Half-cock Trigger Safety Assembly for Firearm

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Solution Overview

Problem

Current trigger assemblies for firearms may unintentionally discharge due to reduced friction between the trigger sear surface and hammer sear surface, which can be exacerbated by mechanisms like the 'half-cock' notch, affecting the trigger pull and increasing the risk of accidental discharge.

Innovation Solution

The development of trigger assemblies with a trigger sear surface and hammer sear surface design that includes a significant angular distance between the cocked and safety positions, featuring a trigger safety engagement surface and hammer release barrier surface to prevent unintended hammer rotation, thereby preserving the integrity of the trigger sear surface and reducing the risk of unintentional discharge.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If the trigger sear surface and hammer sear surface are polished to reduce friction, then the force required to pull the trigger is decreased, but the risk of unintentional discharge increases

Engineering Contradiction:

Improvetrigger pull forceVSAvoidunintentional discharge risk

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The hammer's engagement surface is segmented into two distinct zones: a hammer sear surface for engaging the trigger sear surface, and a separate half-cock surface for engaging the trigger safety engagement surface. This segmentation allows independent optimization of each surface's function without compromising the other.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different surface qualities are applied to different regions of the hammer. The hammer sear surface maintains higher friction characteristics for reliable trigger engagement, while the half-cock surface is designed with appropriate friction characteristics for safety engagement, allowing each region to have optimized local properties.

Inventive Principle:

Principle #3Local quality

2Reliability

If a half-cock notch is added to the hammer to prevent unintentional discharge, then safety is improved, but the trigger sear surface integrity is compromised due to repeated engagement

Engineering Contradiction:

Improveunintentional discharge preventionVSAvoidtrigger sear surface integrity

Core Design Contradiction:

ReliabilityVSStability of the object's composition

Solution Approach 1:

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The half-cock safety function is extracted from the original sear engagement mechanism and placed on a separate surface of the hammer. This removes the harmful interaction between the trigger sear surface and the half-cock engagement, allowing the trigger sear surface to maintain its integrity while still providing safety functionality.

Inventive Principle:

Principle #2Taking out (Extraction)

3Stability of the object's composition

If the angular distance between cocked and safety positions is increased, then the trigger sear surface is protected from wear, but the device complexity increases

Engineering Contradiction:

Improvetrigger sear surface integrityVSAvoidhammer rotation mechanism

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The hammer serves multiple functions through its rotational movement: it engages the trigger sear surface for firing, rotates to engage the trigger safety engagement surface for half-cock safety, and can fully rotate to strike the firing pin. This multi-functionality is achieved through the inherent rotational capability of the hammer without requiring additional complex mechanisms.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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

This design reduces the force required to disengage the trigger sear surface from the hammer sear surface while maintaining the surface integrity, thereby enhancing safety by preventing accidental hammer rotation and ensuring a consistent trigger pull.

Implementation Method 1

the hammer is free to rotate forward, under force of a biasing spring

Methodology Applied

Scientific EffectElastic force: Elasticity

Implementation Method 2

overcome the friction between the trigger sear surface and hammer sear surface

Methodology Applied

Scientific EffectFriction: Friction

Data Source

PatentUS10871338B2Half-cock trigger safety assembly

Publication Date: 2020.12.22 SPRINGFIELD INC

AI summary

Trigger assemblies that preserve the integrity of the trigger sear surface when the trigger assembly enters a “half-cocked”, safety configuration are disclosed. In certain embodiments, a trigger safety engagement surface engages a hammer safety engagement surface in the safety configuration, preventing the hammer from rotating into contact with a firing pin. In some instances, the trigger sear surface is suspended within a safety recess (e.g., a notch) of the hammer and free of contact with the hammer when the trigger assembly is in the safety configuration.