EP2513594B1 - Safety device for a fuze of a projectile - Google Patents

Description

The invention relates to a safety device for an igniter of a projectile, which has an ignition device for igniting the igniter, comprising a safety device with a process means for securing an ignition process of the ignition device.

A safety device for an igniter is used to prevent inadvertent activation of a main charge of a projectile, but an activation of the main charge after a release should be possible. The safety device is part of a detonator for igniting the main charge, which may be provided with a detonating chain of two or more ignition means. To ignite the main charge, the first ignition means is first activated, z. B. a tap-sensitive Minidetonator that is pierced by a piercing needle. Explosive energy of the first ignition means is transmitted by a corresponding arrangement of the first two ignition means to the second ignition means, which may be designed as a booster. This can transfer its explosive energy to an initial charge or main charge.

Previous detonators, especially simple projectiles, such as mortar shells, have as a first securing means a Vorstecker and second securing means on a device which detects the launch shock. The disadvantage of this securing means is that before loading the mortar shell, the Vorstecker must be pulled manually. Relatively often it happens that the pulling of the Vorsteckers is forgotten and the mortar shell becomes a dud.

From the US 3,332,354 A There is known a weightlessness sensing device which can be used in bullet securing devices. Over a construct with a ball held between two plates, gravity always acts on the ball, regardless of the direction of gravity Net force caused by the ball on the plates. If the net force exceeds a certain value, the pins provided on the plates are kept in a safe position. If the net force falls below this value, the pins can move from a safe to a focus position. The value of the net force thus serves as a release parameter.

From the DE 695 23 637 T2 For example, an arming unit or safety device is known in which a speed is determined by means of an acceleration sensor and an integrator and compared with a reference speed. Arming is initialized only when the reference speed is reached within a given time slot.

The US Pat. No. 7,191,707 B1 deals with a round, rolling weapon in the form of a bomb. The bomb has a fuse unit where either arming is triggered by computer or is in the presence of a motion profile indicating that the bomb is not moving. To determine the motion profile, the bomb may be equipped with three motion sensors, with a release takes place only if none of the sensors detects a movement. Alternatively it can be provided that, although a release is made, but only then a detonation is possible if no rolling motion of the bomb is more detectable.

It is an object of the present invention to provide a safety device for a detonator of a projectile, which uses a physical Entsicherungsparameter independent of a launch parameter for unlocking the securing means without a Vorstecker must be pulled.

1. a) einem Prozessmittel zum Sichern eines Zündvorgangs der Zündeinrichtung, wobei das Prozessmittel dazu vorbereitet ist, in Abhängigkeit vom Vorliegen eines Freigabesignals ein Steuersignal zum Entsichern der Sicherungseinheit auszugeben, und
2. b) einer Sensoreinheit, die dazu vorbereitet ist, bei einem festgelegten Beschleunigungszustand, der unterhalb der Erdbeschleunigung liegt, das Freigabesignal auszugeben, wobei die Sensoreinheit zum Messen von drei Richtungsbeschleunigungen in drei zueinander orthogonalen Raumrichtungen vorbereitet ist und die Ausgabe des Freigabesignals zu einem Zeitpunkt erfolgt, an dem jede der drei Richtungsbeschleunigungen zumindest um jeweils einen festgelegten Beschleunigungswert unter der Erdbeschleunigung liegt.

This object is achieved by a fuse device for an igniter of a projectile, which has an ignition device for igniting the igniter, comprising a fuse unit

1. a) a process means for securing an ignition process of the ignition device, wherein the processing means is prepared to issue in response to the presence of a release signal, a control signal for unlocking the fuse unit, and
2. b) a sensor unit prepared to output the enable signal at a predetermined acceleration condition lower than the acceleration due to gravity, the sensor unit being prepared to measure three directional accelerations in three mutually orthogonal directions, and outputting the enable signal at a time; where each of the three directional accelerations is at least one set acceleration value below the acceleration due to gravity.

The object is also achieved in particular by a fuse for a projectile of a projectile, which has a detonation chain for igniting the igniter and an interrupting means for interrupting the ignition chain, wherein the safety device comprises a sensor unit which is prepared, in an accelerated state in the detonator, which is at least a predetermined acceleration value below the acceleration due to gravity, to output a release signal, and a processing means which is prepared to output a control signal for releasing the interruption means in response to the presence of the release signal.

To unlock the igniter, the weightlessness or a state of low severity, ie low acceleration can be used. This parameter is independent of a launch parameter and can be used with it, eg. B. in connection with the use of a launch parameter, a high security against unwanted ignition can be achieved.

Since a ballistic flight is characterized by a substantially weightless state of the projectile, the sensing of the weightless state or a state of low acceleration may serve as a release parameter be used. If a predetermined acceleration state is registered in the igniter or detonator by an acceleration sensor, which, for example, is far below the acceleration due to gravity, then it can be deduced that the flight phase is present and the interrupting means can be released.

