Elastic Washer Link System for Munition Combustible Case

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Solution Overview

Problem

Existing solutions for connecting propulsive loading means to combustible cases in large caliber ammunition do not allow for rear loading of propulsive powder, do not enable the use of an elastic washer for flexibility, and require complex assembly processes, including rotation restrictions of the ignition device.

Innovation Solution

A link system between the ignition means and the fuel case, featuring an axial opening for the ignition means and peripheral openings for propulsive load loading, with a maintenance mechanism using a buoyary ring and a solidarity support ring to immobilize the ignition means before loading and fixing, ensuring the elastic washer can rotate with the case.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an elastic washer is used to connect the base to the combustible case, then flexibility and limited relative movement are improved, but rear loading of propellant powder becomes impossible

Engineering Contradiction:
Improveconnection flexibilityVSAvoidrear loading capability
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The connection system is divided into separate functional components: the elastic washer provides flexibility and shock absorption, while the retaining ring with notches and the base with protrusions provide positioning and loading access. This segmentation allows each component to fulfill its specific function without interfering with others, enabling both flexible connection and rear loading capability.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If a plastic bowl is interposed between the base and combustible case to facilitate rear loading, then loading capability is improved, but the connection becomes fragile and requires many parts

Engineering Contradiction:
Improverear loading capabilityVSAvoidnumber of parts
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The invention merges the functions of the plastic bowl, retaining mechanism, and elastic washer into a unified system. The retaining ring integrates the retention function with the elastic washer, while the notches and protrusions provide both positioning and loading access. This merging reduces the number of separate parts and creates a more robust connection while maintaining rear loading capability.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If the ignition means is made integral with the sealing cap after loading, then sealing is improved, but the ignition means cannot be positioned or secured before loading

Engineering Contradiction:
Improvesealing capabilityVSAvoidpositioning during assembly
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The retaining ring with notches and the corresponding protrusions on the base are designed to preliminarily position and secure the ignition means before the sealing cap is attached. This preliminary positioning ensures correct alignment and secure placement during assembly, while the sealing cap is subsequently made integral with the ignition means to provide the final sealing function.

Inventive Principle:
Principle #10Preliminary action

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 solution allows for rear loading of propulsive powder, maintains the flexibility of the bond between the cheek and the fuel case, and simplifies the assembly process by preventing rotation of the ignition device, ensuring effective and efficient ammunition construction.

Implementation Method 1

a stop ring integral with the ignition means and bearing against an internal surface of the case base via a spring washer

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4033198B1Connecting device between a primer of a propellant charge and a combustible case of a munition, combustible case and elastic washer associated with such a connecting device
Publication Date: 2025.04.16 KNDS AMMO FRANCE
  • EP4033198B1 patent drawingFigure 1~2
  • EP4033198B1 patent drawingFigure 3~4
  • EP4033198B1 patent drawingFigure 5~6

AI summary

The invention relates to a linking device between an ignition means (8) of a propellant charge and a combustible case (2) of a munition having a base pierced with an axial opening (20) through which the ignition means (8) is placed and at least one peripheral vent (21) intended to allow the case to be loaded with the propellant charge. This device is characterized in that it comprises a means for retaining the ignition means (8) on the fuel case (2), a means which ensures the immobilization of the ignition means before the fuel case is loaded, the retaining means comprising on the one hand a stop ring (12) integral with the ignition means (8) and bearing against an internal surface (2a) of the bottom of the case by means of an elastic washer (17) and on the other hand a retaining ring (19) integral with the ignition means (8) which cooperates with at least one stop surface (22) integral with the bottom of the case (2).