Arrow Broadhead Threadless Shank Concentricity
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Solution Overview
Problem
Current arrow systems face issues with eccentricity and instability due to multiple components and varying tolerances, which hinder the ability to make accurate adjustments to spine stiffness, front of center balance, and broadhead clocking.
Innovation Solution
The proposed arrow system features a glue-in broadhead to arrow shaft connection with a threadless shank for improved concentricity and a screw-over configuration with female threading on the broadhead and male threading on an insert, allowing for modular broadhead interchangeability and precise clocking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If male threading is used on the broadhead shank to screw into the arrow shaft, then the broadhead can be securely attached, but the perimetral boundary increases causing it to no longer fit inside micro-diameter arrow shafts
Solution Approach 1:
The patent removes the male threading from the broadhead shank entirely, extracting the problematic feature that increased the perimetral boundary. Instead, a threadless shank is used that fits inside the micro-diameter arrow shaft, eliminating the conflict between attachment strength and diameter constraints.
Solution Approach 2:
The threadless broadhead shank is designed to nest inside the micro-diameter arrow shaft (inner diameter less than 0.250 inches), allowing the broadhead to be securely attached while maintaining a compact profile that fits within the constrained diameter of the arrow shaft.
2Adaptability or versatility
If multiple components (broadhead, outsert/insert, arrow shaft) are combined from different manufacturers, then component availability and selection increase, but intolerances between connected components increase causing eccentricity
Solution Approach 1:
The patent merges the broadhead shank and arrow shaft into a direct fit configuration, eliminating the intermediate outsert/insert component. This reduction in the number of connection interfaces minimizes the accumulation of manufacturing tolerances and reduces eccentricity, while still allowing compatibility across different manufacturers through standardized dimensions.
3Ease 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
Solution Approach 1:
The patent removes the collar outsert component entirely, extracting the source of spine stiffness degradation and eccentricity. The threadless broadhead shank is designed to fit directly into the micro-diameter arrow shaft, eliminating the need for the outsert and preserving the structural integrity and stability of the arrow shaft.
4Ease of manufacture
If varying thread end points and overall length are used by different manufacturers, then manufacturing flexibility increases, but clocking consistency from arrow to arrow decreases
Solution Approach 1:
The patent changes the critical parameters of the broadhead-shaft interface by eliminating threading and specifying precise dimensional parameters for the threadless shank (diameter, length, tolerance). This standardization of parameters ensures consistent clocking and repeatability across different arrows and manufacturers, while still allowing manufacturing flexibility through conventional machining processes.
Data Source
AI summary
An arrow system embodying a screw-over configuration of broadhead to arrow shaft connection is provided. 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.