The invention is particularly suitable for ballistic missiles, such as missiles, in particular mortar shells, missiles with a non-powered flight phase, bombs and the like. Ballistic missiles fly through a trajectory that is approximately characterized by a parabolic parabola and in which the missile is in a weightless state, apart from the deceleration acceleration due to air resistance.

The ignition device may contain a priming charge. In particular, it may be part of or contain a detonating chain for igniting the detonator. The fuse unit serves to secure the ignition process, in particular against inadvertent release of the igniter. It may be embodied purely electronically, for example by processing signals from sensors which measure physical parameters and, in the presence of a predetermined signal state or a corresponding physical state of the igniter, initiating a release by issuing a control signal. In another embodiment or in addition to the described electronic variant, the securing unit may comprise mechanical securing means, for. B. an interruption means for breaking the ignition chain. The interrupting means can serve for receiving and / or deflecting the ignition energy of an ignition means, so that ignition of the further ignition means is reliably prevented by ignition energy of the first ignition means. The interrupting means may be a barrier, a means for extinguishing two firing means, or any other means for preventing or interrupting firing by the firing chain. The interruption means may comprise a plurality of securing means which unlock a barrier and advantageously have to be activated independently of one another.

In an advantageous embodiment of the invention, the ignition device comprises a firing chain with a primer for igniting the igniter and the fuse unit comprises an interrupting means for interrupting the ignition chain. As a result, an ignition process can be mechanically secured in a simple manner.

The acceleration state may be the instantaneous acceleration of the sensor unit and / or the igniter. The specified acceleration state is in particular an acceleration state in the igniter. It is at least below a specified acceleration value below the acceleration due to gravity, that is to say below a limiting value which is below the acceleration due to gravity, and may be any value below the gravitational acceleration or gravitational acceleration which is approximately 9.81 m / s ² . An acceleration range below the acceleration due to gravity is also possible, for example between 0 m / s ² and 5 m / s ² . Advantageously, the predetermined acceleration state in the longitudinal direction or flight direction of the projectile is below 5 m / s ² , it is expediently below this value in all three spatial directions, in particular the overall acceleration is below this value. The specified acceleration state or limit value or acceleration value can be determined by a corresponding setting in the securing device, for example, the sensor unit and / or the process means, or be deposited in another unit.

The sensor unit expediently contains an acceleration sensor which may be prepared to compensate for the instantaneous acceleration, e.g. B. in the igniter to measure. The acceleration may be measured due to a force acting on the acceleration sensor as a result of gravity and / or as a result of a change in the speed of the sensor as it moves through the space. The sensor unit can measure the acceleration state as one-dimensional acceleration. Expediently, the acceleration state is measured multidimensionally, in particular three-dimensionally.

Conveniently, the sensor unit is designed so that a release process begins when the acceleration state falls below the limit. The release process may begin by one or more signals that are output below the limit as the acceleration falls. The release process results in the enable signal, but may not until further conditions exist, e.g. the acceleration state is below the threshold for a predetermined period of time or it is aborted, e.g. if the acceleration state rises too fast again above the limit value.

The process means is prepared to check the presence of the enable signal and, depending on its presence, to output the control signal for unlocking. Such a preparation can be provided by a corresponding control program, the sequence of which-for example in conjunction with the input signals from the acceleration sensor-effects such a control. The control signal is expediently an electrical signal on a data line which can trigger a release in conjunction with a corresponding arming device. The enable signal is expediently also an electrical signal which is transmitted to the process agent via a data line.

The sensor unit is prepared for measuring three directional accelerations in three mutually orthogonal spatial directions. In this way, a total acceleration or an acceleration state in the igniter can be calculated in a simple manner from the three direction accelerations.

In this case, the release signal takes place only when each of the three directional accelerations is at least one fixed acceleration value below the acceleration due to gravity. For this purpose, for example, the sensor unit may comprise a logical AND link, which is only fulfilled when each directional acceleration is at least by the respective predetermined acceleration value below the gravitational acceleration.

It is also proposed that the specified acceleration value in the direction of flight be different than the specified value in the two other directions which are expediently orthogonal thereto. Whether the specified acceleration value in the direction of flight is chosen to be greater or smaller than the specified value in the other two directions can be made dependent on the missile or on mission data. If the missile is possibly subject to major imbalance or vibration during flight, it is advantageous to increase the values perpendicular to the direction of flight to ensure detente during the flight despite the disturbances. If the missile is very fast, it also experiences a relatively large negative acceleration due to the air resistance, during which it is permanently decelerated, even during the ballistic flight, which in itself is not heavy. In this case, the value in the direction of flight can be selected to be larger, so that the release signal can already take place if the acceleration state in the direction of flight is still somewhat greater.

