Abstract: A method for rotating a toggle link upon an acceleration event greater than a predetermined threshold. The method including: biasing a toggle link against a stop when the acceleration event is less than the predetermined threshold, a position of the toggle link against the stop being on a first side of a singular position of the toggle link; biasing the toggle link towards an opposite direction from the stop when the toggle link is positioned on a second side of the singular position; and moving the toggle link from the first side of the singular position to the second side of the singular position when the base structure undergoes an acceleration event greater than a predetermined threshold.

Abstract: A micro-electrical-mechanical system (MEMS) cantilever assembly includes an intermediary cantilever portion, a main cantilever arm configured to couple a moveable portion of a micro-electrical-mechanical system (MEMS) and the intermediary cantilever portion, and a plurality of intermediary links configured to couple the intermediary cantilever portion to a portion of the micro-electrical-mechanical system (MEMS).

Abstract: A mechanism including: a toggle link rotatably connected to a base structure; a first element associated with the toggle link; a second element associated with the base structure; a biasing element having a first end attached to the base structure and a second end attached to the toggle link such that the first element moves towards the second element; and a blocking element movably disposed between a first position blocking movement of the toggle link and a second position allowing to first element of the toggle link to move towards the second element when the base structure undergoes an acceleration event greater than a predetermined threshold.

Abstract: The safing system employs a multi-axis accelerometer system and multi-axis gyroscope system and a processor that is programmed to iteratively read acceleration data from the accelerometer system and apply a multi-axis rotation on the acceleration data using gyroscope data iteratively read from the gyroscope system to generate rotationally corrected acceleration data and further programmed to calculate a cumulative distance measure using the rotationally corrected acceleration data. The processor then compares the cumulative distance measure with a predetermined reference measure and to issue a control signal to enable arming of the device when the cumulative distance measure exceeds the reference measure.

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 G-switch including: a base and posts, the posts having a hole; a locking ball with a portion disposed in the holes; a striker mass movably disposed relative to the posts and having a concave portion, wherein a portion of the locking balls is disposed the concave portion; a collar movable relative to the posts; a biasing element for biasing the collar in a position which retains the locking balls within the concave portions, the biasing element permitting movement of the collar to a position in which the locking balls are released from the concave portions to release the striker mass upon a predetermined acceleration profile; and a member on the striker mass and first and second electrically conductive contacts on a portion of the body, the first member opening or closing an electrical circuit between the first and second contacts upon release of the striker mass.

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 safety device for a fuze of a projectile that includes a detonating device for detonating the fuze. The safety device has a safety unit with a processor for safeguarding a detonation process of the detonating device. The safety unit contains a sensor unit configured to output a disengagement signal at a predetermined acceleration state. The processor is set up to output a control signal to release the safety unit in accordance with the presence of the disengagement signal. A low-acceleration state of the flight of the projectile can thus be detected and used as release parameter.

Abstract: A time control device for the movement of a micro-machined or micro-engraved counterweight with respect to a substrate, said counterweight incorporating at least one face having at least one indentation intended to cooperate with at least one other indentation on a housing in which said counterweight moves so as to ensure the delaying of said movement of said counterweight, wherein said one indentation on said counterweight respectively on said housing receiving said counterweight is made on at least one flexible tongue itself integral with said counterweight respectively said housing, said at least one flexible tongue being able to be deformed by bending during the displacement of said counterweight.

Abstract: A micro-machined or micro-engraved safety and arming device for a projectile pyrotechnic train, said device comprising a substrate onto which a shutter is positioned to ensure the blocking of a channel, said shutter being mobile in translation on said substrate, said shutter being held immobile in the safety position by at least one acceleration lock that is released further to the application of the axial acceleration imparted to said projectile during firing, wherein said acceleration lock is constituted by at least one breakable tongue linking said shutter to said substrate, said tongue being oriented and dimensioned such that the axial inertial stresses developed during firing and exerted on said shutter cause said tongue to break.

