Agricultural Tractor Draft Force Sensing via Magnetic Deflection
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Solution Overview
Problem
Current draft force sensing systems for agricultural tractors are prone to environmental contamination, require frequent maintenance, and have reliability issues due to moving parts and exposure to mud and dirt, leading to inaccurate readings and increased costs.
Innovation Solution
A draft force sensing system with sealed and protected components, utilizing L-shaped draft bars and a sensing unit that deflects to generate a draft force signal, reducing the need for maintenance and minimizing space requirements, while using a single linear displacement transducer to sum horizontal draft loads effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If draft force sensing systems use moving parts and open components, then the system can detect draft force through mechanical deflection, but the components accumulate mud and dirt which prevents movement and causes false sensing
Solution Approach 1:
The patent replaces the mechanical plunger and linkages with a magnetic field-based sensing system. Magnets mounted on the draft links interact with a magnetic sensor (such as a Hall effect sensor or magnetoresistive sensor) to detect draft force. This eliminates physical contact and moving parts that accumulate mud and dirt, while maintaining the ability to measure draft force through magnetic field changes rather than mechanical deflection.
Solution Approach 2:
The patent introduces a magnetic field as an intermediary between the draft links and the sensing system. Instead of direct mechanical contact, the magnets on the draft links create magnetic field changes that are detected by the magnetic sensor. This intermediary allows force transmission without physical contact, preventing contamination while maintaining measurement capability.
2Measurement precision
If draft force sensing systems use multiple instrument pins, then the cost increases and reliability decreases, but the system can measure draft force through pin deflection
Solution Approach 1:
The patent combines the functions of multiple instrument pins into a single integrated magnetic sensing system. Instead of using two separate pins to measure draft force, the system uses magnets mounted on the draft links that interact with a single magnetic sensor. This consolidation reduces the number of components from two to one, thereby increasing reliability while maintaining measurement capability through the magnetic field interaction.
3Measurement precision
If draft force sensing systems use bending bars and draft sensing shafts with moving parts, then the system can detect draft force through deflection, but the system requires sealed compartments and occupies significant space
Solution Approach 1:
The patent replaces the mechanical bending bar and draft sensing shaft assemblies with a compact magnetic sensing system. The magnets mounted on the draft links and the magnetic sensor create a space-efficient solution that eliminates the need for large sealed compartments. The magnetic field interaction occurs in a compact configuration, significantly reducing the space required for draft force sensing while maintaining detection accuracy.
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 system provides accurate draft force measurements with reduced maintenance needs, improved reliability, and cost-effectiveness by protecting components from environmental contamination and eliminating the need for periodic lubrication, while optimizing space usage.
Implementation Method 1
A draft force transducer generates a draft force signal in response to deflection thereof
Implementation Method 2
Draft forces applied by the left and right draft links to the left and right draft link supports deflect the second parts of the left and right draft bars
Data Source
Figure 1
Figure 2
Figure 2A
AI summary
A draft force sensing system (30) for an agricultural tractor comprises a hitch frame (10) adapted to be attached to a rear frame of the agricultural tractor. Left and right draft link supports (12, 14) couple a corresponding left and right draft link (24, 26) to a corresponding left and right side of the hitch frame (10). Left and right draft bars (32, 34) have a first part (36, 38) attached to a corresponding one of the left and right draft link supports (12, 14). Each of the left and right draft bars (32, 34) have a second part (44, 46) positioned rearwardly and inwardly with respect to its first part (36, 38). Draft forces applied by the left and right draft links (24, 26) to the left and right draft link supports (12, 14) deflect the second parts (44, 46) of the left and right draft bars (32, 34). A draft force transducer generates a draft force signal in response to deflection thereof. A sensing unit (52) deflects the draft force transducer in response to deflection of the second parts (44, 46) of the left and right draft bars (32, 34).