Firearm Sear Mechanism Reducing Trigger Pull Force
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Solution Overview
Problem
Current sear mechanisms in firearms require excessive force to trigger discharge and lack tactile feedback, affecting accuracy and reliability.
Innovation Solution
A sear mechanism design featuring a sear lever with a stop surface, a running surface, and an actuator lever with a ramp surface, along with springs to bias these components, providing a pivoting motion that reduces trigger pull force and offers tactile feedback through angular orientations and spring biases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a conventional sear mechanism is used, then the firearm can be discharged, but excessive force is required to pull the trigger
Solution Approach 1:
The sear mechanism is divided into separate functional components: a sear lever with distinct surfaces (engagement surface, running surface, contact surface) and an actuator lever with corresponding surfaces. This segmentation allows each surface to perform a specific function in the trigger activation sequence, reducing the overall force required by distributing the mechanical interaction across multiple controlled contact points.
Solution Approach 2:
The mechanism employs pivoting motion for both the sear lever and actuator lever, transforming the static engagement into a dynamic sequence. The angularly oriented contact surface on the sear lever works with the ramp surface on the actuator lever to create a controlled pivoting action that reduces trigger pull force while maintaining reliable engagement.
2Loss of information
If a conventional sear mechanism is used, then the firearm can be discharged, but tactile feedback is insufficient
Solution Approach 1:
The mechanism incorporates an intermediate actuator lever that provides partial action before full discharge. The ramp surface on the actuator lever engages with the angularly oriented contact surface on the sear lever, creating a progressive tactile feedback sequence that allows the user to sense and control the discharge process more precisely.
Solution Approach 2:
The angularly oriented contact surface on the sear lever works in conjunction with the ramp surface on the actuator lever to provide progressive tactile feedback during trigger activation. This feedback mechanism allows the user to sense the engagement and release sequences, improving control and precision in the discharge process.
3Ease of operation
If the trigger pull force is reduced, then ease of operation improves, but reliability may be compromised
Solution Approach 1:
The mechanism changes the geometric parameters of the contact surfaces, specifically the angular orientation of the contact surface on the sear lever relative to the running surface. This angular orientation, combined with the complementary ramp surface on the actuator lever, allows for reduced trigger pull force while maintaining reliable engagement through optimized mechanical geometry.
Solution Approach 2:
The sear spring provides pre-biasing force on the engagement surface, and the actuator spring provides pre-biasing force on the ramp surface. These spring biases ensure reliable engagement is maintained throughout the reduced trigger pull stroke, cushioning any potential reliability issues that might arise from the lower activation force.
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
This design reduces the force required to pull the trigger while enhancing tactile feedback, improving accuracy and reliability by allowing for a more measured discharge.
Implementation Method 1
A sear spring acts on the sear body to bias the engagement surface toward the stop surface
Implementation Method 2
An actuator spring acts on the actuator lever to bias the ramp surface away from the contact surface
Implementation Method 3
A sear lever mountable on the frame for pivoting motion about a lever axis
Data Source
AI summary
A sear mechanism for a firearm pivotably mounts a sear body on a sear lever which is pivotably mounted on the firearm frame. An actuator lever is also pivotably mounted on the frame. The actuator lever is pivoted by a trigger bar connected to the firearm's trigger. Pivoting of the actuator lever when the trigger is pulled allows the sear lever to pivot. Pivoting of the sear lever allows the sear body to fall off of a surface on a striker, releasing the striker to discharge the firearm.