Abstract: An inertial igniter including: a body having a base and three or more posts, each post having a hole; a locking ball corresponding to each post, wherein a portion of the locking balls are disposed in the hole; a striker mass movably disposed relative to the posts and having a surface corresponding to the posts, the striker mass further having a concave portion corresponding to the locking balls, wherein a second portion of each locking ball is disposed in a corresponding concave portion for retaining the striker mass relative to the posts; a collar movable relative to the posts; and a biasing element for biasing the collar in a first position which retains the striker mass, the biasing element permitting movement of the collar to a second position to release the striker mass relative to the posts upon a predetermined acceleration profile.

Abstract: A device for enabling safe/arm functionality in a gravity dropped weapon. The device including: a rack for attaching the weapon to an airframe; an elastic element disposed in the weapon; a releasable connection between the weapon and the airframe to release a stored energy in the elastic element; and a piezoelectric member connected to one end of the elastic member for converting the stored energy to an electrical energy.

Abstract: A method for determining one or more of an impact level and direction of a weapon as it strikes a target. The method including: providing an elastic element in the weapon; providing a piezoelectric member attached to the elastic element such that elongation and/or depression of the elastic element will generate an electrical power output from the piezoelectric member; and determining the impact level based on the output of the piezoelectric member.

Abstract: A multi-stage inertial switch including: a housing having a first electrical contact; two or more members disposed in the housing, at least one end of each of the two or more members being sequentially movable upon a different level of acceleration of the housing; and a movable member movable within the housing by the sequential movement of the two or more members, the movable member having a second electrical contact capable of engagement with the first electrical contact to one of open or close an electrical circuit between the first and second electrical contacts upon an occurrence of a predetermined magnitude and/or duration acceleration event.

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 safety and arming unit for a fuse includes a firing chain having first and second firing devices defining an intermediate space therebetween and a barrier blocking the intermediate space in a safe position. The firing chain is brought into an armed position by a releasing movement vacating the intermediate space. First and second mutually independent securing devices lock the barrier in the safe position and execute an unlocking action based on two mutually independent physical arming parameters. A compact and very reliable safety and arming unit can be achieved in this way.

Abstract: A SAFE and ARM mechanism includes an elongated casing having a first end and a second end. A high-G force firing pin is arranged relatively near to the first end and a low-G force firing pin is arranged relatively near to the second end. A detonator is arranged between the high-G force firing pin and the first end. When a G-force within a first range of magnitudes is applied to the casing along its longitudinal axis, the low-G force firing pin is displaced to strike a portion of the high-G force firing pin, and if a G-force within a second range of magnitudes is applied to the casing along its longitudinal axis, the high-G force firing pin is displaced to strike the detonator. The device may become ARMED in response to a centrifugal force generated by spinning the casing on its longitudinal axis.

Abstract: A method for enabling safe/arm functionality in weapons. The method including: attaching the weapon to an airframe; providing an elastic element in the weapon; releasing the weapon from the airframe to release a stored energy in the elastic element; converting the stored energy to an electrical energy; and providing the electrical energy to one or more components in the weapon.

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: 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: Methods and apparatus for sensing acceleration according to various aspects of the present invention comprises a non-rigid membrane and a switching latch electrically coupled to the membrane. The membrane is responsive to acceleration forces and is configured to produce a signal as a result of deflections in the membrane caused by acceleration. The signal is transmitted to the switching latch causing a change in state of the switching latch. This change in state allows a second signal to be sent to an activating device such as a squib.

Abstract: Methods and apparatus for sensing acceleration according to various aspects of the present invention comprises a non-rigid membrane and a switching latch electrically coupled to the membrane. The membrane is responsive to acceleration forces and is configured to produce a signal as a result of deflections in the membrane caused by acceleration. The signal is transmitted to the switching latch causing a change in state of the switching latch. This change in state allows a second signal to be sent to an activating device such as a squib.

