Abstract: A method for actuating a device, the method including: biasing a first movable member in a first direction; biasing a second movable member in a second direction; blocking a movement of the second movable member at a position along a second path when the first and second movable members experience a first acceleration having a first magnitude and a first duration; and allowing the second movable member to move along the second path past the position when the first and second movable members experience a second acceleration having a second magnitude and a second duration, the second magnitude being less than the first magnitude and the second duration being greater than the first duration.

Abstract: A method for detecting a number of events having an acceleration profile greater than a predetermined threshold. The method including: detecting a number of events having the acceleration profile greater than the predetermined threshold; counting the number of events detected having the acceleration profile greater than the predetermined threshold; and outputting a mechanical or electrical signal based on whether the counted number of events having the acceleration profile greater than the predetermined threshold is greater than a predetermined number.

Abstract: A method for igniting a thermal battery upon a predetermined acceleration event. The method including: rotatably connecting a striker mass to a base; aligning a first projection on the striker mass with a second projection on the base such that when the striker mass is rotated towards the base, the first projection impacts the second projection; and preventing impact of the first and second projections unless the predetermined acceleration event is experienced.

Abstract: A method of igniting one of a pyrotechnic material and primer during or after an all fire setback acceleration. The method including: positioning a mass element along an inclined surface; biasing the mass element in a direction into the inclined surface such that the mass element traverses the inclined surface upon the all fire setback acceleration against the biasing; drawing the mass element toward one of a pyrotechnic material and primer with the biasing after the mass element traverses the inclined surface. The method can further include delaying the drawing until the mass element experiences a set forward acceleration. The delaying can include drawing the mass element into a delay well after the mass element traverses the inclined surface and drawing the mass element across a delay wedge when the mass element experiences the set forward acceleration.

Abstract: A fuze for a submunition comprises a fuze housing with a stabilizer ribbon for aerodynamic orientation, a fuze slider released by tension on the stabilizer ribbon, an air-powered electric generator extended into the airstream by the fuze slider and powered in flight by high-speed airflow, a MEMS safety and arming device, a fuze circuit board including an explosive fireset, and an electrically initiated firetrain. The fuze is fixed to and communicates explosively with the end of a grenade warhead.

Abstract: A representative embodiment of the invention provides a MEMS-based safety and arming (S&A) device having a shuttle movably connected to a frame by one or more bowed springs. The device has an electrical path adapted to electrically connect the frame and a contact pad. In the initial state, the electrical path has an electrical break. If the inertial force acting upon the shuttle (e.g., during launch) reaches or exceeds a first threshold value, then displacement of the shuttle with respect to the frame causes the electrical break to close. If the inertial force reaches or exceeds a second threshold value greater than the first threshold value, then a latching mechanism employed in the S&A device latches to keep the electrical break irreversibly closed thereafter.

Abstract: A MEMS mechanical initiator having a striker arm extending from a striker body. The tip of the striker arm is adjacent to, but does not touch, the side of a microdetonator. A cocking and release mechanism moves the striker body such that the striker arm pulls away from the side of the microdetonator against the action of a set of springs connected to the striker body. Thereafter the cocking and release mechanism releases the striker body such that the tip of the striker arm swipes the side of the microdetonator causing initiation thereof.

Abstract: An inertia igniter including a mechanical delay mechanism having two or more members which are movable under different acceleration conditions to sequentially move a movable member upon sequential movement of the two or more members and an ignition member actuatable by the movable member such that movement of the movable member by the two or more members ignites the ignition member. The movable member can be movable by one of translation and rotation. The inertia igniter can further comprise an impact mass releasably movable in the housing, wherein the impact mass is released and movable by movement of the movable member to impact the ignition member. The inertia igniter can also further comprise a stop member for preventing movement of the impact mass until the movable member has moved a predetermined distance.

