Skid Shoe Float Arm Support for Harvester Head Height Control
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Solution Overview
Problem
Existing agricultural machines, such as combine harvesters, face challenges in maintaining a consistent height of the harvester head relative to the underlying terrain, especially when encountering varying topography, which can affect the efficiency of crop harvesting and processing.
Innovation Solution
A float arm support system utilizing skid shoes that are selectively raised and lowered by a remote-controlled powered actuator, allowing for precise control of the height of the active member (cutter bar) above the terrain, with linkages and actuators that adjust the angular positioning to follow ground contours and maintain optimal height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional float arm support systems are used, then the structure is simple, but the height control precision and ground following performance are insufficient
Solution Approach 1:
A skid shoe is introduced as an intermediary element between the float arm and the terrain. The skid shoe directly contacts the ground and transmits terrain height variations to the float arm through a linkage mechanism, enabling precise height control without complex sensors or actuators on the float arm itself
Solution Approach 2:
The patent replaces electronic height sensing and hydraulic control systems with a purely mechanical linkage system. The skid shoe-ground-contact mechanism mechanically translates terrain variations into float arm position adjustments through levers and linkages, eliminating the need for complex electronic control systems
2Reliability
If gage wheels or sensor canes are used to sense ground height, then height sensing is achieved, but the system complexity and response time increase
Solution Approach 1:
The skid shoe performs dual functions: it serves as both the ground-contact sensing element and the mechanical actuator. By directly contacting the terrain and being mechanically linked to the float arm, the skid shoe automatically senses and responds to ground variations without requiring separate sensing and actuation systems
Solution Approach 2:
The patent extracts the height-sensing function from complex electronic sensors and implements it through the simple geometric relationship between the skid shoe, linkage, and float arm. The terrain height is sensed purely through mechanical contact and lever geometry
3Speed
If the skid shoe is positioned far from the float arm, then the ground following response is slower, but if positioned close, then the control authority is reduced
Solution Approach 1:
The linkage mechanism is designed with adjustable geometry that allows optimization of the trade-off between response speed and control authority. By adjusting linkage lengths and pivot points, the system can be tuned for either faster response or greater control force depending on operating conditions
Solution Approach 2:
The patent resolves the position conflict by utilizing the vertical dimension through the linkage mechanism. The skid shoe can be positioned horizontally close to the float arm while the linkage provides vertical leverage amplification, effectively decoupling horizontal position from control authority
Data Source
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AI summary
A float arm support system may include a float arm supporting an active member, the float arm being pivotable about a first axis, a skid shoe to bear against and follow local ground contours of the underlying terrain while supporting the active member of the float arm above the underlying terrain and a powered actuator. The skid shoe may be coupled to the float arm between the first axis and the active member. The powered actuator may be operably coupled to the skid shoe to vertically move the skid shoe to adjust a spacing at which the skid shoe supports the active member of the float arm relative to the underlying terrain.