Fire Control Assembly Bumper Design for Trigger Stability
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Solution Overview
Problem
Existing fire control assemblies for firearms face issues such as damage from impacting parts, fitment problems due to manufacturing tolerances, and a trade-off between lighter trigger pull and robustness, leading to potential misalignment and reduced performance.
Innovation Solution
A fire control assembly design featuring a frame with a hammer stop, preloading mechanism, and distinct materials for the frame and bumper, which includes a stem and enlarged contacting surface to prevent hammer disconnector contact and stabilize the assembly within the firearm housing, using a biasing member and contacting member to apply forces that counteract manufacturing variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If the hammer is allowed to reach the end of its travel path and impact the disconnector, then the trigger pull weight can be reduced, but the parts can be damaged
Solution Approach 1:
A bumper is introduced between the hammer and disconnector that compresses before impact occurs, absorbing the shock and preventing damage to the disconnector while allowing the hammer to reach the end of its travel path for reduced trigger pull weight
Solution Approach 2:
The bumper serves as an intermediary element positioned between the hammer and disconnector, mediating the interaction by providing a compliant surface that allows full hammer travel while preventing direct hard impact with the disconnector
2Ease of manufacture
If standard manufacturing tolerances are used, then production cost is reduced, but fitment issues and position shifting occur
Solution Approach 1:
The bumper is designed with specific dimensional parameters (width, height, thickness) that can be adjusted to compensate for manufacturing tolerances in other components, allowing the assembly to maintain proper fitment and position stability without requiring extremely tight tolerances throughout the entire assembly
Solution Approach 2:
The compliant bumper material provides beforehand cushioning that absorbs dimensional variations and misalignments caused by manufacturing tolerances, preventing position shifting during operation while allowing cost-effective manufacturing
3Ease of operation
If a non-mil-spec trigger assembly is used, then trigger pull weight is reduced and trigger feel is improved, but robustness is lost
Solution Approach 1:
The bumper combines a metal stem for structural strength with an elastomeric material for shock absorption, creating a composite structure that provides both the robustness needed for reliable operation and the compliance needed to protect against damage, thereby maintaining assembly robustness while enabling improved trigger characteristics
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 solution enhances the robustness and stability of the fire control assembly by preventing hammer disconnector contact, improving fitment, and stabilizing the assembly within the firearm housing, thereby reducing damage and enhancing performance by maintaining consistent trigger operation.
Implementation Method 1
a preloading mechanism comprising a biasing member and a contacting member, the contacting member moveable with respect to the frame via resilient deformation of the biasing member
Data Source
AI summary
In some embodiments, a fire control assembly comprises a frame, a hammer, a trigger and a disconnector. The frame is arranged to be supported along a trigger axis and a hammer axis. The hammer is rotatable about the hammer axis and the trigger is rotatable about the trigger axis. The frame comprises a hammer stop arranged to impede rotation of the hammer. The frame comprises a preloading mechanism arranged to contact a safety selector.