Rotatable Firearm Bolt With Dual Cam Systems
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Solution Overview
Problem
Existing firearm bolt designs, such as the Dillon bolt, face issues with cam arm fatigue due to asymmetrical loads during high firing rates in rotary firearms like the M-134, leading to potential bolt failure.
Innovation Solution
The design incorporates a first and second cam system, each defined by a pair of single complementary cam surfaces, where the first cam system bears predominant compressive forces during compression and the second cam system bears forces during retraction, distributing loads more evenly and reducing stress on weaker areas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single cam assembly is used in the bolt design, then the device complexity is reduced, but the reliability deteriorates due to asymmetrical loads causing cam arm fatigue
Solution Approach 1:
The single cam assembly is divided into two separate cam assemblies (first and second cam assemblies) positioned on opposite sides of the bolt. Each cam assembly has its own cam arm and cam slot, allowing the load to be distributed across multiple components rather than concentrated on a single cam arm, thereby reducing fatigue and improving reliability
Solution Approach 2:
The patent addresses the asymmetrical loading problem by creating a symmetrical configuration with cam assemblies on opposite sides of the bolt. This balanced arrangement ensures that compressive forces are distributed evenly across both cam assemblies during firing, preventing the asymmetrical stress that causes cam arm fatigue in single-cam designs
2Reliability
If multiple cam assemblies are used to distribute loads, then the reliability improves, but the device complexity increases
Solution Approach 1:
The two cam assemblies are integrated into a unified bolt structure where the cam bodies are formed as part of the bolt head and body. The cam arms are positioned on opposite sides but are structurally connected through the bolt assembly, creating a balanced system that improves reliability without requiring completely separate mechanisms
Solution Approach 2:
Each cam assembly is specifically designed to handle compressive forces in its local region of the bolt. The first cam assembly is positioned to bear forces on one side while the second cam assembly handles forces on the opposite side, allowing each component to be optimized for its specific loading conditions while contributing to overall system reliability
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 configuration enhances the durability of the firearm bolt assembly by localizing compressive forces, reducing the likelihood of cam arm failure and extending the bolt's operational lifespan, even at high firing rates.
Implementation Method 1
A firing pin including a firing pin spring is disposed within a cavity of the bolt body and the bolt head. The firing pin is spring biased by the firing pin spring
Implementation Method 2
Interaction of the first and second helical cam surfaces causes the bolt head to twist/rotate relative to the bolt body as the bolt body is compressed and retracted relative to the bolt head
Data Source
AI summary
Firearm bolt assemblies and firearms including the same are described. In embodiments the firearm bolt assemblies are configured to localize compressive forces applied during a transition from an initial position to a firing position to a first cam system on one side of the firearm bolt assembly, and to localize compressive forces applied during a transition from the firing position to the initial position to a second cam system another side of the firearm bolt assembly. Localizing the forces in that manner enables the use of a first cam system that is relatively robust compared to the second cam system.