Trigger Resistance Mechanism With Rotary Cam Adjustment
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Solution Overview
Problem
Conventional trigger resistance setting mechanisms in rifles are complex, require disassembly of the weapon to adjust, and lack control over actual resistance values, with screws being prone to loss.
Innovation Solution
A trigger resistance mechanism using a class 1 lever with a spring bearing on one arm and a cam with variable recesses, allowing for quick and precise adjustment of trigger resistance without disassembly, featuring a rotary cam and adjustable bushing for compensation of production tolerances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a screw is used to set the trigger resistance, then the trigger resistance can be adjusted, but the adjustment process becomes complex and requires disassembly of the weapon
Solution Approach 1:
The adjustment mechanism is segmented into modular components: a cam with discrete recesses for different resistance values, a bearing element that engages these recesses, and a setting tool interface. This segmentation allows independent adjustment of trigger resistance without disassembling the entire weapon, resolving the contradiction between ease of operation and device complexity
Solution Approach 2:
A cam acts as an intermediary between the spring and the trigger mechanism. The cam translates rotational positioning into linear spring compression, enabling resistance adjustment through a simple rotational motion of the setting tool rather than direct screw manipulation, thus simplifying the adjustment process
2Shape
If a hidden screw inside the stock is used, then the appearance is clean, but the adjustment process requires removing the stock
Solution Approach 1:
The adjustment function is extracted from the internal stock structure and relocated to the trigger mechanism area where the cam and bearing element are positioned. This extraction allows the adjustment interface to be accessible without compromising the clean appearance of the weapon stock, resolving the contradiction between aesthetic shape and operational accessibility
3Device complexity
If a conventional screw mechanism is used, then the structure is simple, but control over the actual resistance value is impossible
Solution Approach 1:
The cam is designed with non-uniform local qualities: recesses at different positions and depths around its perimeter create distinct engagement points that correspond to specific resistance values. This local variation in the cam geometry provides precise control over the spring compression and thus the trigger resistance, while maintaining overall structural simplicity
Solution Approach 2:
The mechanism controls trigger resistance by changing the positional parameter of the cam. Rotating the cam to different angular positions engages the bearing element with different recesses, thereby changing the spring pre-compression parameter and achieving precise control over the resistance value without complex measurement systems
4Adaptability or versatility
If a screw is excessively released, then the adjustment range is increased, but the screw may fall out and get lost
Solution Approach 1:
The cam recesses are pre-positioned at specific locations around the cam perimeter, defining the maximum and minimum adjustment limits before the mechanism is operated. The bearing element is preliminarily designed to engage these recesses with a snap-fit or friction fit, preventing the mechanism from being over-adjusted or having components detach, thus ensuring reliability while maintaining adaptability
Solution Approach 2:
The cam and bearing element form a self-retaining mechanism where the geometric shape of the recesses and the bearing element's engagement geometry automatically prevent excessive rotation or detachment. The mechanism serves itself by using its own structure to limit adjustment range and secure components, eliminating the need for additional retention 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 easy, precise setting and verification of trigger resistance without disassembly, reducing the risk of lost components and simplifying the adjustment process.
Implementation Method 1
a trigger resistance spring (4) bearing on the other arm
Implementation Method 2
a cam (1) which is seated in the firearm frame in a rotary way
Implementation Method 3
the spring is fitted, at the end averted from the trigger, with a bearing element (3) that bears on a cam (1)
Data Source
AI summary
A trigger resistance mechanism, especially of rifles, comprising a trigger device, containing at least one class 1 lever (12) whose one arm is adapted to be controlled by the trigger (2) while a trigger (2) resistance spring (4) bears on the other arm. The spring (4) is fitted, at the end averted from the trigger (2), with a bearing element (3) that bears on a cam (1) that is seated in the firearm frame in a rotary way.