Rail Joint Staggering for Weld Strength and Side Thrust

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Solution Overview

Problem

Existing methods for forming rail joints in solid-profile rails are laborious, unsatisfactory in terms of functionality and durability, and require complex welding processes, especially for heavy-duty applications, and often result in uneven load distribution and instability.

Innovation Solution

The method involves leaving the lower edges of rail ends unstaggered for full-width welding to mountings, with only the upper areas staggered to accommodate side thrust, allowing for smooth wheel transition and eliminating on-site welding by completing the rail joint assembly in a workshop.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If rail ends are completely staggered to accommodate side thrust, then the rail can handle lateral loads, but the welding area is reduced and joint stability is compromised

Engineering Contradiction:
Improveside thrust accommodationVSAvoidwelding area
Core Design Contradiction:
ForceVSStrength

Solution Approach 1:

The rail joint applies different staggering configurations to different parts of the rail: the lower edges remain unsubtracted to provide full-width welding area for structural strength, while the upper areas are staggered to accommodate side thrust forces. This local differentiation resolves the contradiction by optimizing each region for its specific functional requirement.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If rail joints are assembled on-site with welding, then the connection can be made flexible, but the assembly becomes laborious and time-consuming

Engineering Contradiction:
Improveon-site assembly flexibilityVSAvoidassembly time
Core Design Contradiction:
Adaptability or versatilityVSProductivity

Solution Approach 1:

The rail ends are prepared with precise staggerings and welding surfaces in advance at the factory before delivery to the construction site. This preliminary preparation eliminates the need for time-consuming on-site welding operations, as the components can be quickly assembled using mechanical connections alone, thereby resolving the contradiction between assembly flexibility and productivity.

Inventive Principle:
Principle #10Preliminary action

3Strength

If rail ends are welded at the final assembly site, then the joint can be made strong, but special skills, tools and time are required

Engineering Contradiction:
Improvejoint strengthVSAvoidassembly complexity
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

All welding operations are completed at the factory before the rail components are shipped to the construction site. The rail ends are pre-welded to their respective mountings with full-width welding surfaces, eliminating the need for specialized welding equipment and skilled workers at the final assembly location. This resolves the contradiction by maintaining joint strength through factory welding while dramatically simplifying on-site assembly.

Inventive Principle:
Principle #10Preliminary action

4Force

If the lower edges of rail ends are staggered, then the rail can accommodate side thrust, but the welding area is reduced compromising joint durability

Engineering Contradiction:
Improveside thrust capacityVSAvoidjoint durability
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The invention applies staggerings only to the upper areas of the rail ends while keeping the lower edges unsubtracted and fully aligned. This local differentiation ensures that the lower welding surfaces provide maximum contact area for durable, reliable joints, while the upper staggered portions accommodate side thrust forces. This resolves the contradiction by assigning different geometric characteristics to different regions based on their functional requirements.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP2951117B1Method to form a rail joint, and a rail joint
Publication Date: 2017.09.13 KONECRANES GLOBAL OY
  • EP2951117B1 patent drawingFigure 1~3
  • EP2951117B1 patent drawingFigure 4~5

AI summary

The invention relates to a method to form a rail joint, in which staggerings (6, 7) corresponding to each other are made in joinable solid-profile rail ends (4, 5) of parts (2, 3) of a rail (1) so that when a completed rail joint is viewed from above the rail heads bond; both rail ends are secured to a corresponding mounting; the rail ends secured to the mountings are brought against each other whereby said bonding is established; and the mountings that are against each other are secured to one another. The staggerings (6, 7) are made in such a manner that the lower edges (4a, 5a) of the rail ends (4, 5) are left substantially unstaggered whereby the staggerings extend from these lower edges towards the top surfaces or the rail ends; and the rail ends (4, 5) are welded by their lower edges(4a, 5a)at their entire width to their mountings (8, 9). The invention also relates to a rail joint made by this method.