Abstract: An ammunition firing device incorporating a firing pin intended to impact a pyrotechnic composition to activate its ignition, wherein said firing pin incorporates a rod that slides when said ammunition is fired through the effect of the firing acceleration from a starting position to a deployed position, able to be locked in said deployed position, said rod being integral with a percussion tip occupying a fixed position in contact with said pyrotechnic composition, said rod being located fully inside said tip in said starting position and protruding from said tip in its deployed position, said device further incorporating a hammer to strike said rod during the impact of said ammunition on a target to cause the ignition of said composition.

Abstract: An inertial igniter including: a housing; a striker mass movable relative to the housing; a biasing element for biasing the striker mass towards a percussion primer; one or more movable members each having one or more stops, the one or more stops having a first position for preventing a portion of the striker mass from striking the percussion primer and a second position allowing the portion of the striker mass to strike the percussion primer; wherein the movable members move the one or more stops to the second position when subjected to a predetermined acceleration profile.

Abstract: An inertial igniter for use with a thermal battery for producing power upon acceleration is provided. The inertial igniter including: a base; at least one member disposed on the base, the at least one member having a hole; a mass movable towards the base, the mass having a concave portion; a locking ball disposed in the hole in the at least one member and having a portion thereof disposed in the concave portion for preventing relative movement of the mass with the base when an acceleration time profile is below a predetermined threshold; and a biasing spring including a portion for preventing the locking ball from leaving the concave portion when the acceleration time profile is below the predetermined threshold and for allowing the locking ball to leave the concave portion when the acceleration time profile is below the predetermined threshold to unlock the mass and permit movement of the mass relative to the base.

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 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 multi-stage inertial switch including: a housing having a first electrical contact; two or more members disposed in the housing, at least one end of each of the two or more members being sequentially movable upon a different level of acceleration of the housing; and a movable member movable within the housing by the sequential movement of the two or more members, the movable member having a second electrical contact capable of engagement with the first electrical contact to one of open or close an electrical circuit between the first and second electrical contacts upon an occurrence of a predetermined magnitude and/or duration acceleration event.

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: An inertia igniter including: a housing; and a movable striker supported by first and second stages, the first stage having a first locking element for releasing the second stage upon a first predetermined acceleration of the housing and the second stage having a second locking element for releasing the striker upon a second predetermined acceleration of the housing greater than the first predetermined acceleration. Wherein the first and second locking elements of the first and second stages occupy a common cross-sectional volume along a longitudinal axis of the housing.

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: 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: An inertial igniter including: a first member having a wall and internal cavity; a second member slidable in the internal cavity, a striker disposed thereon and a first concave portion; a third member slidable on an exterior surface of the wall, a second concave portion; biasing springs for biasing the first and second members in a direction opposite an acceleration; locking balls in the first and second concave portions for preventing movement of the second and third members when the acceleration time profile is below a predetermined threshold; and a percussion cap primer on the first member; wherein when the acceleration time profile is greater than the predetermined threshold the locking balls are released from the concave portions to first permit relative movement of the third member with the first member and after a time delay to permit relative movement of the second member with the first member.

Abstract: A switch mechanism is provided that has a tubular enclosure; a contact pin electrically insulated from the tubular enclosure; a g-weight positioned inside the tubular enclosure and movable from an open position to a closed position; and a transparent closure that encloses one end of the tubular enclosure. The g-weight is in electrical contact with the contact pin and the tubular enclosure when the g-weight is in the closed position, such that a continuous electrical path exists from the contact pin to the tubular enclosure. The g-weight is for moving from the open position to the closed position when the switch mechanism is subjected to an acceleration greater than a threshold acceleration. The g-weight is visible through the transparent closure such that the position of the g-weight can be determined without removing the transparent closure from the tubular enclosure.

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: 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 aims to increase the overflight safety of a projectile, comprising a time-fuse which has an acceleration-activated battery. To this end, the safety device actuates a switch, whose position is interrogated during the flight phase and the fuse function is deactivated, if the switch is not in the correct position.

