Straw Chopper Drum Zone Knife Arrangement
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Solution Overview
Problem
Existing straw choppers in combine harvesters suffer from uneven crop distribution due to knife arrangements that divert crop material excessively to the outside, leading to manufacturing and energy inefficiencies, as well as increased costs and spare part complexity.
Innovation Solution
A straw chopper design with a rotatable drum divided into neutrally aligned conveying zones and intermediate zones, where knives are arranged to deflect crop material in the circumferential direction within conveying zones and axially in intermediate zones, ensuring optimal width distribution and reducing the need for different knife types.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If double-sided sharpened knives are used in the central area and single-sided sharpened knives are used on the sides, then crop spreading is improved, but manufacturing cost increases and device complexity increases
Solution Approach 1:
The patent applies local quality by creating different conveying zone types (neutrally aligned zones and intermediate zones with outward deflection) in specific locations along the drum. The intermediate zones are positioned at locations where crop accumulation occurs, providing localized crop redistribution without requiring different knife designs throughout the entire drum.
Solution Approach 2:
The drum conveying path is segmented into distinct zones: neutrally aligned conveying zones and intermediate zones with outward-deflecting knives. This segmentation allows different functional regions to handle crop flow differently, with intermediate zones specifically targeting areas of crop accumulation to achieve uniform distribution.
2Ease of manufacture
If single-sided sharpened knives are used throughout, then manufacturing cost decreases, but crop width distribution becomes uneven
Solution Approach 1:
The patent applies local quality by creating different conveying zone types (neutrally aligned zones and intermediate zones with outward deflection) in specific locations along the drum. The intermediate zones are positioned at locations where crop accumulation occurs, providing localized crop redistribution without requiring different knife designs throughout the entire drum.
Solution Approach 2:
The drum conveying path is segmented into distinct zones: neutrally aligned conveying zones and intermediate zones with outward-deflecting knives. This segmentation allows different functional regions to handle crop flow differently, with intermediate zones specifically targeting areas of crop accumulation to achieve uniform distribution.
3Productivity
If knives deflect crop outward in all areas, then crop is redistributed, but excessive crop accumulates in outer regions and is ejected inefficiently
Solution Approach 1:
The patent applies local quality by creating different conveying zone types (neutrally aligned zones and intermediate zones with outward deflection) in specific locations along the drum. The intermediate zones are positioned at locations where crop accumulation occurs, providing localized crop redistribution without requiring different knife designs throughout the entire drum.
Solution Approach 2:
The patent applies partial action by implementing outward-deflecting knives only in intermediate zones rather than throughout the entire drum. This partial application of outward deflection is sufficient to redistribute crop from accumulation zones without causing excessive ejection to outer regions, optimizing energy efficiency.
Data Source
Figure 1
Figure 2a~2b
Figure 3~4
AI summary
The invention relates to a straw chopper (20) with knives (25) arranged on a rotatable drum (23) for chopping crop material (4), wherein the knives (25) have sharpened grinding surfaces (29) on one side in the respective cutting area (28), wherein the knives (25) are arranged on the drum (23) in such a way that the drum (23) is divided into at least three neutrally oriented conveying zones (32) and two intermediate zones (33) which deflect the crop material (4) outwards.