Firearm Slide Cam Mechanism for Barrel Orientation Control
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Solution Overview
Problem
In semiautomatic pistols using the short recoil system, the downward drop of the barrel's breech end causes the barrel's longitudinal axis to become angularly oriented relative to the slide's direction of motion, potentially leading to failures in extracting spent cartridge casings due to the rim dropping below the extractor's controlling surface.
Innovation Solution
The use of cams and cam followers on the slide and barrel to control the orientation angle between the barrel's longitudinal axis and the slide's axis, with specific angular orientations for the cams and cam followers to ensure proper alignment and prevent excessive breech end drop, thereby enhancing the reliability of the firearm.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the short recoil system is used, then the barrel unlocks from the slide and the breech end drops downwardly, but the longitudinal axis of the barrel becomes angularly oriented with respect to the direction of motion of the slide, causing potential extraction failures
Solution Approach 1:
A cam mechanism is introduced as an intermediary element between the slide and barrel. The cam is positioned on the slide and engages with a cam follower on the barrel, mediating the relative motion between these two components. This intermediary mechanism controls the angular orientation of the barrel during recoil, preventing the breech end from dropping too far and ensuring reliable extraction.
Solution Approach 2:
The cam mechanism changes the parameter of angular orientation between the barrel's longitudinal axis and the slide's direction of motion. By designing the cam with specific geometric parameters (radius, angular position, profile shape), the system controls the orientation angle to remain within acceptable limits during recoil operation, thereby preventing extraction failures.
2Productivity
If the barrel's breech end drops significantly, then the spent cartridge casing can be extracted, but the rim of the spent casing may drop below the controlling surface of the extractor, causing extraction failure
Solution Approach 1:
The cam mechanism provides continuous feedback control during the extraction process. As the slide moves rearward and the barrel rotates, the cam follower tracks the cam profile, which continuously adjusts the barrel's angular orientation. This feedback mechanism ensures that the barrel maintains the correct orientation throughout the extraction cycle, preventing the spent casing rim from dropping below the extractor's controlling surface.
3Device complexity
If no cam mechanism is used, then the structure remains simple, but the orientation angle between the barrel and slide becomes uncontrolled, leading to misfeeds and extraction failures
Solution Approach 1:
The cam mechanism is segmented into distinct functional components: the cam element mounted on the slide, the cam follower mounted on the barrel, and the interaction interface between them. This segmentation allows each component to be optimized independently for its specific function while working together to control the barrel's angular orientation, achieving reliable operation without excessive overall complexity.
Data Source
AI summary
A barrel for a semiautomatic firearm operating under the short recoil system has one or more cam followers projecting outwardly to engage one or more cams positioned on an inner surface of a slide surrounding the barrel. Interaction between the cams and the cam followers controls the angle between the longitudinal axis of the barrel and the axis of motion of the slide to prevent the breech end of the barrel from moving too far as the barrel tilts as it unlocks from the slide, ensuring that the extractor will engage the rim of a spent casing and extract it from the chamber during recoil.