Crossbow Trigger Arm Non-Parallel Geometry
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Solution Overview
Problem
Crossbows with traditional trigger assemblies experience hard and rough trigger pulls due to high bowstring tension, leading to torsion issues that can result in unanticipated early or late release of the string, compromising comfort and safety.
Innovation Solution
An adjustable trigger assembly with a trigger arm coupled between the trigger and sear, allowing for adjustable trigger travel and pull weight, featuring a non-parallel trigger arm design to reduce torsion and enhance mechanical advantage, comfort, and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional trigger assembly with solid sear engagement is used, then mechanical advantage is provided, but trigger pull becomes hard and rough
Solution Approach 1:
The trigger assembly is divided into separate functional components: a trigger body, a sear with distinct engagement surfaces, and a trigger arm. This segmentation allows each component to be optimized independently - the sear provides mechanical advantage through its geometry while the trigger arm's angled configuration ensures smooth operation by distributing force along its length rather than concentrating it at a single point.
2Stability of the object's composition
If firm engagement between sear and trigger assembly is used, then stability is improved, but torsion of trigger assembly occurs
Solution Approach 1:
The sear features asymmetric engagement surfaces with a first surface angled relative to the trigger arm's longitudinal axis and a second surface perpendicular to the first. This asymmetric geometry creates a mechanical advantage that stabilizes the trigger assembly by distributing engagement forces along the angled surface, preventing torsion while maintaining firm engagement. The angled configuration ensures forces are directed along the strongest axis of the trigger arm.
3Adaptability or versatility
If adjustable trigger arm connection point is implemented, then trigger pull and travel are adjustable, but device complexity increases
Solution Approach 1:
The trigger arm includes a slot that receives an adjustment mechanism, allowing the connection point between the trigger arm and sear to be dynamically repositioned along the slot's length. This dynamic adjustment capability enables customization of trigger pull weight and travel distance without requiring multiple different trigger arm components. The slot geometry is designed to maintain proper alignment and mechanical advantage throughout the range of motion while enabling adjustment.
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 adjustable trigger assembly provides a comfortable, smooth, and predictable trigger pull, reducing the risk of inadvertent projectile launch and improving dry fire characteristics while maintaining low-cost, efficient manufacturing.
Implementation Method 1
A trigger arm is coupled between the trigger and a sear. The trigger arm is not parallel with the projectile path. Preferably, the connection point of the trigger arm to the trigger bar is adjustable to change the trigger draw length and pull.
Data Source
AI summary
A trigger assembly for a crossbow or other weapon system. The trigger assembly includes a trigger arm coupled between a trigger and a sear. The trigger arm is not parallel to the line of fire, thereby allowing for increased mechanical advantage and a smoother, safer trigger pull. The trigger assembly incorporates various safety measures, including a dry fire mechanism which prevents the unintentional damaging and potentially dangerous release of the bowstring before an arrow is positioned on the rail of the crossbow. The trigger assembly allows for various adjustments to vary the trigger length and pull, while maintaining smoothness and preventing the unintentional or inadvertent release of the bowstring.