Threshing Drum Slats with Polyurethane Surface for Grain Protection

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Solution Overview

Problem

Conventional agricultural combines cause significant cracking and splitting of grain during threshing, leading to increased susceptibility to fungus and reduced grain value.

Innovation Solution

The use of threshing slats with an outer surface segment made from a material with Shore A hardness between 90 and 95, preferably polyurethane, which reduces the impact on grain and increases wear resistance, combined with a metal core for strength and a curved cross-sectional shape with grooves to enhance efficiency and reduce grain damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If conventional metal threshing slats are used, then wear resistance is sufficient for complete harvesting season operation, but grain cracking and splitting increases significantly

Engineering Contradiction:

Improvegrain cracking and splittingVSAvoidwear resistance

Core Design Contradiction:

Object-affected harmful factorsVSReliability

Solution Approach 1:

The threshing slat is constructed as a composite structure with a metal core providing structural strength and a polyurethane outer surface segment providing grain-friendly threshing properties. This composite design combines the advantages of both materials: the metal core ensures durability and wear resistance throughout the harvesting season, while the polyurethane surface reduces grain cracking and splitting by providing a more compliant threshing surface that absorbs impact energy without transmitting excessive force to the grain.

Inventive Principle:

Principle #40Composite materials

2Object-affected harmful factors

If rubber covers are applied to metal threshing slats, then grain cracking and splitting is reduced, but wear resistance becomes insufficient

Engineering Contradiction:

Improvegrain cracking and splittingVSAvoidservice life of rubber cover

Core Design Contradiction:

Object-affected harmful factorsVSDuration of action of stationary object

Solution Approach 1:

Instead of applying rubber covers to metal slats, the invention integrates a polyurethane outer surface segment directly onto a metal core. Polyurethane provides superior wear resistance compared to traditional rubber covers, enabling the threshing slat to maintain its grain-protection properties throughout the entire harvesting season without degradation or replacement. The metal core provides the structural backbone that supports the polyurethane surface during high-stress threshing operations.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention changes the material parameter from traditional rubber to polyurethane with a specific Shore A hardness between 90 and 95. This parameter optimization provides the ideal balance between softness for grain protection and hardness for wear resistance. The polyurethane material maintains its mechanical properties throughout the harvesting season, unlike softer rubber materials that wear down quickly.

Inventive Principle:

Principle #35Parameter changes

3Productivity

If drum rotating speed is increased to improve threshing efficiency, then productivity increases, but grain cracking and splitting worsens

Engineering Contradiction:

Improvethreshing efficiencyVSAvoidgrain cracking and splitting

Core Design Contradiction:

ProductivityVSObject-affected harmful factors

Solution Approach 1:

The invention changes the material parameter of the threshing slat surface from hard metal to polyurethane with Shore A hardness between 90 and 95. This material parameter change allows the drum to rotate at higher speeds for improved productivity while the polyurethane surface absorbs the increased impact forces, preventing grain cracking and splitting even during high-speed operation.

Inventive Principle:

Principle #35Parameter changes

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

Significantly decreases grain cracking and splitting, maintaining wear resistance throughout the harvesting season without the need for slat replacement, while efficiently separating grain from residue.

Implementation Method 1

when the outer surface segment of the threshing slat is formed from a material with a Shore A hardness lower than 95, the impact on the grain when the threshing slat hits the grain at a predetermined speed is significantly decreased

Methodology Applied

Scientific EffectImpact force reduction: Elasticity

Implementation Method 2

when the outer surface segment is formed from a material having a Shore A hardness higher than 90, the wear resistance is sufficient for the agricultural combine to operate during a complete harvesting season without the necessity of replacing the threshing slats

Methodology Applied

Scientific EffectWear resistance: Wear

Data Source

PatentUS10123483B2Threshing drum

Publication Date: 2018.11.13 BLUE LEAF I P INC

AI summary

An agricultural combine has a threshing drum and a matching concave, the threshing drum comprising multiple threshing slats having an outer surface segment which, when the drum is rotated with respect to the concave with crop material in the drum, beats and squeezes the crop material thereby releasing grain from residue in the crop material, wherein at least the outer surface segment is formed from a material having a Shore A hardness higher than 90 and lower than 95.