Mower Blade Bent Knife Back Deflects Clippings

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Solution Overview

Problem

Existing mower blade devices with double blade cutting systems face issues such as clippings getting stuck in the gap between the blades and knife bar, leading to reduced service life and increased power requirements due to heavier construction, and triangular blade elements causing partial cutting angles that result in more clippings being stuck.

Innovation Solution

A mower blade device with a double knife cutting system featuring translationally movable upper and lower cutting knives with bent knife backs adjacent to the gap between the knives and knife bar, eliminating the need for additional reinforcements and shielding the gap to prevent clippings from getting stuck, thereby improving stability and reducing clippings accumulation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stability of the object's composition

If additional reinforcements are attached to stabilize the double-blade cutting system, then stability is improved, but device complexity and weight increase

Engineering Contradiction:
Improvestability of double-blade cutting systemVSAvoidnumber of additional reinforcements
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The blade back is bent in the direction of the orthogonal axis to create a curved structure that provides stability. This curvature strengthens the blade back inherently, eliminating the need for additional straight reinforcements and reducing overall device complexity while maintaining stability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Stability of the object's composition

If additional reinforcements are attached to stabilize the double-blade cutting system, then stability is improved, but weight increases and power requirements increase

Engineering Contradiction:
Improvestability of double-blade cutting systemVSAvoidweight of mowing blade device
Core Design Contradiction:
Stability of the object's compositionVSWeight of moving object

Solution Approach 1:

The bent blade back provides structural stability through its curved geometry, which inherently resists deformation without requiring additional heavy reinforcement components. This reduces the overall weight of the mowing blade device while maintaining the necessary stability for operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Productivity

If triangular blade elements are used, then cutting capability is provided, but clippings become lodged at angles on the device

Engineering Contradiction:
Improvecutting capabilityVSAvoidclippings lodging on device
Core Design Contradiction:
ProductivityVSObject-generated harmful factors

Solution Approach 1:

The bent blade back creates a curved surface that prevents clippings from lodging at angles. The curvature guides clippings smoothly along the blade surface and away from the gap between the blade bar and double-blade cutting system, reducing accumulation and harmful lodging effects while maintaining the triangular blade elements' cutting capability.

Inventive Principle:
Principle #14Spheroidality (Curvature)

4Ease of operation

If a gap is maintained between the blade bar and double-blade cutting system, then blade movement is enabled, but clippings become caught and lodged in the gap

Engineering Contradiction:
Improveblade movement capabilityVSAvoidclippings caught in gap
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The bent blade back curves in the direction of the orthogonal axis, creating a protective shape that shields the gap between the blade bar and double-blade cutting system. This curvature prevents clippings from entering and lodging in the gap while still allowing the necessary blade movement for cutting operation.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 enhances the stability of the cutting system, reduces the number of components, and increases the service life by minimizing clippings accumulation and power requirements, as the bent knife backs effectively deflect cuttings away from the gap, preventing them from getting stuck.

Implementation Method 1

the section of the blade back of the upper cutting blade adjacent to the gap and the section of the blade back of the lower cutting blade adjacent to the gap are curved in the direction of the orthogonal axis... the curved sections of the back of the upper and lower cutting blades adjacent to the gap in the direction of the orthogonal axis further shield the gap between the blade bar and the double-blade cutting system such that less clippings, which move from the blade elements towards the blade bar when the inventive mowing blade device is used, enter the gap and become lodged there

Methodology Applied
Scientific EffectDeflection:

Implementation Method 2

A bend in the section of the back of the upper cutting blade and the back of the lower cutting blade adjacent to the gap improves the stability of both cutting blades. Due to the inventive bend in the two cutting blades, no additional reinforcements, to which clippings can become lodged, are required to stabilize the double-blade cutting system, as the flexural strength of the two cutting blades is improved.

Methodology Applied
Scientific EffectFlexural strength:

Data Source

PatentEP4378296A1Mowing blade device
Publication Date: 2024.06.05 WEPFER TECHNICS AG
  • EP4378296A1 patent drawingFigure 1
  • EP4378296A1 patent drawingFigure 2
  • EP4378296A1 patent drawingFigure 3

AI summary

The invention relates to a mower blade device (100) comprising (i) a double-blade cutting system (111), wherein the double-blade cutting system (111) has an upper cutting blade (140) and a lower cutting blade (180) which are designed to be translationally movable relative to each other, wherein the upper cutting blade (140) and the lower cutting blade (180) each have several blade elements (145) and a blade back (144, 184), wherein the blade elements (145) are connected to each other via the blade back (144, 183) and are arranged substantially in a blade plane (150), and (ii) a blade bar (110) which has a first extension (112) in the direction of an axis (170) orthogonal to the blade plane (150) and which is designed to hold the double-blade cutting system (111), wherein between the blade bar (110) and the Double knife cutting system (111) a gap (160) is arranged, wherein a section of the knife back (144,184) adjoins the gap (160), wherein the section of the knife back (144, 184) adjoining the gap (160) is bent in the direction of the orthogonal axis (170).