Harrow tine spring inversion for constant ground pressure

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Solution Overview

Problem

Existing field harrow devices face challenges in maintaining constant ground pressure regardless of height, with existing solutions like tension springs reducing ground clearance, being prone to failure, and offering limited adjustable ranges and stepless adjustments.

Innovation Solution

A field harrow design featuring a compression spring with a central guide rod and pivot points, where the vertical force is adjusted by altering the longitudinal distance between fulcrums, allowing for a wide adjustment range and protected installation, enabling simultaneous adjustment of all tines using a single actuator.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a tension spring is used under the tine, then the ground pressure can be maintained, but the ground clearance is reduced and the spring is prone to failure

Engineering Contradiction:
Improveground pressureVSAvoidspring failure
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent inverts the conventional arrangement by placing the compression spring above the tine instead of below it. This inversion resolves the technical contradiction because the spring is now protected from ground contact and potential damage, eliminating the reliability issue while still maintaining ground pressure control through the same mechanical principle

Inventive Principle:
Principle #13The other way round (Inversion)

2Force

If a tension spring is used under the tine, then the ground pressure can be maintained, but the installation length becomes inconveniently long

Engineering Contradiction:
Improveground pressureVSAvoidspring installation length
Core Design Contradiction:
ForceVSLength of moving object

Solution Approach 1:

By inverting the spring arrangement from below to above the tine, the effective installation length is reduced. The spring now works in compression rather than tension, allowing for a more compact configuration that achieves the same ground pressure control with a shorter, more manageable installation length

Inventive Principle:
Principle #13The other way round (Inversion)

3Adaptability or versatility

If individual adjustment mechanisms are used for each tine, then the ground pressure can be adjusted, but the device complexity increases and adjustment is not simultaneous

Engineering Contradiction:
Improveground pressure adjustmentVSAvoidadjustment mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent merges the adjustment mechanisms by connecting all tines to a common adjustable support structure. This allows a single adjustment action to simultaneously modify the ground pressure for all tines, reducing device complexity while maintaining full adaptability. The compression springs remain individual but are collectively controlled through the shared support mechanism

Inventive Principle:
Principle #5Merging (Combining)

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 ensures constant ground pressure across varying heights with a wide adjustable range, from maximum to minimum ground force, and a transport position, maintaining consistent tine operation and adaptability to different soil conditions.

Implementation Method 1

A compression spring 17, which exerts a force F in its longitudinal direction, is arranged between a second pivot point 13 and a point 14 on the tine

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP3808163B1Harrow
Publication Date: 2023.07.26 ALOIS POETTINGER MASCHFAB
  • EP3808163B1 patent drawingFigure 1~2
  • EP3808163B1 patent drawingFigure 3~4
  • EP3808163B1 patent drawingFigure 5~6

AI summary

A harrow consisting of a frame (3) and at least one row of spring-loaded tines (16) arranged side by side at intervals, which are pivotable about first pivot points (15). A compression spring (17) is arranged between a second pivot point (13) and a lower pivot point (14) on the tine (16) and above it. The kinematic conditions provide a soil force (B) independent of the height of the soil (1) and allow stepless adjustment of the soil force (B). The distance between the first pivot point (15) and the second pivot point (13) is adjustable in the longitudinal direction. A sliding frame (23) is guided on the underside of the longitudinal beams (7) of the frame (3) and accommodates the first pivot point (15).