Expandable Broadhead Blade Locking Notch Design
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Solution Overview
Problem
Existing arrow broadheads do not effectively maintain cutting blades in a retracted position during flight and fail to securely lock them in an extended position upon target contact, leading to suboptimal performance in hunting.
Innovation Solution
An expandable arrow broadhead design featuring a sliding shaft with a pointed tip and cutting blades that are initially retracted and then expand outwardly into a locked position upon impact, utilizing a threaded collar and beveled cam surface to ensure blades remain extended for increased cutting diameter and humane kill.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If cutting blades are extended outwardly upon target contact, then cutting diameter is increased for better hunting performance, but blades may deflect or fail to remain securely locked in the extended position
Solution Approach 1:
A locking notch is introduced as an intermediary feature on the cam surface that engages with the collar to mediate between the blade and the collar, ensuring positive locking in the extended position and preventing blade deflection or failure to remain secured
Solution Approach 2:
The cam surface is pre-configured with a locking notch that is positioned to engage with the collar automatically when the blade reaches the extended position, ensuring the blade is locked in place before any potential deflection can occur
2Speed
If blades are held in a retracted folded position during flight, then aerodynamic performance is improved, but blades must reliably transition to extended position upon impact
Solution Approach 1:
The blade assembly is designed with dynamic characteristics that allow it to transition from a static retracted position during flight to an extended locked position upon impact, with the cam surface and locking notch ensuring reliable transition
Solution Approach 2:
The cam surface is pre-configured with a locking notch that ensures the blade automatically transitions to and locks in the extended position upon impact, making the expansion action reliable and predictable
3Reliability
If a locking mechanism is added to secure blades in extended position, then blade locking reliability is improved, but device complexity increases
Solution Approach 1:
The locking notch is merged with the cam surface, combining the cutting blade's structural element with the locking mechanism, so the blade itself serves dual purposes of cutting and locking without requiring a separate locking component
Solution Approach 2:
The blade's own cam surface with the locking notch serves the dual function of enabling blade extension and providing the locking mechanism, making the blade self-sufficient for both cutting and locking functions
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
The design ensures blades remain locked in an extended position, providing a larger cutting diameter for increased hemorrhaging and a quicker, more humane kill, while allowing for easy attachment to various arrow shaft sizes through press fit or threading.
Implementation Method 1
The inner edge of the blades includes a beveled cam surface disposed next to a portion of the length of the sliding shaft. As the sliding shaft moves rearwardly, the beveled cam surface engages a portion of the threaded collar and moves the blades outwardly into an extended position.
Implementation Method 2
The locking notch is received around a portion of the threaded collar for holding the cutting blades in the extended position during the engagement of the target.
Data Source
AI summary
An expandable arrow broadhead used for releasable attachment to one end of a hollow arrow shaft. The broadhead includes a sliding shaft with a pointed tip and tip base having two or more of cutting blades mounted thereon. Each of the blades includes an outer cutting edge and an inner edge with a beveled cam surface and locking notch therein. A portion of the sliding shaft is slidably received inside a hollow collar. The collar is attached to a sliding shaft housing. The sliding shaft housing is attached to an arrow shaft insert. The arrow shaft insert is adapted for receipt inside one end of the arrow shaft. In a retracted position, the blades are disposed next to and parallel to the length of the sliding shaft. When the pointed tip engages a target, the sliding shaft moves inwardly and rearwardly sliding inside the collar and inside a sliding shaft bore hole in the sliding shaft housing. As the sliding shaft moves rearwardly, the beveled cam surface of the blades engages a portion of the collar, which moves the blades outwardly with locking notch securing the blades in an extended position.