Fin Retention Mechanism for Gun-Launched Projectiles
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Solution Overview
Problem
Existing fin control actuators for gun-launched projectiles are complex and expensive due to the need for robust designs to withstand high acceleration forces, and known deployment mechanisms introduce reliability issues and complexity, especially during extended storage and flight.
Innovation Solution
A fin retention and deployment mechanism that uses a telescoping shaft with a latching mechanism, where the actuator for controlling fin angles also initiates deployment, eliminating the need for separate cover retention or release systems and allowing the shaft to be supported over its entire diameter, reducing the need for costly bearings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing actuators with separate deployment mechanisms are used, then fins can be deployed, but device complexity increases and reliability decreases
Solution Approach 1:
The patent combines the deployment function and the control function into a single actuator mechanism. The actuator that controls fin angles during flight also initiates deployment by rotating the shaft to unlatch the retaining member, eliminating the need for separate deployment actuators and reducing overall system complexity
Solution Approach 2:
The actuator is designed to perform multiple functions: it both deploys the fins by releasing the latch mechanism and controls the fin angles during flight. This multi-functionality reduces the number of components needed and simplifies the overall system architecture
2Reliability
If separate cover retention systems are used, then fins are retained during storage, but device complexity and cost increase
Solution Approach 1:
The retaining member is integrated directly into the actuator mechanism rather than being a separate cover or retention system. The actuator's rotation directly unlatches the retaining member, combining the retention and deployment functions into one mechanism
Solution Approach 2:
The patent eliminates the separate ejectable cover and its associated retention springs by integrating the retention function directly into the actuator mechanism. The retaining member is part of the actuator assembly itself, removing the need for separate retention systems
3Strength
If short shafts with bearings are used, then fins are supported during flight, but cost increases
Solution Approach 1:
The patent uses an asymmetric support arrangement where the shaft is supported at its ends by the actuator housing rather than using bearings along the entire shaft length. This asymmetric support structure provides sufficient strength while reducing manufacturing costs
Solution Approach 2:
The patent replaces expensive precision bearings with simpler, cheaper support structures such as bushings or direct contact surfaces in the actuator housing. These simpler components provide adequate support for the shaft while significantly reducing manufacturing costs
Data Source
AI summary
A fin retention and deployment mechanism that has the advantage of providing for the deployment of aerodynamic control surfaces on command without the need for an additional actuation device or control circuitry separate from the actuator that controls the angle of the fins during flight. The actuator that is already required for operation of the control surfaces after deployment initiates the deployment of the fins, as well. A latch mechanism comprises a retaining member and a lath, which engages the retaining member enabling a biasing mechanism to force the fins from a stowed position to a fully deployed position.