Arrow System Broadhead Connection Eccentricity Reduction

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Solution Overview

Problem

Current arrow systems face issues with eccentricity and instability due to male threading in micro-diameter arrows, which affect spine stiffness, front of center balance, and broadhead blade clocking, making it difficult for archers to achieve consistent accuracy and require time-consuming adjustments.

Innovation Solution

The introduction of a glue-in or screw-over broadhead to arrow shaft connection that eliminates external threading, allowing for a snug, concentric fit and enabling selective adjustments to spine stiffness and broadhead blade configurations through internal threading and modular designs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If male threading is used on the broadhead shank for connection to the arrow shaft, then the broadhead can be securely attached, but the perimetral boundary of the broadhead shank increases causing it to no longer fit inside micro-diameter arrow shafts and introducing eccentricity

Engineering Contradiction:

Improvebroadhead attachment securityVSAvoidbroadhead shank perimetral boundary

Core Design Contradiction:

StrengthVSArea of stationary object

Solution Approach 1:

The external male threading is completely removed from the broadhead shank. Instead, internal female threading is provided within the hollow shank, allowing the threaded connection to occur inside the shank bore rather than on its external surface. This extraction of the threading from the external surface eliminates the increased perimetral boundary while maintaining secure attachment capability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The threaded connection structure is nested within the hollow shank. The external threading is replaced by internal threading that fits within the shank's hollow interior, allowing the connection mechanism to be contained within the existing shank boundary rather than extending it outward.

Inventive Principle:

Principle #7Nested doll (Nesting)

2Ease of operation

If a collar outsert is used to accommodate male threaded broadhead shanks in micro-diameter arrows, then the broadhead can be attached, but the arrow shaft spine stiffness is detrimentally altered and eccentricity is introduced

Engineering Contradiction:

Improvebroadhead attachment capabilityVSAvoidarrow shaft spine stiffness

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The collar outsert component is completely eliminated from the system. By removing external threading from the broadhead shank, the need for a collar outsert is eliminated, allowing direct insertion of the threadless shank into the arrow shaft without adding external components that would alter spine stiffness or introduce eccentricity.

Inventive Principle:

Principle #2Taking out (Extraction)

3Adaptability or versatility

If multiple components (broadhead, outsert/insert, arrow shaft) are combined from different manufacturers, then component availability and selection are improved, but intolerances between connected components increase causing eccentricity

Engineering Contradiction:

Improvecomponent selection flexibilityVSAvoidcomponent connection concentricity

Core Design Contradiction:

Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The broadhead shank and arrow shaft connection is simplified to a direct fit relationship without intermediate components. By eliminating the outsert/insert layer and using a simple threaded hole in the shank that receives a set screw from the arrow shaft, the number of component interfaces is reduced, thereby reducing cumulative tolerances and improving concentricity.

Inventive Principle:

Principle #5Merging (Combining)

4Adaptability or versatility

If male threading with varying end points and overall length is used, then manufacturer flexibility in design is improved, but consistent clocking from arrow to arrow becomes difficult requiring time-consuming adjustments

Engineering Contradiction:

Improvemanufacturer design flexibilityVSAvoidclocking adjustment time

Core Design Contradiction:

Adaptability or versatilityVSLoss of time

Solution Approach 1:

The arrow shaft is pre-configured with a set screw that threads into the hollow shank at a predetermined location and angle. This preliminary positioning of the set screw in the arrow shaft creates a fixed reference point that automatically establishes consistent clocking when the broadhead is installed, eliminating the need for time-consuming adjustments by the archer.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The threaded hole in the broadhead shank and set screw in the arrow shaft are designed to automatically self-align and self-position during installation. The threading geometry and set screw orientation cause the broadhead to naturally assume the correct clocked position without requiring manual adjustment, making the system self-configuring.

Inventive Principle:

Principle #25Self-service

Data Source

PatentUS11740060B2Arrow system

Publication Date: 2023.08.29 FORREST RICHARD M

AI summary

A arrow system embodying a glue-in configuration or screw-over configuration of broadhead to arrow shaft connection is provided. The glue-in configuration provides an externally threadless broadhead shank for slidably reception into the complementary and cross-sectionally coextensive lumen of the arrow shaft. The screw-over configuration provides a broadhead with female internal threading that operatively associates with male threading of an insert that interconnects the broadhead to the lumen of the arrow shaft.