EP2752637B1 - Safety for a fuze of a sub-caliber projectile and process for arming said fuze - Google Patents

Description

The invention relates to a safety device for an igniter of a subcaliber projectile and a corresponding Entsicherungsverfahren for the safety device according to the invention.

It is well known that sub-caliber ammunition with a sabot, or sabot, and a slipping guide band is fired from a drawn tube. If such ammunition is provided with an active charge, then the existing detonator must be secured by appropriate security devices in accordance with current regulations. The safety device is therefore part of the igniter. Arming must be achieved by the occurrence of two mutually independent environmental conditions. In order to avoid unwanted unlocking, various security devices are known.

In recent igniters wing-stabilized ammunition, which is fired from smooth tubes are in the security device z. B. gas pressure switch provided at the rear of the ammunition, so that a signal for unlocking the detonator can be generated during firing. In an unintentional implementation of the propellant charge at a Unterkalibermunition, in which a part of the propellant charge between the bullet tail and tail section is, an unwanted partial sharpening of the detonator could be brought about at least by the resulting gas pressure in the ammunition magazine. Continue to come z. B. 3D acceleration sensors in safety devices for measuring the accelerations in three spatial directions for the application, whose principle is based on the sensing of the trajectory or steering maneuvers. However, this method requires significant trajectories or the execution of certain steering maneuvers in order to obtain clear signals. The latter can become one Reduce firing range and negatively affect the flight stability of the projectile.

From the US publication US 5,265,539 is a sensor element of a fuse device for an igniter is known, which senses a second environmental condition. The sensor element has for this purpose two sensory coils, which are arranged in the igniter in the projectile body, and a permanent magnet in the sabot. The first coil is used for induction measurement, that is to say that the change in the magnetic flux density upon removal of the permanent magnet causes a change in the electric field. The second coil allows a gradient measurement by difference measurement between the first and the second coil, whereby external interference fields are compensated. In the sabot a corresponding dipole magnet is arranged so that the departure of the sabot is sensed as a change in the magnetic field. Disadvantage of this fuse element is that the installation of the coils in the projectile body is structurally complex and requires an increased space requirement. In addition, interference signals are to be expected in such an arrangement, for example, by leaving the gun barrel during firing, which may be of the order of the signals to be measured. The signal generated by this method for a deliberate weft-related departure has in comparison to a manual unwanted detachment only a small difference, so that this signal is to evaluate the release of a detonator as not sufficiently clear. Measuring with solenoids requires signal amplification.

The invention is based on the object to increase the safety of detonators, in particular of detonators in sub-caliber bullets, and to minimize the risk of unwanted sharpening. In addition, cost-effective ways to realize a safety device of a detonator are to be created.

This object is achieved by the features of claim 1 and the independent method claim 4.

An igniter of a subcaliber projectile with a projectile body, a slipping guide band and a sabot consisting of sabot segments has for this purpose a securing device. The safety device has two safety elements for sensing environmental conditions, designed such that a signal can be generated. The security device has at least one logic unit and is such designed such that by means of the logic unit, the signal of the fuse elements evaluable and a Entsicherungssignal for detonator release can be generated. The securing device is characterized in that a first securing element has a sensor element and at least one permanent magnet. The sensor element has a magnetic sensor, in particular a magnetoresistive (MR) sensor, in the projectile body. The permanent magnet is the magnetic sensor corresponding and arranged radially extending from the magnetic sensor in the guide band. The first securing element is designed such that a rotational frequency of the guide belt can be sensed as the first environmental condition and a first signal can be generated. A second securing element also has a sensor element and at least one permanent magnet. The sensor element has at least one magnetic sensor, in particular a magnetoresistive (MR) sensor, in the projectile body. The permanent magnet is corresponding to the magnetic sensor and arranged radially extending from the magnetic sensor in at least one sabot segment. The second securing element is designed such that the outlet of the sabot segment can be sensed as a second environmental condition and a second signal can be generated.

When a subcaliber projectile is fired from a drawn pipe, the leader tape is forced through the fields and trajectories of the pipe. In this case, a rotation is transmitted to the guide belt, which, however, is designed to slip through, so that the projectile body itself remains de-twisted. The rotation of the guide band is tube-specific and depends on the respective load, ie the initial speed during firing, and corresponds to a few hundred hertz. This rotation is so specific that it is particularly well suited for use as an environmental condition. Sensing of the rotation is made possible by the use of the MR sensor in conjunction with the permanent magnet, since the MR sensor sits in the de-twisted projectile body and the permanent magnet in the rotating guide band. The MR sensor changes its resistance value when exposed to an external magnetic field. At each complete revolution of the slipping guide band of the permanent magnet passes the MR sensor, so that from the period of the periodically generated change in resistance, a rotational frequency of the guide band can be calculated and thus is sensed as a first environmental condition. The periodic change in resistance or the resistance over time provides a clear signal, which is a criterion for the Entsicherungsvorgang as the first environmental condition. This signal is so specific that the risk of manipulation is almost eliminated. The sensor element is here as a basic component for the realization of the electrical ignition system to understand, for example, in terms of power supply and signal processing and calculation. A particular advantage is further that over the measured rotational frequency, the departure speed of the subcaliber projectile can be calculated back. This information can be used in a programmable detonator to ensure, for example, for a given period, an overflight safety by delaying the release or to optimize an ignition timing of the active charge.

