Road Milling Ejector Assembly for Fast Wear Reversal

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Solution Overview

Problem

The existing ejector units in road milling machines are prone to severe wear and tear, requiring frequent replacement and alignment, which is tedious and time-consuming, leading to increased machine downtimes and maintenance workloads.

Innovation Solution

An ejector unit that can be attached to a carrier in at least two different operating positions, allowing for rotation by 180° when wear is reached, extending the service life and enabling quick and easy replacement, with a mechanical interface for secure fastening and optimized geometry for load distribution and wear protection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the ejector is welded to the milling tube, then the ejector is securely fixed, but the replacement and alignment work is tedious and time-consuming

Engineering Contradiction:
Improvesecure fixationVSAvoidreplacement time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The ejector system is divided into separate components: the ejector element can be removed and replaced independently from the carrier, eliminating the need to replace the entire welded assembly. This segmentation allows for quick replacement of only the worn ejector while retaining the carrier structure.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The ejector is designed with a dynamic replacement mechanism that allows it to be quickly attached and detached from the carrier using simple fastening elements, transitioning from a static welded connection to a dynamic, easily replaceable connection that reduces maintenance time.

Inventive Principle:
Principle #15Dynamics

2Reliability

If the ejector is replaced frequently due to wear, then fresh ejectors maintain performance, but machine downtime increases

Engineering Contradiction:
Improveejector performanceVSAvoidmachine availability
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The carrier is prepared in advance with mounting structures and fastening elements that enable rapid installation of replacement ejectors. The modular design allows operators to quickly swap ejectors without extensive preparation or alignment work, minimizing machine downtime.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The ejector replacement system is designed to be easily serviceable by operators without requiring specialized welding equipment or extensive training. The simple fastening and replacement mechanism enables maintenance personnel to quickly replace worn ejectors themselves, reducing dependency on specialized services and minimizing downtime.

Inventive Principle:
Principle #25Self-service

3Manufacturing precision

If the ejector is precisely aligned during installation, then ideal ejection performance is achieved, but the alignment process becomes more complex

Engineering Contradiction:
Improveejector alignmentVSAvoidalignment process
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The ejector and carrier are designed with self-aligning features through their mechanical interfaces and fastening structures. The mounting geometry automatically guides the ejector into the correct position during installation, eliminating the need for complex alignment procedures while ensuring precise positioning and ideal ejection performance.

Inventive Principle:
Principle #25Self-service

4Duration of action of stationary object

If the ejector works until wear limit, then service life is maximized, but ejection performance degrades

Engineering Contradiction:
Improveejector service lifeVSAvoidejection performance
Core Design Contradiction:
Duration of action of stationary objectVSReliability

Solution Approach 1:

The ejector system separates the wear-prone ejector element from the durable carrier structure. This allows the ejector to be replaced independently when it reaches wear limits, while the carrier continues to provide structural support and positioning, maximizing overall system service life without compromising ejection performance.

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP2411582B2Ejector unit for a road milling machine
Publication Date: 2021.03.17 WIRTGEN GMBH
  • EP2411582B2 patent drawingFigure 1~2
  • EP2411582B2 patent drawingFigure 3
  • EP2411582B2 patent drawingFigure 4~5

AI summary

The invention relates to an ejecter unit, in particular for a road milling machine, comprising an ejecter which is replaceably attached to a carrier.