Sporting Firearm Trigger Mechanism with Cam and Spring Adjustment

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Solution Overview

Problem

Conventional firing mechanisms in sporting firearms face challenges in achieving precise, fluid, and safe firing due to friction and wear issues, requiring complex customization and disassembly for optimal settings, with a risk of accidental shots and difficulty in adjusting resistance to the trigger pull.

Innovation Solution

A firing mechanism with a tensioned coil spring and external regulating means, such as a screw, to minimize resistance and friction by calibrating the elastic force, allowing for adjustable trigger sensitivity without disassembly, ensuring sharp and fluid firing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the sears are made very smooth, hardened and mirror polished to reduce friction, then the firing becomes sharper and more fluid, but the overlapping portion of the sears must be minimized which reduces the stability of the locked position

Engineering Contradiction:
Improvefluidity of firingVSAvoidstability of locked position
Core Design Contradiction:
Ease of operationVSStability of the object's composition

Solution Approach 1:

The patent introduces a cam mechanism as an intermediary element between the trigger and the sear release. The cam profile is designed to provide a specific motion path that ensures clean, sharp firing while maintaining stable engagement of the sears during the locked position. This mediator allows the system to achieve both fluid firing and stable locking without requiring minimal overlap.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If the firing mechanism components are made very light to improve responsiveness, then the firing becomes sharper, but the mechanism becomes more sensitive to accidental shots and harder to control

Engineering Contradiction:
Improveresponsiveness of firingVSAvoidsafety against accidental shots
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The patent employs dynamic elements including a cam mechanism with specific motion profiles and spring-loaded components that provide controlled resistance. The cam profile is designed to remain engaged during normal handling but releases cleanly when the trigger is pulled. This dynamic design allows the mechanism to be responsive when needed while resistant to accidental activation.

Inventive Principle:
Principle #15Dynamics

3Force

If the mainspring compression force is increased to ensure reliable firing pin release, then the firing pin strikes the primer with sufficient force, but the friction on the small overlapping portion of the sears increases

Engineering Contradiction:
Improveforce of firing pin impactVSAvoidfriction on sears
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

The cam mechanism serves as a force distribution intermediary. Instead of concentrating the mainspring force on a small overlapping area of the sears, the cam profile distributes this force along a longer engagement path. The cam converts the linear spring force into a controlled rotational motion that maintains steady pressure on the sears throughout the engagement, reducing peak friction while ensuring sufficient force is transmitted to release the firing pin.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Stability of the object's composition

If the sears have substantial overlapping portion to reduce friction, then the firing mechanism is more stable, but the firing becomes less sharp and fluid

Engineering Contradiction:
Improvestability of locked positionVSAvoidsharpness of firing
Core Design Contradiction:
Stability of the object's compositionVSEase of operation

Solution Approach 1:

The cam mechanism introduces dynamic motion characteristics that complement the stable overlapping sear engagement. The cam profile is designed with specific curvature and transition zones that ensure smooth, controlled release of the sears. This allows the system to maintain stable locked position through substantial overlap while achieving sharp firing through the dynamic release motion provided by the cam.

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 mechanism provides a calibrated and adjustable firing mechanism that reduces friction and wear, allowing for precise and safe shooting with minimal resistance, enabling shooters to adjust settings easily and maintain firearm performance over time.

Implementation Method 1

elastic means applied to said release lever, and adapted to oppose the rotation thereof caused by the force exerted by the mainspring on the firing pin held back by the detent pawl

Methodology Applied
Scientific EffectElastic force: Elasticity

Implementation Method 2

the compression force of the mainspring, usually around 15 kg, rests, at least until the time of firing, on an extremely small portion of the overlapping sears, with the risk of friction occurring

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3540360B1Firing mechanism for a sporting firearm
Publication Date: 2020.10.14 PARDINI ARMI SRL
  • EP3540360B1 patent drawingFigure 1
  • EP3540360B1 patent drawingFigure 2
  • EP3540360B1 patent drawingFigure 3

AI summary

The invention relates to a firing mechanism (1) for a sporting firearm (A) of the type comprising a barrel (2) with a chamber, a breech block (3) comprising a firing pin (13) driven by a mainspring (23) and positioned to strike a round of ammunition (M) contained in said chamber, and a firing mechanism (1) adapted to cooperate with said firing pin (13). Said firing mechanism (1) comprises: - a release lever (4) comprising a detent pawl (24) adapted to cooperate reversibly with said firing pin (13); - a trigger (5); - a plurality of levers (6, 7), interposed between said trigger (5) and said release lever (4), adapted, upon activation of said trigger (5), to cause the rotation of said release lever (4) about its fulcrum (14) and to free said firing pin (13); - a containment structure (8) adapted to house said components (4,5,6,7), - elastic means (9) applied to said release lever (4), adapted to oppose the rotation thereof caused by the force exerted by the mainspring (23) on the firing pin (13) held back by the detent pawl (24).