Firearm Receiver Connection Eliminating Slop via Locking Member
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Solution Overview
Problem
The dual pin design in the AR-15/M16 firearm platform results in excessive slop between the upper and lower receivers, making it difficult to achieve a secure and easily serviceable connection.
Innovation Solution
The introduction of a locking member that is displaceable into a perimeter opening of a takedown lug, eliminating the need for axial displacement of pins, and providing a continuous force to secure the upper receiver against the lower receiver.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a dual pin design (takedown pin and pivot pin) is used to connect upper and lower receivers, then the connection is secured, but excessive slop occurs between the receivers making it difficult to achieve a secure connection
Solution Approach 1:
The patent removes the pivot pin from the dual-pin system, extracting only the essential takedown pin function while eliminating the problematic pivot pin that contributed to slop. The takedown lug is redesigned with a perimeter opening that provides structural support without requiring a second pin, thereby reducing slop while maintaining connection security.
Solution Approach 2:
Instead of using two pins to secure the connection (traditional approach), the invention inverts the approach by using a single pin combined with a redesigned takedown lug structure that provides the necessary support and eliminates slop through its perimeter opening geometry, rather than relying on a second pin.
2Ease of repair
If axial displacement of pins is used to disconnect receivers, then the connection can be broken, but the process becomes complex and less serviceable
Solution Approach 1:
The patent simplifies the disconnection process by removing the pivot pin entirely, extracting unnecessary complexity from the system. The remaining takedown pin system with the perimeter opening design allows for straightforward insertion and removal without requiring axial displacement of multiple pins, thereby improving serviceability while reducing device complexity.
3Reliability
If a locking member is made displaceable into a perimeter opening, then continuous force is applied to reduce slop, but the structure becomes more complex
Solution Approach 1:
The patent merges the locking function with the structural support function by integrating the perimeter opening directly into the takedown lug. This eliminates the need for a separate locking mechanism, as the perimeter opening itself provides both structural support to reduce slop and the locking function through its geometry, thereby maintaining connection tightness while avoiding additional complexity.
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.