Firearm Trigger Mechanism Reset Lever Design
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Solution Overview
Problem
Conventional trigger mechanisms in semi-automatic firearms cause discomfort due to the sharp trigger snap and limit the speed of repeated fire due to the hammer's over-travel from the cocked to past-cocked position, affecting accuracy and shooter comfort.
Innovation Solution
A trigger mechanism with a reset lever and disconnector assembly that isolates the hammer from the trigger disconnector assembly in the past-cocked position, using a spring to maintain tension and facilitate a controlled trigger pull by pivoting the reset lever to position the trigger nose and disconnector hook effectively, reducing the trigger snap and improving the hammer reset speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the hammer is returned to the cocked position by the bolt carrier, then the trigger mechanism is reset for the next shot, but the sear hook strikes the hammer-receiving surface of the disconnector causing a sharp trigger snap that can cause injury to the operator's finger
Solution Approach 1:
A reset lever is introduced as an intermediary component between the hammer and the disconnector. The reset lever receives the blow from the hammer in the past-cocked position and uses this energy to pivot the trigger disconnector assembly, thereby mediating the interaction and eliminating the harmful direct strike that causes trigger snap.
Solution Approach 2:
The reset lever is positioned to engage the hammer in the past-cocked position before the hammer can strike the disconnector. By intercepting the hammer's motion preliminarily and redirecting it through the reset lever, the system prevents the harmful strike from occurring in the first place.
2Ease of operation
If the trigger nose resets into the trigger notch of the hammer, then the hammer is prepared for firing by another trigger pull, but there is a substantial pause as the hammer travels rearwardly from the cocked position to the past-cocked position and then forwardly, which limits the speed of repeated trigger pulls
Solution Approach 1:
The reset lever is actuated in the past-cocked position, before the hammer completes its return to the cocked position. This preliminary action initiates the trigger disconnector assembly's movement early in the hammer's rearward travel, reducing the overall pause time and enabling faster repeated firing.
Solution Approach 2:
The reset lever maintains continuous engagement with the hammer throughout the hammer's rearward and forward movement, ensuring that the trigger disconnector assembly is constantly being positioned. This continuous action eliminates idle pause periods and maintains useful motion throughout the reset cycle.
3Device complexity
If the pull of the trigger occurs in one uncontrolled stroke, then the trigger mechanism is simple, but the trigger snap can compromise aim and lead to missed shots, especially when shooting at targets at long distances
Solution Approach 1:
The trigger pull is segmented into two distinct stages: a first stage where the trigger disconnector assembly pivots from the charged to discharged orientation, and a second stage where the trigger nose engages the trigger notch. This segmentation allows the trigger snap to occur in a controlled manner during the second stage, preventing aim compromise while maintaining reasonable mechanism complexity.
Solution Approach 2:
The trigger disconnector assembly is preliminarily positioned in the charged orientation before the trigger pull begins. This preliminary positioning ensures that when the trigger is pulled, the system is already prepared to execute the controlled two-stage sequence, improving aim accuracy without requiring complex additional mechanisms.
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 solution reduces trigger snap, enhances accuracy by allowing a controlled trigger pull, and increases the speed of repeated fire, providing comfort to the shooter and improving shooting performance.
Implementation Method 1
A spring keeps tension on the reset lever urging the reset lever toward the closed position
Data Source
AI summary
A trigger mechanism includes a trigger assembly having a trigger nose and a preparator. A hammer includes a striking end. The hammer pivots about a hammer pivot between a cocked position of the hammer and a firing position of the hammer. The trigger assembly is mounted for movement between a charged stage, a partially discharged stage, and a fully discharged stage. The trigger nose is engaged to the hammer holding the hammer in the cocked position, in the charged stage. The trigger nose is released from the hammer, and the preparator is engaged to the hammer holding the hammer in the cocked position, in the partially discharged stage. The preparator is released from the hammer, in the fully discharged stage.