Modular Fire Control Assembly with Adjustable Sear Spring
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Solution Overview
Problem
Adjusting the trigger pull weight of firearms like the Model 1911 requires experimentation with leaf springs, necessitating disassembly and reassembly, which is cumbersome and often requires a gunsmith's expertise.
Innovation Solution
A modular fire control assembly with an adjustable sear spring and disconnector spring housed in a modular assembly that allows for precise adjustment of trigger pull weight without disassembly, using a coiled torsion spring and threaded adjustment screw, eliminating the need for bending leaf springs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a leaf spring is used for the sear spring, then the trigger pull weight can be adjusted by bending the leaf, but the adjustment process requires disassembly, experimentation, and gunsmith expertise
Solution Approach 1:
The patent changes the physical parameters of the spring system by replacing a leaf spring with a coiled spring and adding an adjustment screw mechanism. This allows continuous adjustment of spring tension through screw rotation, changing the force parameter without requiring disassembly or experimentation. The adjustment screw modifies the pre-load on the coiled spring, providing precise control over trigger pull weight.
Solution Approach 2:
The patent substitutes the traditional leaf spring mechanical system with a coiled spring and threaded adjustment mechanism. Instead of bending a leaf spring to adjust tension, the new system uses a coiled spring with an adjustment screw that applies controlled mechanical force. This replacement transforms the adjustment method from experimental bending to precise threaded mechanical adjustment.
2Ease of manufacture
If individual fire control components are used separately, then the firearm can be assembled from separate parts, but precise dimensional configuration requires gunsmith expertise and trial-and-error adjustment
Solution Approach 1:
The patent merges the sear spring, disconnector spring, and associated adjustment mechanisms into a single integrated fire control assembly. This consolidation ensures that all components are pre-configured with precise dimensional relationships during manufacturing, eliminating the need for field adjustment. The merged assembly maintains proper spacing, alignment, and force distribution without requiring gunsmith expertise.
Solution Approach 2:
The patent performs preliminary configuration and precision adjustment during the manufacturing of the integrated assembly, before the firearm is assembled. The springs and components are pre-adjusted to exact specifications, and the entire assembly is tested and calibrated in advance. This preliminary action eliminates the need for trial-and-error adjustment during firearm assembly or maintenance.
3Ease of repair
If a modular fire control assembly is used, then component replacement and adjustment become simpler, but the housing and integration mechanism must be precisely designed
Solution Approach 1:
The patent segments the fire control system into a removable modular assembly that can be easily replaced as a unit. The housing contains all spring mechanisms and components, allowing the entire assembly to be removed and replaced without complex disassembly. This segmentation simplifies repair and maintenance while the housing design ensures precise integration through standardized mounting features.
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
Enables quick and precise adjustment of trigger pull weight without a gunsmith, simplifying assembly and maintenance, and increasing interchangeability of components across similar firearms.
Implementation Method 1
The disconnector spring is a coiled torsion spring
Implementation Method 2
The modular fire control assembly also includes a sear spring that is adjustable
Data Source
AI summary
Apparatus for a modular fire control assembly for a firearm. The modular fire control assembly integrates a hammer, a sear, a disconnector, and sear and disconnector springs in a single housing. The force applied by the sear spring is adjustable by a set screw, which enables the sear spring force to be dialed in. The sear spring and set screw are contained in a block in the housing. The sear spring engages a detent that applies spring force to the sear. The sear spring moves in a smooth bore that has a ledge that allows the spring to maintain a minimum force even when the set screw is removed. A self-contained disconnector spring ensures constant spring force on the disconnector regardless of adjustments to the sear spring force. The modular assembly is configured to be received in a lock cavity of the firearm and secured using conventional pins.