Haymaking Machine Rake Tine Spring Coil Orientation

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Solution Overview

Problem

The existing hay-making machines face a risk of fatigue fracture in rake tines due to bending stresses, which limits their service life and long-term strength.

Innovation Solution

The winding axis of the resilient coil is aligned perpendicularly to the direction of the maximum bending force, with a tangential angle of attack α and an axial angle of attack β relative to the vertical axis, optimizing the damping effect of the spring coils and reducing the risk of fatigue fracture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rake tines are equipped with spring legs and resilient coils to reduce bending stresses, then the damping effect is improved, but the risk of fatigue fracture remains due to misalignment of the winding axis with the maximum bending force direction

Engineering Contradiction:
Improvedamping effectVSAvoidfatigue fracture risk
Core Design Contradiction:
StrengthVSReliability

Solution Approach 1:

The invention changes the orientation parameter of the spring coil by aligning the winding axis perpendicular to the maximum bending force direction. This parameter optimization ensures that the spring coil's elastic deformation occurs in the direction that best absorbs the bending stress, maximizing the damping effect while minimizing stress concentration that leads to fatigue fracture.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The invention introduces asymmetry in the spring coil configuration by setting the winding axis at a specific angle (perpendicular) to the maximum bending force direction rather than using a symmetric alignment. This asymmetric orientation allows the spring to optimally counteract the asymmetric bending loads experienced by the rake tine during operation, improving both damping and fatigue resistance.

Inventive Principle:
Principle #4Asymmetry

2Duration of action of stationary object

If the winding axis of the resilient coil is aligned perpendicular to the maximum bending force direction, then the service life is extended, but the device complexity increases due to precise angular positioning requirements

Engineering Contradiction:
Improveservice lifeVSAvoidangular positioning complexity
Core Design Contradiction:
Duration of action of stationary objectVSDevice complexity

Solution Approach 1:

The invention optimizes the geometric parameter of the spring coil (winding axis orientation) to achieve maximum service life. By defining a specific angular relationship (perpendicular alignment) between the winding axis and the maximum bending force direction, the design extends service life while keeping the complexity manageable through a clear, definable geometric relationship rather than complex active control mechanisms.

Inventive Principle:
Principle #35Parameter changes

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 configuration significantly extends the service life of the rake tines by effectively managing bending loads and stresses, enhancing their long-term strength and durability.

Implementation Method 1

The rake tines accordingly have, as is known, springy coils, so that the spring legs subjected to bending, due to the resilient coils of the rake tines, can be supported flexibly in relation to their attachment to their tine arms and thus reduce force amplitudes.

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The maximum stress in terms of bending stress arises in the transition area of the spring leg into the first resilient coil, which at the same time also defines the point of fracture in the event of a fatigue fracture.

Methodology Applied
Scientific EffectDamping: Damping

Data Source

PatentEP2399446B1Haymaking machine
Publication Date: 2015.08.26 CLAAS SAULGAU GMBH
  • EP2399446B1 patent drawingFigure 1
  • EP2399446B1 patent drawingFigure 2
  • EP2399446B1 patent drawingFigure 3~4

AI summary

The hay-making machine has rack forks (2) that have rack spinners (1) with fork arms, where the rack spinners are driven around a vertical axis (8) in a circulating manner. The winding axis of one of the rack forks stands in a space in a sloped manner such that the winding axis has a tangential setting angle and an axial setting angle relative to the vertical axis of the rack spinners.