Arrowhead with Fixed Tip and Expandable Blades

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Solution Overview

Problem

Existing expandable blade arrowheads often deflect or ricochet if they do not hit a solid target area directly or strike at an angle, due to the mechanical deployment mechanism requiring significant entry depth and lever arm limitations, which reduces their effectiveness in hunting and archery.

Innovation Solution

An arrowhead design featuring a fixed spear-point blade at the tip with actuator spurs situated close to the fixed blade, allowing for rapid deployment of multiple parallel expandable blades upon impact, minimizing deflection and ensuring effective penetration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of operation

If expandable blade arrowheads use actuator members spaced away from the fixed tip, then the blades can be mechanically deployed, but the arrowhead requires significant entry depth before blades begin to expand, increasing deflection risk

Engineering Contradiction:

Improveblade deployment mechanismVSAvoidpenetration effectiveness

Core Design Contradiction:

Ease of operationVSReliability

Solution Approach 1:

The fixed blade is positioned to penetrate the target first, creating a stable anchor point before the expandable blades are deployed. This preliminary action by the fixed blade ensures the arrowhead is properly positioned and stabilized before the larger blades expand, reducing deflection risk.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The arrowhead is divided into a fixed blade component and separately deployable expandable blade components. The fixed blade remains stationary while the expandable blades are mounted on actuator members that can independently deploy, allowing each component to perform its specific function optimally.

Inventive Principle:

Principle #1Segmentation

2Device complexity

If expandable blade arrowheads use actuator members located close to the pivot point, then the blades can be deployed, but the lever arm is too small to effectively pivot the blades

Engineering Contradiction:

Improveactuator positioningVSAvoidblade pivoting force

Core Design Contradiction:

Device complexityVSStrength

Solution Approach 1:

The actuator members extend outward from the support body in a direction perpendicular to the blade pivot axis, creating a longer lever arm. This dimensional arrangement allows the actuators to apply force more effectively to pivot the blades open without requiring the actuators to be located far from the pivot point along the blade length.

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Area of stationary object

If expandable blade arrowheads deploy blades after fixed tip entry, then larger cutting area is achieved, but the arrowhead may deflect or bounce off target before blades expand

Engineering Contradiction:

Improvecutting areaVSAvoidpenetration stability

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The fixed blade penetrates the target first to establish a stable entry point and anchor the arrowhead before the expandable blades are deployed. This preliminary penetration action prevents deflection and ensures the arrowhead is properly positioned before the larger cutting surfaces are engaged.

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The fixed blade acts as a cushioning element that absorbs the initial impact and establishes a stable penetration path before the expandable blades are deployed. This preliminary action cushions against deflection forces that might otherwise cause the arrowhead to bounce off the target.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

4Area of stationary object

If arrowhead uses only expandable blades, then large cutting area is achieved upon deployment, but effectiveness is lost if blades fail to deploy

Engineering Contradiction:

Improvecutting areaVSAvoidcutting effectiveness

Core Design Contradiction:

Area of stationary objectVSReliability

Solution Approach 1:

The arrowhead design changes the operational parameter of blade configuration from exclusively expandable to a hybrid state with both fixed and expandable blades. The fixed blade provides a baseline cutting capability that remains constant, while the expandable blades provide enhanced cutting area when successfully deployed, creating a reliable system with variable performance.

Inventive Principle:

Principle #35Parameter changes

Data Source

PatentUS8062155B2Arrowhead having both fixed and mechanically expandable blades

Publication Date: 2011.11.22 FERADYNE OUTDOORS LLC

AI summary

An improved arrowhead features two sets of expandable blades. The expandable blades are pivotally movable from a first, concealed position to a second expanded position when spurs on the front of the blades contact a target. The first concealed position of the blades allows the arrowhead to penetrate the target upon contact. The fixed blades may be diamond-shaped, double-edged replaceable blades. The expandable blades comprise at least two pivotable blades that can be held in the first safe position by an elastic band. The spurs are located at a first end of the expandable blades, and these spurs are located proximate the base of the fixed blade portion of the arrow head, to allow the fixed portion to penetrate the target before the expandable blades are deployed by the spurs contacting the target.