Spring Linkage for Three-Point Hitch Centering

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Solution Overview

Problem

Existing three-point hitch systems for agricultural machines face difficulties in handling heavy upper links due to increased weight and tensile forces, making coupling and decoupling cumbersome and prone to operator effort, with susceptibility to damage from objects during field work.

Innovation Solution

The implementation of a link device with spring elements connected to the handlebar and pivot joint, allowing the handlebar to be pushed into a central pivot position and held there, using flexible spring rods or helical springs to facilitate easier handling and reduce the need for complex operations, while being designed to withstand maximum deflection paths and provide sufficient spring force for positioning.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the upper link is designed with larger dimensions to withstand higher tensile forces from heavy equipment, then the strength and load-bearing capacity are improved, but the weight increases and handling becomes more difficult

Engineering Contradiction:
Improvetensile force capacityVSAvoidupper link weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The spring element acts as a counterbalancing mechanism that compensates for the weight of the heavy upper link. By providing an upward spring force, the system reduces the effective weight that the operator must overcome during handling, allowing strong but heavy links to be managed more easily

Inventive Principle:
Principle #8Anti-weight (Counterweight)

2Adaptability or versatility

If the upper link is made hydraulically adjustable in length, then the adaptability to different positions is improved, but the device complexity and handling difficulty increase

Engineering Contradiction:
Improvelength adjustment capabilityVSAvoidhandling complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring element enables the upper link to automatically return to its central position after being moved to any adjusted position. This self-returning mechanism eliminates the need for complex control systems or additional actuators to reset the link, allowing hydraulic adjustment without proportionally increasing operational complexity

Inventive Principle:
Principle #25Self-service

3Stability of the object's composition

If the spring element arrangement is used to hold the upper link in position, then the positioning stability is improved, but the system becomes susceptible to damage from objects entering the inner area during field work

Engineering Contradiction:
Improvelink positioning stabilityVSAvoidsusceptibility to object damage
Core Design Contradiction:
Stability of the object's compositionVSObject-affected harmful factors

Solution Approach 1:

The spring element is detached from the bracket and reconnected to the pivot joint, extracting the spring from the vulnerable inner area between the bracket and link. This relocation removes the spring from the danger zone where objects could enter during field work, while the spring continues to provide positioning stability through its connection to the pivot joint

Inventive Principle:
Principle #2Taking out (Extraction)

4Ease of operation

If the bracket and spring element arrangement is used to center the upper link, then the ease of operation is improved, but releasing the top link from the bracket requires significant operating effort

Engineering Contradiction:
Improvelink handling easeVSAvoidforce required for release
Core Design Contradiction:
Ease of operationVSForce

Solution Approach 1:

The spring element is extracted from the bracket connection and reconnected to the pivot joint. This eliminates the bracket-spring interaction that created the release difficulty, allowing the link to be released from the bracket without having to overcome spring force, while the spring continues to provide centering through the pivot joint connection

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

The solution simplifies the handling of heavy upper links by maintaining them in central or basic pivot positions, reducing operator effort, and preventing damage from protruding objects, enhancing the operational efficiency and safety of three-point hitch systems.

Implementation Method 1

at least one first spring element which is connected at one end to the link and at the other end to the pivot joint in such a way that pivoting the link about the first axis in both pivoting directions causes the spring element to deflect, so that the handlebar is pushed into a predeterminable central pivot position or is held in such a position

Methodology Applied
Scientific EffectSpring deflection: Spring

Implementation Method 2

The second spring element is connected at one end to the handlebar and at the other end to the pivot joint in such a way that pivoting the handlebar about the first axis in both pivoting directions causes the spring element to be deflected from its neutral position

Methodology Applied
Scientific EffectElastic deflection: Elasticity

Data Source

PatentEP1982854B1Linkage device for a three-point coupling device
Publication Date: 2010.01.20 DEERE & CO
  • EP1982854B1 patent drawingFigure 1
  • EP1982854B1 patent drawingFigure 2
  • EP1982854B1 patent drawingFigure 3

AI summary

The device (17) has a guide (18) rotatably linked to a mounting frame (12) by a pivoting joint. A spring element is connected with the pivoting joint in such a manner that the rotation of the guide around an axis in both rotational directions causes deflection of the spring element so that the guide is pushed and/or held in a predetermined middle rotational position. The spring element is designed as a spring bending rod (34). The pivoting joint is designed in such a manner that the guide is rotatable around two axes.