Helmet Mount Night Vision Switch Using Bowden Cable Actuation

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Solution Overview

Problem

Existing night vision goggle mounting assemblies struggle to accurately distinguish between in-use and stowed positions, leading to false activations and visibility issues due to emitted light, and often require tools for switching between left and right eye use.

Innovation Solution

A helmet mounting assembly with a magnet module and magnetically-responsive sensor that automatically shuts down the night vision device when stowed and activates it when in use, using a Bowden cable or proximity sensors for precise positioning, and a symmetrical dovetail plate for easy side switching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Extent of automation

If a magnetic switch is used for semi-automatic shutdown, then the ENVG can be turned off automatically when stowed, but false activation occurs when the user looks up or down beyond certain angles

Engineering Contradiction:
Improveautomatic shutdownVSAvoidfalse activation
Core Design Contradiction:
Extent of automationVSReliability

Solution Approach 1:

The patent replaces the magnetic field-based reed switch with a mechanical switch actuated by a magnet coupled to a Bowden cable. The Bowden cable transmits mechanical force from the pivot assembly to the switch, providing positive mechanical actuation that is not susceptible to false activation by head movements or magnetic interference. This mechanical substitution resolves the reliability issue while maintaining automatic shutdown functionality.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a Bowden cable as an intermediary mechanism between the pivot assembly and the switch. The Bowden cable acts as a mechanical mediator that translates the rotational movement of the pivot assembly into linear actuation of the switch, ensuring that only the intended stowing motion triggers shutdown and not incidental head movements. This intermediary mechanism provides reliable signal transmission without false activation.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Illumination intensity

If the ENVG is emitted visible light when switched on, then the user can see the image, but the user's position can be given away to the enemy when falsely activated

Engineering Contradiction:
Improvevisible light emissionVSAvoidposition detection by enemy
Core Design Contradiction:
Illumination intensityVSObject-affected harmful factors

Solution Approach 1:

The patent employs a mechanical switch system with a magnet and Bowden cable that provides definitive on/off control. The mechanical actuation ensures the ENVG is truly off when stowed, preventing any visible light emission that could reveal the user's position. The system accepts a simple mechanical switching mechanism that reliably eliminates the harmful effect of unintended light emission.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Shape

If a specially shaped cavity is used for the magnet to travel in, then the magnet can be positioned to activate the switch, but it is difficult to automatically distinguish the operational mode

Engineering Contradiction:
Improvecavity shapeVSAvoidoperational mode detection
Core Design Contradiction:
ShapeVSMeasurement precision

Solution Approach 1:

The patent replaces the complex cavity-shaped magnetic path with a direct mechanical linkage system. The magnet is coupled to the pivot assembly via a Bowden cable, which directly transmits the stowing motion to the switch. This mechanical substitution eliminates the need for specially shaped cavities and provides precise operational mode detection through direct mechanical actuation, resolving the measurement precision issue.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

4Difficulty of detecting and measuring

If electronic sensors are placed within the ENVG, then the position can be sensed, but false activation still occurs if the user looks up or down beyond a preset angle

Engineering Contradiction:
Improveposition sensingVSAvoidfalse activation
Core Design Contradiction:
Difficulty of detecting and measuringVSReliability

Solution Approach 1:

The patent replaces electronic orientation sensors with a mechanical switch system actuated by a magnet coupled to the pivot assembly through a Bowden cable. This mechanical system provides binary on/off control based on the physical stowing motion, eliminating the false activation problems associated with electronic sensors that interpret head movements as operational mode changes. The mechanical linkage ensures only intentional stowing triggers shutdown.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

Provides reliable automatic shutdown and activation, maintaining user visibility and reducing false activations, while allowing easy conversion between left and right eye use without tools.

Implementation Method 1

a magnet module and magnetically-responsive sensor that automatically shuts down the night vision device when stowed and activates it when in use

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

using a Bowden cable or proximity sensors for precise positioning

Methodology Applied
Scientific EffectMechanical force transmission: Mechanical Force

Data Source

PatentEP3846652B1Operational mode sensing switch system and multi-orientated mounting system for a helmet mounted night vision device
Publication Date: 2026.03.18 DESIGNWORKS DEFENCE SYST PTY LTD
  • EP3846652B1 patent drawingFigure 1
  • EP3846652B1 patent drawingFigure 2~3
  • EP3846652B1 patent drawingFigure 4~5

AI summary

The present invention relates to a helmet mounting assembly for enhanced night vision goggles, and more particularly to a flip-up helmet mount (2) designed to allow for automatic shutoff of an attached ENVG (8) when stowed, and automatic activation of an ENVG when returned to the in-use position. An automatic shutdown assembly including a magnet module (26) and a magnetically- responsive sensor (36) wherein the magnet module comprising a magnet (28) that emits the necessary magnetic field (34) which influences the magnetically-responsive sensor when in the stowed position in order to turn the ENVG off.