136), which are mounted or can be mounted below the row unit (152) of the corn harvester (108) and are rotatable about at least substantially vertical axes of rotation. The circumscribed circles of the blades (134, 136) overlap below a stalk discharge area (154) of the row unit (152) of the corn harvester (108). The blades (132, 134) act from different directions on the stalks discharged downwards by the row unit (152).