AR-15 Bolt Catch Actuator with Displaceable Follower for Rimfire Hold Open
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Solution Overview
Problem
Existing bolt catch mechanisms for firearms, such as AR-15, do not securely hold open the bolt for inspection after the last round is fired, especially when using rimfire ammunition, leading to potential miscounting of remaining cartridges.
Innovation Solution
A bolt catch assembly with a uniquely configured follower and actuator housing that includes a spring-loaded follower component and an adjustable actuator, allowing for precise engagement with the bolt catch to maintain the bolt in an open position until the last round is discharged, even with rimfire ammunition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a standard bolt catch mechanism is used with rimfire ammunition, then the firearm can be operated, but the bolt fails to hold open securely after the last round is fired
Solution Approach 1:
The follower is modified with a displaceable member that changes its position based on ammunition type. When rimfire ammunition is detected, the member displaces to engage the bolt catch actuator, adjusting the engagement parameters to ensure reliable bolt hold open functionality specific to rimfire cartridges.
Solution Approach 2:
The system automatically detects the presence of rimfire ammunition and self-adjusts through the displaceable follower member, which moves to the appropriate engagement position without requiring manual intervention or separate mechanisms for different ammunition types.
2Adaptability or versatility
If the bolt catch mechanism is modified to work with rimfire ammunition, then compatibility is improved, but the structure becomes more complex
Solution Approach 1:
The follower is divided into distinct functional segments: a main body that provides structural support and a displaceable member that provides the adaptive engagement function. This segmentation allows the complex adaptive function to be isolated to a single movable component rather than requiring complex modifications throughout the entire follower structure.
Solution Approach 2:
The follower incorporates a displaceable member that can dynamically change its position based on the type of ammunition loaded. This dynamic element allows a single follower structure to adapt to different ammunition types (centerfire and rimfire) without requiring multiple separate followers or complex mechanical linkages.
3Reliability
If the actuator engagement is made more precise for rimfire ammunition, then bolt hold open security is improved, but the adjustment mechanism becomes more complex
Solution Approach 1:
The displaceable member of the follower acts as an intermediary between the ammunition type and the bolt catch actuator engagement. It translates the presence of rimfire ammunition into the appropriate engagement position, providing precise control of actuator engagement without requiring complex adjustment mechanisms in the actuator itself.
Solution Approach 2:
The adjustment function is extracted from the actuator housing and placed into the follower's displaceable member. This allows the actuator itself to remain relatively simple while the follower handles the complexity of positioning and engagement adjustment based on ammunition type.
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
Ensures a secure and reliable last shot bolt hold open position, preventing premature bolt closure and ensuring accurate counting of remaining cartridges, enhancing operational safety and usability.
Implementation Method 1
A follower component is upwardly and biasingly disposed within the magazine and which, upon contacting the catch actuator, displaces an associated bolt catch of the firearm in an upper and bolt restraining position.
Implementation Method 2
A spring is supported in an extending and seating fashion within a hidden location of the superstructure so that an opposite end is biased an abutting end surface of the upper follower body in a rearward induced direction.
Data Source
AI summary
A bolt catch assembly for use with a firearm including a receiver with an exposed receiving chamber and an underside engageable magazine. The assembly includes a bolt catch actuator housing supported in seating fashion relative to the receiving chamber and communicating with an attachable magazine. A catch actuator is supported in elevatable fashion relative to an end of the actuator housing. A follower component is upwardly and biasingly disposed within the magazine and which, upon contacting the catch actuator, displaces an associated bolt catch of the firearm in an upper and bolt restraining position.