Propellant Shell Radial Release Mechanism

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Solution Overview

Problem

Existing propellant charge cases with two-stage chambers are prone to uncontrolled explosions when exposed to high temperatures due to incomplete melting of fusible safety rings and potential blockages, which can prevent pressure reduction and ventilation.

Innovation Solution

Incorporating radially movable holding elements made of memory materials that change shape upon temperature increase, allowing for active mechanical release of the pressure plate and ensuring reliable ventilation by eliminating axial fixation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fusible safety ring is used as the safety mechanism, then the pressure plate can be released thermally, but the ring may not melt completely under temperature gradients or may be blocked, preventing reliable ventilation

Engineering Contradiction:
Improvereliability of thermal activationVSAvoidincomplete melting and blockages
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The safety mechanism is divided into multiple independent holding elements (at least two) instead of a single fusible ring. Each holding element can independently respond to thermal activation, ensuring that if one element fails to melt or becomes blocked, the others can still facilitate pressure plate release and ventilation.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The holding elements are made of memory material that undergoes a phase change at a specific transition temperature. This parameter change enables the holding elements to automatically move from a fixed position to a released position, providing reliable thermal activation without depending on complete melting like traditional fusible rings.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the holding elements are fixed axially to ensure secure mounting, then the pressure plate is securely held, but thermal activation cannot reliably move the holding elements radially to release the pressure plate

Engineering Contradiction:
Improveaxial fixation stabilityVSAvoidradial movement reliability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The holding elements are designed with dynamic characteristics that allow them to transition between fixed and released states. Axially, they are fixed to provide stable mounting. Radially, they can move when thermally activated due to the memory material phase change, enabling reliable pressure plate release while maintaining secure axial fixation.

Inventive Principle:
Principle #15Dynamics

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 ensures reliable thermal activation of the safety mechanism, preventing explosions by allowing pressure reduction and ventilation, even under varying temperature gradients and potential blockages, thus enhancing the safety and functionality of the propellant charge case.

Implementation Method 1

the security element will change its shape when it is thermally activated, that is to say it will consist of a memory material which changes from a first to a second shape when a transition temperature is reached

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Data Source

PatentEP2905572B1Propellant shell for cartridged ammunition
Publication Date: 2017.07.19 DIEHL DEFENCE GMBH & CO KG
  • EP2905572B1 patent drawingFigure 1~2
  • EP2905572B1 patent drawingFigure 3
  • EP2905572B1 patent drawingFigure 4~5

AI summary

Propellant cartridge case for a cartridge ammunition, comprising a case body (3) with a high-pressure chamber (7) for receiving a propellant charge and a low-pressure chamber (12) communicating with the high-pressure chamber (7) when the propellant charge is ignited, and a pressure plate (17) for receiving a primer (20), wherein the pressure plate (17) is detachably arranged on the case body (3) or a carrier plate (13) via a thermally actuated locking element (22), and wherein one or more retaining elements (26, 27) axially fixing the pressure plate (17) are provided, which are radially movable or are moved from their fixing position when the locking element (22) is thermally activated.