Dual Locking Barrel Nut for Free Float Handguard Mounting

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Solution Overview

Problem

Bolt action rifles with screw-in barrels face challenges in securely mounting free floating tubular handguards, requiring additional material and complexity, whereas AR-15 rifles have a simpler and more rigid mounting system that is not compatible with bolt action rifles.

Innovation Solution

A dual locking barrel nut system, comprising a primary and secondary barrel nut, allows for the secure attachment of AR-15 style free floating tubular handguards to bolt action rifles, providing improved rigidity and a wider range of handguard options by creating a tighter and more stable barrel to receiver interface.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a traditional jam nut system is used to secure the barrel to the receiver in bolt action rifles, then the barrel can be held in place with simple components, but the mounting of free floating tubular handguards becomes complex requiring additional material and parts

Engineering Contradiction:
Improvehandguard mounting complexityVSAvoidadditional material and parts
Core Design Contradiction:
Device complexityVSQuantity of substance

Solution Approach 1:

The barrel nut is designed to perform multiple functions: securing the barrel to the receiver and providing a mounting interface for the handguard. By integrating the handguard mounting function into the barrel nut itself, the patent eliminates the need for separate mounting components, thereby reducing device complexity and material quantity while maintaining secure handguard attachment

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent combines the barrel securing function and handguard mounting function into a single integrated barrel nut assembly. This merging of functions allows the handguard to be mounted directly to the barrel nut without requiring additional brackets, adapters, or mounting parts, thus resolving the contradiction between simplicity and material requirements

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If AR-15 style barrel nut with castellations is used directly on bolt action rifles, then handguard mounting is simplified, but the screw-in barrel interface is incompatible with the slide-in barrel design

Engineering Contradiction:
Improvehandguard mounting compatibilityVSAvoidbarrel to receiver interface
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The barrel assembly is segmented into distinct functional components: the screw-in barrel interface for bolt action rifles, the barrel nut with castellations for handguard mounting, and the connection mechanism. This segmentation allows each component to be optimized for its specific function while working together as an integrated system, enabling AR-15 style handguard compatibility without compromising the screw-in barrel interface

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The barrel nut acts as an intermediary component that bridges the incompatible interfaces between screw-in bolt action barrels and AR-15 style handguards. By introducing this intermediate element with threaded engagement for the barrel and castellation for the handguard, the patent enables compatibility between otherwise incompatible systems without requiring modification to the barrel or handguard

Inventive Principle:
Principle #24Intermediary (Mediator)

3Manufacturing precision

If a secure barrel to receiver interface is achieved with precise machining, then tight headspace dimensions are maintained, but the mounting of handguards requires additional parts adding weight and complexity

Engineering Contradiction:
Improveheadspace dimensionsVSAvoidmounting parts and material
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The barrel nut is designed as a multi-functional component that maintains precise headspace dimensions through its threaded engagement with the barrel while simultaneously providing a mounting interface for the handguard. This eliminates the need for separate mounting parts, reducing overall device complexity and weight while preserving manufacturing precision requirements

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP3212947B1Firearm with tubular handguard mounting system
Publication Date: 2019.09.25 STURM RUGER & CO INC
  • EP3212947B1 patent drawingFigure 1
  • EP3212947B1 patent drawingFigure 2
  • EP3212947B1 patent drawingFigure 3

AI summary

A firearm with tubular handguard mounting system is provided. The firearm includes receiver, a barrel having a breech threadably engaging the receiver, and a handguard. A primary barrel nut threadably engages the breech end of the barrel and is moveable into abutting contact with the receiver to form a tightened barrel to receiver connection. A secondary barrel nut threadably engages the primary barrel nut and is tightened thereto to trap an external annular barrel flange between the primary barrel nut and an annular abutment surface on the secondary barrel nut. The secondary barrel nut provides a means for mounting a free float tubular handguard, such as an AR-15 type handguard. Additionally, the primary barrel nut and secondary barrel nut provide a dual locking feature which resists loosening of the barrel connection.