Firearm Bolt Lock Interface Insert for Wear Reduction

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Short recoil weapons, such as the Browning M2 and 1919 machine guns, experience premature wear at the locking surface due to high cyclic rates of fire, leading to unsafe operation and the unnecessary discard of the entire bolt even if only a small portion is worn beyond limits.

Innovation Solution

A bolt design featuring a shaped cavity with acute forward and rear angles to accommodate a lock interface insert, which reduces movement relative to the receiver and allows for the replacement of only the worn insert, extending the bolt's service life and reducing inventory needs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the bolt is used at high cyclic rates of fire, then the weapon maintains operational capability, but the locking surface experiences substantial wear leading to dysfunction

Engineering Contradiction:

Improvecyclic rate of fireVSAvoidlocking surface wear

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The locking surface is segmented from the bolt body by providing a replaceable lock interface insert that can be independently replaced when worn, while the rest of the bolt remains serviceable

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The material properties of the locking surface are changed by using a hard coat material for the lock interface insert that is more wear-resistant than the original bolt material, thereby increasing durability under high cyclic rates of fire

Inventive Principle:

Principle #35Parameter changes

2Reliability

If the entire bolt is discarded when the locking surface wears beyond limits, then safety is maintained, but unnecessary portions of the bolt are wasted

Engineering Contradiction:

ImprovesafetyVSAvoidbolt material waste

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The bolt is segmented into a reusable bolt body and a replaceable lock interface insert, allowing only the worn insert to be discarded while the majority of the bolt structure is retained and reused

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Instead of discarding the entire bolt when the locking surface wears, only the lock interface insert is discarded and replaced, while the bolt body is recovered and continues to be used

Inventive Principle:

Principle #34Discarding and recovering

3Stability of the object's composition

If the lock interface insert is made to selectively engage the breech lock, then movement of the bolt body relative to the receiver is reduced, but the complexity of the bolt assembly increases

Engineering Contradiction:

Improvebolt movement controlVSAvoidbolt assembly structure

Core Design Contradiction:

Stability of the object's compositionVSDevice complexity

Solution Approach 1:

A lock interface insert is introduced as an intermediary component between the bolt body and the breech lock, providing the engagement function while keeping the bolt body design relatively simple

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The lock interface insert is nested within a shaped cavity in the bolt body, allowing the insert to be housed within the existing bolt structure without requiring significant external modifications

Inventive Principle:

Principle #7Nested doll (Nesting)

Data Source

PatentUS9664466B2Lock interface insert for bolt assembly of a firearm

Publication Date: 2017.05.30 GRYPARIS CHRIST STRATIS

AI summary

A bolt for a firearm includes, among other things, a bolt body extending between a first bolt end and a second bolt end, the bolt body defining a shaped cavity adjacent to a breech lock recess. The shaped cavity is defined by a cavity floor extending between a forward cavity face and a rear cavity face, the forward cavity face defines a forward angle relative to the cavity floor, the rear cavity face defines a rear angle relative to the cavity floor, and each of the forward angle and the rear angle is acute. A bolt assembly for a firearm and a method of fabricating a bolt for a firearm are also disclosed.