Torque Sensing for Disc Distributor Grit Spreaders

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Solution Overview

Problem

Existing disc spreader technologies face challenges in accurately determining the actual mass flow of grit due to limitations in measuring accuracy, sensitivity to mechanical and environmental influences, and the need for frequent no-load torque measurements, which disrupt operation and lead to incorrect dosing.

Innovation Solution

A non-contact sensor system is used to detect torque on a shaft carrying the distributor disk, positioned between the disk and the sensor, and on an axial section opposite the disk, ensuring measurement independence from drive type, ambient temperature, and mechanical influences, allowing for precise determination of actual mass flow without interrupting operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If weighing cells are used to determine mass flow, then universal usability is achieved, but measurement precision deteriorates due to sluggish response and long time averaging requirements

Engineering Contradiction:

Improveuniversal usabilityVSAvoidmass flow measurement precision

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical weighing cell system with a torque sensor system that measures torque on the drive shaft of the distributor disc. This substitution enables direct, real-time measurement of mass flow through torque detection, eliminating the sluggish response and long averaging requirements inherent in weighing-based systems while maintaining universal applicability across different drive types.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If no-load torque measurements are performed frequently, then measurement accuracy improves, but productivity deteriorates due to operational interruptions

Engineering Contradiction:

Improvetorque measurement accuracyVSAvoidspreading operation efficiency

Core Design Contradiction:

Measurement precisionVSProductivity

Solution Approach 1:

The patent implements continuous torque measurement during normal spreading operations using non-contact optical sensors that monitor the drive shaft continuously. This eliminates the need to interrupt operations for no-load measurements, as the system can determine actual mass flow in real-time by comparing loaded torque with pre-stored idle torque characteristics, thereby maintaining both accuracy and productivity.

Inventive Principle:

Principle #20Continuity of useful action

Solution Approach 2:

The patent performs idle torque measurements and stores the characteristics in advance, before actual spreading operations begin. These pre-acquired idle torque values are then used as reference during continuous operation, allowing the system to calculate mass flow without requiring frequent interruptions for re-calibration, thus maintaining productivity while ensuring measurement accuracy.

Inventive Principle:

Principle #10Preliminary action

3Difficulty of detecting and measuring

If contact sensors are used for torque detection, then measurement capability is achieved, but reliability deteriorates due to sensitivity to mechanical and environmental influences

Engineering Contradiction:

Improvetorque detection capabilityVSAvoidmeasurement robustness

Core Design Contradiction:

Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent replaces contact-based torque sensors with non-contact optical sensors that detect shaft position and torque through optical encoding. This eliminates direct mechanical contact, making the measurement system immune to mechanical wear, contamination by fertilizer or moisture, and environmental influences, thereby significantly improving reliability and robustness while maintaining full torque detection capability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This approach provides high measurement accuracy, robustness, and insensitivity to vibrations and environmental factors, enabling precise and continuous determination of actual mass flow, ensuring accurate grit dosing without frequent interruptions.

Implementation Method 1

the torque, which is representative of the actual mass flow, being determined in a drive train of a drive of the distributor disk by contactless sensors

Methodology Applied

Scientific EffectMagneto-elastic effects: Magnetoelastic Effects

Data Source

PatentEP2625945B1Method for torque sensing for distributor discs of a disc distributor and respective disc distributor

Publication Date: 2016.04.20 RAUCH LANDMASCHINENFABRIK GMBH

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AI summary

The method involves determining target mass flow rate of the grit using a computer controlled control device in dependence of current running speed of the disc scatterer. The actual mass flow rate of the grit is determined by dispatcher disc of disc scatterer, which represents rotational torque in powertrain of dispatcher disc of disc scatterer. The sensor housing (9) is provided with sensor (10) for enabling contactless acquisition of the rotational torque of the shaft (2) of the powertrain. An independent claim is included for disc scatterer.