Firearm Selector with Flat Detent Surfaces

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Solution Overview

Problem

Current firearm control mechanisms using spring-loaded detents require precise machining of conical or hemispherical tips and notches, leading to wear issues and a dead zone between mode positions, complicating manufacture and operation.

Innovation Solution

A firearm control mechanism employing flat surfaces on the selector and detent, with a spring-loaded detent having a flat top and perpendicular cam surfaces, allowing for stable positions and biasing the selector towards adjacent modes, reducing wear and improving manufacturability.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring-loaded detent with conical or hemispherical tip is used to control selector rotation, then the selector can be limited to specified angles corresponding to different firing modes, but the manufacture becomes complex requiring specially contoured tips and precise notches in the selector

Engineering Contradiction:

Improveselector rotation controlVSAvoiddetent and selector manufacturing

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

Instead of using a conical or hemispherical detent tip that requires precise machining, the patent inverts the approach by using a flat-faced detent that engages with corresponding flat faces on the selector. This inversion simplifies manufacturing while maintaining reliable angular positioning through the flat-to-flat contact geometry.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent changes the geometric parameters of the detent and selector interfaces from conical/hemispherical surfaces to flat surfaces. This parameter change reduces manufacturing complexity while maintaining the functional requirement of limiting selector rotation to specific angles for different firing modes.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If conical or hemispherical detent tips are used, then selector rotation can be controlled, but wear issues occur between mode positions

Engineering Contradiction:

Improveselector rotation controlVSAvoiddetent wear resistance

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The patent inverts the traditional conical/hemispherical detent geometry to a flat-faced design. This inversion eliminates the wear problems associated with conical surfaces by providing a larger contact area and more uniform stress distribution, thereby extending the operational life of the detent mechanism.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

By changing the surface geometry from conical/hemispherical to flat, the patent improves wear resistance. The flat surfaces provide better contact mechanics that reduce stress concentration and minimize wear between mode positions, ensuring longer durability of the selector mechanism.

Inventive Principle:

Principle #35Parameter changes

3Reliability

If conical or hemispherical detent tips with precise notches are used, then firing mode control is achieved, but a dead zone exists between mode positions

Engineering Contradiction:

Improvefiring mode controlVSAvoidselector operation smoothness

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent inverts the traditional detent geometry to use flat faces instead of conical or hemispherical surfaces. This inversion eliminates the dead zone between mode positions by creating continuous engagement surfaces that provide smooth transitions and eliminate gaps in the selector's rotational path.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

By changing the geometric parameters from conical/hemispherical to flat surfaces, the patent eliminates the dead zone between firing modes. The flat-to-flat contact geometry provides continuous mechanical engagement that ensures smooth selector operation without the gaps or dead zones present in traditional designs.

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

The solution enhances the ease of manufacture and operation by eliminating the dead zone between mode positions, providing a robust and reliable mechanism for switching between firing modes without wear issues.

Implementation Method 1

A spring-loaded detent has a flat top and perpendicular cam surfaces that can be biased against a selector

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS11609056B2Selector for firearms

Publication Date: 2023.03.21 FRANKLIN ARMORY HOLDINGS INC

AI summary

Firearm control mechanisms have a frame, a trigger element connected to the frame and movable with respect to the frame, a selector connected to the frame and pivotable with respect to the frame about a pivot axis, the selector including a first cam surface operably engaged to a follower portion of the trigger element, the selector having a detent portion having a detent surface opposing a spring biased detent follower connected to the frame and operable to reciprocate against the detent surface, the detent surface having a plurality of stable positions, each corresponding to an operating condition of the fire control mechanism, and the detent portion being a body lacking any concave surfaces. The detent surface may have a plurality of flat cam surfaces. At least two of the flat cam surfaces may be perpendicular to each other. A corner may join the plurality of flat cam surfaces.