Quick-Connect Muzzle Accessory With Keyed Locking Alignment

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Solution Overview

Problem

Existing methods for attaching muzzle accessories to firearm barrels are time-consuming, require specialized tools, and are not suitable for frequent removal and replacement, often leading to damage and inefficiency.

Innovation Solution

A muzzle accessory assembly featuring a biased detent assembly and a lock mechanism that allows for quick and easy alignment and installation without specialized tools, using a keyed bore and lugs to secure the accessory to the firearm barrel, with a spirally-extending slot providing frictional locking.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If threaded holes and high torque are used to attach muzzle accessories, then the attachment is secure and reliable, but the installation requires specialized tools and bracing equipment, and is time-consuming

Engineering Contradiction:
Improveattachment securityVSAvoidinstallation convenience
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The attachment system is segmented into a quick-release mechanism with separate locking components. The muzzle accessory and firearm barrel are divided into mating parts with keyed interfaces, allowing incremental engagement rather than requiring complete threading and high-torque fastening. This segmentation enables secure attachment through multiple discrete locking points rather than a single high-stress connection.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The attachment system transitions from a static, permanent-looking threaded connection to a dynamic quick-release mechanism. The keyed receptacle and keyed bore allow the accessory to be rapidly engaged and disengaged through rotational motion, converting the attachment process from a time-consuming threading operation into a quick mechanical coupling that maintains security while enabling frequent changes.

Inventive Principle:
Principle #15Dynamics

2Stability of the object's composition

If set screws are used to apply lateral frictional forces, then rotation of muzzle accessories is prevented, but repeated tightening results in stripping of set screws and damage to barrel threads

Engineering Contradiction:
Improverotational stabilityVSAvoidcomponent durability
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

A keyed interface acts as an intermediary between the muzzle accessory and barrel, providing a positive mechanical engagement that prevents rotation without relying on friction from repeatedly tightened set screws. The keyed receptacle and keyed bore create a geometric fit that mechanically locks the accessory in place, distributing stresses across the keyed interface rather than concentrating them on set screw threads.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The system replaces the friction-based set screw mechanism with a positive mechanical locking system using keyed interfaces. Instead of relying on lateral frictional forces from set screws that degrade with repeated use, the keyed receptacle and keyed bore create a geometric interlock that provides rotational stability through shape complementarity rather than friction, eliminating wear and stripping issues.

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

3Manufacturing precision

If shims or crush washers are used for alignment, then proper alignment of muzzle accessories is achieved, but new shims/washers and careful alignment are required for each installation

Engineering Contradiction:
Improvealignment accuracyVSAvoidinstallation time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The keyed interface uses asymmetric geometric features (keyed bore and keyed receptacle with specific lug configurations) that provide inherent alignment during engagement. The asymmetric shape of the key and receptacle ensures that the accessory can only be installed in the correct rotational orientation, eliminating the need for shims or washers and providing automatic alignment through the geometric fit itself.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The keyed interface system is self-aligning during installation. The geometric features of the keyed bore and keyed receptacle automatically guide the accessory into proper alignment as it is engaged with the barrel, without requiring external alignment tools, shims, or washers. The system services its own alignment function through its inherent geometric design, reducing installation steps and time.

Inventive Principle:
Principle #25Self-service

4Reliability

If threaded attachment methods are used, then muzzle accessories can be securely attached, but frequent removal and replacement is not suitable due to required retorquing and realignment

Engineering Contradiction:
Improveattachment securityVSAvoidaccessory change frequency
Core Design Contradiction:
ReliabilityVSProductivity

Solution Approach 1:

The attachment system is designed for dynamic reuse with a quick-release mechanism. The keyed interface allows the accessory to be rapidly engaged and disengaged multiple times without degradation of the connection. Each engagement maintains the same secure level of attachment as the first, enabling frequent changes while preserving reliability through consistent geometric locking rather than degrading friction-based connections.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system replaces the irreversible or semi-permanent threaded connection with a reversible mechanical coupling system. The keyed receptacle and keyed bore create a positive mechanical lock that can be quickly engaged and disengaged without the need for retorquing or realignment procedures. This substitution enables frequent accessory changes while maintaining secure attachment through geometric interlocking rather than thread engagement.

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

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 rapid and reliable attachment and detachment of muzzle accessories, preventing inadvertent unlocking and maintaining secure alignment, thus eliminating the need for specialized equipment and reducing wear on the firearm.

Implementation Method 1

a biased detent assembly configured to prevent the lock from being positioned into the unlocked position

Methodology Applied
Scientific EffectMechanical constraint: Mechanical Force

Implementation Method 2

a spirally-extending slot providing frictional locking

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP4400799B1Quick-connect muzzle accessory
Publication Date: 2025.10.15 SHADOW SYSTEMS LLC
  • EP4400799B1 patent drawingFigure 1
  • EP4400799B1 patent drawingFigure 2
  • EP4400799B1 patent drawingFigure 3

AI summary

A muzzle accessory assembly (100) is provided. The assembly includes a muzzle accessory (300) having a main body (400) with a proximal end, a distal end, a through-channel (440) extending longitudinally between the proximal end (405) and the distal end (410), a keyed receptacle (445) within the through-channel, and a slot (430), and a lock (500) within the slot of the main body, the lock being positionable into an unlocked position and a locked position; and a firearm barrel (200) within the through-channel of the main body, the firearm barrel having a chamber for receiving a firearm round, a firing tube extending distally from the chamber, and a coupling engaging the keyed receptacle of the main body, in which the firearm barrel is removable from the through-channel of the main body when the lock is in the unlocked position, and the firearm barrel is locked longitudinally and rotationally within the through-channel of the main body when the lock is in the locked position.