Gyro Projectile Arming Device with Centrifugal Locking

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Solution Overview

Problem

Existing safety and arming devices for gyrostabilized explosive projectiles, particularly those of medium caliber, face challenges in integrating electrically initiated detonators without a primer on a rotor and in accommodating larger screens due to complex drive means and control locks, making them difficult to implement effectively.

Innovation Solution

A safety and arming device with a screen formed by two half-screens that move transversely and are locked by both an inertial lock and a centrifugal lock, allowing for electrical initiation without a rotor-mounted primer, where the half-screens are slidably mounted in a coaxial rotor and locked by a spiral spring that unfolds under centrifugal force.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a primer is placed on the rotor for percussion initiation, then the device is suitable for traditional pyrotechnic priming, but it increases device complexity and is incompatible with electrical initiation systems

Engineering Contradiction:
Improvecompatibility with electrical initiationVSAvoidstructure of rotor-mounted primer system
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The invention extracts the primer from the rotor assembly and places it in a fixed position along the projectile axis, separate from the rotating components. This allows the rotor to function purely for stabilization and alignment while the primer remains stationary, compatible with electrical initiation systems without requiring flexible conductors or complex rotor-integrated primer mechanisms.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The safety and arming device is segmented into distinct functional components: a fixed primer assembly, a separate rotor for stabilization, and a screen mechanism with dual locks. This segmentation allows each component to be optimized independently - the primer for electrical initiation, the rotor for gyrostabilization, and the screen for safety control - reducing overall system complexity while maintaining versatility.

Inventive Principle:
Principle #1Segmentation

2Reliability

If larger screens are used to close off the transmission channel, then safety is improved, but drive means and control locks become difficult to integrate

Engineering Contradiction:
Improvesafety function of screenVSAvoidintegration of drive means and control locks
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The screen mechanism employs dynamic locking - a first lock active during firing to maintain screen closure, and a second lock (centrifugal) that activates after firing to secure the screen in the open position. This dynamic approach allows larger screens to be effectively controlled without requiring overly complex drive mechanisms, as the locking system adapts to different operational phases.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The first lock is designed to be released by axial acceleration during firing, preliminarily preparing the system for the subsequent action of the second centrifugal lock. This preliminary action sequence allows the screen to be safely managed in large dimensions by coordinating multiple locking actions rather than relying on a single complex locking mechanism.

Inventive Principle:
Principle #10Preliminary action

3Adaptability or versatility

If flexible conductors are used to supply electric current to the rotor-mounted primer, then electrical initiation is enabled, but the movement of the rotor is disturbed

Engineering Contradiction:
Improveelectrical initiation capabilityVSAvoidsmooth pivoting of rotor
Core Design Contradiction:
Adaptability or versatilityVSEase of operation

Solution Approach 1:

The invention extracts the primer from the rotating assembly and positions it in a fixed location along the projectile axis, eliminating the need for flexible conductors to supply electrical current to rotating components. This allows the rotor to pivot smoothly without any electrical connections, while the fixed primer can be reliably initiated by electrical current from the firing control system.

Inventive Principle:
Principle #2Taking out (Extraction)

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

Facilitates the integration of electrically initiated detonators into the projectile, enabling simplified assembly and reliable operation by ensuring the screens are securely locked and released at the appropriate time for programmed initiation.

Implementation Method 1

a second lock or centrifugal lock which consists of a spiral spring surrounding an outer cylindrical surface of the rotor and thus applied against the ends of the half-screens, the spiral unfolding under the effect of centrifugal force

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Implementation Method 2

the two half-screens being locked in the channel closing position by a first lock or inertial lock which is erased when the projectile is fired

Methodology Applied
Scientific EffectInertia: Inertia

Data Source

PatentEP2434252B1Security and arming device for a gyrostabilised explosive projectile and priming device implementing such a security and arming device
Publication Date: 2015.04.22 NEXTER MUNITIONS SA
  • EP2434252B1 patent drawingFigure 1a
  • EP2434252B1 patent drawingFigure 1b~2a
  • EP2434252B1 patent drawingFigure 2b~2c

AI summary

The invention relates to a safety and arming device for a gyrostabilized explosive projectile, comprising a screen (10) that closes a transmission channel (11) connecting a detonator (4) and a pyrotechnic relay (12). The screen is made up of two half-screens (10a, 10b) that can move relative to each other and transversely to the transmission channel (11). This device is characterized in that the two half-screens (10a, 10b) are slidably mounted in a bore carried by a rotor (14) coaxial with the projectile and pivotally mounted about the axis (6) of the projectile. The rotor carries the transmission channel (11). The two half-screens are further locked in the channel-closing position by at least two latches (26, 24). The invention also relates to a priming device implementing such a safety and arming device.