Arrowhead Gear Mechanism for Stable Flight and Impact Expansion
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Solution Overview
Problem
Conventional expanding blade arrowheads experience flight stability issues due to self-expansion during flight, requiring additional means to keep blades retracted, which is inconvenient and prone to failure upon impact.
Innovation Solution
An arrowhead with a gear mechanism that includes a rack gear on a shaft engaging with pinion gears of expanding blades, utilizing a spring to maintain blades in a retracted state during flight and automatically expanding upon impact, eliminating the need for external bundling or securing mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If expanding blades are used to enhance killing capability, then penetration and bleeding ability are improved, but flight stability deteriorates due to self-expansion during flight
Solution Approach 1:
The blade structure transitions from a static design to a dynamic one where blades can automatically change state based on impact conditions. The gear mechanism enables blades to remain retracted during flight (maintaining stability) and automatically expand upon impact (enhancing killing capability), resolving the contradiction between flight stability and killing capability.
Solution Approach 2:
The patent changes the physical state parameter of the blades from expanded to retracted during flight, and back to expanded upon impact. This parameter change is controlled by the gear mechanism which responds to impact forces, allowing the blades to adapt their configuration based on operational requirements.
2Stability of the object's composition
If additional securing means are used to keep blades retracted, then flight stability is improved, but device complexity increases and reliability decreases due to potential band failure
Solution Approach 1:
The gear mechanism provides self-service functionality where the system automatically maintains blade retraction during flight and automatic expansion upon impact without requiring external securing means. The mechanism uses the impact force itself to trigger expansion, eliminating the need for additional bands or strings and reducing both complexity and potential failure points.
Solution Approach 2:
The patent removes the additional securing means (bands or strings) from the system by integrating the retention function directly into the gear mechanism. This extraction of unnecessary components simplifies the overall structure while maintaining flight stability.
3Stability of the object's composition
If expanding blades are manually retracted and tied before shooting, then flight stability is improved, but ease of operation deteriorates due to repeated bundling requirements
Solution Approach 1:
The gear mechanism is pre-configured in a retracted state ready for flight, eliminating the need for manual bundling before each shot. The preliminary setup is built into the mechanism itself, which automatically maintains the correct configuration throughout flight and transitions to expansion upon impact without user intervention.
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
Ensures stable arrow flight without additional securing means and reliable expansion upon hitting a target, enhancing killing capability and simplifying manufacturing.
Implementation Method 1
a spring (140) mounted on the shaft (150)
Implementation Method 2
a rack gear portion (154) provided on an outer peripheral surface of the body portion to engage with the pinion gear portion (134)
Implementation Method 3
a rack gear formed on a shaft is engaged with pinion gears of expanding blades coupled to a main body, and thus a relative movement between the main body and the rack gear causes the retraction or expansion of the expanding blades
Data Source
AI summary
Disclosed is an arrowhead in which a plurality of expandable blades can be quickly and reliably retracted or expanded without using an additional means to bundle the expanding blades, thereby enhancing the penetrating capability or killing capability of an arrow. Particularly, a portion of a shaft forming the arrowhead is provided with a rack gear portion installed thereon and a lower end of each of the expanding blades is provided with a pinion gear portion, such that the rack gear portion and the pinion gear portion engage with each other and such a rack-pinion action controls the operation of retracting or expanding the expanding blades.