Interlocking Expansion Joints for Overhead Line Power Rails

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Solution Overview

Problem

Existing expansion connection arrangements for conductor rails in overhead line systems face challenges in accommodating thermal expansion and contraction, leading to limited joinable sections without expansion compensation, which affects the stability and efficiency of power transmission.

Innovation Solution

A generic expansion connection arrangement featuring interlocking connecting and counter-profiles that allow relative displacement in the direction of the contact wire, with half-rails carrying the contact wires and maintaining a defined spacing, enabling large expansion length compensation while ensuring high connection stability and low weight, using self-lubricating sliding elements and contact strips for secure power transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If busbars are joined together without expansion compensation, then the connection is simple and stable, but the number of joinable busbars is limited due to thermal expansion and contraction

Engineering Contradiction:
Improveconnection stabilityVSAvoidexpansion compensation capability
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The connection arrangement is divided into a first connection element attached to the first busbar and a second connection element attached to the second busbar. These segmented elements can move independently relative to each other, allowing each busbar to expand and contract freely while maintaining electrical connection. This segmentation resolves the contradiction by enabling expansion compensation without compromising connection stability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The distance between the first and second connection elements is designed to be adjustable within a range, allowing the connection arrangement to adapt to different expansion states. This parameter change capability enables the system to accommodate thermal expansion and contraction while maintaining reliable electrical connection, thus resolving the contradiction between connection stability and expansion adaptability.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If conductor rails are connected rigidly, then connection stability is high, but the ability to accommodate thermal expansion and contraction is limited

Engineering Contradiction:
Improveconnection stabilityVSAvoidexpansion length
Core Design Contradiction:
Stability of the object's compositionVSLength of moving object

Solution Approach 1:

The connection arrangement incorporates movable elements that allow relative displacement between the first and second connection elements. This dynamic capability enables the system to accommodate changes in the length of conductor rails due to thermal expansion and contraction, while the electrical connection remains stable. The dynamic design resolves the contradiction by allowing length variation without compromising connection stability.

Inventive Principle:
Principle #15Dynamics

3Adaptability or versatility

If expansion joints are introduced to accommodate thermal expansion, then expansion compensation is improved, but the complexity of the connection arrangement increases

Engineering Contradiction:
Improveexpansion compensation capabilityVSAvoidconnection arrangement complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The connection arrangement merges the functions of electrical connection and expansion compensation into a single integrated structure. The first and second connection elements serve both to conduct electricity and to accommodate relative movement due to thermal expansion. This merging reduces the need for separate expansion joint components, thereby reducing overall complexity while maintaining expansion compensation capability.

Inventive Principle:
Principle #5Merging (Combining)

4Power

If multiple busbars are joined together, then power transmission capacity increases, but the weight of the connection arrangement increases

Engineering Contradiction:
Improvepower transmission capacityVSAvoidconnection arrangement weight
Core Design Contradiction:
PowerVSWeight of stationary object

Solution Approach 1:

The design extracts only the essential functions needed for connection and expansion compensation, eliminating unnecessary heavy components. The connection elements are designed to be lightweight while maintaining sufficient mechanical strength and electrical conductivity. This extraction of essential functions allows multiple busbars to be joined together to increase power transmission capacity without proportionally increasing the weight of the connection arrangement.

Inventive Principle:
Principle #2Taking out (Extraction)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The solution effectively compensates for large expansion lengths, providing stable and efficient power transmission with minimal vibration and arcing, eliminating the need for complex cable connections and maintaining optimal weight and stability ratios.

Implementation Method 1

Due to changing ambient temperatures and the changing current heat, the change in temperature of the conductor rails in the overhead line system is accompanied by a change in length.

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 2

using self-lubricating sliding elements and contact strips for secure power transmission

Methodology Applied
Scientific EffectSelf-lubrication: Lubrication

Implementation Method 3

the connecting profile and the counter-profile interlocking in such a way that they can be displaced relative to one another in the direction of the contact wire and are locked transversely thereto

Methodology Applied
Scientific EffectMechanical interlocking: Mechanical Fastener

Data Source

PatentEP2691256B1Expansion connection arrangement for adjoining power rails of an overhead line system for electric locomotives
Publication Date: 2017.11.01 SIEMENS AG
  • EP2691256B1 patent drawingFigure 1~2
  • EP2691256B1 patent drawingFigure 3~5
  • EP2691256B1 patent drawingFigure 6~7

AI summary

The invention relates to an expansion connection arrangement for adjoining power rails (20, 20') of an overhead line system for electric locomotives. The power rails (20, 20') to be connected are arranged spaced apart from one another here at a joint distance (s) and each have a contact wire (10, 10') along which a current collector of a locomotive vehicle can slide for the purpose of transmitting energy. According to the invention, a connection profile (50) is connected to the one power rail (20), and a corresponding profile (50') is connected to the other power rail (20'). The connecting profile (50) and the corresponding profile (50') engage one in the other in a positively locking fashion such that they can slide one into the other in the direction of the contact wire (10 and 10', respectively) and are locked transversally with respect thereto. Each of the power rails (20, 20') is respectively connected to a half rail (60, 60') assigned thereto, which half rails (60, 60') support the contact wires (10, 10') between the power rails (20, 20') with the connection profile (50) and the corresponding profile (50'), respectively, and secure them parallel to one another at a defined contact wire distance (d) over an overlapping length (1). As a result, an expansion connection arrangement is made available which is low in weight, compensates large expansion lengths and has good override properties.