Swaged Vent Plug for Insensitive Munitions Sealing

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Solution Overview

Problem

Energetic materials in ordnance, rocket motors, and warheads are prone to unplanned ignition due to internal pressure or excess heat, necessitating effective venting systems to prevent such incidents.

Innovation Solution

A venting system comprising a casing with a hole and a plug formed by swaging or crimping a plug slug into the hole, which provides reliable sealing and compliance with insensitive munition requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional threaded plugs are used to seal vent holes, then sealing reliability can be achieved, but they are not feasible for thin holes and may loosen under vibrations

Engineering Contradiction:
Improvesealing reliabilityVSAvoidapplicability to thin holes
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the threaded mechanical connection system with a swaged mechanical deformation system. Instead of using threads that engage with the hole, the plug is swaged (radially compressed) to deform and lock into the hole, providing a secure connection suitable for thin-walled applications where threads cannot be formed.

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

Solution Approach 2:

The patent changes the physical state and geometry of the plug during installation. The plug starts as a cylindrical form and undergoes radial compression during swaging, transforming its dimensions and creating interference fit with the hole. This parameter change enables the plug to securely seal thin holes that cannot accommodate traditional threaded fasteners.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If threaded plugs are used, then sealing can be achieved, but they may loosen due to vibrations and temperature variations

Engineering Contradiction:
Improvesealing reliabilityVSAvoidresistance to loosening under vibrations
Core Design Contradiction:
ReliabilityVSStability of the object's composition

Solution Approach 1:

The patent replaces the threaded mechanical connection system with a swaged mechanical deformation system. Instead of using threads that engage with the hole, the plug is swaged (radially compressed) to deform and lock into the hole, providing a secure connection suitable for thin-walled applications where threads cannot be formed.

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

Solution Approach 2:

The swaging process creates a curved, deformed profile in the plug that locks into the hole. This curved deformation pattern provides mechanical interlocking that resists loosening from vibrations and temperature variations, unlike straight threaded connections that can gradually back out.

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Object-affected harmful factors

If vent holes are provided to prevent unplanned ignition, then safety is improved, but environmental sealing is compromised

Engineering Contradiction:
Improveprevention of unplanned ignitionVSAvoidenvironmental sealing
Core Design Contradiction:
Object-affected harmful factorsVSObject-generated harmful factors

Solution Approach 1:

The patent creates a dynamic sealing system where the swaged plug can respond to pressure changes. The radial deformation of the plug allows it to maintain contact with the hole walls under varying pressure conditions, providing both venting capability and environmental sealing throughout the operational lifecycle of the ordnance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The swaged plug creates localized deformation zones at the interface with the hole that provide sealing. The radial compression concentrates the sealing action at specific locations where the plug meets the hole walls, ensuring environmental sealing while maintaining the venting function.

Inventive Principle:
Principle #3Local quality

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 prevents unplanned ignition by ensuring reliable venting and maintaining environmental sealing, even under varying conditions such as vibrations and temperature changes, while being suitable for thin holes where traditional threaded plugs are not feasible.

Implementation Method 1

transforming a plug slug positioned within the vent hole into a plug

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS9964387B2Insensitive munitions swaged vent plug
Publication Date: 2018.05.08 NORTHROP GRUMMAN SYSTEMS CORP

AI summary

A venting system for ordnance or rocket motors comprising a casing having at least one hole and a plug, the plug being formed from a plug slug swaged into the at least one hole. A method to fill a vent hole in a casing comprising transforming a plug slug positioned within the vent hole into a plug.