One-Sided Rail Electrical Contact via Radial Bush Expansion

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Solution Overview

Problem

Existing methods for applying permanent electrical contacts to metal wall portions, such as rail webs or tubular profiles, require access from both sides, making them unsuitable for cases where access is limited to one side only.

Innovation Solution

A method and kit that utilize a bush and punch assembly with a pulling device to radially expand a tubular stem, allowing permanent anchoring in a hole from one side, accompanied by a terminal lug connection using an expansion bolt, enabling installation and electrical connection from a single access point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a hydraulic jack is used to expand the bush from the opposite side, then stable anchoring is achieved, but access from both sides of the rail web is required

Engineering Contradiction:
Improvestable anchoringVSAvoidaccess from both sides
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The tool is divided into two functional parts: a punch with expansion elements that is inserted through the bush from the accessible side, and a pulling device that remains on the accessible side to apply expansion force. This segmentation allows the expansion function to be performed from one side only, eliminating the need for access to both sides of the rail web while maintaining stable anchoring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The punch acts as an intermediary tool that transmits the pulling force from the pulling device (on the accessible side) to the bush, causing radial expansion. The punch with its expansion portions mediates between the pulling device and the bush, enabling one-sided access while achieving the same anchoring effect as the hydraulic jack.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of operation

If the bush is inserted from one side only, then ease of operation is improved, but stable anchoring becomes difficult to achieve

Engineering Contradiction:
Improveaccess from one sideVSAvoidstable anchoring
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The punch is designed with movable expansion portions that can dynamically change shape from a compact insertion configuration to an expanded anchoring configuration. This dynamic transformation allows the punch to first pass through the bush easily, then expand to create stable anchoring forces on the bush, achieving both one-sided access and reliable fixation.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The expansion portions of the punch change their geometric parameters (size and shape) during the installation process. They start with a smaller cross-section to facilitate insertion through the bush, then expand to a larger cross-section to engage the bush walls and create stable anchoring, thereby achieving both ease of operation and reliable fixation.

Inventive Principle:
Principle #35Parameter changes

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

Enables the secure and stable installation of a permanent electrical contact on metal wall portions from a single side, ensuring tight contact and mechanical stability without the need for dual access.

Implementation Method 1

activating the pulling device to pull the punch with its expansion portion proximally completely through the tubular stem of the bush, while the abutment portion pushes distally against the proximal end of the tubular stem, thereby radially expanding the tubular stem and permanently anchoring it in the hole

Methodology Applied
Scientific EffectRadial expansion: Elasticity

Data Source

PatentEP2514035B1Method and kit for the application of a permanent electrical contact in a rail
Publication Date: 2016.11.02 CEMBRE LTD
  • EP2514035B1 patent drawingFigure 1~4
  • EP2514035B1 patent drawingFigure 5~9

AI summary

Method for applying an electrical contact to a hole (2) of a metal wall portion (1), comprising the steps of providing a bush (12), a punch (11) with a shaft (16), an expansion portion (19) and a connecting portion (20) thereof, a pulling device (21) with an abutment portion (22) and a pulling mechanism (23) for engaging the punch (11) and to pulling it proximally with respect to the abutment portion (22), inserting the punch (11) in a passage hole (25) of the bush (12) so that the connecting portion (20) protrudes proximally from the bush and the expansion portion (19) is located on end (14), bush connecting the punch (11) to the pulling device (21), inserting the preassembled bush (12) -punch (11) -unit from a proximal side of the wall portion (1) distally in the hole (2) and activating the pulling device (21) to pull the punch (11) proximally through the bush, thereby radially expanding bush and permanently anchoring it in the hole (2).