Harrow Tine Spring System with Coaxial Series Springs

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Solution Overview

Problem

Conventional tine harrows with fixed spring characteristics are limited in their adaptability to varying soil conditions, requiring spring replacement or selection when conditions change, and lack effective damping functions.

Innovation Solution

A tine harrow design featuring two connected springs in series, where a helical compression spring and a coaxial helical tension spring provide adjustable tine pressure, allowing for initial weed control with lower stiffness and increased resistance handling with higher stiffness, enabling compact and space-saving design without needing spring changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If conventional coil springs with fixed spring characteristic are used, then the structure is simple, but the adaptability to different soil conditions is limited and spring replacement is required

Engineering Contradiction:
Improveadaptability to different soil conditionsVSAvoidspring system complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The spring system is divided into two separate springs (first spring and second spring) with different spring characteristics, allowing each spring to be optimized for specific soil conditions. The first spring handles lighter soil conditions while the second spring handles harder soils, eliminating the need to replace the entire spring system when conditions change.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent introduces a dynamic selection mechanism that allows the operator to switch between the first spring and the second spring based on current soil conditions. This dynamic adaptability enables the harrow to respond to varying field conditions without requiring complete spring replacement.

Inventive Principle:
Principle #15Dynamics

2Reliability

If a single spring is used for all conditions, then the device complexity is low, but the damping function is insufficient for varying resistance

Engineering Contradiction:
Improvedamping functionVSAvoidspring arrangement complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The damping function is segmented across two springs with different characteristics. The first spring provides initial damping for normal conditions, while the second spring provides additional damping for harder soils, creating a progressive damping system that maintains reliability across varying conditions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The spring system functions as a composite mechanical system where two springs with different material properties (spring characteristics) are combined to achieve a performance that neither spring could achieve alone, providing superior damping across a wider range of conditions.

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If multiple springs with different characteristics are used, then the adaptability improves, but the space requirement increases

Engineering Contradiction:
Improvetine pressure adjustment rangeVSAvoidspace requirement
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The first spring and second spring are arranged coaxially, with one spring positioned inside or alongside the other, similar to nested dolls. This compact arrangement allows two springs with different characteristics to occupy minimal space while maintaining full functionality for adapting to different soil conditions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 adaptable tine pressure adjustment for different soil conditions, enhancing weed control and soil interaction without requiring spring replacements, while allowing central adjustment of tine pressure during operation.

Implementation Method 1

The first spring is designed as a helical compression spring and the second spring as a helical tension spring arranged coaxially around the first spring

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP2656708B1Harrow
Publication Date: 2016.11.02 TREFFLER PAUL
  • EP2656708B1 patent drawingFigure 1
  • EP2656708B1 patent drawingFigure 2~4

AI summary

The tine harrow is arranged pivotably with several support frames (1) on which bias spring (3) is provided to bias comb tines (2) against a stop (4). The bias spring has two springs such as compression coil spring and coaxial spring which are connected in series, so that at the start of deflection of tines the first spring is effective, and after a predetermined larger displacement of the tines the second spring is effective.