Undercarriage Maintenance Vehicle With Retractable Rail Support Arms

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Solution Overview

Problem

Existing undercarriage maintenance vehicles for trains are prone to collisions with rail attachments and fixing members on conventional track sections, leading to damage and hindered movement, and require costly and time-consuming maintenance in purpose-built sections.

Innovation Solution

The undercarriage maintenance vehicle features retractable support arms with active and support wheels that contact the rail at different points, allowing the vehicle to avoid obstacles by retracting arms individually or in pairs, ensuring safe propulsion and enabling passage through conventional track sections with attachments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the maintenance vehicle uses fixed support arms to contact the rail for propulsion, then sufficient contact and traction are achieved, but collisions with rail attachments and fixing members occur causing damage and movement hindrance

Engineering Contradiction:
Improvesafe propulsionVSAvoidcollisions with rail attachments
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The support arms are made dynamically adjustable through retraction mechanisms that allow them to extend and retract based on track conditions. When rail attachments are detected, the support arms can be retracted to avoid collision, and extended when clear of obstacles, transforming a static structure into a dynamic one that adapts to environmental hazards

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The propulsion system is segmented into multiple independent support arms, each capable of individual retraction and extension. This segmentation allows selective retraction of specific arms when encountering obstacles while maintaining contact with other arms, enabling the vehicle to navigate around attachments rather than suffering complete propulsion failure

Inventive Principle:
Principle #1Segmentation

2Object-affected harmful factors

If purpose-built track sections with few attachments are used for maintenance, then collisions are avoided, but construction time and cost increase significantly

Engineering Contradiction:
Improvecollisions with rail attachmentsVSAvoidconstruction time for maintenance sites
Core Design Contradiction:
Object-affected harmful factorsVSLoss of time

Solution Approach 1:

The maintenance vehicle is designed with universal adaptability to operate on conventional track sections rather than requiring dedicated maintenance tracks. The retractable support arms enable the vehicle to function safely on standard tracks with numerous attachments, eliminating the need for specialized infrastructure and allowing use of existing track networks for maintenance operations

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

Solution Approach 2:

Instead of avoiding conventional tracks with their numerous attachments, the invention embraces them by using the retractable support arms to navigate around attachments. The presence of attachments on conventional tracks becomes manageable rather than prohibitive, converting what was previously a harmful condition into an acceptable operating environment

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

3Adaptability or versatility

If the support arms are made retractable to avoid obstacles, then passage through conventional track sections is enabled, but device complexity increases

Engineering Contradiction:
Improveability to pass rail attachmentsVSAvoidretraction mechanism complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The support arms incorporate retraction mechanisms that transform them from static to dynamic structures. Each support arm can independently adjust its position, allowing the vehicle to adapt its configuration to navigate around rail attachments while maintaining propulsion capability through coordinated extension and retraction of different arms

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4491486B1An undercarriage maintenance vehicle and a method for moving along a rail track using the undercarriage maintenance vehicle
Publication Date: 2025.09.10 DTEC
  • EP4491486B1 patent drawingFigure 1~2
  • EP4491486B1 patent drawingFigure 3~4
  • EP4491486B1 patent drawingFigure 5~6

AI summary

The invention relates to an undercarriage maintenance vehicle (1, 100) for the maintenance of the underbody of trains, wherein the undercarriage maintenance vehicle (1, 100) is configured to be movable on a rail track (2) having two rails (10) which extend parallel to each other and are spaced apart by a gauge (g). The undercarriage maintenance vehicle (1, 100) comprises: a platform (3) having a width (w), a maintenance unit (4) coupled to the platform (3) and configured to perform service operations at the underbody of trains, and located along a length (I) of the platform (3) at least two pairs of support arms (5) extending substantially in the width direction, which is when used in a track system (6) perpendicular to the rail track (2). Each support arm (5) comprises: a support wheel (7) that is configured to freely rotate around a rotational axis, an active wheel (8) that is configured to rotate around a rotational axis, wherein the support arms (5) are arranged to couple the support wheels (7) and the active wheels (8) to the platform (3), wherein at least two active wheels (8) are motorized driven wheels. The undercarriage maintenance vehicle is characterized in that the active wheels (8) are configured to contact a foot (9) of a rail (10) of the rail track (2), the support wheels (7) are configured to contact an underside of a rail head (11) of the rail (10), and in that a retraction mechanism (12) is provided for each support arm (5) configured to retract the support arms (5) towards the platform (3).