Decocking Safety Lever for External Hammer Shotgun

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Solution Overview

Problem

Break-open shotguns lack an effective safety mechanism to prevent unwanted discharge, especially when the safety lever fails or is disengaged, leading to potential accidental firings due to the hammer remaining in a cocked position, which is exacerbated in hammerless designs where the firing mechanism is internal and not visually accessible.

Innovation Solution

A decocking safety lever is introduced, allowing the shotgun to be selectively positioned in safe, fire, or decocked states, with a safety rod that engages cammed sears to prevent hammer release, ensuring the hammer remains decocked even upon impact or drop, thus preventing accidental firings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a traditional safety lever is used to prevent unwanted firing, then the trigger cannot be squeezed, but the hammer remains cocked and can still strike the striking pin upon impact or dropping

Engineering Contradiction:

Improveprevention of unwanted firingVSAvoidaccidental discharge due to hammer impact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The safety mechanism is segmented into two independent functions: (1) a safety lever that prevents trigger squeezing, and (2) a decocking mechanism that lowers the hammer to a safe position. This segmentation ensures that even if one function fails, the other provides protection against accidental discharge.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The decocking mechanism performs a preliminary action by lowering the hammer to a decocked position before firing. This preliminary positioning of the hammer eliminates the hazard of accidental discharge from impact, while the safety lever provides a secondary layer of protection by preventing trigger activation.

Inventive Principle:

Principle #10Preliminary action

2Shape

If the shotgun uses a hammerless design with internal firing mechanism, then the firearm has a more streamlined appearance, but the user cannot visually see whether hammers are cocked or shells are loaded

Engineering Contradiction:

Improvestreamlined appearanceVSAvoidvisual detection of hammer and shell status

Core Design Contradiction:

ShapeVSDifficulty of detecting and measuring

Solution Approach 1:

The patent employs visual indicators (such as color-coded markings or transparent portions) on the receiver or safety mechanism that change appearance based on the hammer position and shell loading status. This allows users to visually detect the firearm's state without exposing the internal hammerless mechanism, maintaining the streamlined appearance while improving detectability.

Inventive Principle:

Principle #32Color changes

3Ease of operation

If the safety lever is disengaged or fails, then the shotgun returns to fire position, but the cocked hammer can still cause unintentional release and firing

Engineering Contradiction:

Improvesafety lever disengagementVSAvoidprevention of unintentional release

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The decocking mechanism serves as an intermediary between the safety lever and the hammer. Even when the safety lever is disengaged or fails, the decocked hammer position acts as an intermediate safe state that prevents direct contact between the hammer and striking pin, thereby maintaining reliability during safety lever transitions or failures.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS10451371B2Shotgun with decocking mechanism

Publication Date: 2019.10.22 AMERICAN TACTICAL INC

AI summary

A decocking safety lever for use with an external hammer shotgun includes a safety rod selectively positionable between a safe position wherein squeezing of the trigger is prevented; a fire position wherein squeezing of the trigger fires a shotgun shell; and a decocked positioned wherein the hammer is positioned in a decocked position and unable to fire the shotgun shell.