Mower Blade Device With Pre-Tensioned Spring Guide Bushing

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing mower blade devices experience high wear and tear, leading to increased maintenance costs due to dirt accumulation and uneven pressure distribution between cutting blades.

Innovation Solution

A mower blade device with a double knife cutting system featuring a prestressed tension spring in a guide bushing, which ensures even contact pressure and automatic dirt removal, reducing wear and allowing for easy blade changes.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the two superimposed blade bars are pressed together to prevent contaminants from getting between them, then protection against contaminants is improved, but the pressure between the blade bars causes excessive wear

Engineering Contradiction:
Improvecontaminant protectionVSAvoidblade wear
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The patent employs dynamic elements including a movable upper blade bar that can shift position, spring elements that provide variable pressing force, and adjustable mechanisms that allow the pressing pressure to be modified during operation. This dynamic approach enables the system to maintain adequate pressure to prevent contaminant ingress while avoiding excessive constant pressure that would cause wear.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention utilizes parameter changes by varying the pressing force between blade bars through adjustable mechanisms and spring elements. The pressing pressure can be modified based on operating conditions, material being cut, and blade wear state, allowing optimization between contaminant protection and wear prevention by changing the pressure parameter as needed.

Inventive Principle:
Principle #35Parameter changes

2Loss of substance

If the blade bars are pressed together to reduce wear, then blade protection is improved, but the contact pressure becomes uneven leading to localized wear

Engineering Contradiction:
Improveblade wearVSAvoidpressure distribution uniformity
Core Design Contradiction:
Loss of substanceVSManufacturing precision

Solution Approach 1:

The patent divides the blade bar structure into multiple segments including upper and lower blade bars with intermediate elements. This segmentation allows independent adjustment and positioning of each segment, enabling more uniform pressure distribution across the contact surfaces. The segmented structure with multiple contact points distributes the pressing force more evenly compared to a single-point pressure system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces intermediary elements such as spring mechanisms, adjustment devices, and intermediate structural components between the blade bars. These intermediaries act as mediators that distribute and equalize the pressing force, transforming concentrated or uneven pressure into more uniform contact pressure across the blade bar surfaces, thereby reducing localized wear.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Productivity

If the cutting blades are held firmly to maintain cutting performance, then cutting effectiveness is improved, but the blades are more susceptible to damage from stones and contaminants

Engineering Contradiction:
Improvecutting performanceVSAvoidblade durability
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The patent implements dynamic holding mechanisms that allow the cutting blades to maintain firm contact during normal cutting operations for optimal performance, while simultaneously providing mobility and flexibility to accommodate impacts from stones and contaminants. The dynamic system can absorb shocks and adjust positioning, preventing damage while maintaining cutting effectiveness.

Inventive Principle:
Principle #15Dynamics

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

Significantly reduces wear on cutting blades, increases the service life of the mower blade assembly, and minimizes maintenance costs by evenly distributing contact pressure and automatically removing dirt.

Implementation Method 1

a pre-tensioned tension spring (170) is arranged within the guide bushing (160A). The tensile force of the tension spring (170) is designed to exert a contact force of the upper cutting blade (140) against the lower cutting blade

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a pre-tensioned tension spring (170) is arranged within the guide bushing (160A). The tensile force of the tension spring (170) is designed to exert a contact force

Methodology Applied
Scientific EffectSpring force: Spring

Data Source

PatentEP3881664B1Mower blade device
Publication Date: 2022.10.19 WEPFER TECHNICS AG
  • EP3881664B1 patent drawingFigure 1~2
  • EP3881664B1 patent drawingFigure 3~5

AI summary

The invention relates to a mower blade device (100) with a cutter bar (110) and a double-blade cutting system, wherein the double-blade cutting system comprises an upper cutting blade (140) and a lower cutting blade (180), which are designed to be movable relative to each other, wherein the upper cutting blade (140) is connected to the cutter bar (110) by means of an upper holding device (150) and the lower cutting blade (180) by means of a lower holding device (190), wherein the upper holding device (150) is mounted on the cutter bar (110) by means of a guide bushing (160A) and a pre-tensioned tension spring (170) is arranged within the guide bushing (160A), wherein the tension force of the tension spring (170) is designed to exert a contact force of the upper cutting blade (140) on the lower cutting blade (180) via the upper holding device (150).