Variable Shoulder Polymer Cartridge for Weight Reduction
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Solution Overview
Problem
Conventional ammunition cartridge cases made of brass are heavy, expensive, and prone to uneven deformation during firing, leading to inconsistent bullet performance due to variations in material thickness, which affects accuracy and pressure distribution.
Innovation Solution
Development of a high-strength polymer-based cartridge casing with a variable shoulder and neck design, featuring a frangible portion that can split upon discharge, and a unique molding process using polymers like nylon with glass fibers, allowing for standard loading and improved manufacturing efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If conventional brass cartridge cases are used, then strength and structural integrity are maintained, but weight increases significantly and manufacturing cost increases
Solution Approach 1:
The patent employs composite materials by combining polymer matrix (such as nylon) with glass fibers to create a cartridge case that achieves both weight reduction and strength enhancement. The glass fiber reinforcement provides the necessary mechanical strength while the polymer matrix binds the fibers together, forming a composite structure that is both lightweight and strong enough to withstand firing pressures.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical and chemical properties of the polymer material through additives and processing conditions. By adjusting parameters such as polymer composition, fiber content, and molding temperature, the cartridge case achieves optimal balance between weight reduction and structural integrity required for safe operation.
2Reliability
If conventional brass cartridge cases with uniform thickness are used, then manufacturing is simplified, but uneven deformation occurs during firing leading to inconsistent bullet performance
Solution Approach 1:
The patent applies local quality by varying the wall thickness of the polymer cartridge case at different locations. The case features non-uniform thickness distribution with thicker sections in high-stress areas and thinner sections where less strength is required. This localized variation in material distribution optimizes structural performance, prevents uneven deformation during firing, and ensures consistent bullet release while maintaining overall design simplicity.
3Ease of manufacture
If polymer cartridge cases are used, then weight is reduced and manufacturing cost decreases, but ensuring structural integrity under high pressures becomes more difficult
Solution Approach 1:
The patent employs composite materials by combining polymer matrix (such as nylon) with glass fibers to create a cartridge case that achieves both weight reduction and strength enhancement. The glass fiber reinforcement provides the necessary mechanical strength while the polymer matrix binds the fibers together, forming a composite structure that is both lightweight and strong enough to withstand firing pressures.
Solution Approach 2:
The patent utilizes parameter changes by modifying the physical and chemical properties of the polymer material through additives and processing conditions. By adjusting parameters such as polymer composition, fiber content, and molding temperature, the cartridge case achieves optimal balance between weight reduction and structural integrity required for safe operation.
Data Source
AI summary
A high strength polymer-based cartridge casing can include a first end having a mouth and a neck extending away from the mouth. Next, a shoulder extends below the neck and away from the first end. An inside of the shoulder can be shaped in at least one of a convex or concave shape. The shoulder can have unequal outside and inside shoulder angles. Further, the inside shoulder can be textured or coated.