Multi-Part Cartridge Case Joining With Conical Annular Wall Deformation
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Solution Overview
Problem
Existing methods for joining the base piece and case jacket of multi-part cartridge cases are complex and not suitable for mass production and automation, requiring additional fastening parts and prefabricated undercut features.
Innovation Solution
A method involving plastic deformation of the base piece and case jacket to create a form and force fit, using a conical annular wall and undercut features without additional fastening structures, facilitated by a tool with a shaping die and press plunger for efficient assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If additional fastening parts and prefabricated undercut features are used to join base piece and case jacket, then the joining reliability is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the additional fastening part from the system. Instead of using a separate fastening component, the invention creates the fastening function through the interaction between the base piece and case jacket themselves, specifically through the undercut feature and conical annular wall configuration that enables direct form-fit joining without extra parts.
Solution Approach 2:
The patent merges the fastening function with the structural components. The conical annular wall of the base piece and the corresponding undercut feature of the case jacket work together as an integrated fastening system, combining what were previously separate functions (structural support and fastening) into a unified design that eliminates additional components.
2Reliability
If additional fastening parts and prefabricated undercut features are used to join base piece and case jacket, then the joining reliability is improved, but the manufacturing cost and production time increase
Solution Approach 1:
The undercut feature is formed as an integral part of the case jacket manufacturing process itself, rather than being a separate prefabricated component. The conical annular wall is created during the forming of the base piece, enabling the fastening function to be built-in during primary manufacturing operations rather than requiring additional assembly steps.
Solution Approach 2:
The base piece and case jacket are designed to create their own fastening mechanism through their geometric features. The conical annular wall and undercut feature work together to generate the necessary fastening force through their interaction during assembly, eliminating the need for external fastening parts and reducing manufacturing complexity.
3Ease of manufacture
If a conical annular wall with undercut features is used for joining, then the ease of manufacture is improved, but the gas tightness may be compromised
Solution Approach 1:
The conical annular wall utilizes a curved, conical geometry rather than a flat or cylindrical surface. This curved configuration provides a progressive sealing interface that accommodates minor dimensional variations and enhances the form-fit between the base piece and case jacket, improving gas tightness while maintaining manufacturing simplicity through the conical shape's inherent geometric properties.
Solution Approach 2:
The undercut feature is strategically positioned at the critical sealing interface between the base piece and case jacket. This localized geometric modification creates a precise form-fit at the most important location for gas tightness, while the rest of the components maintain their simple conical and cylindrical geometries for ease of manufacture.
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
Facilitates simple, cost-effective, and reliable joining of the base piece and case jacket, suitable for mass production, with enhanced gas tightness and reinforcement during firing, reducing manufacturing costs by about 30%.
Implementation Method 1
The base piece and the case jacket are joined to one another by plastic deformation of the base piece and/or of the case jacket
Data Source
AI summary
A cartridge case for ammunition may include a rotationally shaped case jacket for receiving a projectile and an annular base piece for receiving a primer and the case jacket. An annular wall of the base piece on the side of the case jacket is conically shaped at least in sections with respect to its axis of rotation. A retaining section of the case jacket on the side of the base piece is adapted in shape thereto so that the retaining section engages at least in sections behind the annular wall for fastening the case jacket and the base piece to one another. A distancing of the base piece and case jacket from each other may be prevented in the direction of the axis of rotation. The conical annular wall and the retaining section may be formed by plastic deformation of the base piece.