US Government As Represented by the Secretary of the Army

Joseph A Donini

Keith R Fulton

Louis J Adimari

Edward F Cooper

John C Yoo

Marc E Ball

John R Hertzler

A fuze operates in two modes. In a primary mode, the fuze functions similarly to a conventional M223 fuze. In a secondary, self-destruct mode, a pyrotechnic delay mechanism is initiated. The slide assembly is comprised of an aerodynamic safety release, a safety pin, a rotational firing pin fitted with a resilient member such as a spring, a M55 detonator, pyrotechnic initiator, a pyrotechnic delay mix and end cap. In use, the fuze is fitted to a grenade. As the grenade is dispensed from its carrier, a grenade stabilizer starts to oscillate. The oscillation results in an arming screw and an inertial weight to back out from a slide assembly, allowing the slide assembly to move to an in-line position relative to a main M55 detonator in-line with the arming screw (firing pin). Concurrently, the aerodynamic safety release is lifted in the upward direction under the force of the airstream, releasing the safety pin. This releases the rotational firing pin, which forces the rotational firing pin to contact the pyrotechnic initiator. The pyrotechnic delay mix burns to the end cap which propagates to the M55 detonator. The initiation of the main detonator causes the fuze to function in the primary mode or, if for any reason the primary mode fails to function the grenade, the grenade is rendered safe to handle by the secondary mode.

Pyrotechnic slide assembly

A secondary self-destruct fuze that functions in the event the primary fuze mode fails to function, and that meets the design requirements for a low cost, highly producible no-spin/low velocity operating environment. The fuze includes a bottom plate, two spacers, a firing pin, a striker, a rotor, a pyrotechnic mix, a rotor spring, a striker spring, a weight with a firing pin, a weight spring, a bore rider, a bore rider spring, a housing, a handling safety pin, and a ribbon retainer. In use, the handling safety pin is removed upon loading of the grenade in the main carrier. When the grenade is ejected, the expulsion event forces the ribbon retainer to be uncovered and the ribbon to unfurl, which releases the safety lock feature. The unfurling of the ribbon in the air stream stabilizes the grenade by causing an upward pull force. Simultaneously, the air stream forces the bore rider and the bore rider spring out of the fuze. In addition, the upward pull force translates to the weight firing pin and causes the latter to move up and away from the rotor. Both the rotor and the striker are free to move under the action of their respective springs. The burning of the pyrotechnic mix is initiated by the striker firing pin hitting the match tip at the open end of the channel in the rotor. After a predetermined delay, the detonator is functioned. In the meantime, the rotor, together with the striker have moved into their respective in-line positions. Upon impact, the firing pin of the weight is forced into the detonator, thereby igniting the lead charge of the grenade.

Self-destruct fuze for munitions

A secondary self-destruct fuze that functions in the event the primary fuze mode fails to function, and that meets the design requirements for a low cost, highly producible no-spin/low velocity operating environment. The fuze includes an improved slide assembly comprised of an aerodynamic safety release (ASR), a safety pin, a secondary firing pin fitted with a spring, a secondary detonator which is placed in alignment with the secondary firing pin, a slide, an omni directional weight release that operates at various impact angles, and a weight release support. In use, the fuze is fitted to a munition or grenade. As the grenade is dispensed from its carrier, the oscillation of a grenade stabilizer causes an arming screw to back out from the fuze slide, allowing the slide assembly to move to an in-line position relative to the center of the fuze. Concurrently, the aerodynamic safety release is lifted in the upward direction under the force of the airstream, releasing the safety pin. This releases the weight release support, which slides out of the fuze. Upon impact with ground, the omni directional weight release drops in a corresponding cavity in the slide, freeing the secondary firing pin, which then impacts the secondary detonator initiating it, which, in turn, initiates a main detonator. If for any reason the primary mode fails to function the grenade, the grenade is rendered safe to handle by the secondary mode that sterilizes a main detonator of the fuze.

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Dover, NJ, United States of America

Joseph A Donini