If the subcaliber projectile leaves the pipe during firing, the separation of the sabot occurs due to the occurring wind resistance. In this case, this is decomposed at predetermined breaking points in its individual sabot segments, so that the projectile body begins its wing-stabilized flight. The departure of the sabot is therefore particularly suitable as a second environmental condition. The sensing of the second environmental condition with the second securing element is also made possible by the use of at least one MR sensor, which is located in the projectile body and provides a constant resistance by the presence of a corresponding permanent magnet in the sabot. The departure of the sabot and thus the separation of the permanent magnet of the magnetic sensor causes a change in the resistance within milliseconds and thus a clear measurement signal, which can use the fuse element as a second signal from a second environmental condition for the safety device.

Due to the fact that MR sensors in thin-film technology are manufactured from silicon wafers, the components are very small, so that their installation can be carried out with little design effort. They are also characterized by a very high sensitivity to external magnetic fields, so that the sensing is possible even at an increased distance to the corresponding permanent magnet. No amplification of the signal is required. Particularly due to their resistance, for example in shock loads, and their longevity, the use in ammunition is particularly suitable, especially since MR sensors are inexpensive and can be produced in large numbers and commercially available.

In an advantageous embodiment of the invention, the first securing element has a sensor element and at least two permanent magnets. The permanent magnets are the magnetic sensor corresponding and arranged radially extending from the magnetic sensor at a predetermined angle to each other. The first securing element is such designed so that two rotational frequencies of the guide band can be sensed as an environmental criterion. Due to the arrangement of the permanent magnets in the predetermined angle to each other to obtain a unique, coded signal, which is generated only when passing these magnets, z. B. offset by positioning radially by 45 °. As a result, manipulation by magnetic fields from the outside is not possible and minimizes the risk of unintentional release.

In a further advantageous embodiment of the invention according to claim 3, the second securing device on a sensor element and a plurality of permanent magnets. The sensor element has magnetic sensors, in particular MR sensors, corresponding to the number of sabot segments in the projectile body. At least one permanent magnet is in each case corresponding to a magnetic sensor and arranged radially extending from the magnetic sensor in each sabot segment. The second securing element is designed such that the outlet of each sabot segment can be sensed as a second environmental condition. By such an arrangement, the departure and thus the separation of the respective permanent magnet from the associated magnetic sensor is given for each sabot segment individually, which causes a change in the resistance within milliseconds in each MR sensor. Each individual sabot segment thus provides a unique measurement signal, which can be evaluated as an environmental condition. This has the advantage that in case of defect of an MR sensor, the function remains guaranteed. In addition, several signals are available for evaluation, the timing of which can be evaluated. This allows, for example, a safety backup, such that the fuse element sends a second signal to the logic unit only if the departure of the individual sabot segments took place in a predetermined time window. This is a tamper-evident because, for example, the manual detachment of all sabot segments at the same time within a second is almost impossible.

• Das erste Sicherungselement sensiert eine Rotationsfrequenz des Führungsbandes als erste Umweltbedingung und sendet ein Rotationsfrequenz-Signal an die Logikeinheit
• die Logikeinheit führt einen ersten Soll-/Ist-Abgleich des Rotationsfrequenz-Signals durch
• das zweite Sicherungselement sensiert einen Abgang des Treibkäfigsegmentes als zweite Umweltbedingung und sendet mindestens ein Treibkäfig-Abgangs-Signal an die Logikeinheit
• die Logikeinheit führt einen zweiten Soll-/Ist-Abgleich des Treibkäfig-Abgangs-Signals durch
• die Logikeinheit sendet ein Entsicherungssignal oder kein Entsicherungssignal zur Zünderentsicherung.

According to the independent claim 4, an arming method of a safety device for an igniter of a subcaliber projectile with the features according to one of claims 1 to 3 comprises the following steps:

• The first fuse element senses a rotational frequency of the guide belt as a first environmental condition and sends a rotational frequency signal to the logic unit
• the logic unit performs a first setpoint / actual adjustment of the rotation frequency signal
• the second securing element senses a departure of the sabot segment as a second environmental condition and sends at least one sabot output signal to the logic unit
• the logic unit performs a second setpoint / actual adjustment of the sabot output signal
• the logic unit sends a release signal or no release signal for detonator release.

