Polymer Cartridge Primer Diffuser for Pressure Sealing

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Solution Overview

Problem

Conventional brass ammunition cartridge casings are heavy, expensive, and hazardous, while plastic alternatives have failed to provide reliable, safe, and consistent ballistic performance due to issues like bullet displacement, insufficient chamber pressure, and casing breakage.

Innovation Solution

A polymeric ammunition cartridge design featuring a diffuser cup and primer recess with a cylindrical insert, a propellant chamber, and a bullet-end component, utilizing ductile and fiber-reinforced polymers to ensure consistent pressure and mechanical strength, with a diffuser positioned to support the primer and enhance sealing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional brass cartridge casings are used, then mechanical strength and reliability are improved, but weight and cost increase

Engineering Contradiction:

Improvecartridge reliabilityVSAvoidcartridge weight

Core Design Contradiction:

ReliabilityVSWeight of moving object

Solution Approach 1:

The patent changes the material parameter from traditional brass to polymer composite materials, specifically using fiber-reinforced polymers that maintain mechanical strength while reducing weight. The polymer case is designed with specific structural parameters including wall thickness, reinforcement fiber orientation, and molecular weight characteristics to achieve brass-equivalent reliability at reduced weight.

Inventive Principle:

Principle #35Parameter changes

Solution Approach 2:

The invention employs composite materials consisting of polymer matrices reinforced with high-strength fibers (such as aramid, carbon, or glass fibers). This composite structure provides the necessary mechanical properties including tensile strength, impact resistance, and pressure containment while significantly reducing the overall cartridge weight compared to solid brass construction.

Inventive Principle:

Principle #40Composite materials

2Weight of moving object

If plastic cartridge casings are used, then weight is reduced, but ballistic performance consistency deteriorates

Engineering Contradiction:

Improvecartridge weightVSAvoidballistic performance consistency

Core Design Contradiction:

Weight of moving objectVSManufacturing precision

Solution Approach 1:

The patent incorporates preliminary reinforcement structures during the molding process, including pre-positioned fiber orientations, embedded sealing rings, and pre-formed crimp zones. These preliminary structural features ensure consistent bullet seating depth, uniform case dimensions, and reliable chamber pressure generation across all cartridges, eliminating the variability that plagues conventional plastic cases.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The invention controls critical manufacturing parameters including polymer molecular weight distribution, fiber length and orientation, molding temperature and pressure, and cooling rates. These parameter controls ensure that each cartridge meets precise dimensional tolerances and mechanical property specifications, achieving ballistic performance consistency comparable to brass cartridges while maintaining weight advantages.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If plastic cartridge casings are used, then cost is reduced, but safety and structural integrity worsen

Engineering Contradiction:

Improvemanufacturing costVSAvoidcasing breakage and safety hazards

Core Design Contradiction:

Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The patent uses fiber-reinforced polymer composites that provide superior impact resistance, tensile strength, and fracture toughness compared to conventional plastics. The fiber reinforcement prevents catastrophic failure modes such as case head separation, bullet penetration, and rim cracking, ensuring safety levels equivalent to brass while maintaining the cost and manufacturing advantages of polymer construction.

Inventive Principle:

Principle #40Composite materials

Solution Approach 2:

The invention incorporates energy-absorbing structural features including layered composite construction, controlled fiber distribution patterns, and impact-resistant geometric designs that dissipate stress before it can cause failure. These beforehand cushioning features protect against handling impacts, shipping shocks, and firing stresses, preventing the safety hazards associated with conventional plastic cases.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Device complexity

If conventional primer sealing methods are used, then manufacturing simplicity is maintained, but primer sealing adequacy deteriorates

Engineering Contradiction:

Improveprimer assembly complexityVSAvoidprimer sealing

Core Design Contradiction:

Device complexityVSReliability

Solution Approach 1:

The patent introduces a primer sealant or grommet as an intermediary component between the primer assembly and the polymer case. This sealant fills micro-gaps and ensures positive sealing around the primer flash hole and primer cup interface, preventing propellant gas leakage and ensuring reliable primer ignition while adding minimal complexity to the overall assembly process.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10048049B2Lightweight polymer ammunition cartridge having a primer diffuser

Publication Date: 2018.08.14 TRUE VELOCITY IP HOLDINGS LLC

AI summary

The present invention provides a polymeric ammunition cartridge having polymer cartridge with a metal primer insert having a primer recess and a primer diffuser cup or ring inserted into the primer recess.