Firearm Receiver Locking Assembly to Eliminate Upper-Lower Slop
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Solution Overview
Problem
The dual pin design in AR-15/M16 firearm platforms results in excessive slop and user insecurity due to tight or loose connections, requiring makeshift solutions that are cumbersome and inefficient.
Innovation Solution
A locking member that displaces into a perimeter opening of the takedown lug, exerting continual force for a secure connection, and a detent assembly to maintain the locking member in place, eliminating axial displacement of pins.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a dual pin design (takedown pin and pivot pin) is used to connect upper and lower receivers, then the connection strength is improved, but the device complexity increases and ease of operation deteriorates due to tight or loose connections requiring makeshift solutions
Solution Approach 1:
The patent removes the pivot pin from the connection mechanism, extracting only the essential takedown pin function while eliminating the problematic dual-pin complexity. This simplifies the connection mechanism while maintaining sufficient connection strength through the remaining takedown pin and lever assembly.
Solution Approach 2:
The patent combines the functions of the takedown pin and pivot pin into a single integrated takedown pin assembly with a lever mechanism. This merging eliminates the need for separate pins while providing equivalent or improved connection security and ease of operation through the unified design.
2Strength
If a dual pin design is used to connect upper and lower receivers, then the connection strength is improved, but the ease of operation worsens due to excessive slop and tight connections requiring makeshift solutions
Solution Approach 1:
The patent introduces a dynamic lever mechanism that allows the takedown pin to be easily displaced between locked and unlocked positions. This dynamic element provides controlled movement that eliminates excessive slop while maintaining strong connection when locked, and enables easy operation when disconnection is needed.
Solution Approach 2:
Instead of using pins that require axial displacement for removal, the patent inverts the mechanism to use a lever that rotates to engage and disengage the takedown pin. This inversion allows operation in a different dimensional space (rotational vs. linear), making the connection and disconnection process more intuitive and easier to operate.
3Device complexity
If axial displacement of pins is used for connection, then the connection mechanism is simple, but the reliability deteriorates due to excessive slop and user insecurity
Solution Approach 1:
The patent employs a curved or angled bearing surface on the takedown lug that guides the locking member into a precise locked position. This curved geometry eliminates excessive slop by providing a defined engagement path, while maintaining the simplicity of the overall pin-based connection mechanism.
Data Source
AI summary
A firearm platform and method of connecting an upper receiver to a lower receiver. The upper receiver has a pivot lug and a takedown lug with perimeter openings in opposite directions. The lower receiver has a locking member that pushes against the takedown lug which causes the upper receiver to displace forward. As a result of the forward displacement, a pivot pin in the lower receiver exerts an opposing force against the pivot lug. The locking member is displaced between a locked and unlocked position through a lever located on an exterior surface of the lower receiver. When the locking member is in the locked position, the lower receiver and uppers receiver form a connection that is tight and free from slop.