A further advantageous embodiment of the invention provides that the specified acceleration state is below the gravitational acceleration by at least one specified acceleration value and the processing means is prepared to monitor the acceleration value in the direction of flight and to detect an absolute minimum in the course of the acceleration value. The absolute minimum indicates the lowest air resistance during the flight and thus the achievement of the vertex of the trajectory of the projectile. If the presence of this absolute minimum is used as the arming criterion which must be present for the output of the control signal, in particular simultaneously with the presence of the enable signal, the control signal is not carried out until the projectile has passed the vertex of its path. This allows a high Vorrohrsicherheit be ensured. Accordingly, the process means checks for the presence of the minimum before it outputs the control signal.

A simple check of the acceleration state to a value below the limit value, ie at least the specified acceleration value under acceleration due to gravity, can be achieved with a comparator with which the acceleration value or limit value can be set. Thus, a signal of an acceleration sensor can be compared with a preset value and a corresponding release signal can be output if the specified signal value is exceeded or fallen short of.

To increase the safety, it is advantageous if a short-term and unintentional dropping of the projectile does not lead to an unlocking of the safety device, but the release signal is only used as such when the weightless or poor condition exists for a fixed period of time. For this purpose, the securing device advantageously comprises a time element for specifying a time interval, wherein the processing means expediently outputs the control signal only when the release signal is present during the time interval, in particular is present uninterrupted.

The time element may be part of the sensor unit, part of the process means or separately. A particularly inexpensive circuit can be achieved if the time element is prepared to block the enable signal of the sensor unit during the time interval. By an RC element and a potential evaluator in the RC element, the time element can be made particularly inexpensive and reliable. Conveniently, the time interval is greater than one second, so that a free fall must be longer than 5 m in order to use the enable signal to generate the control signal can. If the time interval is greater than two seconds, an unlocking case must be more than 19.62 m.

A further advantageous embodiment of the invention is based on the following considerations. When using a three-axis acceleration sensor, a low-power condition of the igniter can be detected during the flight of the projectile. The low-energy state can be characterized by an acceleration state in which the total acceleration of the igniter is below the limit value. In this way, a state "flight" can be distinguished from the state "ground" to generate the control signal as a release criterion, in particular as a further arming criterion according to a first arming criterion.

Projectiles usually spin around their longitudinal axis during a flight, even if they are fired without a spin. A usual roll rate is up to 2 Revolutions per second, whereby modern ammunition for flight stabilization by a tail unit during flight is brought up to 20 revolutions per second. If the sensor unit is not located exactly in the axis of rotation of the projectile during flight, it is subject to a centrifugal force of the projectile in the air, which acts as a lateral acceleration and is measured by the sensor unit accordingly.

Mechanically, the sensor unit can be mounted sufficiently accurately in the longitudinal axis of the projectile, since manufacturing tolerances can be kept low. However, the geometric longitudinal axis of the projectile is usually not in the axis of rotation of the projectile, ie the axis about which the projectile rolls during the flight. The deviation can result from an asymmetrical loading of the projectile with other components and above all disintegration agents, which draw the center of gravity of the projectile from the geometric longitudinal axis. Such imbalance can lead to disturbing transverse acceleration values of the sensor unit at high roll rates, which reduce the reliability of outputting a control signal for the purpose of arming.

If the sensor unit has a roll sensor which is prepared to detect a roll of the projectile and to output a roll signal in the event of a rolling movement of the projectile, then the roll can be recognized and processed as additional information, e.g. from the process means for outputting the control signal for unlocking. Conveniently, the process means is prepared to output the control signal for unlocking in dependence on the presence of the roll signal.

The rolling of the bullet is to be distinguished from a spin of bullets. While a twist is usually above 100 Hz, rolling is already below 100 Hz. In the following, a rotation between 1 Hz and 50 Hz, in particular between 2 Hz and 25 Hz, is defined as a roll and above 50 Hz as a twist. The roll sensor detects a twist-free rolling of the projectile and outputs the roll signal even in a swirl-free state of the projectile.

If a rolling of the projectile, that is to say a rolling movement of the projectile in the air, is detected, which fulfills a predetermined property, the state "flight" can be clearly recognized from this. The predetermined property is expediently chosen to be the condition "flight" with predetermined sufficient certainty characterized. With the roll signal is thus in addition to the enable signal before another signal that can be used as a trigger for unlocking. Accordingly, it is advantageous if the process means is prepared to check both the enable signal and the roll signal on their presence and output in the presence of at least one of the two signals, the control signal for unlocking. For the output of the control signal for the release, a logical OR circuit of the two signals can be used, which indicates whether one or the other signal is present. The control signal can also be output if both signals are present simultaneously.

Although in flight, the sensor unit of the projectile may experience a lateral acceleration due to an imbalance of the projectile, however, the longitudinal acceleration is small in any case. It is only determined by the delay due to air resistance. It is therefore advantageous if the state "flight" detected by the roll signal is verified by a query of the longitudinal acceleration, that is to say the acceleration of the fuze in the direction of flight or in the direction of its longitudinal axis or in the axial direction. Conveniently, the process means is therefore prepared to check in the presence of the roll signal, whether the acceleration of the projectile in the axial direction is below a predetermined value and to output the control signal for unlocking only when the value is exceeded.

