Trigger Bar Cam for Sear Disconnect in Semi-Automatic Pistols
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Solution Overview
Problem
Existing semi-automatic pistols face challenges in achieving smooth and timely sear disconnection and reliable resetting of firing elements during a firing sequence due to the limitations of the thin upper portion of the stamped trigger bar riding on an arced cam surface.
Innovation Solution
A modified trigger bar design with a ski-shaped tab that slides along the arced cam surface of the slide, providing optimal variable breaking force and improved sear disconnection, includes a first end connected to the trigger, a second end with a sear disconnect surface, and a trigger bar spring for upward bias, ensuring smooth operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a thin upper portion of a stamped trigger bar rides on an arced cam surface, then the structure is simple and easy to manufacture, but the sear disconnection is not smooth and timely
Solution Approach 1:
The trigger bar is divided into distinct functional segments: a first portion with a first surface for initial engagement, and a second portion with a second surface for sear disconnection. This segmentation allows each portion to be optimized for its specific function, ensuring smooth and timely sear disconnection while maintaining manufacturing simplicity.
Solution Approach 2:
Different portions of the trigger bar are given different surface characteristics. The first surface has specific geometric properties for initial engagement, while the second surface has different properties optimized for sear disconnection. This local differentiation ensures optimal performance at each stage of the firing sequence without complicating the overall structure.
2Reliability
If a thin upper portion of a stamped trigger bar is used, then manufacturing is easy, but the resetting of firing elements is not reliable
Solution Approach 1:
The trigger bar is segmented into multiple portions with distinct surfaces. The second portion with its specific second surface is designed to reliably reset the sear and firing elements, while the first portion handles initial engagement. This segmentation enables reliable resetting without requiring complex manufacturing processes.
Solution Approach 2:
The second surface of the trigger bar is configured with curved or rounded geometric features that facilitate smooth engagement and disengagement of the sear and firing elements during resetting. This curvature ensures reliable resetting while maintaining ease of manufacture through standard stamping processes.
3Loss of time
If the trigger bar operates without optimized surfaces, then the device is simple, but the timing of sear disconnection is suboptimal
Solution Approach 1:
The trigger bar is divided into first and second portions with distinct surfaces optimized for different timing functions. The first surface handles initial engagement timing, while the second surface is specifically designed for sear disconnection timing. This segmentation enables precise timing control without significantly complicating the overall trigger bar geometry.
Solution Approach 2:
The second surface of the trigger bar is given specific local geometric properties that optimize sear disconnection timing. This localized optimization ensures precise timing at the critical sear disconnection moment without requiring complex modifications to the entire trigger bar structure.
Data Source
AI summary
A semi-automatic pistol is provided having a frame, a slide and an arced cam surface extending longitudinally on an inner surface of the slide. The pistol has a barrel mounted between the frame and the slide, and a firing pin mechanism mounted in the slide. A trigger is mounted on the frame. A trigger bar and a sear are also provided. The trigger bar includes a generally planar surface extending between the ends of the trigger bar. The first end is connected to the trigger and the second end has a sear disconnect surface to engage and disengage a sear rotatably disposed in the frame that engages an end of the firing pin. A tab is disposed at an angle to the generally planar surface, where the tab has a top curved surface to slide along the arced cam surface of the slide as the slide moves.