Arrow Spline Identification Using Vertical End-Compression Testing

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Solution Overview

Problem

Existing methods for identifying the spline of an arrow are prone to human error and do not accurately account for the forces imposed on the ends of the shaft when shot from a bow, leading to inconsistencies and potential damage.

Innovation Solution

A device with a rail and pressing assembly that allows for precise, vertical orientation of the arrow, applying even pressure from both ends to identify the spline by measuring the arrow's deflection, minimizing gravitational and human error.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If traditional shooting methods are used to locate spline, then the arrow can be tested in use condition, but the process is time-consuming and prone to human error

Engineering Contradiction:

Improvespline identification accuracyVSAvoidtime required for spline identification

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the mechanical shooting process with a controlled mechanical testing device. The device uses a pressing assembly that applies controlled force to the arrow shaft in a vertical orientation, eliminating the need for actual shooting while providing consistent, repeatable measurements that reduce human error and time requirements.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent performs spline identification before the arrow is shot. By pre-testing the arrow in a controlled environment with the testing device, the spline can be located without requiring multiple shooting attempts, thus saving time and reducing the risk of damage during actual use.

Inventive Principle:

Principle #10Preliminary action

2Measurement precision

If a spine tester is used to identify spline, then the arrow can be tested horizontally, but gravitational forces and human error introduce measurement inaccuracies

Engineering Contradiction:

Improveshaft deflection measurement accuracyVSAvoidgravitational error

Core Design Contradiction:

Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The patent inverts the traditional horizontal testing approach by using a vertical orientation. The pressing assembly applies force vertically along the arrow shaft, which eliminates gravitational effects that interfere with horizontal measurements. This vertical approach allows for more precise deflection measurements without the harmful influence of gravity.

Inventive Principle:

Principle #13The other way round (Inversion)

Solution Approach 2:

The patent introduces a pressing assembly as an intermediary mechanism between the operator and the arrow. This assembly provides controlled, consistent force application through a vertical pressing mechanism, eliminating the need for direct human judgment and reducing measurement errors associated with manual operation of traditional spine testers.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Adaptability or versatility

If weight is applied to the center of the shaft for spline testing, then the shaft can be tested, but the forces do not account for bow-imposed forces on the ends of the shaft

Engineering Contradiction:

Improvetesting configuration flexibilityVSAvoidspline identification accuracy

Core Design Contradiction:

Adaptability or versatilityVSReliability

Solution Approach 1:

The patent divides the testing process into two separate actions: first, the pressing assembly applies force to the center of the shaft to initiate deflection; second, the fixed receivers at either end of the rail provide counterbalancing support. This segmentation allows the system to simulate the actual bow-loading conditions where forces are applied at both ends of the shaft, improving the reliability of spline identification.

Inventive Principle:

Principle #1Segmentation

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

Accurately identifies the spline of an arrow with minimal human intervention, ensuring consistent fletching orientation and improving shooting accuracy without damaging the arrow.

Implementation Method 1

The spine of an arrow shaft is the shaft's strength as measured by the deflection of the shaft when a certain weight is hung from the center of an arrow shaft oriented horizontally to the ground.

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS20260078978A1Devices for identification of arrow splines

Publication Date: 2026.03.19 BA LEGEND ARCHERY INC

AI summary

A device comprising a rail with a mounting bracket at a first end, a lower receiver at the first end for engaging one end of an arrow shaft, and a pressing assembly mounted on the rail. The pressing assembly includes a brake for positional adjustment, a carriage flexibly connected to the brake, an upper receiver mounted to the carriage for engaging the opposite end of the shaft, and a handle rotatably mounted to the brake to transfer force to the carriage. A method for testing an arrow includes securing the pressing assembly at a location corresponding to the arrow's length, actuating the handle, and inserting a quick-release pin to hold the handle in place. The arrow is inserted into the lower receiver, the upper receiver is adjusted to contact the arrow, and the pin is removed. The handle is actuated to compress the arrow, and the deflection direction is observed to identify the spline.