Firearm Trigger Sear Asymmetry for Sear Flutter Reduction
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Solution Overview
Problem
Firearms, particularly semi-automatics, suffer from 'sear flutter' issues, which render them unusable, and current trigger configurations can lead to trigger detachment due to loose attachment pins, complicating user preferences for trigger feel and accuracy.
Innovation Solution
A firearm design featuring a trigger assembly with a sear and sear spring that rotates between pivotal positions, utilizing a fulcrum and camming surface to control trigger pull weight, and incorporating a rearward stop shoulder to prevent trigger bar pin force exertion, ensuring reliable operation and accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the sear spring weight is increased to reduce sear flutter, then the reliability of the firearm is improved, but the maximum trigger pull weight increases greatly
Solution Approach 1:
The patent applies parameter changes by modifying the sear geometry parameters (camming surface angle, fulcrum position, sear length) to alter the mechanical advantage and force distribution. This allows the sear spring weight to be increased for reliability while the trigger pull weight remains controlled through optimized geometric parameters
2Ease of operation
If the trigger pull weight is reduced to improve user preference and accuracy, then the ease of operation is improved, but the reliability decreases due to increased sear flutter
Solution Approach 1:
The patent optimizes geometric parameters including camming surface angle (20-45 degrees), fulcrum position (30-70% from sear tip), and sear length to achieve a balance where moderate trigger pull weights (1.5-3.0 pounds) are maintained while reducing sear flutter through improved mechanical advantage and reduced lateral forces
Solution Approach 2:
The sear is designed with asymmetric geometry where the camming surface angle and fulcrum positioning create different mechanical advantages for the trigger pull direction versus the sear retention direction. This asymmetry allows light trigger pulls while maintaining strong sear engagement and minimizing flutter
3Adaptability or versatility
If the trigger attachment pin is made loose to allow adjustment, then the adaptability is improved, but the reliability deteriorates due to trigger detachment
Solution Approach 1:
The trigger attachment system employs a dynamic retention mechanism where the pin is secured through engagement with recesses or detents in the trigger body and frame. This allows the pin to remain firmly attached during operation while permitting controlled removal and repositioning for adjustment, balancing security with adaptability
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 design reduces the likelihood of sear flutter and prevents trigger detachment by managing trigger pull weight and maintaining trigger assembly integrity, enhancing user experience and firearm reliability.
Implementation Method 1
the sear spring can be configured to bias the sear in the first pivotal position
Implementation Method 2
utilizing a fulcrum and camming surface to control trigger pull weight
Data Source
AI summary
A firing mechanism for a firearm is provided for reducing maximum trigger pull weight attributable to a sear and for reducing trigger pre-travel and over-travel distances. By this, the likelihood of sear flutter phenomena is greatly reduced while also decreasing or maintaining maximum trigger pull weight. Also, hand movement during firing is reduced helping to increase accuracy.