Abstract: A MEMS fuze having a moveable slider with a microdetonator at an end for positioning adjacent an initiator. A setback activated lock and a spin activated lock prevent movement of the slider until respective axial and centrifugal acceleration levels have been achieved. Once these acceleration levels are achieved, the slider is moved by a V-beam shaped actuator arrangement to position the microdetonator relative to a secondary lead to start an explosive train in a munitions round.

Abstract: Microelectromechanical (MEM) safe-arm devices comprise a substrate upon which a sense mass, that can contain an energetic material, is constrained to move along a pathway defined by a track disposed on the surface of the substrate. The pathway has a first end comprising a “safe” position and a second end comprising an “armed” position, whereat the second end the sense mass can be aligned proximal to energetic materials comprising the explosive train, within an explosive component. The sense mass can be confined in the safe position by a first latch, operable to release the sense mass by an acceleration acting in a direction substantially normal to the surface of the substrate. A second acceleration, acting in a direction substantially parallel to the surface of the substrate, can cause the sense mass to traverse the pathway from the safe position to the armed position.

Abstract: A projectile comprises a payload portion and an airburst fuze mounted on a rear of the projectile and explosively connected to the payload portion. The airburst fuze comprises an arming and firing electrical circuit including a setback generator; a slider that is movable from a safe position to an armed position, the slider including a detonator attached thereto; a setback lock and a spin lock that lock the slider in the safe position and, in response to a setback acceleration and a spin rate, respectively, unlock the slider; and an actuator that moves the slider to the armed position in response to a first input from the arming and firing electrical circuit; wherein a second input from the arming and firing circuit activates the detonator when the slider is in the armed position.

Abstract: A MEMS resettable timer including a primary inertial element and at least one secondary inertial element, which includes a camming surface. When the secondary inertial element moves, its camming surface engages the camming surface of a locking element to remove it from the notch of a subsequent inertial element. When the primary inertial element is released for movement it activates a resetting arrangement to place the secondary inertial element back to the initial position and prevent further movement of the primary inertial element. The cycle is repeatable to commence some predetermined action.

Abstract: A two-stage acceleration sensing apparatus is disclosed which has applications for use in a fuze assembly for a projected munition. The apparatus, which can be formed by bulk micromachining or LIGA, can sense acceleration components along two orthogonal directions to enable movement of a shuttle from an “as-fabricated” position to a final position and locking of the shuttle in the final position. With the shuttle moved to the final position, the apparatus can perform one or more functions including completing an explosive train or an electrical switch closure, or allowing a light beam to be transmitted through the device.

Abstract: A two-stage acceleration sensing apparatus is disclosed which has applications for use in a fuze assembly for a projected munition. The apparatus, which can be formed by bulk micromachining or LIGA, can sense acceleration components along two orthogonal directions to enable movement of a shuttle from an “as-fabricated” position to a final position and locking of the shuttle in the final position. With the shuttle moved to the final position, the apparatus can perform one or more functions including completing an explosive train or an electrical switch closure, or allowing a light beam to be transmitted through the device.

Abstract: The fuze is armed only if muzzle exit is sensed by a magnetic sensor within a predetermined time after setback is sensed and either one or both of a minimum spin rate is sensed by the magnetic sensor and/or a minimum number of turns are counted.

Abstract: The invention provides a safety system for a small arms projectile in which an initiating device is impacted by a firing member in order to detonate a main explosive charge. The system requires the firing member to be retained in a safe position in relation to the initiating device by at least two independent mechanisms. The firing member is initially supported in a forward position, in which it assists in holding the initiator device in a safe condition, and is caused to move rearwardly, through inertia, when the projectile is fired, destroying one of the retaining mechanisms and allowing the initiator device to adopt a primed position in which it can be activated by the firing member which at this time is retained by the other retaining mechanism which is automatically released when the projectile is in flight.