The roll sensor is expediently an acceleration sensor, which is arranged in particular outside the geometric longitudinal axis of the projectile. If this experiences a permanent acceleration, ie beyond a predetermined period of time, above the acceleration due to gravity, or more generally: above a predetermined value, this is an indication of the presence of the condition "flight". The roll signal can be output to the process agent. Alternatively, a magnetic field sensor is conceivable which senses the geomagnetic field and recognizes the roles and thus the state "flight" based on the relative rotation of the earth's magnetic field. Also advantageous is a gyroscope or a revolution counter.

To increase the security in the detection of the state "flight", it is advantageous if the process means is prepared to distinguish on the basis of signals, in particular signals from the sensor unit, a free rolling of the projectile from a rolling of the projectile on a substrate. Such a distinction may be based on measurements of lateral acceleration over time. In a free-rolling these are constant, possibly even zero or near zero, whereas bottom roll is characterized by alternating lateral acceleration values in the orthogonal transverse directions. The signals are therefore expediently signals which were obtained from the measurement of the lateral acceleration of the projectile or of the detonator. For this purpose, a corresponding acceleration sensor is present, in particular as part of the sensor unit.

If there is ground rolling, the output of a control signal for unlocking the interruption means is expediently avoided. For this purpose, it is advantageous if the sensor unit has a floor roll sensor which is prepared to detect a floor roll of the projectile on a substrate and to output a floor roll signal in the event of floor rolls. The floor rolling may be a rolling movement with a lateral acceleration of the projectile which is in a predetermined relationship with the rolling movement. Conveniently, the process means is prepared to suppress the output of the control signal for unlocking the interruption means in the presence of the ground roll signal. Underpressure is also understood to mean that the control signal will not output, regardless of whether it has already been generated in a signal pre-stage. The bottom roll sensor may be part of the sensor unit or may be configured separately.

The invention is also directed to an igniter of a projectile having a safety device as described.

In addition, the invention relates to a method for releasing a fuse of a projectile, which comprises an ignition device with a detonator for igniting the igniter and a safety device with a fuse unit with a breaker for interrupting the ignition chain, which includes a process means for securing an ignition of the igniter. According to the invention, an acceleration state in the igniter is detected by means of a sensor unit after the acceleration state has fallen below the acceleration due to gravity by at least one specified acceleration value Release signal is output from the sensor unit and in response to the presence of the enable signal, a control signal for unlocking the interruption means is output by the process means.

Further advantages emerge from the following description of the drawing. In the drawings, embodiments of the invention are shown. The drawing and the description contain numerous features in combination, which the skilled person expediently consider individually and will summarize meaningful further combinations.

Fig. 1

eine Übersichtsdarstellung einer Sicherungseinrichtung,

Fig. 2

eine Schaltungsdarstellung einer Sicherungseinrichtung eines Zünders und

Fig. 3

eine Schaltungsdarstellung einer alternativen Sicherungseinrichtung eines Zünders.

Show it:

Fig. 1

an overview of a safety device,

Fig. 2

a circuit diagram of a safety device of a detonator and

Fig. 3

a circuit diagram of an alternative safety device of a detonator.

Fig. 1 1 shows an operating scheme of a safety device 2 of a fuze 4 (FIG. Fig. 2 ) of a projectile. A launch of the projectile is detected by a first securing means 6, for example a double-bolt system. By unlocking another securing means 8, in this embodiment, a timer, set in motion, which ensures a Vorrohrsicherheit. A third securing means 10, which may be a sensor unit for measuring an acceleration state, detects a low-acceleration flight condition and outputs a corresponding signal. This is given together with an action of the timer on an AND logic 12, which can be realized mechanically or electronically. An action can be done mechanically, z. B. by a mechanical release, or an electrical signal. The operation of the AND logic 12 is switched to a further AND logic 14, which also acts on a third securing means 16, z. B. another time element. The AND logic 14 acts on a means 18 for focusing the igniter 4, so that, for example, a force element is unlocked. By a fire signal 20, which must coincide with a sharp state of the igniter 4 by the means 18 - according to the further AND logic 22 - an ignition 24 of the igniter 4 is effected.

The safety device 2 off Fig. 1 is in Fig. 2 shown by a circuit diagram representation. It is housed in the igniter 4, which comprises a detonating chain with two ignition means 26, 28, wherein the ignition means 26 ignites the ignition means 28 with an ignition energy. To break the ignition chain, the igniter 4 may include an interrupting means 30, e.g. B. in the form of a movable barrier, which can be swung out by a mechanism 32 from the ignition chain, so that the ignition means 26 can ignite to the ignition means 28. The mechanism 32 is controlled by a processing means 34 via a signal line 36, on which the processing means 34 sends a control signal for releasing the interruption means 30 to the mechanism 32, which converts the control signal into a mechanical movement for leading out of the interruption means 30 from the firing chain.

