Three-Point Hitch Lock Release for In-Cab Implement Uncoupling

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Solution Overview

Problem

Existing coupling arrangements for agricultural tractors require the operator to leave the cab or seek assistance to manually open the locking mechanism for uncoupling agricultural implements, compromising safety and convenience.

Innovation Solution

A coupling arrangement with a deflection lever and pull ropes allows the driver to operate the locking mechanism from within the cab by pivoting the deflection lever, enabling the pull ropes to guide the locking bolt into the release position without leaving the cab.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a manual pull lever is used to open the locking mechanism, then the locking mechanism can be securely locked, but the operator must leave the cab or seek assistance to operate it

Engineering Contradiction:
Improvelocking mechanism securityVSAvoidoperator accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

A pull rope is introduced as an intermediary element that transmits the operator's pulling force from inside the cab to the locking mechanism. The pull rope passes through the coupling body housing, allowing the operator to actuate the locking mechanism remotely without leaving the protected environment of the cab.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The direct mechanical connection between the pull lever and the operator's hand is replaced with a rope-based transmission system. This substitution allows the operator to exert force on the locking mechanism from a distance, converting direct manual operation into remote actuation through the pull rope.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If the pull lever extends through the coupling body housing, then the locking mechanism can be actuated manually, but the operator is exposed to moving parts and must leave the cab

Engineering Contradiction:
Improvemanual actuation capabilityVSAvoidoperator safety
Core Design Contradiction:
Ease of operationVSObject-affected harmful factors

Solution Approach 1:

The pull rope serves as a safety intermediary, allowing the operator to interact with the locking mechanism without direct contact with moving parts. The rope transmits force while maintaining physical separation between the operator and potential hazards in the coupling arrangement.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The pull rope is extracted through the housing of the coupling body, creating a safe interface that allows operation from inside the cab. This extraction removes the need for the operator to physically access the pull lever in its original position, eliminating exposure to harmful moving parts.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If the locking bolt projects beyond the attachment area, then secure locking is achieved, but the coupling arrangement becomes more complex

Engineering Contradiction:
Improvelocking securityVSAvoidcoupling body structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The coupling body housing serves multiple functions: it houses the locking mechanism, provides structural support, guides the pull rope, and protects internal components. This multi-functionality reduces the need for additional separate components, managing complexity while maintaining reliability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables safe and convenient uncoupling of agricultural implements from the three-point linkage without the need to exit the tractor cab, enhancing user-friendliness and operational efficiency.

Implementation Method 1

the locking bolt can be deflected by means of a pull lever attached thereto against a restoring spring force from a first locking position locking the catch hook to a second locking position releasing the catch hook

Methodology Applied
Scientific EffectSpring force: Spring

Implementation Method 2

a first pull rope section (52) connected to the pull lever (30) is attached in such a way that a pivoting movement caused on the deflection lever (36) by means of a second pull rope section (54) leads to a deflection of the locking bolt (28) into the second locking position

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP4480290B1Hitch assembly for a three point power lift of an agricultural tractor
Publication Date: 2026.02.25 DEERE & CO
  • EP4480290B1 patent drawingFigure 1
  • EP4480290B1 patent drawingFigure 2
  • EP4480290B1 patent drawingFigure 3

AI summary

Coupling arrangement (10) for a three-point linkage (12) of an agricultural tractor (14), comprising a tractor-side lower link (16) and a lifting strut (18) attached thereto for raising and lowering the lower link (16) by means of a lifting mechanism, wherein a catch hook (22) with a coupling body (24) and a locking mechanism (26) with a locking bolt (28) being longitudinally displaceable in the coupling body (24) is provided at a free end (20) of the lower link (16), wherein the locking bolt (28) can be deflected by means of a pull lever (30) attached thereto against a restoring spring force from a first locking position (32) locking the catch hook (22) to a second locking position releasing the catch hook (22).In this case, a deflection lever (36) is pivotably attached to the lifting strut (18), at the free end (50) of which a first pull rope section (52) connected to the pull lever (30) is attached in such a way that a pivoting movement caused on the deflection lever (36) by means of a second pull rope section (54) leads to a deflection of the locking bolt (28) into the second locking position.