Rail Vehicle Floor Panel Joints for Flush Tolerance Compensation

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Solution Overview

Problem

Existing floor panel assemblies in vehicles, such as rail vehicles, face challenges in achieving easy connection of individual panels with necessary force transmission properties while maintaining high surface evenness and preventing steps in the floor covering.

Innovation Solution

A floor panel assembly design featuring male and female connection portions with specific geometric alignments and protrusions/recesses, allowing for form-fitting connections that ensure a flush and even surface, using materials like polyurethane resin to accommodate varying panel thicknesses.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If individual floor panels are connected using conventional methods (half milling and gluing), then the panels can be joined together, but the connection strength and force transmission properties are insufficient

Engineering Contradiction:
Improveconnection strengthVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The connection system is divided into separate male and female connection portions that can be independently manufactured and then assembled. The male connection portion includes a protrusion that fits into the female connection portion's recess, creating a segmented but strong joint system that improves connection strength while maintaining manufacturing ease.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The connection portions utilize composite construction with a core material (such as foam or honeycomb) bonded to surfacing and backing materials. This composite structure provides both strength for force transmission and lightweight properties, resolving the contradiction between strong connections and manufacturing complexity.

Inventive Principle:
Principle #40Composite materials

2Adaptability or versatility

If floor panels of different thicknesses are used to accommodate manufacturing tolerances, then adaptability improves, but surface evenness deteriorates due to steps forming at panel joints

Engineering Contradiction:
Improvetolerance compensationVSAvoidsurface evenness
Core Design Contradiction:
Adaptability or versatilityVSShape

Solution Approach 1:

The male connection portion's protrusion is nested within the female connection portion's recess. This nesting arrangement allows panels of different thicknesses to be joined while the protrusion-recess geometry ensures that the outer surfaces remain coplanar, compensating for thickness variations without creating steps.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The connection portions have specific geometric features (protrusion and recess with defined depths) at the joint locations that differ from the panel centers. The protrusion depth is specifically designed to compensate for thickness variations, providing local adaptation while maintaining overall surface evenness.

Inventive Principle:
Principle #3Local quality

3Shape

If the male and female connection portions are designed with precise geometric alignment, then surface evenness is improved, but manufacturing precision requirements increase

Engineering Contradiction:
Improvesurface evennessVSAvoidgeometric alignment precision
Core Design Contradiction:
ShapeVSManufacturing precision

Solution Approach 1:

The protrusion and recess geometries are pre-designed with predetermined depth relationships during the manufacturing of individual panels. The protrusion depth is pre-calculated to compensate for expected thickness variations, so that when panels are assembled, the surfaces automatically align without requiring high-precision field adjustments.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The connection portions are designed to self-align and self-level during assembly. The geometric features (protrusion fitting into recess) automatically position the panels at the correct height relationship, allowing the connection system to compensate for manufacturing tolerances without requiring external intervention or high-precision machining at the joint.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4149815B1Floor panel assemblies for vehicles and method of manufacturing thereof
Publication Date: 2026.01.28 ELBE FLUGZEUGWERKE GMBH
  • EP4149815B1 patent drawingFigure 1
  • EP4149815B1 patent drawingFigure 2~3
  • EP4149815B1 patent drawingFigure 4~5

AI summary

A floor panel assembly for rail vehicles, such as trains or tramways, and a method of manufacturing such a floor panel assembly, which can be used for floating floors, are disclosed. The floor panel assembly comprises a first floor panel and a second floor panel. The first floor panel has a male connection portion, and the female floor panel has a female connection portion. The male connection portion and the female connection portion are configured to interfit in a form-fitting manner to provide a frictional connection between the individual floor panels and a flat surface of the floor panel assembly. The geometry of the connection portions and the sprue tools is referenced only to the top of the floor panels, thus providing a high surface flatness with small steps between the individual floor panels.