Firearm Takedown Pin Rotational Mechanism
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Solution Overview
Problem
Conventional takedown pin systems for firearms require axially-disengaging from the upper receiver to open the firearm, making the process inefficient, difficult, and potentially unsafe, especially under stressful conditions, and result in uncontrolled pivoting movements during maintenance tasks.
Innovation Solution
A takedown pin system that allows the upper receiver to pivot relative to the lower receiver without axially-disengaging from the upper receiver, utilizing a reduced-dimension portion and detent track system to achieve secure, semi-secure, and unsecure positions through rotational positioning, enabling controlled separation and alignment of the receivers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the takedown pin is axially-disengaged from the upper receiver to open the firearm, then the receivers can be separated for maintenance, but the process becomes inefficient, difficult, and potentially unsafe with uncontrolled pivoting movements
Solution Approach 1:
The takedown pin system transitions from a static axial engagement to a dynamic rotational mechanism. The pin can rotate between a locked position (securing receivers) and an unlocked position (allowing controlled separation), enabling the system to adapt its state based on operational requirements without compromising safety
Solution Approach 2:
The engagement mechanism is segmented into distinct rotational positions: a locked position where the pin secures the receivers together, and an unlocked position where the pin allows controlled separation. This segmentation enables clear distinction between secured and unsecured states, eliminating ambiguous intermediate positions
2Ease of repair
If the takedown pin is axially-disengaged to allow receiver separation, then maintenance access is improved, but the number of steps and time required increases
Solution Approach 1:
The rotational mechanism allows rapid transition between locked and unlocked states through simple rotation rather than complex axial disengagement. This dynamic action significantly reduces the time and steps required to access internal components for maintenance while maintaining secure engagement during operation
3Reliability
If the takedown pin system allows controlled pivoting without axial disengagement, then safety is enhanced, but the device complexity increases
Solution Approach 1:
The system uses a simple rotational degree of freedom instead of complex multi-component mechanisms. The takedown pin rotates within its housing to engage or disengage the detent, providing controlled pivoting capability with minimal additional complexity compared to traditional axial disengagement systems
Solution Approach 2:
The detent and detent track system provides automatic engagement and disengagement through the rotational motion of the takedown pin. The mechanism self-locks in the secured position and self-unlocks when rotated, eliminating the need for additional control components or complex actuation systems
Data Source
AI summary
A takedown pin system may be used for the processes of securing, semi-securing, and/or un-securing the rear connection points of firearm lower and upper receivers, for example, of an AR-15, with an option to maintain axial engagement of the pin to the receivers throughout two or more of the processes. An enhanced pin detent track allows pin rotation when axially-engaged in the receivers. A narrow pin body portion, for example, a recessed side surface portion or a narrow flange, cooperates with the pin hole and/or a slot in an upper receiver rear knuckle. Rotating the pin may locate the recess or flange to make room between the pin and the inner surface(s) of the upper receiver pin hole so the upper receiver can pivot slightly open from the lower receiver. A slot at the bottom of the rear knuckle hole may receive a flange of the takedown pin.