Abstract: The invention provides a safety system for a small arms projectile in which an initiating device is impacted by a firing member in order to detonate a main explosive charge. The system requires the firing member to be retained in a safe position in relation to the initiating device by at least two independent mechanisms. The firing member is initially supported in a forward position, in which it assists in holding the initiator device in a safe condition, and is caused to move rearwardly, through inertia, when the projectile is fired, destroying one of the retaining mechanisms and allowing the initiator device to adopt a primed position in which it can be activated by the firing member which at this time is retained by the other retaining mechanism which is automatically released when the projectile is in flight.

Abstract: A projectile fuze includes a detonator carrier having a safety position and an armed position; a pin having a blocking position in which it holds the detonator carrier in the safety position and a releasing position in which the pin allows the detonator carrier to move into the armed position; a spring urging the pin into the releasing position; a pyrotechnical delay element exposed to hot propellant gases for causing ignition and combustion of the delay element; and a pin-supporting component maintaining the pin in the blocking position against a force of the spring. The pin-supporting component is held in the pin-maintaining state by the delay element until combustion thereof, whereby the pin is allowed to move into the releasing position upon combustion of the delay element.

Abstract: A device for firing a pyrotechnic propellent composition having a sensor mass (3) which for firing purposes releases a locking lever (4) which in the rest position bears lockingly against a ring (9) of the firing pin (1).

Abstract: An arming and safing system for a missile having an acceleration responsive mechanism for actuating a timing device upon launching to insure arming only after the passage of a predetermined period of time, and an omnidirectional impact switch for activating a dudding switch in case of missile impact at a distance less than a minimum safe distance from the launching vehicle.

Abstract: A decoy flare ignition system is disclosed which includes an ignition initiator disposed at the aft end of the flare housing. An illuminant igniter is positioned in direct contact with the flare illuminant. The illuminant igniter includes at least one illuminant igniter pellet selected such that the firing of the ignition initiator triggers combustion of the illuminant igniter pellet if the safe-and-initiation device has been actuated. The igniter pellet is preferably configured as a circular cylindrical shell and is positioned over the bore of the flare illuminant.

Abstract: An apparatus and method for safing and arming a projectile is disclosed. The apparatus utilizes an out of line rotor configuration where the detonator is mounted in the rotor. In the safe position, the detonator is out of line with an explosive lead. The rotor is locked out of line with two independent locks. One lock is removed at gun launch setback and the second lock is removed at the time of arming, when a preselected environment is detected by electronics and safe separation is assured. The first lock includes a spring and a weight where the weight is biased in a position to prevent the rotor from moving to an in line position. At setback, the g-forces act on the weight to overcome the spring and the weight is removed from the path of the rotor. Once the selected environment is sensed and safe separation is established the electronic input to arming is permitted.

Abstract: An inertia element within a projectile is displaced to a retracted position y acceleration of the projectile during launch to unblock displacement of a slider to an armed position in response to subsequent pressurization of a projectile flight motor. Safe separation timers are thereby enabled in response to proper launch to delay pressurization of the flight motor and powering of an explosive firing circuit through switches actuated by said displacement of the slider from a safe position to the armed position. The slider is held in its safe position by an electrically grounded shear wire that is ruptured in response to slider displacement thereby removing a power disabling shunt connection to the firing circuit.

Abstract: A propellant igniter that is controlled by temperature and is activated by cceleration. The igniter includes a booster or primer for igniting a propellant charge. A spring-loaded firing pin is cocked by a rotating sear that, when released, energizes the booster. Rotation of the sear is controlled by a plurality of springs one of which produces a moment on the sear that is a function of temperature while others, a plurality of captive springs, produce restoring forces that are inversely proportional to acceleration as detected by an acceleration sensor. When the captive springs are sufficiently relaxed by the acceleration sensor, due to an increased acceleration, to allow the sear to rotate, the cocked firing pin is released, the booster is activated and ignition occurs.

Abstract: An after-firing safety device in a projectile with percussion fuze includes a spiral spring set having at least three springs wound up in series with respectively opposite directions. The spring set, maintained under tension by a cage, starts to uncoil as soon as the cage slides off the spiral spring set on account of the acceleration of the projectile during firing. The time elapsing until a central aperture has been entirely vacated depends on the number of springs, the spring lengh, the spring tension, and the friction characteristic. The after-firing safety device is equally well suited for spinning projectiles as well as nonspinning projectiles.

