Adjustable Screw Trigger Assembly with Locking Spring
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Solution Overview
Problem
Existing screw and spring assemblies for adjusting trigger pull force in weapons lack a mechanism to maintain consistent pressure without slippage and do not provide a clear upper limit for screw tightening, leading to inconsistent trigger pull forces.
Innovation Solution
A screw and spring assembly comprising a trigger housing, trigger shoe, spacer, trigger-shoe compression spring, adjustable screw, and a pressed-fitted compression spring that locks the screw into place, ensuring consistent pressure and limiting screw tightening to prevent slippage, with the compression spring maintaining minimum tension even when the screw is removed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the screw is tightened to increase pressure on the trigger shoe, then the trigger pull force increases, but the assembly may slip when the weapon is fired
Solution Approach 1:
The second compression spring automatically clicks the screw into place every half turn, providing self-locking functionality that maintains pressure without slippage during firing
Solution Approach 2:
The clicking mechanism provides tactile feedback to the user, confirming each adjustment position, while the spring's locking action provides mechanical feedback to maintain the selected pressure setting
2Force
If the screw is tightened beyond a certain point, then the trigger pull force increases, but there is no mechanism to limit the maximum pressure
Solution Approach 1:
The threaded hole is designed with a predetermined depth that limits how far the screw can be tightened, establishing an upper bound on trigger pull force before assembly is complete
Solution Approach 2:
The adjustment range is divided into discrete half-turn positions, each locked by the second spring, creating segmented adjustment steps rather than continuous adjustment
3Ease of repair
If the screw is removed from the assembly, then the assembly can be disassembled, but the trigger shoe loses all tension
Solution Approach 1:
The first compression spring serves multiple functions: it maintains minimum tension on the trigger shoe during operation and continues to provide tension even when the screw is removed for disassembly or repair
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 assembly allows for precise adjustment of trigger pull force with each position, ensuring consistent pressure and preventing slippage, thereby providing a reliable and adjustable mechanism for firing a weapon.
Implementation Method 1
a spring keeps a minimum amount of tension on the trigger shoe at all times, even if the screw is removed from the assembly
Implementation Method 2
a pressed-fitted compression spring that 'locks' the adjustable screw into place every half turn, which also prevents the assembly from slipping (thereby maintaining the pressure as selected) when the weapon is fired
Data Source
AI summary
A screw and spring assembly for adjusting trigger pull force comprises (1) a trigger housing, (2) a trigger shoe that is inside of the trigger housing (typically sitting on a bushing that runs through the housing and the trigger shoe) (3) a spacer, (4) a trigger-shoe compression spring, (5) an adjustable screw, and (6) a pressed-fitted compression spring that “locks” the adjustable screw into place in various positions, wherein the pull force needed to pull the trigger is different at each of the various positions.