Firearm Stock Hinge Mechanism Preventing Translation
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Solution Overview
Problem
Current firearm stock assemblies face issues such as manufacturing tolerance variance, reduced reliability due to translation requirements, complexity in use, and potential for breakage during folding or when using a cheek riser, especially with quick detach mechanisms and length of pull adjustments.
Innovation Solution
A stock assembly with a modifiable firearm mount, detent notch, lock catch, and quick detach mount that allows for a folding stock assembly to be hingedly coupled, preventing translation along the hinge axis, distributing forces effectively, and featuring a safe-open mechanism to prevent breakage, along with an adjustable length of pull mechanism that eliminates the need for a 'third hand'.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a folding stock assembly requires translation along the hinge axis during rotation, then the folding mechanism can achieve compact configuration, but the reliability of the weapon is reduced and the complexity of use increases
Solution Approach 1:
The stock assembly is divided into separate components: a stock-to-firearm interface and a folding stock assembly. The hinge mechanism is segmented to allow rotation without translation, with the hinge axis positioned to enable pure rotational movement. This segmentation allows the folding function to be isolated and optimized independently from the firearm interface, improving reliability by eliminating the translation requirement while maintaining compact folded configuration.
2Device complexity
If a single lock mechanism is used to maintain both folded and unfolded configurations, then the device complexity is reduced, but the freedom to control folding and unfolding forces is limited
Solution Approach 1:
Different locking mechanisms are applied to different configurations: a detent mechanism with detent notches is used for the folded configuration to provide snap-action locking with controlled folding forces, while a separate lock mechanism is used for the unfolded configuration to provide secure locking with controlled unfolding forces. This local differentiation allows independent optimization of locking characteristics for each configuration without increasing overall system complexity.
3Manufacturing precision
If the same lock is used for both folded and unfolded configurations, then the manufacturing precision requirements are reduced, but the control over folding and unfolding forces is limited
Solution Approach 1:
The detent mechanism incorporates multiple detent notches positioned at different locations and orientations, each engineered with specific dimensional tolerances and geometric features tailored to control the folding force characteristics. The separate lock mechanism for the unfolded configuration has its own set of precision requirements optimized for that state. This allows each mechanism to be manufactured with precision targeted to its specific function, rather than requiring all components to meet the most stringent tolerance requirements.
4Ease of operation
If a quick detach mechanism concentrates forces at a single point, then the ease of operation is improved, but the mechanism experiences early failure due to force concentration
Solution Approach 1:
The quick detach mechanism is redesigned to distribute forces across multiple surfaces and dimensions rather than concentrating them at a single point. The interface incorporates multiple contact surfaces and load paths that spread the detach forces throughout the stock-to-firearm interface structure. This dimensional distribution of force application maintains the quick detach operation capability while significantly improving the durability and reliability of the mechanism by eliminating stress concentration points.
5Adaptability or versatility
If length of pull adjustment requires depressing a catch while moving the buttstock laterally, then the adaptability is improved, but the ease of operation deteriorates due to requiring a third hand
Solution Approach 1:
The length of pull adjustment mechanism is merged with the existing stock assembly structure, integrating the adjustment function into the buttstock itself. The adjustment mechanism uses a cam or lever system that combines the catching and releasing actions with the lateral movement of the buttstock into a single integrated motion. This allows the user to adjust the length of pull with one hand by simply moving the buttstock laterally, eliminating the need to separately depress a catch and removing the requirement for a third hand while maintaining full adaptability of the length of pull adjustment.
Data Source
AI summary
A stock for a firearm is disclosed. The stock comprises a stock-to-firearm interface, and a folding stock assembly hingedly coupled to the stock-to-firearm interface. The stock comprises a folded configuration and an unfolded configuration. The stock-to-firearm interface comprises a modifiable firearm mount, a lock catch, a quick detach mount, and one of a detent notch and a detent. The folding stock assembly comprises a buttstock, a lock for engaging the lock catch in the stock-to-firearm interface to selectively maintain the stock in the unfolded configuration, and the other one of a detent and a detent notch. The detent is shaped to engage the detent notch to selectively maintain the stock in the folded configuration. The quick detach mount is shaped to distribute a carry force between a first surface of the stock-to-firearm interface and at least one of a second surface of the stock-to-firearm interface and a firearm.