Although the type of securing means 6, 8, 16, the ignition of the igniter and the fuse of the ignition process is described concretely in the illustrated embodiment, but the invention is not limited to these specific means. Rather, it is just as possible to use more or less and / or other securing means and to dispense with the ignition chain and in particular the interruption means and to use a different ignition and in particular interruption. In particular, an electronically controlled ignition and / or a purely electronic interruption of an ignition process is conceivable.

The process means 34 is connected to a sensor unit 38, which is an acceleration sensor unit. It is designed as a low-g sensor unit, which detects an acceleration state in which the amount of the total acceleration, z. B. in igniter 4, below the acceleration due to gravity, that is below the g-value of about 9.81 m / s ² . Conveniently, it is therefore an acceleration sensor that responds to a total acceleration whose magnitude is below the acceleration due to gravity. The sensor unit 38 comprises a sensor 40 with three outputs 42, 44, 46, each with a filter 48, three comparators 50, 52, 54, a time element 56 with an ohmic resistor 58 and a capacitor 60 and a comparator 62. An output stage 64, which may be part of the processing means 34 is designed to output a release signal. Furthermore, the securing device 2 comprises a self-test unit 66 with a controller 68.

Not shown is another safety device in the form of a double pin system, which triggers on a launch of the projectile and the Breaker 30 releases shortly after launch. In this state, the interruption means 30 is still blocked by the mechanism 32, so that the ignition chain is still interrupted.

During operation, the sensor 40, which is a three-axis acceleration sensor, measures the acceleration in three orthogonal spatial directions, namely in the direction of flight of the projectile, ie parallel to its longitudinal axis, and in two transverse directions perpendicular to each other and perpendicular to the direction of flight. As a result of its measurement, it outputs an output signal for each spatial direction which is in a known relation to the acceleration of the sensor 40 in the corresponding spatial direction. The three signals are output on the three outputs 42, 44, 46, wherein the sensor 40 is mounted in the fuse or igniter 4 so that on the output 42, the signal is applied, the acceleration of the igniter 4 and the securing device 2 indicates in the direction of flight of the projectile. On the other two outputs 44, 46 are the two signals that correspond to the acceleration of the sensor 40 in the transverse directions.

The three signals are filtered by one of the filters 48, which is a low-pass filter. This filter 48 filters the high-frequency component of the signal above z. B. 100 Hz out. As a result, the noise and caused by vibration of the projectile disturbing the acceleration signal are at least largely eliminated. The filtered signals are applied to the three comparators 50, 52, 54. At their inputs is thus in each case the corresponding signal and in each case a comparison signal v ₁ , v ₂ , v ₃ , wherein the comparators 50, 52, 54 compare the signals respectively. The comparison signals v ₁ , v ₂ , v _{3 in} this case form threshold values. For example, if the input signal of the comparator 50 from the filter 48 in the electrical potential below the comparison signal v ₁ , the output signal of the comparator 50 is located on a z. B. negative or low voltage value in relation to ground or another reference potential value. Exceeds the signal from the filter 48, the comparison signal v ₁ , the output signal of the comparator 50 z. B. a positive or higher voltage.

The signals from the outputs 42, 44, 46 correspond to the respective acceleration of the sensor 40 in a spatial direction, the sensor 40 outputs the signals inverted. The higher the acceleration in one direction, the lower the signal at the corresponding output 44, 44, 46. The comparison signals v ₁ , v ₂ , v ₃ thus form limit or threshold values, wherein when the signals exceed the above Comparison signals v ₁ , v ₂ , v ₃ - ie at a decrease in the accelerations below the threshold values - the respective output signal of the comparators 50, 52, 54 from z. B. negative in a z. B. transferred positive potential. In this way, the comparison signals v ₁ , v ₂ , v _{3 form} threshold values which correspond to acceleration limit values in each case in one spatial direction. If the acceleration in a spatial direction, for example in the direction of flight, falls below the limit, the signal on the output 42 rises above the comparison signal v ₁ and the output voltage of the comparator 50 is positive.

The limit values are each below a specified value below the acceleration due to gravity, so that if the accelerations fall below their limit values in all three spatial directions, there will in any case be an acceleration state which is a specified further value below the acceleration due to gravity. If, for example, the limit value in the direction of flight is 0.14 m / s ² and the limit value for the other two spatial directions is 0.1 m / s ² , then the total acceleration is <0.2 m / s ² if the release signal is present.

By the parallel connection of the comparators 50, 52, 54 and the voltage source 72, an AND circuit is formed. If only one of the comparators 50, 52, 54 has a positive output signal, ie if only one acceleration value is below the limit value, then the signal on the output line 70 is negative, since it is held negative by the other two comparators 50, 52, 54. If the outputs of two comparators 50, 52, 54 are positive, a voltage source 72 ensures that the signal on the output line 70 is also negative or at a corresponding electrical potential. Only when all three outputs of the comparators 50, 52, 54 are positive, then the signal on the output line 70 is positive.