Abstract: A fuse for low-spin or non-spin projectiles comprises a detonator-carrying rotor movable to a live position. The rotor is released for movement in response to firing recoil. Movement of the rotor is effected by a spring which is relaxed prior to recoil firing and is energized in response to firing recoil.

Abstract: A combined warhead arming and drive motor ignition device for a self-propelled missile having a warhead and a drive motor comprises a first acceleration responsive means (1, 2, 3, 4) to provide an output when the missile achieves a first acceleration, a timer initiated by the output from the first acceleration responsive means and providing a first output (i) after expiry of a first period and before expiry of a second period and a second output (v) after expiry of a third period, and a speed responsive means (5, 6) to provide a speed output (ii) when the missile has attained a predetermined speed and also to provide a first distance indication output (vi) when the missile has travelled a first distance but has not yet travelled a second distance and a second distance indication (vi) output when the missile has travelled a third distance.

Abstract: A projectile fuse comprises a rotor rotatable from a safety position to a live position. A slide is arranged to immobilize the rotor in its safety position. A piston is operably connected to the slide for displacing the slide to release the rotor for rotation. A conduit communicates one end of the piston with air pressure generated in response to firing of the projectile to shift the slide in a manner displacing the slide to release the rotor.

Abstract: A safety device for a fuze of a spinning projectile comprises a spin acceleration safety element and a firing forward acceleration safety element. The firing forward acceleration safety element contains a ball displaceable by the action of the firing forward acceleration. The spin acceleration safety element employs an escapement or delay mechanism including an asymmetrically structured balance wheel whose center of gravity is radially displaced from its pivot axis such that the escapement or delay mechanism can begin to operate and time out only after the spin acceleration has ceased to be effective.

Abstract: A fuze of the type used in a rifle grenade assembly with a striker, a rotor nd a rotor lock includes one or more improvements. One pertains to the striker to prevent it from reaching a detonator-striking forward position more than once. Once it advances to the forward position it is locked in it by a spring biased locking pin. Other improvements relate to the release of the rotor by the rotor lock. The rotor remains locked, i.e. in the disarmed state even after intentional launching. It is released to assume the armed state only when the launched assembly accelerates at a certain rate toward the target.

Abstract: The projectile fuse comprises a piezoelectric generator located forward of a piercing part (2) and formed by a striker (5), a hammer (6) and a crystal (8). The firing device comprises a watch movement (11) providing a muzzle safety and making possible the positioning of a rotary support (15) for at least one primer (24). A part (2) of material with high mechanical resistance acts as the piercing head for the projectile after the dislodging of the electric generator at the moment of impact and effectively protects the watch movement (11) and the rotary support (15).

Abstract: A fuze includes a conically shaped body having a central longitudinal chal communicating with a rearward central chamber, a firing pin assembly containing a primary and a biased secondary firing pin disposed in the channel, a delay arming assembly disposed in the chamber, a sleeve containing a setback locking assembly disposed in chamber, and a pyrotechnic smoke cartridge located in the hollow of the sleeve. The arming assembly contains two V-shaped pivotable levers held in the safe position by the secondary firing pin extending into a hole in each lever and by a detent pin extending into a hole in the lower lever, each lever having a hole containing a firing ball. On firing the projectile from the gun, the biased detent pin is withdrawn by setback force and the detents on the secondary firing pin are withdrawn by centrifugal force, releasing both levers to pivot by centrifugal force and align the firing balls with the firing pins and the cartridge primer.

Abstract: A safety apparatus for a spinning projectile fuze comprises a rotor with which there is operatively associated a toothed segment which, under the action of the spin, drives a retarding or restraining mechanism and following expiration of the action of the retarding mechanism moves the rotor into its armed or live position. The safety apparatus further comprises a spin safety element and an acceleration-spin safety element. The acceleration-spin safety element contains a ball displaceable by the action of the firing acceleration, and a disc member, and the spin safety element possesses a piston displaceable by the action of the projectile spin in order to release the rotor.

