Silicon MEMS Safety Priming Device for Rotating Ammunition
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Solution Overview
Problem
Current safety priming devices for ammunition, particularly those using micro-electro-mechanical systems (MEMS) technology, face reliability issues due to axial and centrifugal forces during the rotation and propulsion of ammunition, leading to potential accidental activation during storage or transport.
Innovation Solution
A silicon micro-mechatronic safety priming device with two independent safeties, utilizing an inertial screw and a sliding mechanism, where axial and lateral accelerations deactivate the safeties, combining silicon MEMS technology with a different material technology for enhanced reliability and cost-effectiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single safety device is used in conventional ammunition, then the device complexity is reduced, but the reliability of the safety system deteriorates due to potential common causes of failure
Solution Approach 1:
The safety device is segmented into two independent safety mechanisms: a first safety based on an inertial screw responsive to axial acceleration, and a second safety based on a slide responsive to lateral acceleration. This segmentation eliminates common causes of failure between the two safeties while maintaining overall device functionality.
Solution Approach 2:
The inertial screw is nested within the slide structure, with the screw positioned inside the recess formed by the central element and closure elements. The slide itself is contained within the recess, creating a compact nested arrangement that achieves high reliability without proportionally increasing device complexity.
2Manufacturing precision
If silicon MEMS technology is used for the movable element, then manufacturing precision and reproducibility are improved, but the reliability deteriorates due to sensitivity to axial and centrifugal forces during rotation
Solution Approach 1:
Different materials are used for different functional components: the inertial screw is made of silicon MEMS technology for precise axial acceleration detection, while the slide is made of a different material optimized for lateral acceleration response. This local differentiation allows each component to excel in its specific function without compromising overall reliability.
Solution Approach 2:
The device employs composite construction with silicon MEMS elements combined with other materials (metals, plastics, or ceramics) for the movable element and structural components. This composite approach leverages the precision of silicon fabrication while incorporating materials with superior mechanical properties for reliability under rotational and accelerational forces.
3Reliability
If two independent safeties with different response mechanisms are used, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The two independent safety mechanisms (inertial screw and slide) are merged into a single integrated device structure. The inertial screw and slide share common structural elements including the recess, central element, and closure elements, allowing dual safety functionality without duplicating entire subsystems.
Solution Approach 2:
The inertial screw serves multiple functions: it acts as both the movable element for axial acceleration detection and as a positioning element for the slide through its interaction with the recess. The slide similarly serves as both a safety mechanism and a structural component of the device assembly.
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 device provides a highly reliable and cost-effective solution for deactivating safeties in ammunition, ensuring safe storage and transport by effectively responding to axial and rotational accelerations, thereby preventing accidental detonation.
Implementation Method 1
the physical event acting on the movable element being an axial acceleration force along said translation axis EE′ of the movable element for deactivating the first safety
Implementation Method 2
the second safety being deactivated by the presence of a lateral acceleration force perpendicular to the translation axis EE′ of the movable element caused by a rotation movement of said ammunition
Data Source
AI summary
An ammunition safety priming device using silicon micro-mechatronic systems technology, having at least two priming safeties intended to be deactivated by as many external independent physical events, includes at least one movable element, along a translation axis, for deactivating at least one of the priming safeties by action on said movable element of one of the physical events. Said movable element is produced in a material other than silicon. The device has applications including ammunition, rocket stage separation devices, and airbags.