Abstract: A MEMS type safe and arm apparatus for a fuze includes a setback slider responsive to a first setback acceleration, the setback slider moving linearly in response to the first setback acceleration; a setforward slider responsive to a first setforward acceleration, the setback slider unlocking the setforward slider, the setforward slider moving linearly in response to the first setforward acceleration; a first rotor responsive to a second setback acceleration, the setforward slider unlocking the first rotor, the first rotor rotating in response to the second setback acceleration; a second rotor responsive to a second setforward acceleration, the first rotor unlocking the second rotor, the second rotor rotating in response to the second setforward acceleration; and an arming slider that moves linearly in response to the rotation of the second rotor to thereby arm the fuze.

Abstract: The invention relates to an electronically and mechanically-operated ignition delay which is used in cartridge-type pyrotechnic decoy flare ammunition. Said ignition delay comprises a cylindrical sleeve (10), containing an ignition device (1) in the base, a propellant (2) for expelling the inflammable active material (8) and devices (9) for delaying the ignition of the active material. The electric ignition device of the propellant charge is galvanically connected to a capacitor element (3) which is fixed in the propulsion reflector (4). Said capacitor element is galvanically connected to a mechanical switch-on element (7) in the active material, whereby said mechanical switch-on element is, in turn, galvanically connected to an electric ignition unit in the active material. The switch-on process is thus triggered by the relative movement of the active material as it travels along the sleeve axis away from the propulsion reflector.

Abstract: A safe/arm apparatus includes a slider barrier having at least one notch formed therein, the slider barrier including an optically diffuse surface and an optically reflective surface; at least one mechanical lock removably disposed in the at least one notch; a linear actuator for moving the slider barrier from a safe position to an armed position; a battery; a laser diode connected to the battery, the laser diode emitting a light beam towards the optically diffuse surface when the slider barrier is in the safe position and towards the optically reflective surface when the slider barrier is in the armed position; a photodiode for receiving light reflected from the optically reflective surface; a transformer connected to the photodiode; and a capacitor connected to the transformer.

Abstract: The inventive environment sensor apparatus includes an electrostatic sensor carried by the projectile. The electrostatic sensor has first and second electrical conducting areas separated by a dielectric material to form two plates of a capacitor. The first electrical conducting area is conductively connected to a current-to-voltage converter and the second electrical conducting area is conductively connected to the outside projectile body surface. A time changing electric field surrounding the projectile causes a time changing current to flow within the electrostatic sensor, which is converted to a time changing voltage by the current-to-voltage converter. A threshold detector device is conductively connected to an output of the current-to-voltage converter and provides a voltage signal to the safe and arm mechanism when the time changing voltage signal from the current-to-voltage converter exceeds a predetermined level, to indicate that a change has occurred in the sensed muzzle exit environment.

Abstract: A safety and arming unit for a round of ammunition, comprising one or more acceleration sensors for detecting when the acceleration of the ammunition reaches at least two different predetermined linear acceleration values; timer means for measuring the time interval between the detection of two of the predetermined linear acceleration values, means for electronically comparing the said measured time interval with a range of predetermined and pre-set time intervals representing satisfactory firing for the round of ammunition, and means for producing an electronic signal when the said measured time interval falls within the range of predetermined and pre-set time intervals, which signal operates to arm the ammunition ready for detonation.

Abstract: A trimode fuze is provided which comprises a combination of a standard dual ode fuze with the addition of a void sensing mechanism. The modified fuze provides detonation of a warhead under three distinct scenarios: impact upon a hard target with detonation caused by the deformation of the warhead, displacing the hard target firing pin, penetration and continuous deceleration within a solid target with detonation caused by the expiration of a penetration delay timer, and penetration of a soft target with detonation caused by the transition from a target impact deceleration to the lower preset deceleration threshold.The first two modes of detonation are similar to those found in prior art dual mode fuzes. The third mode is brought about when target impact deceleration causes compression of a spring. As the spring compresses, steel balls slide out of a locking mechanism.

