Combustible Time-Delay Fuse for Aerial Vehicle Sensor Release

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Solution Overview

Problem

Aerial vehicles face challenges with pyrotechnic devices used for releasing parts in flight, which increase cost, complexity, and cause vibrations disrupting systems, while also requiring safety precautions during handling, storage, and transportation.

Innovation Solution

A combustible time-delay fuse is used to initiate the release of a retention device, which is propelled by a combustible propellant, allowing for controlled release of parts during flight without the need for explosives.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pyrotechnic devices are used for releasing parts in flight, then the release function is achieved, but cost and device complexity increase

Engineering Contradiction:

Improverelease functionVSAvoiddevice complexity

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts the harmful initiation circuit from the pyrotechnic device by using a purely mechanical fuse system. The fuse is ignited by the propellant combustion and burns for a predetermined time to release the cover, eliminating the need for electrical squibs, initiators, and associated wiring, thereby reducing device complexity while maintaining the release function.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent employs a simple, inexpensive combustible fuse that burns for a predetermined time and is then discarded. This disposable fuse mechanism replaces expensive pyrotechnic devices with initiating circuits, achieving cost reduction while maintaining reliable part release functionality.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

2Reliability

If pyrotechnic devices or explosives are used for releasing parts, then the release function is achieved, but vibrations are caused that disrupt system operations

Engineering Contradiction:

Improverelease functionVSAvoidvibrations

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the mechanical/explosive pyrotechnic release system with a thermal combustion-based fuse system. The fuse burns gradually for a predetermined time and releases the retention device through thermal decomposition rather than explosive force, eliminating harmful vibrations that would disrupt inertial measurement units and other sensitive systems while maintaining the release function.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Reliability

If explosives are used for releasing parts, then the release function is achieved, but safety precautions are required during handling, storage, and transportation

Engineering Contradiction:

Improverelease functionVSAvoidhandling safety

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent extracts the dangerous explosive materials from the release mechanism, replacing them with a simple combustible fuse that burns for a predetermined time. This eliminates the need for complex safety precautions during handling, storage, and transportation of the aerial vehicle while maintaining the reliable release function through controlled combustion.

Inventive Principle:

Principle #2Taking out (Extraction)

4Reliability

If initiating circuits for squibs are used, then the release function is achieved, but cost increases

Engineering Contradiction:

Improverelease functionVSAvoidmanufacturing cost

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The patent uses a simple, inexpensive combustible fuse that burns for a predetermined time and is then discarded. This disposable fuse mechanism replaces expensive initiating circuits and electrical squibs, achieving significant cost reduction in manufacturing the aerial vehicle while maintaining the reliable release function.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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

This solution reduces vibrations, eliminates the need for safety precautions, and simplifies the release mechanism, providing a cost-effective and reliable method for releasing parts during aerial vehicle operations.

Implementation Method 1

a combustible propellant that propels the air vehicle

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

a combustible time-delay fuse, combustion in which is initiated by combustion of the combustible propellant

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentUS9121668B1Aerial vehicle with combustible time-delay fuse

Publication Date: 2015.09.01 RAYTHEON CO

AI summary

An air vehicle includes a combustible fuse that is used for time-delayed release of a retention device. Combustion of a combustible propellant for propelling the air vehicle initiates combustion of the fuse. After a time delay following initiation of the combustion of the fuse, a retention device of air vehicle is released. In one embodiment, the air vehicle is a projectile which is fired from a propellant in a cartridge that is behind the projectile. The retention device may be used to release a cover for a sensor of the air vehicle, such as a cover for an optical sensor or seeker.