As a result, the positive signal reaches the time element 56, which is implemented by the resistor 58 and the capacitor 60 so that the positive signal on the output line 70 is blocked during a predetermined period of time, so that it does not reach the line 74. The duration may, for example, be a few seconds, e.g. B. 1 - be 5 seconds. Only after this period of time is the capacitor 60 charged and the signal is present on the line 74. As a result, the potential on the line 74 is higher than the comparison signal v ₄ at the comparator 62. The output of the comparator 62 changes from z. B. negative to positive potential and thereby generates a release signal to the output stage 64, the release signal in the same or changed form to the process means 34 passes in two outputs, once as a positive signal and in addition to safety as a negative signal.

In the presence of the enable signal, the processing means 34 generates the control signal for driving the mechanism 32 and releasing the interruption means 30 or the ignition chain. Alternatively, it is possible that the release signal is passed on directly to the mechanism 32 or the interruption means 30 for releasing the ignition chain. Alternatively, it is possible that the output stage 64 already outputs the control signal without the process means 34 being necessary for this purpose. The output stage 64 can be understood here as a process agent itself.

The process means 34 is also connected directly to the output 42 of the sensor 40 and thereby monitors the acceleration value of the sensor 40 in the direction of flight. The monitoring is directed to an absolute minimum in the course of this acceleration value, expediently only the frequency part z. B. a Fourier spectrum of the signal on the output 42 with a frequency in the range greater than one second for evaluation to the absolute minimum.

With the detection of the minimum, the flying through of the vertex of the trajectory is detected, and in another embodiment, the presence of this minimum is used as a further safety criterion for generating the control signal on the signal line 36. Thus, if only the enable signal from the output stage 64 is present and the minimum has not yet been detected, then no control signal is given to the mechanism 32. Only when the minimum has been detected and at the same time the release signal from the output stage 64 over a period which is greater than a predetermined limit, in the range of 1-5 seconds, the process means 34 was present, the control signal is switched to the signal line 36.

With the help of the self-test unit 66, the fuse unit 2 can be checked. For this purpose, a switch 76 is closed by the controller 68 and the potential on the line 74 permanently z. B. held negative potential. The command for such a self-test is generated by the processing means 34, which responds, for example, to a command from an operator. The controller 68 outputs a corresponding signal to the sensor 40 due to which the potentials on the outputs 42, 44, 46 are increased by a predetermined value, corresponding to a very low acceleration. The corresponding values are used by the self-test unit 66 for Control tapped, evaluated and the result is communicated to the controller 68. Although this generates the positive signal on the output line 70 and optionally propagates it via the time element 56, the closed switch 76 ensures that the comparator 62 does not generate an enable signal. For safety, the controller 68 outputs an additional blocking signal to the output stage 64.

Fig. 3 shows a further embodiment in which the in Fig. 2 shown sensor unit 38 is extended by a roll sensor 78 and bottom roll sensor 80. For the sake of clarity, the representation of the self-test unit 66 and the controller 68 of the sensor unit 38 has been dispensed with, it being understood that both units can be present. All components shown are part of the fuze 4, which is also in Fig. 3 is indicated.

The following description is essentially limited to the differences from in Fig. 2 illustrated embodiment, to which reference is made with respect to the same features and functions. Substantially identical components are basically numbered with the same reference numerals, and features not mentioned are adopted in the following exemplary embodiments without being described again.

The sensor unit 38 as shown in FIG Fig. 3 includes a roll sensor 78, a bottom roll sensor 80 and a low-g sensor 82, which is already closed Fig. 2 has been described and is the same, how to Fig. 2 is described. The low-g sensor 82 is opposed by the roll sensor 78. Both sensors 82, 78 generate their signal independently and deliver it to output stage 64, with both the low-g signal that low-g sensor 82 supplies to output stage 64 and the roll signal, that of roll sensor 78 to the output stage 64 which can trigger the control signal to enable the interruption means 30.

The roll sensor 78 comprises a sensor 84, in this embodiment a single-axis gyroscope, which detects a rolling movement of the igniter 4 about its roll axis. Equally well an acceleration sensor is possible, which is arranged outside the longitudinal axis of the projectile. The signal from the sensor 84 is filtered by a filter 86, which is a low-pass filter for filtering noise, and given to a comparator 88. The resulting signal is applied to a comparator 92 via a time element 90, which has the same structure as the time element 56 given, which outputs the roll signal. Although the time element 90 and the comparator 92 are used by the bottom roll sensor 80 and are shown as part of the bottom roll sensor 80, they can just as well be components of the roll sensor 78.

