Composite Firearm Barrel Forging Bonding

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Solution Overview

Problem

Conventional composite firearm barrels face challenges in achieving a strong and permanent bond between inner and outer components, leading to potential separation during repeated firearm discharges, and are often labor-intensive and expensive to manufacture.

Innovation Solution

The use of a forging method to integrate a steel inner tube with a lighter-weight outer sleeve, such as aluminum or titanium, where the outer sleeve is forcibly impacted to displace material and bond with the inner tube, creating a secure and durable composite barrel structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If aluminum or synthetic plastic resin outer sleeves are used to reduce barrel weight, then weight is reduced, but bonding strength between inner tube and outer sleeve deteriorates

Engineering Contradiction:
Improvebarrel weightVSAvoidbonding strength
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The invention applies preliminary action by creating protrusions on the inner tube surface before the bonding process. These protrusions are formed in advance to receive and interlock with the outer sleeve material, ensuring strong bonding capability before the actual assembly and bonding operations occur.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention utilizes parameter changes by transforming the physical state and distribution of outer sleeve material through controlled deformation. The material is deformed from a uniform state into a interlocked configuration that fills voids and creates mechanical interlocking with the inner tube, significantly enhancing bonding strength.

Inventive Principle:
Principle #35Parameter changes

2Ease of manufacture

If conventional bonding methods (adhesives, press-fitting, threading, brazing) are used to join inner tube and outer sleeve, then assembly is achieved, but bonding reliability deteriorates under repeated discharge cycles

Engineering Contradiction:
Improveassembly processVSAvoidbonding reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The invention creates a composite material structure where the inner tube and outer sleeve are bonded through a hybrid mechanism combining mechanical interlocking (protrusions receiving material) and metallurgical bonding (heat treatment). This composite approach eliminates the weaknesses of single-method bonding and ensures reliability under repeated discharge cycles.

Inventive Principle:
Principle #40Composite materials

Solution Approach 2:

The protrusions are prepared in advance on the inner tube surface, creating a predetermined bonding architecture that ensures reliable mechanical interlocking before the actual assembly and bonding operations occur.

Inventive Principle:
Principle #10Preliminary action

3Reliability

If multiple fabrication steps and complex bonding techniques are employed, then bonding capability is improved, but manufacturing complexity and cost increase

Engineering Contradiction:
Improvebonding capabilityVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention merges multiple bonding mechanisms (mechanical interlocking through protrusions and metallurgical bonding through heat treatment) into a single integrated process. This combination achieves superior bonding capability without requiring multiple separate fabrication steps, thereby reducing manufacturing complexity.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The outer sleeve material serves a dual function: it provides structural coverage and simultaneously bonds to the inner tube through the protrusion interlocking mechanism and heat treatment process, eliminating the need for separate bonding operations.

Inventive Principle:
Principle #25Self-service

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 method results in a lightweight, economical, and durable composite barrel with a superior bond between components, eliminating the risk of separation and reducing manufacturing complexity and cost, while utilizing existing firearm factory equipment.

Implementation Method 1

the sleeve is forged to the inner tube... material displaced from the outer sleeve by forging to bond the tube and sleeve together

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP1994356B1Composite firearm barrel
Publication Date: 2013.04.24 STURM RUGER & CO INC
  • EP1994356B1 patent drawingFigure 1~2
  • EP1994356B1 patent drawingFigure 3
  • EP1994356B1 patent drawingFigure 4~5

AI summary

A composite barrel for a firearm and method for forming by forging. The barrel includes at least two materials joined together by forging. In a preferred embodiment, at least one material is preferably lighter in weight than the other material. The barrel may include an inner tube and an outer sleeve. The inner tube defines a bore that provides a bullet path and in one embodiment may be made of steel or alloys thereof. The outer sleeve surrounds the inner tube and in some embodiments may be made of aluminum, titanium, or alloys of either thereof. The tube preferably includes an exterior surface containing recessed areas therein for receiving material displaced from the outer sleeve by the forging process. The preferred barrel forming method generally may include inserting the tube into the sleeve, striking an outer surface of the sleeve, and deforming the sleeve to force material to flow into the recessed exterior surface of the tube to bond the tube and sleeve together. The method of forming may be used to produce long and short barrels for rifles and handguns respectively, and more broadly to produce other composite components unrelated to firearms.