Expandable Broadhead Pin-Mounted Blade Deployment
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Solution Overview
Problem
Existing expandable broadheads face issues such as blades sticking in ferrule slots, limited penetration due to ferrule diameter, aerodynamic instability, and blade interference, leading to reduced accuracy and potential jamming during deployment and retrieval.
Innovation Solution
The design features fixed blades with rear-deployable auxiliary blades that rotate and translate on a pin, eliminating slots and notches, allowing for greater clearance and interference-free deployment, and a shock collar with a frangible tab for secure flight and impact-driven deployment, enhancing penetration and ease of removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If blades are housed within slots in a solid ferrule, then the broadhead structure is compact and stable during flight, but the blades may stick or bind in the ferrule slots preventing proper extension upon impact
Solution Approach 1:
The patent removes the ferrule slots and solid ferrule structure entirely, extracting the constraint mechanism that caused blade binding. Instead, blades are mounted on the exterior of the arrow shaft using a simple pin and channel system, eliminating the problematic slot configuration while maintaining structural integrity.
Solution Approach 2:
The broadhead is divided into separate modular components: fixed blades mounted directly to the arrow shaft, and movable blades that can independently deploy. This segmentation allows each blade type to be optimized separately, with movable blades using a simple pin-based mechanism rather than complex ferrule slots.
2Strength
If the ferrule has a relatively large bullet-like tip, then the broadhead structure is stable, but the penetration of the arrow into the target is limited by the diameter of the tip
Solution Approach 1:
The patent completely removes the traditional ferrule structure with its large bullet-like tip from the design. Instead, a lightweight collar is used that provides minimal structural support without creating penetration resistance, allowing the arrow to penetrate targets more effectively while maintaining broadhead stability through alternative means.
Solution Approach 2:
Rather than using a large ferrule tip to provide stability, the design inverts the approach by using a minimal collar and relying on the symmetry and balance of the blade configuration around the arrow shaft to provide aerodynamic stability during flight, eliminating the need for a large penetrating tip.
3Stability of the object's composition
If expandable blades are constrained to prevent early deployment, then aerodynamic stability is improved, but the energy necessary to cause them to pivot to the cutting position is significant, reducing penetration
Solution Approach 1:
The patent removes the complex constraint mechanisms entirely, replacing them with a simple pin-based system where blades are held in place by friction and geometry during flight but can deploy with minimal force upon impact. The channel and pin configuration provides just enough restraint for flight stability while requiring very little energy for deployment.
Solution Approach 2:
The design changes the deployment parameter from high-energy pivoting around a forward axis to low-energy translation along a channel with rearward camming action. This parameter change allows the blades to remain constrained during flight through simple geometric alignment while requiring minimal force to deploy when the camming surface engages upon impact.
4Ease of operation
If blades are pivoted from a forward collapsed position, then deployment is possible, but the blades interfere with one another during deployment and retraction, causing jamming
Solution Approach 1:
The patent inverts the deployment direction from forward-pivoting to rearward-translating with outward rotation. Blades translate rearwardly along channels and rotate outward on pins located toward the rear of the blade assembly, causing deployment in the opposite direction of traditional designs. This inversion eliminates interference between blades during both deployment and retraction cycles.
Solution Approach 2:
The patent introduces channels as intermediary guides that constrain blade movement paths, ensuring blades translate and rotate without interfering with adjacent blades. The channel geometry and pin placement act as mediators that coordinate blade motion, preventing collisions and jamming while enabling smooth deployment and retraction operations.
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
This design ensures reliable and interference-free deployment of blades, increasing penetration power and accuracy while preventing jamming, and maintaining a lightweight structure for improved arrow flight and target engagement.
Implementation Method 1
a shock collar with a frangible tab for secure flight and impact-driven deployment
Implementation Method 2
a camming surface at the rear of the shock collar and a cam follower on the deployable blade to cam the deployable blade outwardly
Data Source
AI summary
An expandable broadhead includes a number of fixed blades cumulating in a point, with each of the fixed blades having a channel for receiving a cammable deployable expansion blade, with the expansion blade having a slot which cooperates with a fixed retaining pin transverse to the channel that cams the deployable blade outwardly when a forward impact shoulder of the deployable blade strikes a target. This moves the blade relative to the fixed retaining pin and thus cams the deployable blade out to an expanded position for maximum blade cutting edge contact to effectuate maximum damage to the target and a quick kill.