Variable Force Trigger Mechanism Using Magnetic Field Control

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Solution Overview

Problem

Traditional firearm triggers have fixed mechanical linkages and springs that limit the adjustability of trigger pull force and displacement profiles, making it difficult to customize the firing experience for different applications and user preferences.

Innovation Solution

An electromagnetically variable trigger mechanism that allows electronic adjustment of trigger pull force and displacement profiles using a programmable microcontroller, magnetorheological fluids, and electromagnetic actuators, enabling dynamic and customizable resistance changes during the trigger pull event.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional mechanical linkages and springs are used in trigger mechanisms, then the structure is simple and reliable, but the trigger pull force and displacement profiles are fixed and cannot be customized

Engineering Contradiction:
Improvetrigger pull force adjustabilityVSAvoidmechanical linkage complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical spring-based resistance mechanisms with an electromagnetic actuator system. The actuator uses electromagnetic fields to generate adjustable resistance forces on the trigger member, eliminating the need for complex mechanical linkages and multiple springs while enabling electronic customization of trigger pull characteristics.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The electromagnetic actuator allows dynamic adjustment of trigger pull force and displacement profiles by changing electromagnetic field parameters through electronic control. A microcontroller can modify current, voltage, or pulse width to vary the resistance characteristics in real-time, providing customizable trigger experiences without physical reconfiguration.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If electromagnetic actuators and magnetorheological fluids are used to enable dynamic trigger adjustment, then trigger pull force and displacement profiles become highly customizable, but the device complexity and manufacturing cost increase

Engineering Contradiction:
Improvetrigger profile customizationVSAvoidmanufacturing complexity
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent incorporates magnetorheological fluid, a smart material that changes its rheological properties in response to magnetic fields. This fluid is used within the electromagnetic actuator to provide variable resistance characteristics. The fluid-based approach allows smooth, continuous adjustment of trigger properties without complex mechanical components, simplifying assembly while maintaining high adaptability.

Inventive Principle:
Principle #29Pneumatics and hydraulics

3Ease of operation

If fixed mechanical springs are used, then the trigger mechanism is reliable and easy to maintain, but the trigger resistance cannot be varied during the pull event

Engineering Contradiction:
Improveuser comfort and safetyVSAvoidelectronic control system complexity
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The patent implements a feedback control system where sensors monitor trigger member position, force applied, and actuator performance in real-time. The microcontroller processes this feedback data and dynamically adjusts electromagnetic actuator output to maintain desired trigger pull characteristics, ensuring consistent user experience and safety while accommodating variations in shooting conditions or user preferences.

Inventive Principle:
Principle #23Feedback

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

Provides a highly customizable and adjustable trigger pull experience, enhancing user safety, accuracy, and comfort by allowing real-time variation of trigger resistance, suitable for various firearms and shooting scenarios.

Implementation Method 1

a permanent magnet generating a static magnetic field in the stationary yoke and rotating member, the static magnetic field creating a primary resistance force opposing movement of the trigger when pulled by the user

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

the electromagnet coil when energized generating a user-adjustable secondary magnetic field interacting with the static magnetic field, the secondary magnetic field operating to change the primary resistance force dynamically during a trigger pull event initiated by the user

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

An electromagnetically variable firing system for a firearm according to the present disclosure includes a trigger assembly or mechanism having an electromagnetically-operated control device which allows the user to preselect and adjust the trigger pull force-displacement profile electronically

Methodology Applied
Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Data Source

PatentEP3759414B1Variable force trigger mechanism for firearms
Publication Date: 2023.03.29 STURM RUGER & CO INC
  • EP3759414B1 patent drawingFigure 1
  • EP3759414B1 patent drawingFigure 2A
  • EP3759414B1 patent drawingFigure 2B~2D

AI summary

A magnetically variable firing system for a firearm includes a trigger mechanism allowing a user to selectively adjust the trigger pull force-displacement profile by changing the static magnetic field in the mechanism. In a closed magnetic loop configuration, the trigger mechanism includes a stationary yoke and pivotably movable trigger member. The trigger member includes a trigger portion and working portion operably interfaced with the firing mechanism of the firearm for discharging the firearm. An openable first air gap formed between the trigger member and yoke is maintained in a closed position via magnetic attraction therebetween absent a trigger pull. A control insert movable relative to a second control air gap in the yoke allows adjustment of the static magnetic field to alter the trigger pull force required to actuate the trigger mechanism. Other embodiments provide an open magnetic loop trigger mechanism design adjustable to magnetically vary the trigger pull force.