Crossbow Trigger Lever with Adjustable Pivot Points

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Solution Overview

Problem

Existing crossbow trigger mechanisms lack the ability to adjust both trigger pull travel and poundage effectively, with previous solutions only altering spring load pressure without changing trigger pull travel.

Innovation Solution

An adjustable trigger system for crossbows that includes a trigger housing, sear lever, sear lock lever, string latch, safety, trigger-to-sear link, and trigger lever, allowing multiple settings for trigger travel and poundage by varying the pivot points and distances of the trigger-to-sear link, enabling selection of preferred trigger poundage and travel.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If spring load pressure on the sear is increased or decreased, then trigger pull poundage is altered, but trigger pull travel remains unchanged

Engineering Contradiction:

Improvetrigger pull poundageVSAvoidtrigger pull travel adjustment

Core Design Contradiction:

ForceVSAdaptability or versatility

Solution Approach 1:

The trigger-to-sear link is made adjustable with multiple mounting positions along the sear lever, allowing the mechanical configuration to be dynamically changed. This enables independent adjustment of both trigger pull poundage (via spring pressure) and trigger pull travel (via mounting position), resolving the limitation of fixed travel distance.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the geometric parameter of the trigger mechanism by providing multiple mounting positions at different distances from the sear lever pivot point. This parameter change allows adjustment of the leverage ratio, thereby controlling trigger pull travel distance while spring pressure controls poundage, achieving independent adjustment of both characteristics.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If mounting positions for the linkage arm on the trigger lever are not on a constant radius relative to the linkage arm pivot point, then adjustment is possible, but smooth operation and function are compromised

Engineering Contradiction:

Improvetrigger adjustment capabilityVSAvoidsmooth operation

Core Design Contradiction:

Adaptability or versatilityVSEase of operation

Solution Approach 1:

The mounting positions for the trigger-to-sear link are arranged on an arc (constant radius) relative to the sear lever pivot point. This curved geometric arrangement ensures that the link maintains proper alignment and smooth angular motion throughout the trigger pull, preventing binding or irregular operation while still allowing multiple adjustment positions.

Inventive Principle:

Principle #14Spheroidality (Curvature)

Data Source

PatentUS10215522B1Adjustable trigger pull for a crossbow

Publication Date: 2019.02.26 ARCHERY INNOVATORS LLC

AI summary

An adjustable trigger mechanism assembly for a crossbow includes a trigger housing, a sear lever, a latch, trigger lever, and a linkage arm. The sear lever is pivotally engaged with the trigger housing and controls the movement of the latch. One end of the linkage arm is pivotally engaged with the sear lever. The trigger lever is pivotally engaged with the trigger housing. The trigger lever includes at least two moment arm holes for pivotally engaging an opposing end of the linkage arm. In an alternative embodiment, the at least two moment arm holes are formed in the sear lever. The at least two moment arms cause the trigger lever to have at least two different pull distances and pull forces.