Firearm Bolt Extractor Leaf Spring Design
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Solution Overview
Problem
Existing firearm extractor devices are prone to damage from high mechanical and thermal loads, and often require tools for assembly and disassembly, leading to potential operational issues and reduced reliability.
Innovation Solution
A bolt design featuring a cylindrical body with a groove-shaped recess for the extractor and leaf spring, allowing for lateral insertion of the leaf spring and pivoting of the extractor, which diverts forces away from the leaf spring and facilitates easy assembly and disassembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If coil springs are used to pretension the extractor, then the extractor can be pretensioned effectively, but the spring softens quickly under heat and may break
Solution Approach 1:
The patent changes the material parameter from coil spring steel to leaf spring steel, and changes the structural parameter from helical coil to flat leaf configuration. This parameter change allows the spring to maintain its elastic properties under high thermal loads that would soften coil springs, thereby resolving the contradiction between reliability and service life.
Solution Approach 2:
The patent employs a simple leaf spring design that can be easily replaced if needed, rather than relying on durable coil springs. The leaf spring is designed to be a simple, replaceable component that maintains functionality throughout the required service life without suffering from the softening issues of coil springs under heat.
2Reliability
If traditional extractor devices are used, then extraction function is provided, but assembly and disassembly require tools and are complex
Solution Approach 1:
The patent segments the extractor assembly into distinct components: the extractor itself, the leaf spring, and the recess in the bolt body. The leaf spring is positioned in the recess and the extractor is mounted on the leaf spring, allowing each component to be independently accessed, removed, or replaced without requiring complete disassembly or special tools.
Solution Approach 2:
The leaf spring is extracted from the complex coil spring design and simplified into a flat leaf configuration that can be easily inserted into and removed from the recess in the bolt body. This extraction of the spring from its traditional enclosed coil form allows for tool-free assembly and disassembly while maintaining the extraction function.
3Reliability
If the groove-shaped recess is closed, then the extractor and spring are securely retained, but assembly becomes difficult without tools
Solution Approach 1:
The recess transitions from a completely closed static structure to a dynamic structure with a movable closure. The closure can be shifted from a closed position (retaining components during operation) to an open position (allowing tool-free assembly and disassembly). This dynamic characteristic resolves the contradiction between secure retention and assembly ease.
Solution Approach 2:
The closure of the recess is designed to be shifted to an open position before assembly begins, allowing the leaf spring and extractor to be easily inserted. After assembly is complete, the closure is shifted to the closed position to secure the components. This preliminary opening of the closure eliminates the need for tools during assembly while maintaining secure retention during operation.
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
The design enhances the robustness and reliability of the extractor device, improves thermal resistance, and allows for simple maintenance, reducing the risk of damage and operational failures.
Implementation Method 1
a spring element, in this case a leaf spring, to pretension the extractor
Data Source
AI summary
A bolt for a firearm having an extractor for cartridge cases, comprising a cylindrical body having a locking portion with a breech face, an undercut, groove-shaped, rearwardly-running recess for an extractor with an extractor claw and a leaf spring, as well as an inwardly-projecting bearing protrusion and a second lever arm with a rearwardly-projecting spring bearing portion. The bearing protrusion is designed to be hook-shaped so as to abut against the extractor axis in the installed state with a bearing opening open rearwardly, and, on the body, the groove-shaped recess for receiving the leaf spring is laterally open at least partially on one side tangentially to the circumferential direction, via an insertion portion, and is designed to merge laterally and/or rearwardly into the undercut, and the body has a cavity for receiving the bearing protrusion relative to an imaginary plane of the recess in the region of the extractor axis.