Two-Stage Trigger with Adjustable Sear Bearing and Safety
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional two-stage triggers in rifles suffer from trigger creep, limited adjustability for trigger-pull weight, and inconvenient safety selector placement, which hinders precision marksmanship and safety, while single-stage triggers are prone to accidental discharge due to fine engagement between the trigger and sear.
Innovation Solution
A novel two-stage trigger design with a large sear bearing area and adjustable second stage let-off using a spring-plunger, combined with a conveniently located safety selector that blocks trigger movement when in the 'safe' position, ensuring a crisp, clean pull without creep and preventing accidental discharges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-stage trigger is used, then the trigger prevents accidental discharge through robust engagement, but the trigger exhibits creep during the second stage pull
Solution Approach 1:
The trigger pull is divided into two distinct stages with different engagement characteristics. The first stage uses a large bearing area for robust engagement and creep-free pull, while the second stage transitions to a smaller bearing area that allows controlled movement. This segmentation resolves the contradiction by providing both reliability in the first stage and precision control in the second stage.
Solution Approach 2:
Different portions of the trigger-sear engagement interface have different bearing areas. The first stage engagement uses a large bearing area for stability and creep prevention, while the second stage engagement uses a smaller bearing area for controlled movement and precision. This local differentiation allows the same trigger mechanism to provide both reliability and precision at different stages of operation.
2Force
If the trigger engagement between trigger and sear is made fine, then the trigger pull weight is reduced, but the trigger becomes prone to accidental discharge
Solution Approach 1:
The trigger-sear engagement is dynamic, transitioning from a large bearing area in the first stage to a smaller bearing area in the second stage. This dynamic adjustment allows the system to start with robust engagement for reliability, then transition to finer engagement for reduced pull weight and increased sensitivity in the second stage.
3Reliability
If the safety selector is placed on the bolt-sleeve, then the safety function is achieved, but the shooter's aim is disturbed when operating the safety
Solution Approach 1:
The safety selector is moved from a vertical position on the bolt-sleeve to a horizontal position on the stock, changing the dimension of operation. This allows the safety to be operated laterally without disturbing the vertical line of sight, resolving the contradiction between safety function and ease of operation during aim.
4Reliability
If the trigger uses a large sear bearing area, then the trigger is safe from accidental discharge, but the trigger pull weight increases
Solution Approach 1:
The trigger pull is segmented into two stages with different bearing area characteristics. The first stage uses a large bearing area for safety and creep-free operation, while the second stage transitions to a smaller bearing area that reduces the overall pull weight required. This segmentation allows the system to achieve both safety and reduced pull weight.
Solution Approach 2:
The bearing area of the trigger-sear engagement is dynamic, changing from large in the first stage to small in the second stage. This dynamic transition allows the system to start with robust engagement for safety, then reduce the bearing area to lower the pull weight and increase sensitivity as needed.
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 novel trigger provides a safe, crisp, and adjustable trigger pull, eliminating creep and accidental discharges, while allowing for easy and silent safety selector operation without disturbing the shooter's aim, and all components are easily mass-produced and interchangeable.
Implementation Method 1
adjustable second stage let-off using a spring-plunger
Implementation Method 2
safety shoe positively engages the trigger to prevent the trigger from moving
Data Source
AI summary
There is disclosed a two-stage trigger with a large trigger/sear bearing area and an optimized sear loading angle that provides a lightweight trigger-pull. There is further disclosed a safety that blocks rotation of the trigger.