Adjustable Trigger Assembly Pivot Arm Ratio
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Solution Overview
Problem
Stock triggers in rifles, such as the Remington 700 series, often have accuracy-robbing characteristics like inconsistent or undesirable pull force, which can be affected by environmental factors, and lack adjustability for personal preference or shooting conditions.
Innovation Solution
An adjustable pull force trigger assembly with a more than one-to-one ratio between the trigger shoe and firing pin release arm, incorporating bearings for reduced friction, an ambidextrous safety knob, and an internal bolt release feature, allowing for customizable trigger pull from less than two ounces to over five pounds, and compatibility with standard rifle receivers without the need for retooling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a stock trigger assembly is used in a rifle, then the rifle can be manufactured and assembled easily, but the trigger pull force is inconsistent and robs accuracy
Solution Approach 1:
The trigger assembly is divided into separate functional components: a trigger shoe, a pivot arm, a firing pin release arm, and a housing. This segmentation allows each component to be precisely manufactured and assembled, improving trigger pull consistency while maintaining ease of assembly. The pivot arm acts as an intermediary element that connects the trigger shoe to the firing pin release arm, enabling precise control over the trigger mechanism.
Solution Approach 2:
The pivot arm serves as an intermediary element between the trigger shoe and the firing pin release arm. It provides a controlled mechanical advantage and ensures smooth, consistent transfer of force from the trigger pull to the firing pin release, thereby improving trigger pull consistency and accuracy.
2Manufacturing precision
If a modular trigger assembly is used to replace stock trigger, then trigger accuracy is enhanced through adjustability, but the device complexity increases
Solution Approach 1:
The trigger assembly incorporates adjustable elements that allow the trigger pull force to be dynamically modified by the user. The modular design enables different configurations to be assembled, providing adaptability for various shooting conditions and preferences while maintaining precision through controlled mechanical relationships.
Solution Approach 2:
The housing is designed with a standardized cavity that can accommodate the modular trigger assembly, making it compatible with various rifle models. This universal design allows the same housing structure to work with different trigger configurations, reducing overall complexity despite the modular nature of the components.
3Ease of operation
If bearings are added to reduce friction in the trigger mechanism, then trigger smoothness is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
Bearings are strategically placed at critical locations within the trigger assembly where friction would most significantly impact operation. This localized application of bearings provides maximum smoothness improvement while minimizing the total number of bearings required, thereby balancing ease of operation with device complexity.
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
Enhances rifle accuracy by allowing shooters to adjust trigger pull to suit their needs, providing a smoother and more predictable trigger operation that is impervious to environmental changes, and can be easily installed without special machining, offering various performance options for manufacturers and users.
Implementation Method 1
incorporating bearings for reduced friction
Implementation Method 2
pivot arm member (68/78) press fitted on the bearing
Data Source
AI summary
Adjustability of trigger pull force is enable by the use of a spring interfacing with a trigger shoe counterweight. The spring force is adjustable by use of a set screw interfacing with the spring. A pivot arm member acts between a trigger shoe counterweight and a firing pin release arm to fix the ratio of trigger shoe pull force and firing pin release arm force.