Tractor Hydraulic Coupler Detection to Prevent Front Linkage Actuation

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Solution Overview

Problem

Agricultural tractors with front linkages experience undesired movements or deflections when hydraulic attachments are connected, due to the lack of control valves in the front area, leading to potential accidents from unnoticed or delayed reactions to actuation.

Innovation Solution

A method that detects the plugged-in state of hydraulic couplers using sensor units and control units to deactivate the operating unit, preventing actuation of hydraulic lifting gear when attachments are connected, and utilizing a pivotable dust protection cover with magnetic switches to ensure safe operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If control valves are located exclusively at the rear of the tractor, then the hydraulic control system is simplified and easier to operate, but unsafe operating conditions cannot be detected when attachments are connected

Engineering Contradiction:
Improvehydraulic control operationVSAvoiddetection of unsafe operating conditions
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The sensor unit detects the plugged-in state of the hydraulic coupling in advance before the operating unit is activated. The control unit evaluates this state variable and deactivates the operating unit preemptively, preventing unsafe operation before it can occur. This preliminary detection and prevention mechanism resolves the contradiction by maintaining ease of operation while adding safety detection capability.

Inventive Principle:
Principle #10Preliminary action

2Adaptability or versatility

If the operating unit remains active without detection, then the hydraulic lifting mechanism can be freely actuated, but undesired movements or deflections of connected attachments occur

Engineering Contradiction:
Improvehydraulic lifting mechanism actuationVSAvoidundesired movements of attachment
Core Design Contradiction:
Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The sensor unit continuously monitors the plugged-in state of the hydraulic coupling and provides feedback to the control unit. The control unit evaluates this feedback signal and automatically deactivates the operating unit when an attachment is detected. This feedback mechanism ensures that the hydraulic lifting mechanism can be freely actuated when safe, while preventing undesired movements when attachments are connected.

Inventive Principle:
Principle #23Feedback

3Reliability

If sensor units are added to detect the plugged-in state, then unsafe operating conditions can be detected, but the device complexity increases

Engineering Contradiction:
Improvedetection of unsafe operating conditionsVSAvoidhydraulic control system
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The detection function is extracted as a separate sensor unit that monitors the plugged-in state of the hydraulic coupling. This modular approach allows the sensor unit to be integrated into the existing hydraulic control system without requiring complete system redesign. The sensor unit provides reliable detection capability while minimizing the increase in overall system complexity through functional separation.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Prevents undesired movements or deflections by ensuring the hydraulic lifting gear is only actuated when no attachments are connected, enhancing safety by deactivating the operating unit and providing visual feedback through display units when attachments are engaged.

Implementation Method 1

a sensor unit detects whether the dust cover is in a pivot position A that closes the hydraulic coupling or in a pivot position B that releases it. The sensor unit can, for example, be a robust magnetic switch actuated by a permanent magnet embedded in the dust cover.

Methodology Applied
Scientific EffectMagnetic field sensing: Magnetic Field

Data Source

PatentEP3794917B1Method for detecting inadmissible operating states of a hydraulic system of an agricultural tractor
Publication Date: 2022.08.10 DEERE & CO
  • EP3794917B1 patent drawingFigure 1
  • EP3794917B1 patent drawingFigure 2

AI summary

In a method for detecting impermissible operating conditions of a working hydraulics (14) of an agricultural tractor, the working hydraulics (14) comprises at least one electrically actuated control valve (16, 18) with a hydraulic coupling (30, 32) for connecting a hydraulic consumer (22), a branch (48) provided in the at least one control valve (16, 18) for supplying a hydraulic lifting mechanism (50) of a front linkage (52) with hydraulic fluid, and an operating unit (54) provided for manual actuation of the working hydraulics (14) of the front linkage (52).According to the invention, a state variable indicating a plugged-in state of the hydraulic coupling (30, 32) is detected by means of a sensor unit (66, 68) and supplied to a control unit (12), wherein the operating unit (54) is deactivated when the control unit (12) recognizes, by evaluating the state variable, that a hydraulic consumer (22) is connected to the hydraulic coupling (30, 32).