Disc Mower Head Scraper and Clearing Blade for Clipping Adhesion

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Solution Overview

Problem

Disc mowing heads experience issues with mowing material adhering to the inner surfaces of the housing due to centrifugal force, leading to uneven cuts and large clippings not being distributed evenly as mulch, and high-speed blades create airflow that hits the housing wall, preventing effective mowing.

Innovation Solution

The solution involves a disc mowing head design where cutting blades rotate in an upright axis within a hood-like housing, with a scraper mechanism to detach and chop compressed clippings from the peripheral wall, allowing them to fall as small mulch, and a dual-layer peripheral wall for flexibility and stone chip protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If cut material is allowed to fall downwards from the housing as mulch, then the mowing pattern should be even, but the moist cut material adheres to the inner surfaces of the housing due to centrifugal force, causing uneven cuts and large compressed pieces

Engineering Contradiction:

Improvemowing pattern uniformityVSAvoidclipping adhesion to housing

Core Design Contradiction:

Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent extracts the harmful compressed clippings from the housing wall by introducing a scraping mechanism. The scraper removes adhering clippings from the inner circumferential wall, preventing them from accumulating and falling as large compressed pieces, thus maintaining even mowing patterns.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary element (scraper) between the housing wall and the clippings. This scraper acts as a mediator that continuously removes clippings before they can adhere strongly to the wall, preventing the harmful effect of compression while allowing even distribution as mulch.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Productivity

If high-speed cutting blades are used to increase productivity, then the mowing efficiency improves, but the blades cause strong airflow that hits the housing wall violently, preventing effective mowing

Engineering Contradiction:

Improvemowing efficiencyVSAvoidairflow impact on housing wall

Core Design Contradiction:

ProductivityVSObject-generated harmful factors

Solution Approach 1:

The patent converts the harmful strong airflow generated by high-speed blades into a beneficial effect. The airflow, which would normally cause violent impact on the housing wall, is instead used to transport clippings towards the rear opening for discharge, reducing wall impact and improving overall system performance.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

3Reliability

If the circumferential wall is made stiff to prevent debris from flying out, then safety improves, but vegetation entry into the working area is hindered and the wall becomes difficult to operate

Engineering Contradiction:

Improvedebris containmentVSAvoidvegetation access to cutting area

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent applies local quality by making different parts of the circumferential wall have different stiffness characteristics. The upper part of the housing is made stiff to contain debris, while the lower part near the opening is made flexible to allow vegetation entry. This localized differentiation resolves the contradiction between safety and operability.

Inventive Principle:

Principle #3Local quality

Solution Approach 2:

The patent introduces dynamic characteristics to the circumferential wall, making it flexible in certain areas to accommodate vegetation movement while maintaining overall structural integrity for debris containment. The flexible lower section can deform to allow plant entry, then returns to its original position to maintain containment.

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

This design minimizes clipping adherence, ensures even mowing patterns, and distributes clippings as small mulch, while maintaining stability and preventing debris from flying out, enhancing the mowing efficiency and cleanliness.

Implementation Method 1

the blades, which rotate at high speed and are usually angled to the blade plane, cause a strong airflow in the housing

Methodology Applied

Scientific EffectAirflow generation:

Implementation Method 2

the moist cut material adheres to the inside of the housing, primarily to the inner surfaces of the circumferential wall, against which it is pressed relatively strongly due to centrifugal force

Methodology Applied

Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP4179864A1Disc mower head and method for cutting off fouling

Publication Date: 2023.05.17 MULAG FAHRZEUGWERK HEINZ WOSSNER GMBH & CO KG

Figure 1
Figure 2
Figure 3a~3b

AI summary

To prevent excessive amounts of compressed material (kM) from adhering to the inner surface of the circumferential wall (2b1) in a disc mower head (50) without suction of the cut material (M), a scraper (4) rotating around the circumferential wall (2b1) is used inside the housing (2), and a clearing blade (5) rotating together with the cutting blades (3) is used, which breaks up the mostly large pieces of compressed material (kH) detached by the scraper (4) as they fall towards the ground.