Modular Threshing Bed Concave for Agricultural Combine
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Solution Overview
Problem
Current concaves in agricultural combines are difficult and costly to maintain, requiring replacement when bars wear out or become damaged, leading to extended downtimes during harvest and inefficient grain separation.
Innovation Solution
A concave design featuring first and second frames that pivotally connect, allowing bars with integrated separating grates to be removably connected and disconnected without axial rotation, enabling non-destructive removal and installation, and reducing maintenance time and costs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If concaves use permanently welded bars to curved end members, then structural strength is improved, but ease of repair deteriorates and loss of time increases
Solution Approach 1:
The concave structure is divided into modular components: curved end members, intermediate members, and bars that can be independently removed. The engagement assembly with tongue and slot components allows segmented disassembly without damaging any part, enabling easy replacement of only the worn bars while retaining the curved members and other intact components.
Solution Approach 2:
The design allows for selective replacement of only the worn or damaged bars while recovering and reusing the curved end members, intermediate members, and engagement assemblies. This partial replacement strategy reduces material waste and lowers maintenance costs compared to replacing entire welded concave assemblies.
2Reliability
If concaves use permanently welded bars, then reliability is improved, but loss of time increases due to extended downtimes during harvest
Solution Approach 1:
The concave transitions from a static welded structure to a dynamic modular system where bars can be quickly engaged and disengaged using the tongue-and-slot mechanism. This dynamic design allows maintenance personnel to rapidly replace bars during harvest operations, minimizing downtime while maintaining structural integrity through properly engineered engagement features.
Solution Approach 2:
Replacement bars can be prepared in advance and stored ready for installation. The modular design with standardized engagement assemblies allows for pre-staging of replacement components, so that when a bar becomes worn or damaged, a ready-to-install replacement can be quickly swapped in without requiring on-site fabrication or complex assembly procedures.
3Ease of repair
If concaves use removable bars with engagement assemblies, then ease of repair is improved, but device complexity increases
Solution Approach 1:
The engagement assembly is segmented into simple, standardized components (tongue and slot) that can be manufactured using conventional processes and assembled without specialized equipment. This segmentation into basic geometric forms reduces manufacturing complexity while providing the necessary removable functionality.
Solution Approach 2:
The engagement assembly design with standardized tongues and slots can serve multiple functions: securing bars to curved members, providing alignment during installation, and enabling tool-free removal and reinstallation. This multi-functionality reduces the need for separate fastening mechanisms, thereby reducing overall device complexity despite the added removable feature.
4Ease of operation
If concaves use bars that can be removed and reinstalled, then ease of operation is improved, but manufacturing precision requirements increase
Solution Approach 1:
The tongue and slot engagement features are designed with localized precision requirements only at the engagement surfaces, while the bulk of the bar and curved member components can be manufactured with standard tolerances. This concentrated approach to precision manufacturing reduces overall manufacturing complexity while ensuring proper fit and function of the removable connection.
Solution Approach 2:
The engagement assembly incorporates features such as tapered slots or spring-loaded tongues that provide self-aligning and self-adjusting capabilities during installation. These parameter changes in the engagement mechanism tolerate variations in manufacturing tolerances, allowing ease of operation without requiring extremely tight manufacturing precision across all components.
Data Source
AI summary
A concave extends circumferentially about a portion of a rotor of a rotary processing unit of an agricultural combine. The concave has threshing beds forming openings therebetween for grain to pass through from a path of crop material between the concave and the rotor. The path of crop material has a flow direction relative to the concave in response to rotation of the rotor in a threshing direction. Each threshing bed includes a first extremity defining a threshing edge, a second extremity, and a separating grate extending across one of the openings between the first extremity and the second extremity, the first extremity overlapping the second extremity of an adjacent one of the threshing beds, locating the threshing edge in the path of crop material facing opposite to the flow direction. Each threshing bed extends from its threshing edge to its second extremity in the flow direction.