Snap-Action Electrical Switch for Point Machine Motor Control

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Solution Overview

Problem

Current electrical switch designs for point machines are prone to failure due to contamination, mechanical stress, and vibrational forces, lacking snap-action, detectable toggle position, and positive override, which are essential for precise and reliable operation in high-stress railroad environments.

Innovation Solution

An electrical switch with an integral elastic element that 'snaps' open to cut off power to the motor, utilizing a toggle assembly to deform the elastic element and reduce arcing, ensuring precise shut-off and integration with existing switch designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If current electrical switch designs are used, then the switch can be integrated into existing point machine footprints, but the switch is prone to failure due to contamination, mechanical stress, and vibrational forces

Engineering Contradiction:
Improveintegration with existing switch designsVSAvoidswitch operation reliability
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The switch incorporates a spring-loaded movable contact that dynamically responds to mechanical stress and vibration, maintaining reliable electrical connection through elastic recovery rather than rigid fixed positioning

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The spring element provides beforehand cushioning by absorbing mechanical shocks and vibrations before they can damage the contact, preventing failure from contamination and stress accumulation

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

2Device complexity

If conventional switch designs without snap-action are used, then the structure is simpler, but arcing occurs between contacts during switching

Engineering Contradiction:
Improveswitch structure complexityVSAvoidarcing between contacts
Core Design Contradiction:
Device complexityVSObject-generated harmful factors

Solution Approach 1:

The spring-loaded contact creates periodic snap-action during switching, rapidly moving contacts between open and closed states to minimize arcing duration while maintaining simple overall structure

Inventive Principle:
Principle #19Periodic action

Solution Approach 2:

The snap-action mechanism rushes through the switching transition in minimal time, skipping the problematic intermediate state where arcing would occur, thereby reducing contact damage

Inventive Principle:
Principle #21Skipping (Rushing through)

3Device complexity

If the switch lacks detectable toggle position, then the design is simpler, but precise shut-off of power to the motor cannot be verified

Engineering Contradiction:
Improveswitch design complexityVSAvoidshut-off position detection
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The switch incorporates a visible indicator that changes position or appearance to signal the toggle state, providing detectable feedback without adding complex sensing mechanisms

Inventive Principle:
Principle #32Color changes

Solution Approach 2:

The switch structure itself provides the detection function through its mechanical configuration, where the toggle position is inherently visible or detectable without requiring separate measurement systems

Inventive Principle:
Principle #25Self-service

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 provides a reliable and precise shut-off mechanism with reduced arcing, ensuring safety and reliability in point machine operations by integrating snap-action and detectable toggle position within the existing footprint of point machine switches.

Implementation Method 1

an elastic element, preferably integral to the switch, disposed within the housing for toggling the switch open and closed to regulate current flow

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

The toggle assembly acts upon the switch to deform the elastic element and cause the switch to 'snap' open, to reducing the likelihood of arcing when the circuit opens

Methodology Applied
Scientific EffectSnap-action: Metastability

Data Source

PatentEP3380386B1Point machine and electrical switch with snap-action and method of operating said point machine
Publication Date: 2021.03.17 SIEMENS MOBILITY PTY LTD
  • EP3380386B1 patent drawingFigure 1
  • EP3380386B1 patent drawingFigure 2
  • EP3380386B1 patent drawingFigure 3

AI summary

A switch for a point machine, point machine having said switch, and a method for operating said point machine. The switch opening and closing a circuit providing current to the motor of the point machine. The switch having an elastic element, such as a spring, to create "snap-action" to open and close the circuit. Operation of the motor compressing the spring to open the circuit and cut-off power to the motor when the point machine has completed movement of a point.