When the projectile or the igniter 4 rolls, the sensor 84 generates a signal which corresponds to the rolling rate, that is to say the rotational speed of the igniter 4 about the rolling or longitudinal axis of the igniter 4 or projectile. The signal grows with increasing roll rate. The signal is compared by the comparator 88 with a comparison signal v ₅ . When the signal rises above the comparison signal v ₅ , the comparator 88 outputs a positive signal, or the signal of the comparator 88 changes from a negative or a low value to a positive or higher value. The comparison signal v ₅ is chosen so that the roll signal only becomes positive at a fixed roll rate, for example 2 Hz. Below this fixed roll rate, the transverse acceleration acting as an interference acceleration, which the sensor 40 experiences as a result of an unbalance of the projectile, is so small that a failure of the low-g signal caused by the imbalance can be ruled out for reasons of fixed production tolerances of the projectile.

The time element 90 checks whether the roll signal is present for a longer period of time, which can be in the range of 1 to 5 seconds, for example, without interruption. Only when this is the case, the roll signal penetrates to the comparator 92 is there - released analogously to the comparator 62 and given to the output stage 64.

The low g signal of the low g sensor 82 and the roll signal of the roll sensor 78 are treated equivalently in the output stage 64. If one of the two signals is present, the output stage 64 and the processing means 34 react as if Fig. 2 described and the control signal for unlocking the interruption means 30 is output. The low-g signal and the roll signal are therefore interconnected in an OR operation, so that the presence of one of the two signals is checked. The control signal can thus be triggered simultaneously even when both signals are present, which is usually the case, that is to say with a small imbalance of the projectile.

A triggering of the control signal for unlocking the interruption means 30 is to be avoided at all costs, when the projectile is rolled on the ground and not in "flight" state, so not flying freely. However, the roll sensor 78 can not distinguish whether the rolling motion is due to a uniform roll on the ground or a free-flying roll. He therefore outputs the roll signal even when rolling on the ground.

In order to prevent such unwanted unlocking, the sensor unit 38 is equipped with the bottom roll sensor 80, which detects a rolling of the projectile on the ground. The ground roll sensor 80 uses an input signal from an output of the sensor unit 20, namely a signal of the output 44 or 46 or both outputs 44, 46, which represent the lateral acceleration.

If the projectile is rolled over the ground, then the two sensors of the sensor unit 40, which measure the transverse accelerations, output an alternating signal, since they measure the gravitational acceleration downward. Since the sensor unit 40, at least its two sensors which measure the lateral acceleration, is arranged in the geometric axis of the projectile, the speed of the rolling does not affect the amplitude of the alternating signal as well, since the sensor unit 40 does not measure any centrifugal force. The alternating signal is filtered by a filter 94, which is a high-pass filter, so that only high-frequency components of the alternating signal above a predetermined frequency, for example 2 Hz, pass through the filter. In this way, only a bottom roll above the predetermined frequency is detected.
Via a rectification smoother 95, the alternating signal is converted into a simply smoothed DC voltage signal, which is now applied to the comparator 98. Rolling of the projectile on a ground causes at the entrance of the filter 94 an alternating signal with the roll frequency and the amplitude, which corresponds to approximately 1 g. By the rectification ripple 95, the frequency information is at least substantially eliminated because the AC signal is converted into a DC voltage. For ground rollers, for example on a flat surface, the magnitude of the DC signal corresponds to the total acceleration value of approximately 1 g and is therefore independent of the type of rolling. With no floor rolls or bottom rolls below the predetermined frequency no signal is present at the comparator 98, apart from interfering signals, which can be caused for example by a shaking of the projectile. Interference resulting from transverse movements of the projectile below a predetermined acceleration, z. B. below 0.5 g, are blocked by the comparator 98.

When the projectile rolls over a ground, the roll sensor 78 outputs a positive roll signal. At the same time, the comparator 98 outputs a ground roll signal indicative of ground roll. The ground roll signal is a negative signal, which dubles the roll signal of the roll sensor 78, so that no sufficiently positive signal can be present at the comparator 92. The release of the roll sensor 78 is thus blocked by the bottom roll sensor 80.

As additional security, the output signal of the comparator 50, which indicates an acceleration in the direction of flight, is applied to the roll signal. This signal also plays over the roll signal. If, for example, a roll signal, that is to say a positive signal, is output, the longitudinal acceleration of the fuze 4 is not below the limit, this is a sign that the projectile is not in free flight. Accordingly, the signal of the comparator 50 is zero or negative and dubbing the positive roll signal so that it can not trigger the control signal for unlocking the interruption means.

The combination of roll sensor 78 and bottom roll sensor 80 may also undergo a self-test, such as Fig. 1 is described. For this purpose, the switch 96 is closed and the sensor 84 is controlled by the processing means 34 or the controller 68, so that the roll sensor outputs the roll signal and at the same time and / or offset in time, the bottom roll sensor 80, the ground roll signal.

