Projectile Fin Deployment via Helical Hinge Pin Shaft
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Solution Overview
Problem
Inconsistent fin deployment and locking in existing projectile launch platforms lead to instability and compromised aerodynamic performance due to erratic movement and distortion during launch.
Innovation Solution
A fin deployment system featuring a non-rotatable hinge pin shaft with a helically-oriented pathway and a unidirectional ratchet collar member that enables simultaneous axial and rotational movement of fin members, utilizing centripetal and aerodynamic loads to deploy fins and retain them in place using a ratchet mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If fins are stowed during gun launch and deployed after exiting the chamber, then the projectile can be launched successfully, but inconsistent deployment and locking occur causing instability
Solution Approach 1:
The hinge pin shaft is designed with a helically-oriented pathway that transforms the static fin structure into a dynamic deployment mechanism. As the projectile rotates during launch, the helical pathway guides the fin member through controlled axial and rotational movement, ensuring consistent deployment timing and position. This dynamic pathway replaces static deployment mechanisms that suffered from inconsistency.
Solution Approach 2:
The unidirectional ratchet collar member acts as an intermediary between the fin member and the hinge pin shaft. It mediates the deployment process by allowing axial movement during deployment while preventing reverse movement after deployment. This intermediary component ensures reliable locking in the deployed position, eliminating the erratic locking behavior of previous systems.
2Ease of operation
If fins are deployed using existing mechanisms, then deployment occurs, but erratic movement and distortion compromise aerodynamic performance
Solution Approach 1:
The helically-oriented pathway in the hinge pin shaft uses curved geometry to guide the fin member's movement. This curved pathway ensures that the fin deploys along a precise arc, eliminating erratic movement and distortion. The helical curvature transforms the deployment motion into a controlled simultaneous axial and rotational movement, ensuring the fin reaches its deployed position with correct orientation for optimal aerodynamic performance.
Solution Approach 2:
The deployment mechanism utilizes the dynamic conditions of launch (centripetal and aerodynamic loads) to drive fin deployment. Instead of relying on complex mechanical actuators that may fail or deploy erratically, the system dynamically responds to the forces already present during launch, ensuring consistent and precise fin deployment that maintains aerodynamic integrity.
3Reliability
If a deployment mechanism is added to ensure consistent fin deployment, then reliability improves, but device complexity increases
Solution Approach 1:
The fin deployment system is designed to self-deploy using the forces generated during launch itself. The unidirectional ratchet collar member automatically engages and locks the fin in its deployed position through the natural rotational and axial movements caused by launch forces, without requiring external actuators, motors, or complex control systems. This self-service approach achieves reliable deployment while minimizing added complexity.
Solution Approach 2:
The unidirectional ratchet collar member serves as a simple intermediary component that provides reliable locking functionality without complex mechanisms. It allows deployment movement in one direction while automatically preventing reverse movement, achieving reliable fin retention with a single, simple component rather than complex multi-part locking systems.
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 system ensures consistent and stable fin deployment, enhancing aerodynamic performance by eliminating mechanism distortion and erratic loading, while maintaining a compact design to maximize payload capacity.
Implementation Method 1
Such simultaneous axial and rotational movement is induced, at least partially, by application of a centripetal load and aerodynamic load as the projectile rotates upon launch from a chamber
Implementation Method 2
Such simultaneous axial and rotational movement is induced, at least partially, by application of a centripetal load and aerodynamic load as the projectile rotates upon launch from a chamber
Implementation Method 3
The unidirectional ratchet collar member, which is to retain the fin member in the deployed position, is disposed on the hinge pin shaft for unidirectional axial movement and radial expansion induced by the simultaneous axial and rotational movement of the fin member
Data Source
AI summary
A fin deployment system for a projectile positioned in a chamber, the fin deployment system including a non-rotatable hinge pin shaft, a fin member, and a unidirectional ratchet collar member. The non-rotatable hinge pin shaft, which is coupled to the shell, defines a helically-oriented pathway. The fin member has a fin lug that couples the fin member on the hinge pin shaft for simultaneous axial and rotational movement along the helically-oriented pathway to a deployed position at an aft region of the projectile. Such movement is induced at least partially by application of a centripetal load and aerodynamic load as the projectile rotates upon launch from a chamber. The unidirectional ratchet collar member is disposed on the hinge pin shaft for unidirectional axial movement and radial expansion induced by the simultaneous axial and rotational movement of the fin member that retains the fin member in the deployed position.