Broach Recoil Mechanism for UUV Stability
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Solution Overview
Problem
Underwater guns on unmanned underwater vehicles (UUVs) face challenges in managing recoil, which can destabilize the vehicle and unpredictably alter the trajectory of projectiles due to fluid dynamic drag, potentially damaging the UUV and affecting aim-point accuracy.
Innovation Solution
A broach recoil system where the barrel 'floats' and engages a broach recoil mechanism only after the projectile exits, decelerating the barrel by cutting into an arresting cartridge, transferring the recoil load to the UUV, allowing it to accelerate away from the target and minimize peak g-loads, thus stabilizing the UUV and maintaining accurate trajectory.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the barrel is rigidly mounted to the UUV, then the structure is simple and strong, but the recoil will destabilize the UUV and alter projectile trajectory
Solution Approach 1:
The barrel is made dynamically movable rather than rigidly fixed. The barrel is free to recoil along its longitudinal axis within the weapon housing, allowing it to move backward when fired. This dynamic configuration absorbs recoil forces without transferring them to the UUV, maintaining both vehicle stability and trajectory accuracy.
Solution Approach 2:
The weapon system is segmented into separate functional components: the barrel is separated from the UUV structure by a weapon housing. The barrel can move independently within the housing, isolating the recoil motion from the vehicle. This segmentation allows the barrel to perform its recoil function without affecting the UUV's stability.
2Stability of the object's composition
If the barrel is allowed to float freely, then recoil stability is improved, but the barrel must be arrested after firing which creates significant load on the UUV
Solution Approach 1:
The weapon housing acts as a pre-configured cushioning structure that absorbs and manages the barrel's recoil motion. The housing provides a controlled environment for the barrel to move, and the broach mechanism is pre-positioned to engage at the appropriate moment, cushioning the arrest of the barrel in a controlled manner that minimizes peak forces on the UUV.
Solution Approach 2:
The broach mechanism is pre-positioned and ready to engage the barrel before the recoil event completes. The timing is arranged so that the broach engages the barrel after projectile exit but before the barrel comes to a hard stop, allowing controlled deceleration. This preliminary preparation of the arrest mechanism spreads the force application over time and distance, reducing peak loads on the UUV.
3Productivity
If the broach mechanism engages immediately, then the barrel is arrested quickly, but the projectile trajectory may be affected by barrel motion
Solution Approach 1:
The timing of the broach engagement is carefully designed to occur after the projectile has exited the barrel. This preliminary sequencing ensures that the barrel is allowed to complete its recoil motion freely during the critical firing phase, maintaining trajectory accuracy. Only after projectile exit does the broach engage to arrest the barrel, at which point trajectory is no longer affected.
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 broach recoil system effectively mitigates recoil-induced yaw and pitching motions, preventing damage to the UUV and ensuring accurate projectile trajectory by distributing the recoil load over a defined distance, ensuring the UUV's survivability and aiming precision.
Implementation Method 1
The cutting surfaces then engage the arresting cartridge, cutting into it (e.g., similar to broaching), producing fine shavings. This arrests the barrel over several inches of travel.
Implementation Method 2
This mechanism decelerates the weapon's barrel while simultaneously accelerating the UUV. Thus, once the recoil mechanism engages, the UUV will accelerate backwards, away from the target.
Data Source
AI summary
A broach recoil mechanism includes an arresting cartridge and a broach having plural cutting surfaces. The broach is disposed on the exterior of the barrel of a weapon. As a projectile is fired from the barrel, the barrel recoils, moving toward the arresting cartridge. The broach engages the arresting cartridge, shaving off pieces thereof, slowing progress of the barrel while transferring the recoil load to the hull of a unmanned underwater weapon containing the weapon.