Non-Lethal Munition Tube Mounting for Speed Control

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing non-lethal ammunition faces challenges in controlling firing speed and reproducibility due to variations in uncapping force and geometry, particularly for medium caliber guns, which require large cases and result in inconsistent projectile speeds.

Innovation Solution

A non-lethal ammunition design featuring a case with a propellant casing and a projectile integral with a coaxial tube, where propellant gases are released inside the tube, allowing for controlled pressure rise and secure mounting without crimping, using a tube with an annular fracture primer and a high pressure chamber separated by a grid, facilitating modulation of firing speed.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If the low pressure chamber volume is reduced to control firing speed, then the projectile elongation increases, but this goes against the desired non-lethal effect

Engineering Contradiction:
Improvefiring speedVSAvoidprojectile length
Core Design Contradiction:
SpeedVSLength of moving object

Solution Approach 1:

The invention divides the case into separate high pressure and low pressure chambers, with the low pressure chamber volume independently controllable through the propellant casing design. This segmentation allows optimization of chamber volumes for speed control without compromising projectile dimensions for non-lethal effect.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention introduces a dynamic pressure control mechanism where the low pressure chamber volume can be adjusted by modifying the propellant casing geometry. This allows the system to adapt firing speed characteristics while maintaining appropriate projectile length for non-lethal applications.

Inventive Principle:
Principle #15Dynamics

2Stress or pressure

If the projectile geometry is modified to adapt pressure rise characteristics, then the mass and ballistic characteristics change, but this also influences its non-lethal nature

Engineering Contradiction:
Improvepressure rise characteristicsVSAvoidnon-lethal effect consistency
Core Design Contradiction:
Stress or pressureVSReliability

Solution Approach 1:

The invention modifies local properties of the propellant casing (volume, shape, material) to control pressure rise characteristics, while keeping the projectile geometry unchanged. This localized modification allows pressure optimization without affecting the projectile's mass and ballistic characteristics that ensure non-lethal effect.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The propellant casing acts as an intermediary element between the high pressure chamber and the projectile. By adjusting the low pressure chamber volume within the casing, the system mediates pressure rise characteristics independently of projectile geometry, maintaining consistent non-lethal performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Quantity of substance

If standard cases with large volume are used for medium caliber guns, then the case dimensions are imposed by caliber, but the small quantity of powder required for non-lethal shooting leads to inconsistent firing speeds

Engineering Contradiction:
Improvepropellant powder quantityVSAvoidfiring speed consistency
Core Design Contradiction:
Quantity of substanceVSSpeed

Solution Approach 1:

The invention segments the propellant system into high pressure and low pressure chambers, allowing the low pressure chamber to be optimized for the small quantity of powder used in non-lethal ammunition. This segmentation enables consistent pressure development and firing speed control despite the large case volume required for medium caliber guns.

Inventive Principle:
Principle #1Segmentation

4Ease of manufacture

If the projectile is crimped at the case mouth for mounting, then the mounting is simple, but the uncapping force varies leading to dispersions in firing speed characteristics

Engineering Contradiction:
Improveprojectile mountingVSAvoidfiring speed reproducibility
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The invention introduces a tube as an intermediary element between the projectile and the case. This tube provides a controlled interface for mounting while ensuring consistent uncapping force through its interaction with the propellant gases, thereby improving firing speed reproducibility without complicating the manufacturing process.

Inventive Principle:
Principle #24Intermediary (Mediator)

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 achieves consistent firing speeds of 60-100 m/s for projectiles between 20-50mm caliber, reducing aerodynamic braking and allowing easy adaptation to different calibers by adjusting the low-pressure chamber volume, while simplifying projectile attachment and maintaining reproducibility.

Implementation Method 1

a propellant charge (8) contained in a high pressure chamber (6)

Methodology Applied
Scientific EffectCombustion: Combustion

Implementation Method 2

The expansion of the propellant gases through the orifice and the gradual rise in pressure inside the low pressure chamber

Methodology Applied
Scientific EffectPressure gradient: Pressure Gradient

Implementation Method 3

The expansion of the propellant gases through the orifice and the gradual rise in pressure inside the low pressure chamber

Methodology Applied
Scientific EffectAdiabatic expansion: Adiabatic Heating

Data Source

PatentEP2620737B1Non lethal munition
Publication Date: 2014.07.23 NEXTER MUNITIONS SA
  • EP2620737B1 patent drawingFigure 1
  • EP2620737B1 patent drawingFigure 2~3a
  • EP2620737B1 patent drawingFigure 3b~3c

AI summary

The munition (1) has a metal case (2) incorporating a propulsive housing (3) that contains propellant powder (8). A projectile (4) is secured to the case by a tube (16) that extends a rear portion (4a) of the projectile. The tube is coaxial to the case and fixed on the propulsive housing at an outlet orifice of propellant gases, where pressure of gases from the propulsive housing is released during shooting inside the tube. The tube has an annular rupture initiation point (17) that is broken by the effect of the pressure of gases during shooting to release the projectile. The tube is made of plastic or composite material.