Combine Harvester Vane Adjustment Mechanism
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Solution Overview
Problem
Existing axial flow combine designs face challenges in efficiently adjusting the pitch angle of vanes in threshing chambers, leading to increased grain losses and inefficiencies, particularly when switching between different types of crops like rice and corn, due to cumbersome and inaccurate adjustment methods.
Innovation Solution
A vane mounting and adjusting system using only two bolts per vane, with one bolt as an off-centre pivot and the other sliding within a slot, along with a tie plate and indexing pin, allows for adjustable vanes that can be set to various pitch angles without requiring simultaneous adjustment of all vanes, enhancing accessibility and stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple bolts are used to secure each vane, then the vane adjustment precision is improved, but the adjustment time and operational complexity increase
Solution Approach 1:
Multiple vanes are connected by tie bars to form a unified adjustable assembly. The tie bars link the vanes together, allowing them to be adjusted as a group rather than individually. This merging reduces the number of adjustment operations needed while maintaining precise pitch angle control for each vane through the shared mounting mechanism.
Solution Approach 2:
The vane mounting system uses movable bolts that can slide within slots on the cover plate, enabling dynamic adjustment of the pitch angle. The bolts can be positioned at different locations along the slots to achieve different pitch angles, and the system allows for quick repositioning without requiring complete disassembly or complex locking mechanisms.
2Loss of substance
If vanes are made adjustable to optimize crop flow, then grain losses are reduced, but the structural complexity and manufacturing difficulty increase
Solution Approach 1:
The cover plate is segmented with multiple slots at different positions, allowing the mounting system to be divided into discrete adjustment positions. Each slot represents a predetermined pitch angle position, enabling the system to achieve precise angular control through simple positional segmentation rather than complex continuous adjustment mechanisms.
Solution Approach 2:
Tie bars serve as intermediary elements that connect multiple vanes to the cover plate mounting system. These tie bars transmit the adjustment motion from the movable bolts to the vanes, mediating the force and motion transfer while simplifying the overall structural design by providing a rigid connection mechanism.
3Ease of operation
If slots for bolt movement are left uncovered for adjustment access, then the ease of operation is improved, but grain loss through the cover plate increases
Solution Approach 1:
The cover plate is designed with selective opening and closing characteristics. The slots remain accessible for bolt movement, but the area around the slots can be covered or opened locally depending on whether adjustment is needed. This local quality change allows the system to maintain grain containment during operation while providing easy access during adjustment periods.
Data Source
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AI summary
An improved combine harvester comprises threshing and separating chambers (26) having cover plates (121) on which groups of vanes (123) may be adjusted by individual tie plates (58) utilising an off-centre pivot point (56) for the vanes (123) and a two-bolt system. Said two bolts being the maximum number of bolts needed to secure each vane (123) wherein one of said bolts (56) is an off-centre pivot point while the other of said bolts (67) extends through the cover plate (121) to secure the tie plate (58) for each group of vanes (123).