Helical Bar Concave Laser Cutting and Segmented Assembly
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Solution Overview
Problem
Conventional helical concaves in axial flow harvesters are costly and time-intensive to manufacture due to intricate welding, which can lead to distortion and precision issues, and lack the aggressive interaction required for effective grain separation.
Innovation Solution
A helical bar concave with a grate having helical cutouts and segmented rub bars mounted in a helical fashion, allowing for easy assembly and configuration using a bolted system, and manufactured through laser cutting and rolling of metal sheets to reduce costs and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If conventional welded construction is used to create helical-shaped rub bars, then the concave can achieve a helical shape conforming to the rotor radius, but the manufacturing process becomes very time and cost intensive with intricate weld fixturing required
Solution Approach 1:
The concave is divided into modular components: a base structure with helical support elements and separately attachable rub bar segments. This segmentation allows each component to be manufactured independently using simpler processes, then assembled together to form the complete helical concave structure, eliminating the need for intricate continuous welding.
Solution Approach 2:
The invention employs adjustable and reconfigurable rub bar segments that can be positioned and secured at different locations along the helical path. This dynamic configuration allows the same base structure to accommodate different rub bar arrangements for different crop types, replacing fixed welded constructions with adaptable mechanical fastening systems.
2Shape
If conventional welded construction is used to create helical-shaped rub bars, then the concave can achieve a helical shape conforming to the rotor radius, but the weld process introduces heat and distortion causing the part to be out of desired manufacturing tolerances
Solution Approach 1:
By segmenting the concave into a base structure and separate rub bar components, the invention eliminates continuous welding that causes cumulative heat distortion. Each component can be precision-manufactured separately to tight tolerances, then assembled with controlled fastening that does not introduce the same level of thermal distortion as welded construction.
Solution Approach 2:
The invention replaces the thermal welding process with mechanical fastening systems (such as bolts, clips, or interlocking mechanisms). This substitution eliminates heat-induced distortion entirely, allowing precision components to be assembled without compromising dimensional accuracy, while still achieving the required helical shape conformance to the rotor radius.
3Ease of manufacture
If straight rub bars perpendicular to the side sheet are used, then the concave construction is simpler, but the bars are not perpendicular to the crop flow reducing grain expulsion effectiveness
Solution Approach 1:
The invention employs asymmetrically oriented rub bar segments that are angled relative to both the side sheet and the crop flow direction. This asymmetric configuration optimizes the interaction between rub bars and spiraling crop material, with each segment positioned at a specific angle to maximize grain expulsion effectiveness while maintaining manufacturability through modular assembly.
Solution Approach 2:
The rub bar segments are designed to be adjustable in their angular orientation, allowing optimization of the angle between rub bars and crop flow for different operating conditions and crop types. This dynamic adjustability replaces fixed straight rub bars with a system that can be configured to achieve optimal perpendicularity to the helical crop flow path.
4Productivity
If angled cross rub bars extending fully across the width of the concave are used, then the bars are more perpendicular to the crop flow increasing grain expulsion, but the construction becomes more complex with multiple part numbers
Solution Approach 1:
The invention segments the full-width rub bar structure into multiple smaller, standardized rub bar components that attach to the helical support elements. This segmentation reduces device complexity by using repeated standard parts rather than single complex custom-shaped bars, while still achieving full width coverage and optimal angular orientation for grain expulsion.
Solution Approach 2:
The invention employs universal mounting mechanisms and standardized rub bar components that can be positioned at different angles and locations along the helical path. This universality allows the same basic part design to serve multiple functions at different positions, reducing the total number of unique part numbers while maintaining the angled configuration needed for effective grain separation.
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
The solution provides a cost-effective, easy-to-manufacture helical bar concave with improved threshing and separation capabilities, allowing for adjustable configurations to suit various crops and reducing the need for complex welding, thus enhancing the efficiency of grain separation.
Implementation Method 1
laser cutting flat metal sheet to form a grate
Implementation Method 2
rolling the flat, cut, metal grate to a predetermined radius
Data Source
Figure 1
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AI summary
A helical bar concave (20) comprises a grate (24) having helical mounting framework (42) and helical cutouts (34) to form a percent open area having a helical geometry. Configurable and segmented rub bars (36) are mounted in a helical fashion to a cylindrical helical surface (38/40) of the grate. There is provided a method of manufacturing a helical bar concave (20) from a flat, rolled laser cut arrangement that provides a net helical concave functionality. Laser cutting a flat metal sheet to form helical cutouts (34) defining a percent open area having a helical geometry in combination with configurable rub bars (36) mounted in a helical fashion results in a configurable helical bar concave (20) in which the number or aggressiveness of the threshing surface (38) on the inside radius of the grate may be changed and/or the rub bars (36) may be moved to the outside of the grate to change the percent open area and hence the separation characteristics of the concave.