Combine Harvester Straw Chopper Guide Fins for Wind Spread
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current straw chopper and spreader technologies face challenges in maintaining even distribution and spread width across a wide cutting area, especially in windy conditions, with existing devices only able to spread 10-12 feet against a 10 mph wind, and often require high horsepower usage.
Innovation Solution
The design incorporates a guide assembly with a plurality of guide members featuring inclined surface portions to redirect crop material from an initial discharge direction to a required spread direction, including a first surface portion extending outwardly and a second surface portion that is inclined inwardly, allowing for more efficient spreading against strong winds by utilizing the geometry of the guide fins to manage airflow and material trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If conventional spreading mechanisms are used, then the device complexity and horsepower requirements increase, but the spread width against wind remains limited to 10-12 feet
Solution Approach 1:
The tail board is divided into multiple fins (typically 3-5 fins) spaced across its width, with each fin independently guiding material flow. This segmentation allows the system to achieve wider spread (15+ feet) against wind without requiring a single complex mechanism, as each fin handles a portion of the material flow independently
Solution Approach 2:
The fins are positioned at specific angles relative to the horizontal plane (typically 10-30 degrees upward inclination) to utilize aerodynamic forces from the wind. By adding this angular dimension to the fin design, the system converts wind resistance into a beneficial force that propels material farther against the wind direction
2Length of moving object
If conventional spreading mechanisms are used, then the horsepower requirements increase significantly, but the spread width against wind remains limited
Solution Approach 1:
The design converts the harmful effect of wind resistance into a beneficial propulsive force. By positioning fins at upward angles, the wind that would normally resist material movement instead provides lift and forward propulsion, reducing the horsepower needed from the chopper while achieving greater spread width against the wind
Solution Approach 2:
The system utilizes aerodynamic forces (pneumatic principles) by positioning fins to catch and redirect airflow. The wind-generated air pressure acts on the inclined fin surfaces to propel material farther, reducing reliance on mechanical horsepower from the chopper system
3Area of stationary object
If the cutting width is increased to cover wider areas, then the spread width must match, but even distribution becomes difficult to maintain
Solution Approach 1:
The tail board is divided into multiple fins (typically 3-5 fins) spaced across its width, with each fin independently guiding material flow to a specific zone. This segmentation ensures that material from different parts of the wide cutting width is distributed evenly across the corresponding spread width, maintaining consistency even as cutting width increases to 45-60 feet
Solution Approach 2:
Each fin is positioned to handle material from a specific local zone of the cutting width and direct it to a corresponding spread zone. This local quality approach ensures that material flow from each section of the wide header is independently managed, maintaining even distribution across the entire spread width
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 solution enables a simplified and cost-effective method to spread over 15 feet against a 10 mph headwind, improving the spread width and consistency while reducing horsepower requirements.
Implementation Method 1
a plurality of guide members each defining a guide member surface shaped along a direction of movement of the materials so as to define a contact side along which the materials flow to turn the materials from an initial discharge direction to a required discharge direction
Implementation Method 2
allowing for more efficient spreading against strong winds by utilizing the geometry of the guide fins to manage airflow and material trajectory
Data Source
AI summary
A straw chopper is mounted at the rear hood of a combine harvester and includes a housing with a feed opening and a discharge opening and a rotor mounted in the housing comprising a hub with a plurality of blades mounted on the hub for chopping the fed materials and accelerating the chopped materials for discharge. A tailboard has a plurality of guide fins arranged relative to the housing so as to receive the chopped materials from the discharge opening to engage onto a guide surface and guide fins of the tailboard construction for spreading of the chopped materials to the sides. On each side of the tailboard an outermost one of the guide fins has a first fin portion extending downwardly from the bottom surface to an lowermost edge, a second fin portion inclined from the lowermost edge downwardly and toward the contact side of the fin and a third fin portion inclined from the second portion to the concave side and toward the bottom surface.