Ultra-miniature electro-mechanical safety and arming device

A MEMS safety and arming device to arm a projectile fired from a rifled launch tube, having a series of safety interlocks responsive to the setback acceleration of firing, spin after firing, and to commands from a fuze circuit to finalize arming and to initiate detonation of the projectile by triggering a firetrain initiation spot charge, the device comprising:

• a substrate;
• a frame, including an elongated arming slider travel slot, disposed on the substrate;
• said arming slider travel slot being positioned generally perpendicular to the direction of acceleration of the projectile and aligned substantively along the longitudinal centerline of said frame;
• an arming slider disposed adjacent a first end of the arming slider travel slot for movement linearly therethrough in an arming direction, to a second end thereof, whereby the arming slider is in an arming position, the linear movement of the arming slider being in response to said spin after firing;
• an arming slider spring having a first end attached to a first arming slider latch head, which is secured in an arming slider bias spring head socket in the frame at the first end of the arming slider travel slot;
• the arming slider spring having a second end, attached to the arming slider on an end of the arming slider in the direction opposite that of the arming direction;
• the arming slider further including, on an end of the arming slider in the arming direction, a second arming slider latch head for locking the arming slider after linear movement of the arming slider by inserting the second arming slider latch head in an arming slider latch socket in the frame at the second end of the arming slider travel slot;
• a setback slider disposed on the frame, in a setback slider travel slot extending perpendicularly from within the arming slider, through the arming slider travel slot toward the edge of the frame in the direction of acceleration of the projectile, the setback slider travel slot being located eccentrically within the arming slider toward the arming direction;
• the setback slider moves linearly within the setback slider travel slot in response to setback acceleration, from a first position, pre-acceleration position, where the setback slider is partially within the arming slider and partially extending therefrom into the frame, to a second, post-acceleration position where the setback slider is nested within the arming slider, enabling the arming slider to move laterally towards its armed position;
• the setback slider having a first end in the direction of setback acceleration, to which end is attached a first end of a setback slider spring, which setback slider spring has a second end, which second end is attached to the arming slider, wherein motion of the setback slider in response to setback acceleration compresses the setback slider spring;
• a flexible arming slider latch, formed as an arm extending from a corner along the edge of the arming slider in the direction of acceleration, which corner is formed by a lateral depression in the arming slider, the arm extending obliquely in the arming direction of the arming slider and into the first side of a duct opening, which opening opens into the arming slider travel slot;
• such that, when the arming slider moves in the arming direction, the arming slider latch will transit the duct opening and impacting upon a safety catch, located in the frame on the second side of the duct opening, preventing any further motion of the arming slider in the arming direction;
• and
• a spot charge, electrically stimulated by an arming command signal from the fuze circuit, which charge generates gases that flow into the duct and expand, thereby forcing the arming slider latch into the depression within the arming slider, freeing the arming slider latch from contact with the safety catch, allowing the arming slider to continue to move into its armed position;
• the arming slider including an elongated transfer charge pocket filled with explosive, the longitudinal axis of the transfer charge pocket being aligned generally parallel to the direction of acceleration of the projectile;
• the transfer charge pocket having a first end adjacent to the edge of the arming slider opposite that of the direction of acceleration, with a thin membrane between the transfer charge pocket and the adjacent edge of the arming slider;
• a receptor charge pocket, filled with explosive, having a first end located in the frame in a position opposed to the transfer charge pocket, when the arming slider is in the armed position;
• the receptor charge pocket is separated from the arming slider travel slot by a thin membrane;
• the receptor charge pocket is integral with a larger output charge pocket, containing an output explosive charge;
• and
• means whereby the fuze circuit initiates detonation of the projectile by triggering a firetrain initiation spot charge within the device, which triggers the explosive in the transfer charge pocket, such that an explosive output therefrom which will penetrate into the receptor charge pocket and trigger the receptor charge, such that an explosive output therefrom will trigger the output explosive charge.