Firearm Trigger Mechanism with Adjustable Sear Engagement

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Solution Overview

Problem

Existing trigger mechanisms for firearms are limited to either single-stage or two-stage operation and do not allow for a wide range of user choice in trigger weight, pull, and travel, lacking flexibility to accommodate different user preferences and circumstances, and they do not inherently provide safety features to prevent unintentional firing.

Innovation Solution

A trigger mechanism with a top sear, transfer arm, safety lever, and second stage sear, along with a reset spring, first and second stage springs, and a selector pin, allowing for both single-stage and two-stage operations, and enhanced safety features to prevent accidental firing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a trigger mechanism is designed for single-stage or two-stage operation with fixed geometry, then the structure is simple and easy to manufacture, but the range of trigger pull weights and travel is limited and cannot accommodate different user preferences

Engineering Contradiction:

Improverange of trigger pull weights and travelVSAvoidtrigger mechanism structure

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic trigger mechanism where the sear engagement point can be adjusted along the travel path of the trigger. This allows the trigger to transition between single-stage and two-stage operations, and enables continuous adjustment of trigger pull weight and travel distance without requiring complete redesign of the mechanism geometry.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The trigger mechanism is divided into distinct functional segments: a first stage spring for initial trigger movement, a second stage spring for additional resistance, and an adjustable sear engagement point. This segmentation allows independent adjustment of each stage's characteristics, providing wide range of trigger pull weights and travel while maintaining manageable structural complexity.

Inventive Principle:

Principle #1Segmentation

2Reliability

If traditional safety mechanisms are added to prevent unintentional firing, then safety is improved, but the trigger mechanism complexity increases and the trigger pull characteristics are compromised

Engineering Contradiction:

Improvesafety against unintentional firingVSAvoidtrigger mechanism structure

Core Design Contradiction:

ReliabilityVSDevice complexity

Solution Approach 1:

The patent incorporates a safety lever that must be manually engaged before the trigger can release the sear. This preliminary safety action is integrated into the trigger mechanism itself rather than being a separate device, and it works in conjunction with the adjustable sear engagement point to provide safety without compromising trigger pull characteristics or significantly increasing complexity.

Inventive Principle:

Principle #10Preliminary action

3Adaptability or versatility

If the receiver or trigger is removed to affect significant changes in trigger weight, pull or travel, then the range of adjustment is improved, but the ease of operation and assembly is worsened

Engineering Contradiction:

Improveadjustment range of trigger weight, pull or travelVSAvoidassembly and adjustment convenience

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The patent designs the trigger mechanism with an adjustable sear engagement point that can be modified by the user through simple manipulation of existing components within the assembled mechanism. The adjustment mechanism allows users to change trigger pull characteristics without requiring removal of the receiver or trigger from the firearm, making the system self-adjusting and easy to operate.

Inventive Principle:

Principle #25Self-service

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 mechanism provides flexibility in trigger operation modes and enhanced safety by allowing precise tuning of trigger pull resistance and preventing unintentional firing, accommodating various user preferences and ensuring safety against accidental discharge.

Implementation Method 1

A reset spring biases the transfer arm

Methodology Applied

Scientific EffectElasticity: Elasticity

Implementation Method 2

A single stage operation involves both a first stage spring and second stage spring upon trigger load application. In a two-stage operation, the first stage spring is engaged and then the second stage spring is also engaged

Methodology Applied

Scientific EffectSpring force: Spring

Data Source

PatentUS11982504B2Single-stage and two-stage trigger mechanism for a firearm

Publication Date: 2024.05.14 CADEQUIP INC

AI summary

A trigger mechanism has a top sear for engaging a cocking piece, a transfer arm for engaging the top sear, and a safety lever and second stage sear which engages the transfer arm. The safety lever prevents unintentional firing of a firearm with the trigger mechanism. A bottom sear cooperates with the safety lever and the second stage sear. A single stage operation involves both a first stage spring and second stage spring upon trigger load application. In a two-stage operation, the first stage spring is engaged and then the second stage spring is also engaged. A selector pin provides flexibility to alter the mode of operation of the trigger mechanism between single stage trigger operation and a double stage trigger operation.