Lightweight Cartridge Casing with Deformable Joint

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Solution Overview

Problem

Conventional cartridge casings are heavy due to their dense material, which increases transport costs and the mass burden on soldiers, necessitating a lightweight construction.

Innovation Solution

A cartridge casing design featuring a casing tube and head cap joined by a deformable member, with a seal material between them, allowing for a lighter weight configuration through the use of different materials and manufacturing processes that include forming a cylindrical tube and head cap, and deforming the deformable member to fix them together.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If conventional brass material is used for the cartridge casing, then the casing is easy to form into the desired shape, but the casing becomes relatively dense and increases the overall mass of the cartridge

Engineering Contradiction:
Improveease of formingVSAvoidcartridge mass
Core Design Contradiction:
Ease of manufactureVSWeight of moving object

Solution Approach 1:

The cartridge casing is divided into separate components: a casing tube and a head cap, which are joined together. This segmentation allows each component to be manufactured from lightweight materials independently and assembled, reducing overall mass while maintaining structural integrity and manufacturability

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention uses composite construction with the casing tube and head cap made from lightweight materials such as aluminum or plastic, combined with a deformable member for joining. This composite approach reduces density and mass compared to solid brass construction while preserving formability through modular design

Inventive Principle:
Principle #40Composite materials

2Weight of moving object

If the cartridge casing is made lighter by using different materials, then transport costs and mass burden are reduced, but the reliability under ignition pressures may be compromised

Engineering Contradiction:
Improvecartridge massVSAvoidperformance under ignition pressures
Core Design Contradiction:
Weight of moving objectVSReliability

Solution Approach 1:

By segmenting the casing into a tube and head cap joined by a deformable member, the design concentrates structural reinforcement at the critical head cap region where ignition pressures are highest. This allows lightweight materials to be used throughout while maintaining reliability at stress concentration points

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The head cap is provided with a deformable member that creates localized reinforcement and sealing at the critical interface between the head cap and casing tube. This local quality enhancement ensures reliable pressure containment and sealing under ignition conditions while the rest of the structure remains lightweight

Inventive Principle:
Principle #3Local quality

3Device complexity

If the casing tube and head cap are joined using traditional methods, then the structure is simple, but the sealing reliability under pressure may be insufficient

Engineering Contradiction:
Improvejoining structureVSAvoidsealing reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The deformable member is designed to dynamically respond to pressure conditions: it deforms during assembly to create the join, and then deforms further under ignition pressure to enhance sealing. This dynamic behavior provides reliable sealing without requiring complex static sealing structures

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The deformable member undergoes parameter changes in its physical state during operation: it transitions from a pre-deformed assembly state to a further deformed sealed state under pressure. This parameter change enables the simple joining structure to achieve reliable sealing by utilizing pressure-induced deformation

Inventive Principle:
Principle #35Parameter changes

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 design results in a lighter weight cartridge casing that maintains performance under ignition pressures, allowing for a larger propellant volume and reduced overall mass, while ensuring reliable manufacturing and environmental sealing.

Implementation Method 1

a deformable member which is deformable between: a first shape in which the deformable member may extend between the casing tube and head cap during assembly; and a second shape which fixes the casing tube and head cap together

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

A seal material is provided between first end of the casing tube and head cap

Methodology Applied
Scientific EffectSealing:

Data Source

PatentEP3201559B1Cartridge casing
Publication Date: 2019.11.06 BAE SYSTEMS PLC
  • EP3201559B1 patent drawingFigure 1
  • EP3201559B1 patent drawingFigure 2
  • EP3201559B1 patent drawingFigure 3

AI summary

A cartridge casing (30) comprises a casing tube (32) having a first end (34) and a head cap (36). The first end (34) of the casing tube (32) abuts and is joined with the head cap (36) such that an orifice (44) in the first end (34) of the casing tube (32) is aligned with a passage (46) in the head cap (36) to define a flash passage (50). The head cap (36) and casing tube (32) are held together by a deformable member (60).