Projectile Tip Axial Mobility for Internal Pressure Venting

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Solution Overview

Problem

Existing projectiles face issues with high internal pressure due to explosive outgassing at elevated temperatures, leading to potential violent reactions and hazards, as the projectile tip is securely fastened and cannot vent pressure effectively, risking detachment and environmental danger.

Innovation Solution

A projectile design featuring a pressure-related axial relative mobility of the tip within the casing, utilizing a shearable threaded connection that opens ventilation channels to reduce pressure while a stop mechanism prevents the tip from separating, ensuring secure retention and controlled venting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the projectile tip is firmly screwed into the projectile casing with high torque, then the connection strength is improved, but the internal pressure cannot be reduced when explosives outgas at high temperatures, leading to violent reactions

Engineering Contradiction:
Improveconnection strengthVSAvoidinternal pressure
Core Design Contradiction:
StrengthVSObject-affected harmful factors

Solution Approach 1:

The threaded connection transitions from a static firmly-screwed state to a dynamic state where the projectile tip can move axially relative to the casing when internal pressure exceeds the holding force of the threaded connection, enabling pressure relief while maintaining secure attachment under normal conditions

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The threaded connection is designed with specific parameters (thread depth, pitch, engagement length) that create a holding force sufficient for normal operation but insufficient to prevent movement when internal pressure reaches a critical threshold, allowing the system to switch between secure attachment and pressure venting states

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If ventilation channels are provided to reduce internal pressure, then the internal pressure is reduced, but the projectile tip may detach from the projectile casing due to high pressure

Engineering Contradiction:
Improveinternal pressureVSAvoidattachment stability
Core Design Contradiction:
Object-affected harmful factorsVSStability of the object's composition

Solution Approach 1:

The system dynamically adjusts the attachment state: under normal pressure the threaded connection maintains secure attachment, but under high pressure the connection allows controlled movement to open ventilation channels while the stop element prevents complete detachment

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The stop element is pre-positioned to limit the axial movement of the projectile tip, providing a safety mechanism that prevents detachment before it can occur, allowing pressure venting while maintaining attachment stability

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

3Object-affected harmful factors

If plastic plugs are used to close ventilation channels, then the ventilation channels are sealed, but the plugs may not be pushed out completely or may detach, leaving individual parts

Engineering Contradiction:
Improvepressure containmentVSAvoidplastic plugs
Core Design Contradiction:
Object-affected harmful factorsVSLoss of substance

Solution Approach 1:

The plastic plugs are extracted from the system entirely, replacing them with a design where the projectile tip itself moves to open ventilation channels, eliminating the risk of plug detachment or incomplete ejection while maintaining pressure containment and venting functions

Inventive Principle:
Principle #2Taking out (Extraction)

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 design effectively reduces internal pressure through controlled venting while maintaining the projectile tip's secure attachment to the casing, preventing detachment and minimizing the risk of accidental ignition and environmental hazards.

Implementation Method 1

a threaded connection is realized with the external thread of the bullet tip and the internal thread of the ring screwed onto it, which is designed in such a way that when a defined axially directed force is applied, which is generated by the high internal pressure, shears off, thus destroying the threaded connection

Methodology Applied
Scientific EffectShear stress: Shear Stress

Implementation Method 2

If such a projectile is exposed to high temperatures, for example in the event of a fire, the explosive begins to outgas due to the increased temperature inside the projectile. A high internal pressure is therefore formed

Methodology Applied
Scientific EffectOutgassing:

Data Source

PatentEP2846124B1Shell
Publication Date: 2018.06.06 DIEHL DEFENCE GMBH & CO KG
  • EP2846124B1 patent drawingFigure 1~2
  • EP2846124B1 patent drawingFigure 3~5
  • EP2846124B1 patent drawingFigure 6~7

AI summary

Projectile comprising a projectile casing containing explosive material, in which a projectile tip containing a detonator is inserted, wherein the projectile tip (4) is movable axially against a stop (24) by means of a gas pressure building up in the interior of the projectile (1) relative to the projectile casing (2) by means of a gas pressure relative to a projectile casing (2) by opening at least one vent channel (16) connecting the interior of the projectile casing (2) with the environment.