Polymer Cartridge Case Neck Thickness for Pressure Resistance
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Solution Overview
Problem
Conventional ammunition cartridge cases made of brass are heavy, expensive, and potentially hazardous, and they may not withstand the pressures generated during firing when made from alternative materials like polymer.
Innovation Solution
Developing a high-strength polymer-based cartridge casing with a neck thickness that is 25% to 125% greater than standard neck thickness for a particular caliber, along with a shoulder and cartridge body formed from polymer, to enhance the mechanical strength and withstand firing pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If polymer material is used instead of brass for cartridge case, then weight is reduced and cost is lowered, but mechanical strength and ability to withstand firing pressures deteriorates
Solution Approach 1:
The patent changes the geometric parameters of the cartridge case by increasing the neck thickness to 1.5 to 2.0 times the standard thickness. This parameter modification compensates for the lower material strength of polymer compared to brass, allowing the polymer case to withstand firing pressures while maintaining the weight and cost advantages of using polymer material.
2Ease of manufacture
If standard neck thickness is used for polymer cartridge case, then manufacturing simplicity is maintained, but reliability of withstanding firing pressures deteriorates
Solution Approach 1:
The patent modifies the neck thickness parameter to 1.5 to 2.0 times the standard thickness, which is a straightforward dimensional change that can be implemented in existing manufacturing processes. This parameter adjustment ensures reliable withstanding of firing pressures while maintaining manufacturing simplicity, as no complex structural changes are required.
3Strength
If increased neck thickness is implemented, then mechanical strength is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent implements increased mechanical strength through a single parameter change - increasing neck thickness to 1.5 to 2.0 times standard thickness. This approach avoids complex structural modifications such as multiple reinforcing elements or composite constructions, thereby maintaining relative simplicity while achieving the desired strength improvement.
Data Source
AI summary
A high strength polymer-based cartridge casing inclosing a volume, with a first end having a mouth, a neck extending away from the mouth, a shoulder extending below the neck and away from the first end and a cartridge body formed below the shoulder. An insert is attached to the cartridge body opposite the shoulder and having a centerline. A projectile is disposed in the mouth having a particular caliber. The neck, the shoulder, and the cartridge body are formed from a polymer. The shoulder comprises a shoulder angle that is standard for the particular caliber. The neck has a neck thickness greater than a standard neck thickness for the particular caliber, and a neck length longer than a standard neck length for the particular caliber as detailed by a standards organization.