Centerfire Cartridge Case Form-Fit Bottom Piece
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Solution Overview
Problem
Existing multipart cartridge cases for centerfire ammunition require complex assembly and multiple parts, particularly due to the need for a separate primer and additional components like felt wads for sealing the ignition charge receiving chamber, making them cumbersome for mass production and automation.
Innovation Solution
A simplified cartridge case design where the casing sleeve and bottom piece are attached via a form-fit or press-fit mechanism, eliminating the need for additional parts by using plastic deformation to create a conical annular wall and anvil, which also enhances gas-tightness and stability, allowing for central ignition without a separate primer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate primer and felt wad are used for sealing the ignition charge receiving chamber, then reliable ignition is achieved, but the number of parts increases and assembly complexity increases
Solution Approach 1:
The patent merges the functions of the felt wad, anvil, and primer into a single integrated bottom piece. The bottom piece includes a sealing surface that directly seals the ignition charge receiving chamber, an anvil portion that serves as a counter-bearing for the firing pin, and eliminates the need for separate primer and felt wad components, thereby reducing part count while maintaining ignition reliability
Solution Approach 2:
The bottom piece is designed as a multi-functional component that simultaneously performs sealing of the ignition charge receiving chamber, provides a counter-bearing surface for the firing pin, and serves as the base structure for the cartridge case, thereby eliminating multiple specialized parts
2Strength
If traditional joining methods are used for attaching bottom piece and casing sleeve, then structural integrity is maintained, but mass production and automation are hindered
Solution Approach 1:
The bottom piece and casing sleeve are designed with pre-formed geometric features (conical annular wall, flared portion, and groove) that enable self-aligning and self-locking during assembly. The conical geometry allows the components to be attached in a predetermined orientation without requiring complex alignment procedures or specialized joining tools
Solution Approach 2:
The patent replaces traditional mechanical joining methods (such as threading, riveting, or welding) with a geometric interlocking system based on conical surfaces and flared portions. This mechanical substitution enables automated assembly through simple pressing or forcing operations, significantly improving productivity while maintaining structural integrity
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
The solution reduces the number of parts, simplifies assembly, and enhances the cartridge case's gas-tightness and stability, facilitating cost-effective and efficient manufacturing while ensuring reliable ignition.
Implementation Method 1
using plastic deformation to create a conical annular wall and anvil
Data Source
AI summary
A cartridge case for centerfire ammunition may include a rotationally shaped casing sleeve for receiving a projectile as well as propellant charge powder, and a separate rotationally shaped bottom piece which is attached to the casing sleeve and has a closed ignition surface to be faced towards a firing pin for ignition of the centerfire ammunition. The closed ignition surface delimits, on the firing pin side, a receiving chamber for an ignition charge. The casing sleeve may have or support an anvil extending in the direction of the ignition surface into the receiving chamber. The ammunition may have a caliber in the range from, for example, 4.6 to 12.7.