Auto-Tensioning Trigger Pins for Modular Rifle Assemblies
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Solution Overview
Problem
Modular trigger assemblies for firearms, such as ArmaLite rifles, face issues with pin walk and pin rotation due to standard hammer and trigger pins, leading to potential safety hazards and performance degradation over time, with existing solutions being unsightly, costly, and increasing maintenance complexity.
Innovation Solution
A modular trigger assembly with auto-tensioning hammer and trigger pins featuring telescoping pegs and a tensioning spring, which securely engage with the lower receiver without external components, preventing pin walk and rotation while allowing for rapid installation and removal with minimal tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If standard hammer and trigger pins are used to retain the modular trigger within the lower receiver, then the modular trigger can be installed, but the pins tend to walk and rotate during use, leading to wear and potential safety issues
Solution Approach 1:
The patent applies the dynamics principle by making the pins self-adjusting through telescoping sections that can extend and retract. The inner pin section telescopes within the outer pin section, allowing the pin to dynamically adjust its length and position in response to operational forces, preventing walk and rotation while maintaining secure retention
Solution Approach 2:
The patent implements self-service through auto-tensioning springs that automatically apply tension to the telescoping pin sections. The springs self-regulate the pin's engagement with the receiver, continuously preventing walk and rotation without requiring external intervention or additional retention components
2Reliability
If exterior set screws or anti-rotation devices are added to prevent pin walk and rotation, then pin retention improves, but the design becomes unsightly and more complex with additional catch points
Solution Approach 1:
The patent merges the retention function into the pin itself by integrating telescoping sections and auto-tensioning springs directly into the pin structure. This eliminates the need for separate exterior set screws, anti-rotation devices, or external retention components, simplifying the overall design while maintaining reliability
Solution Approach 2:
The patent applies nesting by placing the inner pin section within the outer pin section, creating a telescoping structure. The spring is nested within the pin housing, and the entire mechanism is contained within the receiver aperture without external protrusions, achieving a clean integrated design
3Reliability
If exterior components are added to prevent pin walk and rotation, then pin retention improves, but maintenance complexity increases and more components can be lost
Solution Approach 1:
By integrating all retention mechanisms (telescoping sections, springs, and locking features) into the pin itself, the patent reduces the number of separate maintenance components. The entire retention system is contained within the pin assembly, reducing the risk of losing small external components during field maintenance
4Ease of manufacture
If pins are allowed to walk and rotate, then installation is simple, but significant slop and movement develop over time affecting rifle performance and safety
Solution Approach 1:
The telescoping pin sections with auto-tensioning springs provide continuous dynamic adjustment that maintains precise trigger positioning. The spring tension constantly pushes the inner pin section against the outer section, preventing any walk or rotation that would compromise positioning accuracy over time
Solution Approach 2:
The patent applies preliminary anti-action by designing the telescoping mechanism with built-in resistance to walk and rotation forces. The spring tension and telescoping friction create preliminary counter-forces that prevent the pin from moving in the first place, maintaining precision without requiring tight tolerances in the receiver aperture
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
The auto-tensioning pins maintain anti-walk and anti-roll properties while being flush with the receiver exterior, enhancing safety and performance by preventing pin-related issues, reducing maintenance complexity, and maintaining a clean, aesthetically pleasing design.
Implementation Method 1
a first auto-tensioning pin having a first pair of telescoping pegs adapted to secure a first portion of the trigger assembly within a lower receiver of a rifle
Data Source
AI summary
A modular trigger assembly having auto-tensioning hammer pin and trigger pins, which allow for rapid installation and removal of the modular trigger assembly from the lower receiver of an ArmaLite style modular rifle using minimal tools. When installed and under tension, the auto-tensioning pins remain flush with the exterior of the lower receiver and present no external parts outside of the lower receiver while maintaining anti-walk and anti-roll properties.