Bridge Crane Slide Joint Design for Rail Misalignment

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Solution Overview

Problem

Bridge cranes face difficulties due to varying rail distances caused by temperature changes and flexible frame structures, leading to increased wear and tear, high manufacturing costs for precise alignment, and issues with straight movement and drive control.

Innovation Solution

A simplified slide joint design featuring a support platform with slide surfaces and restricting means on the end girder, separate from the main girder, allowing for easier manufacturing and installation, and accommodating varying girder lengths without altering the fixed support structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If precise alignment of rails is implemented to reduce wear and tear, then wear and tear on rails is reduced, but manufacturing costs increase significantly

Engineering Contradiction:
Improvewear and tear on railsVSAvoidmanufacturing costs
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention changes the parameter of rigidity by introducing a flexible joint with slide means between the end girder and main girder. This allows the crane structure to adapt to rail alignment variations through controlled movement, eliminating the need for extremely precise rail alignment while maintaining low wear and tear. The slide means provide controlled flexibility that compensates for rail imperfections without requiring high-precision manufacturing of the rails themselves.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If high accuracy of manufacture is required to eliminate wear and tear problems, then wear and tear is reduced, but costs raise considerably

Engineering Contradiction:
Improvewear and tearVSAvoidaccuracy of manufacture
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The invention introduces dynamic flexibility through the slide means that allow relative movement between the end girder and main girder. This dynamic capability enables the structure to accommodate manufacturing tolerances and rail imperfections without requiring high manufacturing precision. The slide means absorb misalignments through controlled movement, reducing the need for high-precision manufacturing while maintaining low wear and tear.

Inventive Principle:
Principle #15Dynamics

3Reliability

If slide means are arranged inside the main girder, then movement restriction is effective, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvemovement restrictionVSAvoidcomplexity of slide joint
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention extracts the restricting means from the interior of the main girder and relocates them to the outside, attached to the end girder. This external arrangement simplifies the overall structure by eliminating the need for internal modifications to the main girder. The restricting means are mounted on the end girder's outer surface, making them easier to manufacture, install, and maintain while achieving the same movement restriction function.

Inventive Principle:
Principle #2Taking out (Extraction)

4Manufacturing precision

If main girder length is precisely controlled, then alignment accuracy is improved, but adaptability to varying conditions decreases

Engineering Contradiction:
Improvealignment accuracyVSAvoidadaptability to varying girder lengths
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The slide means provide dynamic adjustment capability that compensates for variations in main girder length. Instead of requiring precise control of girder length, the flexible joint allows the structure to adapt to different lengths through controlled movement. This enables the use of standard girder lengths without cutting or precise adjustment, improving both adaptability and ease of manufacture.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3781512B1Bridge crane arrangement
Publication Date: 2023.11.01 KONECRANES GLOBAL OY
  • EP3781512B1 patent drawingFigure 1
  • EP3781512B1 patent drawingFigure 2~3

AI summary

A bridge crane arrangement which comprises at least one main girder (1) for a trolley, the main girder having a longitudinal central web which has at least one web plate (1a), and a longitudinal bottom flange (1b) arranged in the bot-tom part of the central web and protruding from the central web (1a) onto both sides thereof; end girders (4) which are adapted to support opposite ends of the main girder (1) and to move along guides; slide means (11) arranged between an end girder (4) on at least one side and the corresponding end (9) of the main girder (1), the slide means allowing the movement of the end girder (4) in question in relation to the main girder (1) in at least its longitudinal direction and the rotation of the end girder in question and main girder in relation to each other; and restrict-ing means (12, 13) to restrict the movements between the end girder (4) in question and the main girder (1). On the top surface of the end girder (4) in question, there is arranged a support platform (10) wider than the bottom flange, the slide means comprise a slide surface (11) arranged on the top surface of the support platform and/or the bottom surface of the bottom flange (1b) of the main girder, and restricting means (12, 13) are arranged to the support platform (10) on both sides of the bottom flange (1b) of the main girder, outside the main girder (1).