Abstract: The fuze comprises a primer-carrying rotor and an inertia mass tensioning a spring under the effect of the acceleration at the start of the explosion. The inertia mass entrains the rotor at the outlet of the firing muzzle in the armed position, under the action of the spring against the retarding action of an anchor rod. The fuze comprises a reduced number of components permitting ensuring successively detonator safety, muzzle safety and a substantial trajectory safety.

Abstract: A safety and arming device using two counter-rotating gears provides stabty from acceleration forces. The gears have a natural tendency to compensate for lateral shifts which tend to speed up or slow down any one single gear. The gears are anchored by a setback weight which when released is driven back by acceleration freeing the gears to rotate due to inertia effects. Upon completion of the rotation, the detonator switch is keyed to permit fuze detonation. The time required for the gears to rotate is controlled by an escapement device.

Abstract: It comprises a cylindrical body 1 which is intended to be fixed on an explosive projectile. A detonator 12 comprising a casing 13 whose rearward portion serves as armor plating 13' is mounted slidably in a casing 11 which is fixed coaxially in the cylindrical body, from an inactive position within the casing 11 to an active position within a case member 18 which extends the casing 11 rearwardly and which is disposed in the operating position within the explosive charge 4 of the projectile. In the inactive position, the detonator is retained by balls 19 which are partially engaged in a groove 16 provided in a cover 15 which extends the detonator in a forward direction, and emerge from openings 20 provided in the wall of the casing 11. The balls are held in position by the bore of an arming inertia weight member 21 which is mounted slidably outside of the casing 11 and which is subjected to a resilient action and to retardation of its movement in a forward direction.

Abstract: Safety device for fuses, of the type which comprises a mobile element, which can be moved from a position of safety in which aforesaid mobile element may either be part of the pyrotechnical chain, of an electric or of an electronic circuit, or contain any one of such elements, or be solid or hollow in order to obstruct or permit the passage of an element of the fuse towards its active position, characterized by the combining of a tubular bolt, assuring the locking of aforesaid mobile element; of a sheath which at least partially surrounds aforesaid bolt, of balls entered in radial passages provided in aforesaid sheath; of a collar which can move axially by the effect of inertia so as to free aforesaid passages and permit the expulsion of aforesaid balls; and of an elastic means which stresses aforesaid collar towards the closing position of aforesaid passages.

Abstract: The invention relates to a bottom fuse for an explosive projectile for example a rifle grenade comprising a hollow revolution body the rear end of which is provided either with a primer or with a percussion point and inside of which a detonator is slidably mounted. The detonator is movable from an inactive stocking position completely inside said body to an active working position partly outside of said body, and means are provided for locking the detonator in stocking position. A sleeve is further slidably mounted outside of said body and is subjected to a resilient action and to the action of delay means of its forward motion under the effect of said resilient action. Finally a percussion point carrier or a primer carrier is slidably mounted outside of the rear end of said hollow revolution body and is subjected to a resilient action intended to maintain the percussion point away from the primer.

Abstract: A fuse includes a detonator-carrying rotor which can be turned from an armed position to a safety position. A first safety mechanism is provided for preventing return of the rotor to the armed position until the projectile has been fired. An additional safety mechanism is provided which prevents the first safety mechanism from releasing the rotor until the additional safety mechanism is deactuated. The additional safety mechanism includes independently operable elements, one of which shifts from a safety position and the other of which shifts into a safety position, in response to acceleration in one direction.

Abstract: A pyrotechnic delay fuze, for use in extended time explosive ordnances, crising a pyrotechnic delay cord in a spiral race in the base of the fuze. This system is activated through associated ignition materials. Upon initiation and propagation of the delay composition in the spiral race, the fuze provides a longer delay period and greater precision and reliability.