Agricultural Header Double Knife Cutting System
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Solution Overview
Problem
Sickle headers in agricultural combines are prone to picking up small stones, which can become entrapped between the cutting teeth and guards, leading to broken teeth or stones being ejected into the crop stream and ingested by the combine harvester.
Innovation Solution
The design incorporates a cutter bar with a top and bottom knife assembly that reciprocates in a side-to-side motion, driven by a rotatable flywheel and cranks, with spring mechanisms to bias the assemblies toward each other, ensuring effective cutting action while minimizing stone entrapment through the arrangement of angularly related cutting edges and slide plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single knife assembly is used in the cutter bar, then the device complexity is low, but stone entrapment occurs between the cutting teeth and guards causing broken teeth or stone ejection
Solution Approach 1:
The cutter bar is divided into two separate knife assemblies (top and bottom) that operate independently. Each assembly has its own knife bar with multiple knife sections mounted on a slide plate, allowing them to reciprocate separately to cut crop material. This segmentation prevents stones from becoming trapped between a single fixed guard and knife assembly, as stones can pass through the gap between the two reciprocating assemblies without causing damage.
2Productivity
If the knife assembly reciprocates in a linear oscillating fashion, then the cutting action is effective, but stones can become picked up and entrapped between the teeth and guards
Solution Approach 1:
Instead of a single knife assembly moving in one dimension, the invention introduces a second dimension by having both top and bottom knife assemblies reciprocate simultaneously in opposite directions. This creates a dynamic gap between the assemblies through which stones can pass freely, eliminating the entrapment problem that occurs with a single fixed guard and knife assembly configuration.
3Strength
If spring mechanisms are used to bias the knife assemblies toward each other, then the cutting action is maintained, but the device complexity increases
Solution Approach 1:
Spring mechanisms are incorporated into each knife assembly to automatically bias the top and bottom assemblies toward each other, maintaining constant cutting pressure on the crop material. The springs provide self-regulating force that compensates for variations in crop resistance and wear, ensuring consistent cutting performance without requiring external control systems or complex actuation mechanisms.
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 effectively severs plant stems and stalks while reducing the likelihood of stone entrapment, preventing damage to the cutter bar and ensuring smooth operation by forcing the knife assemblies to move in opposite directions, thus preventing stones from becoming trapped.
Implementation Method 1
a spring mechanism connected to the mounting plate causing a downward biasing force on the top slide plate and a spring mechanism connected to the mounting plate causing an upwards biasing force on the bottom slide plate
Implementation Method 2
The sickle drive mechanism having a rotatable flywheel and an upper crank mounted on a first side of the flywheel and a bottom crank mounted on a second side of the flywheel opposite the first side. The upper crank drives the top cutter bar assembly such that the top slide plate slides along the mounting plate as the flywheel rotates, and the bottom crank drives the bottom cutter bar assembly
Data Source
AI summary
A sickle header has a cutter bar having a mounting plate extending along the cutter bar, a top cutter bar assembly mounted to reciprocate in a side-to-side motion relative to the mounting plate, the top cutter bar assembly having an elongate top knife bar mounted on a top slide plate. The cutter bar has a bottom cutter bar assembly mounted to reciprocate in a side-to-side motion relative to the mounting plate, the bottom cutter bar assembly having an elongate bottom knife bar mounted on a bottom slide plate. The top and bottom knife bars have a row of knife sections and oppositely facing adjacent knife sections of the top and bottom knife bars effect a cutting action as the cutter bar assemblies are reciprocatingly moved sidewardly. The cutter bar has a sickle drive mechanism configured to drive the cutter bar assemblies in opposite sideways directions.