Adjustable Firearm Stock Locking Lever for Tool-Free Length Control
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Solution Overview
Problem
Existing firearm stocks face challenges in providing tool-free adjustment of the length of pull and disassembly, which can be inconvenient or time-consuming, especially in situations where tools are not available, and are prone to inadvertent adjustment during use.
Innovation Solution
A firearm stock assembly with a locking mechanism that includes a lever pivotable between locked and unlocked positions, allowing for tool-free adjustment of the length of pull and disassembly, featuring a cam pathway design to prevent inadvertent unlocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional locking mechanism is used for firearm stock adjustment, then the adjustment can be secured reliably, but the adjustment process requires tools and is time-consuming
Solution Approach 1:
The locking mechanism is designed to be self-operating through a cam and lever system. The cam pathway geometry automatically converts rotational motion of the adjustment knob into linear movement of the stock, while the lever engages with the cam to lock the position without requiring external tools. This self-service mechanism eliminates the need for separate locking tools and reduces adjustment time.
Solution Approach 2:
The mechanism transitions from a static locked state to a dynamic adjustment state through the cam pathway. As the adjustment knob rotates, the cam follower travels along the cam surface, dynamically changing the position of the stock relative to the receiver. The lever provides dynamic locking engagement that adapts to different stock lengths, enabling quick adjustment without tools.
2Ease of operation
If a simple locking mechanism is used, then the adjustment is quick and tool-free, but the mechanism is prone to inadvertent unlocking during use
Solution Approach 1:
The cam pathway is designed with a specific geometry that creates a self-latching effect. As the adjustment knob is rotated to the desired position, the cam follower naturally settles into a valley or flat portion of the cam surface that prevents backward movement. This preliminary anti-action is built into the cam profile itself, preventing inadvertent unlocking without requiring additional complex locking components.
Solution Approach 2:
The locking mechanism combines multiple functional elements into a composite system: the cam profile provides both positioning and locking functions, the lever provides mechanical advantage for engagement, and the adjustment knob provides both rotation and locking activation. This composite design achieves reliable inadvertent unlocking prevention while maintaining quick adjustment capability.
3Reliability
If a complex locking mechanism is used to prevent inadvertent adjustment, then reliability is improved, but the device complexity increases
Solution Approach 1:
The patent merges multiple functions into the cam component itself. The cam profile simultaneously provides: (1) the adjustment range definition, (2) the positioning reference, and (3) the inadvertent unlocking prevention through its geometric features. The lever is merged with the cam to provide both mechanical advantage and locking engagement. This merging eliminates the need for separate locking pins, springs, or detent mechanisms, reducing overall device complexity while maintaining reliability.
Solution Approach 2:
The adjustment knob serves multiple functions: it provides the rotational input for adjustment, it acts as the lever to engage/disengage the locking mechanism, and it maintains the locked position through its interaction with the cam. This multi-functionality eliminates the need for separate adjustment and locking controls, reducing device complexity while ensuring reliable prevention of inadvertent adjustment.
4Adaptability or versatility
If the stock is designed for disassembly, then maintenance and adjustment flexibility are improved, but the structural integrity and complexity increase
Solution Approach 1:
The firearm stock is segmented into distinct modular components: the stock body, the adjustment mechanism assembly, and the locking mechanism. These segments are connected through the cam and lever system, allowing the stock to be disassembled by reversing the adjustment process. The cam pathway and lever design enable clean separation of components without requiring special tools or complex disassembly procedures, maintaining structural integrity while providing adaptability.
Data Source
AI summary
A firearm stock includes a stock body slidably mounted on a beam. A lever attached to the stock body can be moved between a locked position and at least one unlocked position, where operating the lever moves a locking mechanism between locked and unlocked positions. For example, when the lever is in a first unlocked position, the locking mechanism permits longitudinal adjustment of the stock body along the beam. When the lever is in a second unlocked position the locking mechanism permits the stock body to be slidably removed from the beam. In one example, the lower portion of the stock body defines a plurality of cam pathways for pins that secure the lever to the stock body. Forward cam pathways permit either a pivoting movement about the rear pin or a downward and forward shifting movement.