Abstract: A miniature, planar, inertially-damped, inertially-actuated delay slider uator is micromachined on a substrate and consists of a "slider", with zig-zag or stair-step-like patterns on the side edges, interacting with similar vertical-edged zig-zag patterns on "racks" which are positioned across a small gap on each side. The slider has been released from the substrate, and is captured vertically in its track by a non-interfering lattice or cover or other feature that bridges across from the top of one rack to the other. The racks are fixed to the substrate and the slider is forced axially down the "track" by an inertial load in the slider's axial direction. The slider is drawn along the track such that the "teeth" on the right edge of the slider engage with the teeth on the right rack. The slider is forced to move to the left as it slides down the faces on the right rack, until it is thrown clear of the right rack and goes across to engage similarly with the left rack.

Abstract: A shock detecting device includes a housing, a weight disposed in the housing and moved by a shock which is more than a predetermined value from outside, an output member rotatably disposed in the housing and rotated in response to the movement of the weight so as to be projected from the housing and a safety mechanism being provided with a stopper pin which is formed on the weight and which contacts with the housing in an initial condition in order to maintain the weight in the initial condition, a rock lever which is rotatably supported on the housing and which being able to engage or disengage with or from the stopper pin and a first urging device which is disposed between the rock lever and the housing always for urging the rock lever so as to be engaged the rock lever with the stopper pin. According to this improved shock detecting device, it is able to maintain the high reliability of the safety mechanism with a simple structure.

Abstract: An safe and arm apparatus is disclosed wherein the apparatus utilizes setback acceleration for in-bore safety and sustained in-bore acceleration to position various members to allow for subsequent alignment of the firing train at arm time. The apparatus includes a rotor that houses an explosive lead and having a side bore hole formed therein which selectively interrupts the initiating explosive train both in front of and after the explosive train lead. The explosive interface between a detonator and a lead is unimpeded when the bore hole is in-line with a second corresponding hole in a protective cover. The rotor is normally secured by a setback lock and a shear tab. Upon launching from a gun, an in-bore lock (in conjunction with a retaining collar) moves down at a low acceleration level to additionally secure the rotor out-of-line while the projectile is in the gun tube.

Abstract: An electro-mechanical base element fuze is disclosed wherein mechanical innovations along with the latest in electronic sensing, signal processing and miniaturization provide safety and simplicity as well as improving performance, reliability and reducing costs.

Abstract: A mechanical sensor for a passenger restraint system includes several primers for activating a gas generating component, and a trigger for setting the primers off in response to a velocity change. The sensor also includes an inertial mass for sensing the change in velocity. The sensor and the restraint system coact to arm the sensor when the sensor is inserted into the system.

Abstract: The invention provides a projectile adapted to be fired from a smooth bore weapon, such as a shotgun, by means of a cartridge containing a propellant charge. The projectile comprises a generally cylindrical casing and a warhead assembly, the warhead being hollow to accommodate an explosive charge and an initiator, the casing being formed with a firing pin spring biased to a safety position and locked in the safety position by a spring biased safety pin. The spring biased safety pin is adapted to release the firing pin in a predetermined period of time after the projectile exits from the weapon. The casing includes a plurality of fins foldable within the cartridge, but which deploy radially on leaving the weapon.

Abstract: The invention relates to an impact fuse (2) having fore-bore safety for a projectile (1), comprising a percussion needle (3) stationary on the fuse and an impact body (4) containing a percussion cap (5) and supported slidingly in the direction of flight, as well as a race for a blocking ball (23) between the impact body and the inner wall of the projectile casing. Which, upon premature impact on an obstacle, is jammed in its race (22) between a shoulder (18, 19, 20) on the inner wall of the casing and a ramp (17) of a groove (14, 15, 16) on the impact body (4), thereby preventing detonation. In order to allow for adjustment of predefined distances for the fore-bore safety, the invention proposes giving the race (22) for the blocking ball (23) a stepped design so that the blocking ball (23) can be jammed at several places within the fuse (2) between shoulders (18, 19, 20) and ramps (17) of different grooves (14, 15, 16).