Compact Two-Stage Trigger Mechanism With Adjustable Pull Weight

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Solution Overview

Problem

Existing two-stage triggers are complex and require additional space, making them impractical for firearms with limited space, and there is a need for a more compact and adjustable trigger mechanism that maintains safety and accuracy.

Innovation Solution

A trigger device with a housing, a trigger, a reverser, a ticker, and adjustable pull weight mechanisms that allow for a two-stage trigger operation, featuring a first pull weight adjustment mechanism to bias the trigger and reverser, and a second pull weight mechanism to maintain the sear in a loaded position, with a ticker that rotates at a predefined tipping point.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a two-stage trigger mechanism is implemented to provide adjustable pull loads and enhance safety, then safety and accuracy are improved, but device complexity and space requirements increase

Engineering Contradiction:
ImprovesafetyVSAvoidtrigger mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines the trigger and reverser into a single integrated assembly that rotates together as one unit. The trigger tooth and reverser tooth are formed as integral parts of the same rotating component, eliminating the need for separate trigger and reverser mechanisms while maintaining the two-stage firing function. This merging reduces the number of parts and simplifies the overall device structure.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The trigger-reverser assembly serves multiple functions simultaneously: it provides the two-stage trigger operation, houses the adjustable pull weight mechanisms, and incorporates the sear engagement and disengagement functions. The single rotating component performs what would traditionally require multiple separate mechanisms, reducing complexity while maintaining safety and functionality.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If a two-stage trigger mechanism is implemented to provide adjustable pull loads, then safety and accuracy are improved, but the space required in the firearm increases

Engineering Contradiction:
ImprovesafetyVSAvoidtrigger mechanism volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

By merging the trigger and reverser into a single rotating assembly, the patent significantly reduces the volume required for the trigger mechanism. The integrated design eliminates gaps and spacing requirements between separate components, allowing the entire two-stage mechanism to occupy a compact space within the firearm.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The adjustable pull weight mechanisms are nested within the trigger-reverser assembly housing. The first and second pull weight adjustment mechanisms are contained within the same structural envelope as the trigger-reverser, allowing multiple functional elements to be nested within a compact volume rather than requiring separate spaces for each component.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Reliability

If spring bias is increased to prevent accidental firing, then safety is improved, but the trigger pull load becomes excessively large affecting accuracy

Engineering Contradiction:
ImprovesafetyVSAvoidtrigger pull load
Core Design Contradiction:
ReliabilityVSForce

Solution Approach 1:

The patent segments the trigger pull force requirement into two distinct stages with different force levels. The first stage requires a relatively light pull to rotate the trigger-reverser assembly to the engagement position, while the second stage requires a heavier pull to overcome the sear bias and fire the weapon. This segmentation allows safety (preventing accidental firing) to be achieved through the sear engagement mechanism rather than through excessive spring bias, maintaining accuracy by keeping the first stage pull load manageable.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The trigger mechanism transitions from a static spring-bias system to a dynamic two-stage system where the required force changes during operation. The first stage operates with lower force to position the trigger-reverser assembly, then encounters increased resistance at the second stage when the sear must be disengaged. This dynamic force profile allows safety to be maintained through the mechanical engagement design rather than through uniformly high spring bias, preserving shooting accuracy.

Inventive Principle:
Principle #15Dynamics

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 device provides a compact two-stage trigger mechanism that allows for adjustable pull loads, enhances safety by preventing accidental firing, and reduces the size of components, while maintaining accuracy and ease of use.

Implementation Method 1

a first pull weight adjustment mechanism coupled between the trigger and the reverser to bias the trigger in a first direction and the reverser in an opposite direction

Methodology Applied
Scientific EffectSpring bias: Spring

Implementation Method 2

actuation of the trigger causes the trigger to rotate in the opposite direction, the trigger tooth to engage the reverser tooth, and the reverser to rotate in the first direction

Methodology Applied
Scientific EffectMechanical engagement: Gear

Data Source

PatentEP3987241B1Trigger device
Publication Date: 2026.01.07 2360216 ONTARIO
  • EP3987241B1 patent drawingFigure 1a
  • EP3987241B1 patent drawingFigure 1b
  • EP3987241B1 patent drawingFigure 1c

AI summary

A trigger device is disclosed. The trigger device comprises a housing, a trigger, a reverser, and a first pull wight adjustment mechanism. The trigger is rotatably mounted in the housing via a trigger pivot pin. The trigger comprises a trigger tooth. The reverser is rotatably mounted in the housing via a reverser pivot pin. The reverser comprises a reverser tooth. The first pull weight adjustment mechanism is coupled between the trigger and the reverser to bias the trigger in a first direction and the reverser in an opposite direction. Actuation of the trigger causes the trigger to rotate in the opposite direction, the trigger tooth to engage the reverser tooth, and the reverser to rotate in the first direction.