Detent Delayed Blowback Mechanism for Lightweight Firearm Bolts
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Solution Overview
Problem
Conventional blowback systems in firearms are hindered by weight, lacking effective means to reduce the weight while maintaining functionality.
Innovation Solution
A delayed blowback system utilizing detent members and a recoil spring guide rod with matching recesses to mechanically amplify resistance, allowing for lighter bolts by perpendicular movement of detent members, enhancing recoil cycle efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional blowback systems use sufficient bolt mass to hold cartridge case in chamber, then cartridge case can be held securely for firing, but bolt weight increases
Solution Approach 1:
The bolt is segmented into multiple functional components: a main bolt body, separate detent members with detents, and a recoil spring guide rod with recesses. This segmentation allows the bolt to achieve reliable cartridge case holding through the coordinated action of multiple lighter components rather than relying on a single heavy bolt mass.
Solution Approach 2:
The detent members act as intermediary elements between the bolt and the cartridge case. The detents engage with the cartridge case to provide holding force, while the recoil spring guide rod with its recesses provides the mechanical pathway and additional holding mechanism. This intermediary system eliminates the need for excessive bolt mass.
2Force
If detent members move perpendicular to initial force direction, then resistance to rearward bolt movement is amplified, but device complexity increases
Solution Approach 1:
The detent members are designed to move in a dimension perpendicular to the initial rearward force direction. The detents engage with the recesses in such a way that the primary movement is lateral/perpendicular rather than directly rearward, creating mechanical advantage and amplifying the resistance force. This dimensional transformation provides force multiplication with relatively simple geometry.
Data Source
AI summary
A delayed blowback system for a firearm is provided. The system includes a bolt with two detent members operatively coupled within the bolt, each detent member comprising a detent. The system further includes a recoil spring guide rod having two matching recesses on opposing sides of the recoil spring guide rod, wherein the bolt and the two detent members are coupled to and slidable along the recoil spring guide rod between a firing position and a recoil position. The firing position includes the detents resting in the matching recesses on the recoil spring guide rod in response to a round being fired, the bolt moves back and pushes the detent members back, wherein by nature of a geometry of the detents and the matched recesses, the detent members outward in opposite directions and perpendicular sliding along the recoil spring guide rail in the recoil position to complete a recoil cycle.