LIST OF REFERENCE NUMBERS

2

safety device

4

fuze

6

securing means

8th

securing means

10

securing means

12

AND logic

14

AND logic

16

securing means

18

medium

20

fire Alarm

22

AND logic

24

Ignite

26

ignition means

28

ignition means

30

interruption means

32

mechanics

34

process means

36

signal line

38

sensor unit

40

sensor

42

output

44

output

46

output

48

filter

50

comparator

52

comparator

54

comparator

56

time element

58

resistance

60

capacitor

62

comparator

64

output stage

66

Self-test unit

68

control

70

output line

72

voltage source

74

management

76

switch

78

roll sensor

80

Floor roll sensor

82

Low-g sensor

84

sensor

86

filter

88

comparator

90

time element

92

comparator

94

filter

95

Gleichrichtungsglätter

96

switch

98

comparator

Claims (14)

1. Safety device (2) for a fuze (4) of a projectile, which has a firing device for firing the fuze (4), comprising a safety unit having

   a) process means (34) for making a firing process of the firing device safe, with the process means (34) being designed to output a control signal, in order to arm the safety unit, as a function of the presence of an enable signal, and

   b) a sensor unit (38) which is designed to output the enable signal when an acceleration state is found which is below the earth's acceleration due to gravity,
   wherein the sensor unit (38) is designed to measure three directional accelerations in three mutually orthogonal spatial directions, and the enable signal is output at a time at which each of the three directional accelerations is below the earth's acceleration due to gravity, at least by a respectively defined acceleration value.
2. Safety device (2) according to Claim 1,
   wherein the defined acceleration value is different in the direction of flight of the projectile than the defined acceleration value in the two other directions.
3. Safety device (2) according to either of the preceding claims,
   wherein the defined acceleration state is below the earth's acceleration due to gravity by at least one defined acceleration value, and the sensor unit (38) comprises at least one comparator (50, 52, 54) by means of which the acceleration value can be adjusted.
4. Safety device (2) according to one of the preceding claims,
   having a timing element (56) for presetting a time interval, with the process means (34) outputting the control signal only when the enable signal has been present without interruption throughout the entire time interval.
5. Safety device (2) according to one of the preceding claims,
   wherein the sensor unit (38) has a roll sensor (78) which is designed to identify rolling of the projectile and to output a roll signal when a rolling movement is present.
6. Safety device (2) according to Claim 5,
   wherein the process means (34) is designed to check both the enable signal and the roll signal for their presence, and to output the control signal to arm the safety unit if at least one of the two signals is present.
7. Safety device (2) according to Claim 5 or 6,
   wherein the process means (34) is designed to check, when the roll signal is present, whether the magnitude of the acceleration of the projectile in the axial direction is below a predetermined value, and to output the control signal for arming only when the value has been undershot.
8. Safety device (2) according to one of Claims 5 to 7,
   wherein the roll sensor (78) is an acceleration sensor.
9. Safety device (2) according to one of the preceding claims,
   wherein the process means (34) is designed to distinguish between free-flight rolling of the projectile and rolling of the projectile on a base.
10. Safety device (2) according to one of the preceding claims,
    wherein the sensor unit (38) has a ground rolling sensor (82), which is designed to identify ground rolling of the projectile on a base, and to output a ground rolling signal in the event of ground rolling.
11. Safety device (2) according to Claim 10,
    wherein the process means (34) is designed to suppress the output of the control signal for arming when the ground rolling signal is present.
12. Safety device (2) according to one of the preceding claims,
    wherein the sensor unit (38)

    - additionally has a roll sensor (78), which is designed to identify rolling of the projectile and to output a roll signal when a rolling movement is present, and

    - additionally has a ground rolling sensor (82), which is designed to identify ground rolling of the projectile on a base, and to output a ground rolling signal during ground rolling,
    and the process means (34) is designed for the following steps:

    - to check both the enable signal and the roll signal for their presence and, if at least one of the two signals is present, to output the control signal for arming the safety unit but

    - when the roll signal is present, to additionally check whether the magnitude of the acceleration of the projectile in the axial direction is below a predetermined value, and to output the control signal for arming only when the value is undershot, and

    - to distinguish between free-flight rolling of the projectile and ground rolling of the projectile on a base, and to suppress the output of the control signal for arming when the ground rolling signal is present.
13. Safety device (2) according to one of the preceding claims,
    wherein the firing device has a firing chain with a firing charge for firing the fuze (4), and the safety unit has an interruption means (30) for interruption of the firing chain.
14. Method for arming a fuze (4) of a projectile, which has a firing device with a firing chain for firing the fuze (4) and a safety device (2) according to one of Claims 1-13 with a safety unit with an interruption means (30) for interruption of the firing chain, which unit contains a process means (34) for making a firing process of the firing device safe,
    wherein

    - a sensor unit (38) is used to detect an acceleration state in the fuze,

    - the sensor unit (38) outputs an enable signal after the acceleration state has fallen below the earth's acceleration due to gravity by at least a defined acceleration value, and

    - a control signal for arming the interruption means of the safety unit is output by the process means (34) as a function of the presence of the enable signal.

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