Interruptable Electromagnetic Firearm Trigger With Shot Authorization

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Solution Overview

Problem

Conventional firearm triggers provide fixed mechanical force and displacement profiles that are difficult to adjust dynamically without physical modification, limiting customization and user experience.

Innovation Solution

An electromagnetic trigger mechanism using magnetorheological fluids and electromagnetic actuators to dynamically control trigger pull force and displacement, allowing real-time adjustment through magnetic fields.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If mechanical linkages and springs are used to provide trigger force and displacement profile, then the trigger provides a fixed mechanical force-displacement curve, but the ability to dynamically adjust the force-displacement profile is limited

Engineering Contradiction:
Improveadjustability of force-displacement profileVSAvoidcomplexity of mechanical adjustments
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent replaces traditional mechanical linkages and springs with an electromagnetic actuator system that uses magnetic fields to control trigger force and displacement. This substitution eliminates the need for physical adjustment of mechanical components and enables dynamic control through electrical signals, directly resolving the contradiction between adaptability and device complexity.

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

Solution Approach 2:

The electromagnetic actuator allows dynamic changing of force and displacement parameters through electrical control, enabling the trigger profile to be adjusted without physical modification. This parameter-based control method provides continuous adjustability while maintaining a relatively simple device structure.

Inventive Principle:
Principle #35Parameter changes

2Adaptability or versatility

If set screws, additional springs, or part changes are used to customize trigger force-displacement profile mechanically, then the trigger characteristics can be adjusted, but the adjustment process is time-consuming and requires physical modification

Engineering Contradiction:
Improvecustomization of trigger characteristicsVSAvoidtime for adjustment and physical modification
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The electromagnetic control system replaces mechanical adjustment mechanisms (set screws, springs, part changes) with an electrically controlled actuator. This allows trigger characteristics to be customized instantly through electrical signals without any physical modification or disassembly, eliminating the time loss associated with mechanical adjustments.

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

Solution Approach 2:

The system can pre-program multiple trigger profiles and switch between them instantly, allowing users to have trigger characteristics prepared in advance and selected without adjustment time. This preliminary preparation of multiple profiles through software eliminates the need for physical reconfiguration.

Inventive Principle:
Principle #10Preliminary action

3Ease of operation

If electromagnetic actuators and magnetorheological fluids are used to dynamically control trigger pull force, then real-time adjustment is enabled, but the device complexity increases

Engineering Contradiction:
Improvereal-time adjustment capabilityVSAvoidcomplexity of electromagnetic control system
Core Design Contradiction:
Ease of operationVSDevice complexity

Solution Approach 1:

The magnetorheological fluid changes its rheological properties (viscosity, yield stress) in response to magnetic field strength, enabling real-time adjustment of trigger pull force. This parameter-based control through magnetic fields provides ease of operation while the integration into the actuator design manages the complexity of the electromagnetic system.

Inventive Principle:
Principle #35Parameter changes

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

Enables a wide range of customizable trigger feel and safety features, improving accuracy, safety, and user experience by tailoring the force-displacement curve to individual preferences and situations.

Implementation Method 1

An electromagnetic actuator with a single closed magnetic flux loop provides a static or fixed magnetic field to a magnetorheological fluid that directly constrains movement of a trigger linkage

Methodology Applied
Scientific EffectMagnetorheological effect: Magnetorheological Fluid

Implementation Method 2

An electromagnetic actuator with a single closed magnetic flux loop provides a static or fixed magnetic field to a magnetorheological fluid

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4168728B1Electromagnetic firing system for firearm with interruptable trigger control
Publication Date: 2025.10.29 STURM RUGER & CO INC
  • EP4168728B1 patent drawingFigure 1
  • EP4168728B1 patent drawingFigure 2A
  • EP4168728B1 patent drawingFigure 2B~2D

AI summary

An interruptible electronic trigger system for firearms includes a trigger unit comprising an electromagnetic actuator operably coupled to the firing mechanism and a programmable trigger microcontroller. The actuator is changeable between a non-powered unactuated position and powered actuated firing position. Upon detecting user initiated trigger activity, the trigger microcontroller transmits a shot initiated signal to an adaptive optics unit of a fire control targeting system mounted to the firearm when the trigger activity exceeds a preprogrammed trigger setpoint. A targeting microcontroller returns a shot authorization signal to the trigger microcontroller after performing ballistics computations based on sensor input and displaying a corrected reticle on the optics unit sight for user visual alignment with the target. Multiple trigger setpoints may be programmed to confirm continued intent to fire. The trigger microcontroller may deactivate the actuator and permit manual firing when preprogrammed maximum trigger force/displacement limits are exceeded.