Rail-road excavator axle conversion for road weight compliance

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Solution Overview

Problem

Two-way excavators with higher operating weights face challenges in being roadworthy due to axle load limitations, necessitating a solution to increase road travel capacity without special permits.

Innovation Solution

The pivotable axles used for rail travel are converted for road travel by attaching a mounting frame with additional axles, allowing the excavator to operate as independent axles, thereby increasing the roadworthy weight capacity beyond 18 tons.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the operating weight of the two-way excavator is increased beyond 18 tons, then the excavator can handle heavier construction tasks and improve productivity, but the excavator becomes non-compliant with road traffic regulations and cannot travel freely on public roads

Engineering Contradiction:
Improveexcavator operating capacityVSAvoidroad travel capability
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The excavator's axle system is segmented into multiple independent axles (first axle, second axle, third axle, fourth axle) that can be independently configured. By dividing the weight distribution across four axles instead of two, the axle load on each individual axle is reduced to comply with legal limits while supporting a total vehicle weight exceeding 18 tons.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent transitions from a two-axle configuration to a four-axle configuration, adding another dimension to the weight distribution system. This dimensional change in the axle arrangement allows the excavator to distribute its weight over more contact points with the road, thereby reducing the load per axle and enabling heavier operating weights while maintaining road legality.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Productivity

If additional axles are added to increase roadworthy weight capacity, then the excavator can exceed 18-ton limit, but the device complexity increases

Engineering Contradiction:
Improveroadworthy weight capacityVSAvoidaxle configuration complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The pivotable axles are designed with multi-functionality, serving dual purposes: they can be positioned in a retracted state for rail travel and extended to a load-bearing position for road travel. This universal design allows the same structural components to fulfill multiple functions, reducing the need for separate dedicated structures for each mode of operation and thereby limiting complexity increases.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The axle system incorporates dynamic positioning capabilities where pivotable axles can be adjusted between a retracted position (for rail operation) and an extended load-bearing position (for road operation). This dynamic adaptability allows the excavator to optimize its configuration for different operational modes, enabling weight capacity expansion without permanent structural complexity.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP1925754B1Rail-road excavator
Publication Date: 2009.12.23 LEIBHERR HYDRAULIKBAGGER GMBH
  • EP1925754B1 patent drawingFigure 1~1b
  • EP1925754B1 patent drawingFigure 2

AI summary

The excavator has a lower trolley (10) with two axles (12, 14) with wheels (16, 18) for road drive and two axles (26, 28) that are rotatable in an operating position, where the axles (26, 28) have wheels for rail travel. The rotatable axles (26, 28) are alternatively convertible for the road travel, and an attachable frame (36) having an additional axle is connected with the rotatable axle. The additional axle bears a wheel for the road travel, where the attachable frame is designed in bifurcate.