High Capacity Rimfire Magazine Undulating Cartridge Path
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Solution Overview
Problem
Current high-capacity magazines for rimfire cartridges, particularly those accommodating the .17 HMR, face challenges in providing reliable and efficient feeding mechanisms that minimize friction and binding, while also being compatible with existing rifle designs and capable of handling the higher power and larger size of these cartridges.
Innovation Solution
A high-capacity magazine design featuring a pair of clamshell halves with a metal header securing polymer portions, a follower assembly with a pivotally coupled follower arm and a spring mechanism using a ribbon to apply a constant upward force, and an undulating cartridge path to alleviate stack-up and presentation issues, along with a user-accessible lever to adjust biasing force, ensuring smooth cartridge translation and enhanced wear resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a rotary magazine design is used for high-capacity rimfire cartridges, then the magazine can be compact and fit within existing rifle receptacles, but the feeding mechanism experiences increased friction and binding
Solution Approach 1:
The magazine body is divided into multiple compartments separated by partition walls, with each compartment holding individual cartridges. This segmentation allows independent movement of each cartridge along its own path, reducing interference and binding between cartridges during the feeding sequence.
Solution Approach 2:
The cartridge paths are designed to undulate in multiple dimensions (port-starboard and forward-aft directions) rather than moving in a single linear plane. This multi-dimensional path allows cartridges to clear each other more easily and reduces friction against the magazine walls during rotation.
2Reliability
If the cartridge path is made undulating to reduce binding, then friction is minimized, but the magazine structure becomes more complex
Solution Approach 1:
The undulating paths for multiple cartridges are merged into a single integrated magazine body structure with shared partition walls and common rotation axis. This combining approach achieves the benefits of complex paths without requiring separate mechanisms for each cartridge, reducing overall structural complexity.
Solution Approach 2:
The cartridge paths are designed with curved and undulating geometries rather than straight lines. This curvature allows cartridges to follow smoother, more natural arcs during rotation, reducing sharp changes in direction that would increase friction and binding, while the paths remain contained within a compact magazine envelope.
3Strength
If a metal header with polymer clamshell halves is used, then wear resistance is enhanced, but manufacturing complexity increases
Solution Approach 1:
The magazine body is segmented into a metal header portion and polymer clamshell halves that can be manufactured separately using different processes (metal machining vs. polymer injection molding), then assembled together. This segmentation allows each component to be optimized for its specific function while simplifying manufacturing compared to monolithic construction.
Solution Approach 2:
The magazine employs a composite construction combining metal (header) and polymer (clamshell halves) materials. The metal provides wear resistance and structural strength, while the polymer provides corrosion resistance, ease of molding, and reduced weight. This composite approach leverages the advantages of both materials while mitigating their individual disadvantages.
4Reliability
If the follower assembly uses a pivotally coupled arm with spring mechanism, then constant upward force is applied to reduce friction, but the device complexity increases
Solution Approach 1:
The follower assembly is designed to be self-regulating through its pivotal coupling and spring mechanism. As cartridges move along the undulating paths, the follower arm automatically pivots to maintain constant upward force on the cartridge, eliminating the need for external control systems or complex actuation mechanisms.
Solution Approach 2:
The follower arm is dynamically coupled to the cartridge path through pivotal connection, allowing it to adapt its position and force application in real-time as cartridges move along the undulating paths. This dynamic response ensures consistent upward force without requiring rigid, pre-programmed positioning mechanisms.
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 magazine design ensures reliable and efficient feeding of rimfire cartridges by reducing friction and binding, providing a robust assembly with enhanced wear resistance and compatibility with existing rifle configurations, while allowing for high-volume firing with reduced user effort.
Implementation Method 1
a spring connecting between the follower assembly and one of the header and arcuate cartridge bank for causing a bias of the follower assembly toward the header
Implementation Method 2
The spring comprises a ribbon biased to form a roll when the ribbon is in an unstressed state with no external forces acting thereon. An inner surface of the ribbon defines a central opening when the ribbon is free to form the roll. A roll end of the ribbon is disposed inside the central opening and a coupled end of the ribbon is coupled to the starboard body portion proximate an upper end thereof. In operation, the ribbon rolls and unrolls during relative translational motion between the follower and the magazine body.
Data Source
AI summary
A high capacity magazine for high powered rimfire cartridges comprises a header portion that has a form factor to be received in a rotary magazine receptacle and an arcuate cartridge bank portion that holds a column of cartridges. A pair of clamshell halves define an arcuate cartridge bank and a lower portion of the header potion. A header caps the upper ends of the clamshell haves securing the clamshell halves together. The head and clamshell halves define the cartridge pathway to the magazine exit to be fed into the rifle chamber.