Agricultural Knife Sharpening Apparatus with Dynamic Track

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Solution Overview

Problem

Existing knife sharpening apparatuses for agricultural machines, such as forage harvesters, often result in undesirable knife profiles like truncated cones or barrels due to uneven abrasive effects, and may not maintain symmetry or efficiency in sharpening, especially when the sharpening stone is adjusted at one or both ends of the carriage guide, leading to issues like non-uniform cutting and increased sharpening time.

Innovation Solution

A sharpening apparatus with a carriage that moves along a track comprising two linear parts oriented at different angles, allowing the stone holder to be adjusted continuously as the carriage moves, ensuring consistent abrasive contact across the knife length without tilting, and using catch mechanisms to maintain the stone's position, preventing overloading and damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stone is adjusted at one or both ends of the carriage guide, then the stone can be repositioned to maintain contact with the knives, but this creates uneven abrasive effects that result in truncated cone or barrel profiles on the knives

Engineering Contradiction:
Improvecontact maintenanceVSAvoidknife profile uniformity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies the dynamics principle by making the track itself movable rather than fixed. The track can change its position relative to the carriage guide, allowing the stone holder to be adjusted continuously along the track's length. This dynamic adjustment mechanism enables the stone to maintain consistent contact with all knives throughout their rotation, eliminating the static end-position adjustment problem that causes non-uniform knife profiles.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If the stone is adjusted at one end of the track, then the apparatus structure is simpler, but the sharpening time is doubled due to the idle return path and the stone is tipped causing wedge-like wearing

Engineering Contradiction:
Improveapparatus structureVSAvoidsharpening efficiency
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The patent implements continuous useful action by eliminating the idle return path. As the carriage moves along the track, the movable track continuously adjusts the stone holder position to maintain optimal contact with the knives throughout the entire sharpening cycle. Every portion of the track movement contributes to productive sharpening, converting what was previously an idle return journey into useful sharpening action, thereby doubling the effective sharpening rate.

Inventive Principle:
Principle #20Continuity of useful action

3Adaptability or versatility

If the end positions of the track are not consistently reached due to wear or tolerances, then the apparatus is more tolerant of variations, but the stone position may not be optimally adjusted

Engineering Contradiction:
Improveposition toleranceVSAvoidstone position accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The patent applies self-service through the spring-loaded stone holder mechanism that automatically maintains optimal contact pressure between the stone and knives. The spring constant is calibrated so that the holder naturally positions the stone at the correct location and maintains consistent pressure throughout operation, compensating for variations in track end position reaching. The system self-adjusts to maintain precision without requiring exact repeatability of end positions.

Inventive Principle:
Principle #25Self-service

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 maintains a uniform cylindrical knife profile, ensures consistent abrasive effect, and prevents stone tilting, thereby improving the sharpening efficiency and maintaining the cylindrical shape of the knives, even when the end positions of the track are not consistently reached.

Implementation Method 1

The abrasive surface of the stone comes into contact with the knives and sharpens them as they rotate past

Methodology Applied
Scientific EffectAbrasion: Abrasion

Data Source

PatentEP3020269B1Knife sharpening apparatus for an agricultural machine
Publication Date: 2019.08.07 AGCO INT GMBH
  • EP3020269B1 patent drawingFigure 1
  • EP3020269B1 patent drawingFigure 2
  • EP3020269B1 patent drawingFigure 3a

AI summary

Sharpening apparatus (2c) for sharpening a plurality of knives (2a) rotating on a chopping drum (2). The apparatus (2c) comprises a carriage (3) having a stone holder (14) for holding a sharpening stone (4). The carriage (3) is provided with adjustment means (11) for moving the stone holder (14) closer to the knives (2a) and holding means (9, 10) for holding a stone holder (14) in a fixed position. The apparatus further comprises a fixed track (5) which extends across the length of the drum along which the carriage (3) moves. The track (5) is not straight and a part of the track (5) activates the adjustment means (11) to move the stone holder (14) closer to the knives (2a) when the carriage (3) moves along part of the track (5).