Rear-Deploying Mechanical Broadhead with Stationary Blades
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Solution Overview
Problem
Mechanical broadheads experience shooting inconsistencies and premature blade opening due to loose blades, leading to errors in arrow accuracy at high arrow speeds, which fixed blade broadheads also face.
Innovation Solution
A rear-deploying mechanical broadhead design with stationary blades that open only through movement of a drive pin/key within a slot in the body, secured by blade pins, ensuring the blades remain secure during flight and open only upon impact, utilizing a drive key as bleeder blades to maximize cutting diameter while maintaining a small in-flight diameter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If mechanical broadheads use loose blades to reduce in-flight diameter, then the broadhead achieves smaller size for better arrow speed, but the blades may open prematurely causing shooting inconsistencies
Solution Approach 1:
The broadhead employs a dynamic blade deployment mechanism where blades transition from a closed, retracted position during flight to an open, deployed position upon impact. The blades are held closed by a cam mechanism during flight, then forced open by target contact, allowing the broadhead to maintain small in-flight diameter while ensuring reliable blade deployment only when needed.
Solution Approach 2:
The broadhead prepares for blade deployment in advance by positioning the blades in a closed, aerodynamic configuration during flight. The cam mechanism is pre-configured to automatically trigger blade opening upon target contact, eliminating the need for loose blade placement and ensuring consistent shooting performance throughout the arrow's trajectory.
2Measurement precision
If mechanical broadheads have smaller in-flight diameter, then arrow accuracy improves, but cutting diameter may be reduced
Solution Approach 1:
The broadhead achieves variable diameter characteristics through dynamic blade deployment. During flight, blades are retracted to minimize in-flight diameter and improve arrow accuracy. Upon impact, blades rapidly deploy to maximize cutting diameter for effective hunting performance, thus resolving the contradiction between small in-flight size and large cutting capacity.
Solution Approach 2:
The broadhead transitions from a two-dimensional cross-section during flight to a three-dimensional expanded structure upon impact. The blades fold against the body during flight, presenting a compact profile, then unfold perpendicular to the arrow shaft upon target contact, creating a large cutting plane without increasing in-flight diameter.
3Reliability
If blades are secured tightly to prevent premature opening, then shooting consistency improves, but the broadhead may not deploy reliably on impact
Solution Approach 1:
The cam mechanism provides dynamic blade retention, holding blades firmly closed during flight through cam lobes that engage blade slots. Upon target impact, the reverse cam mechanism releases, allowing blades to deploy reliably. This dynamic system ensures both secure blade retention during flight and reliable deployment on impact.
Solution Approach 2:
The cam mechanism applies preliminary restraining force to keep blades closed during flight, preventing premature opening. The same mechanism is designed to automatically reverse this action upon target contact, ensuring reliable blade deployment. The preliminary anti-action of blade retention is automatically converted to blade deployment when needed.
Data Source
AI summary
Rear-deploying mechanical broadheads may be provided having stationary blades that open only through movement of a drive pin/key secured within a slot or chamber in the body of the broadhead. The drive pin/key may act as bleeder blades, thereby forming a mechanical broadhead with bleeder blades. The stationary blades may be pinned to the tip of the broadhead through blade pins, thereby keeping the blades stationary during flight toward a target and lessening the likelihood that the broadhead may be errant in its movement toward a target.