Agricultural Hitch Head Translational Locking Device

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Solution Overview

Problem

Agricultural machines with oscillating coupling heads experience detrimental relative translational movements during acceleration and braking phases, leading to shocks that can damage the hitch head and tractor's three-point device, and result in uncontrollable reversing maneuvers due to the freedom in translation.

Innovation Solution

The coupling head incorporates a retractable pivot attachment and an elastic biasing mechanism that automatically engages a hooking means with the pivot when it reaches a certain distance from the rear end, limiting translation and maintaining engagement during maneuvers.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the pivot is allowed to move freely in the slide, then the steering angle between the tractor and the machine can be increased during maneuvers, but the pivot hits the front and rear ends of the slide during acceleration and braking, causing intense shocks that can damage the machine's hitch head and/or the tractor's three-point device

Engineering Contradiction:
Improvesteering angleVSAvoiddamage to hitch head and three-point device
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

A retractable locking pin acts as an intermediary element between the pivot and the slide. The pin can engage with recesses in the slide to lock the pivot in position, preventing it from hitting the front and rear ends during acceleration and braking. The pin itself is guided by a return spring that allows it to retract when needed for steering maneuvers, thus mediating between the need for locked position (reliability) and the need for movement freedom (adaptability).

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The locking system is designed to be dynamic rather than static. The locking pin can automatically engage and disengage based on the operational state of the machine. During normal steering operations, the pin retracts to allow pivot movement. During acceleration and braking phases, the pin engages to lock the pivot and prevent damaging shocks. This dynamic behavior resolves the contradiction by adapting the system's degree of freedom to the current operational requirements.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If the pivot can move freely in the slide, then the distance between the tractor and the machine can be modified, but the machine veers outwards when cornering on roads and reversing maneuvers are practically uncontrollable

Engineering Contradiction:
Improvedistance adjustmentVSAvoidcontrol during cornering and reversing
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The retractable locking pin serves as a mediator that controls the degree of freedom of the pivot. When engaged, it maintains a fixed distance between tractor and machine, providing stability during cornering and reversing. When disengaged, it allows distance adjustment for maneuverability. This intermediary mechanism resolves the contradiction by providing on-demand constraint rather than permanent fixation or complete freedom.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The locking system operates periodically, engaging and disengaging based on operational phases. During transport and road cornering, the lock engages to maintain fixed distance and improve control. During field maneuvers requiring distance adjustment, the lock disengages. This periodic engagement pattern resolves the contradiction by applying constraints only when needed for control, while allowing freedom when needed for adaptability.

Inventive Principle:
Principle #19Periodic action

3Reliability

If a locking mechanism is added to prevent pivot movement, then shocks during acceleration and braking are reduced, but the device complexity increases

Engineering Contradiction:
Improvereduction of shocksVSAvoidcoupling head structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The locking system is designed to be self-actuating through the return spring mechanism. The spring automatically pushes the locking pin into engagement recesses when the pivot moves beyond a certain distance, and the pin's own geometry allows it to retract when force is applied in the opposite direction. This self-service design minimizes the need for additional actuators, controls, or complex mechanisms, thus resolving the contradiction between reliability improvement and device complexity.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent replaces complex mechanical locking systems (such as threaded locks, hydraulic locks, or electric motors) with a simple spring-loaded pin mechanism. The return spring provides the necessary force for engagement without requiring external power sources or complex control systems. This substitution of a simple mechanical system for a potentially complex one resolves the contradiction by achieving the locking function with minimal added complexity.

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 solution effectively limits pivot movement in the slide, reducing impacts and ensuring controlled trajectory during transport and reversing, thereby preventing damage and enhancing operational control.

Implementation Method 1

an elastic biasing means which automatically engages said attachment means with said pivot when the latter is positioned in the slide beyond a determined distance with respect to the rear end

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4147551B1Agricultural machine with a coupling head provided with a translational locking device
Publication Date: 2024.07.24 KUHN-HUARD SAS
  • EP4147551B1 patent drawingFigure 1A
  • EP4147551B1 patent drawingFigure 1B
  • EP4147551B1 patent drawingFigure 2

AI summary

The present invention relates to an agricultural machine comprising a frame carrying at least one tool and a hitch head comprising a hitch cross member (4) and an articulated assembly piece (6) which receives this cross member (4) in a flat mounting space (PM) in which it is mobile with guidance in translation and rotation by means of a pivot (7) / slide (8) linkage.Machine characterized in that the articulated assembly part (6) of the coupling head (3) comprises, on the one hand, a means (11) for hooking the pivot (7) blocking its translation in the slide (8) towards the rear end when this part (6) is subjected to a relative displacement along the direction of advance with respect to the coupling cross member (4), and, on the other hand, an elastic loading means (12) which achieves an automatic engagement of said hooking means (11) with said pivot (7) when the latter is positioned in the slide (8) beyond a determined distance with respect to the rear end.