The sensing of the rotational frequency by the first fuse element and the subsequent evaluation of the first signal, the rotational frequency signal, by the logic unit, in conjunction with the target / actual adjustment ensures that the first signal is actually attributable to a launch of the subcaliber projectile. The same applies to the subsequent evaluation of the sabot output signal, so that the generation of a Entsicherungssignals for detonation takes place only after the occurrence of the first and second environmental conditions and prevents the logic unit in discrepancies of the desired and actual parameters a release. It is also advantageous that the signals of the rotational frequency and the sabot-outgoing signal fundamentally differ from each other. This minimizes the risk of unwanted unlocking.

In a further advantageous embodiment of the invention, the Entsicherungsverfahren on at least a first timer, such that the logic unit sends the Entsicherungssignal for detonation only when the sabot segment outgoing signal, ie the second signal, after the rotational frequency signal, ie after the first signal, within a predetermined time window. Since the process of firing subcaliber ammunition always takes place in the same sequence within a time window with small production- or shot parameter-related deviations, the specification of the order and the time window represents an increase in detonator safety and can be used as an here designated timer as an additional safety criterion. In addition, the implementation of an additional time criterion is easy to implement in a logic unit without significantly increasing costs.

In a further advantageous embodiment of the invention, the Entsicherungsverfahren on at least a second timer, such that the Logic unit sends the Entsicherungssignal to detonator only if the departure of each sabot segment takes place in a given time window. This represents a tampering exclusion, since the manual detachment of all sabot segments at the same time within a second, for example, almost impossible, but takes place in a real firing in a defined, very short time window.

Further advantages and the schematic representation of the invention are the FIG. 1 A and B can be seen. It shows FIGS. 1A and B a sub-caliber projectile in partial longitudinal section with rotating guide band (A) and departure of the sabot (B) and sketched elements of the safety device according to the invention and associated signals.

The FIGS. 1A and B shows a schematic diagram of a subcaliber projectile in partial longitudinal section. The subcaliber projectile 10 has a projectile body 11, a slipping guide band 12 and a sabot 13 consisting of sabot segments 13.1, 13.2, 13.3. The fuse device for the igniter 14 of the subcaliber projectile 10 has at least one fuse element for sensing environmental conditions and is designed such that a signal can be generated. The securing device has at least one logic unit, which is located in the igniter 14 in the projectile nose. The securing device is designed in such a way that the signal of the securing element can be evaluated by means of the logic unit and an arming signal for releasing the igniter 14 can be generated. A first securing element 21 has a sensor element 22 and at least one permanent magnet 23. The sensor element 22 has a magnetic sensor, in particular an MR sensor, in the projectile body 11. The permanent magnet 23 is arranged corresponding to the sensor element 22 and radially extending from the sensor element 22 in the guide belt 12. The first securing element 21 is designed such that a rotational frequency of the guide belt 12 can be sensed as the first environmental condition and a first signal 31 can be generated. The arrow in Figure 1A indicates the rotation of the guide band 12. The signal corresponds in the sketch of a sine wave, wherein a complete revolution of the guide band corresponds to a period length. If a second permanent magnet z. B. 45 ° offset in the guide band is attached, there is a second sine wave, which then follows offset in time to the first signal.

A second securing element 24 has a sensor element 22 and at least one permanent magnet 23. The sensor element 22 has at least one magnetic sensor, in particular an MR sensor, in the projectile body 11. The permanent magnet 23 is arranged corresponding to the magnetic sensor and radially extending from the magnetic sensor in at least one sabot segment 13.1 to 13.3. The second securing element 24 is designed such that the outlet of the sabot segment 13.1 to 13.3 can be sensed as a second environmental condition and at least one second signal 32 can be generated. The sabot 13 consists of three sabot segments 13.1, 13.2, 13.3. In each sabot segment 13.1 to 13.3 in each case a permanent magnet is arranged and opposite each are located in the projectile body 11 each magnetic sensors as a component connected to the sensor element, but these are not visible in the partial longitudinal section. The arrows in FIG. 1B mark the departure of the sabot segments 13.1 to 13.3. Accordingly, three signals 32.1 to 32.3 are displayed per outgoing sabot segment. The signals generated at the departure of the respective sabot segments 13.1 to 13.3 must in this case take place within a predetermined time window 33. By evaluating the negative slope of the signal edge from the change in the resistance over time, the detachment speed of the segments is determined and additionally evaluated via a setpoint / actual adjustment. It can be seen that all signals are within the predetermined time window 33.

The sensor elements 22 as part of the first fuse element 21 and the second fuse element 24 are microcontrollers or a "system on the chip", which are directly connected to the logic unit of the igniter 14. The logic unit is part of the igniter 14 and is also a microcontroller. The power supply of the microcontroller is ensured by the igniter 14. The first securing element 21 senses the rotational frequency of the guide belt 12 as the first environmental condition. For this purpose, the MR sensor of the sensor element 22 of the first securing element 21 registers a change in the resistance when the guide belt 12 rotates. From the periodic change in resistance, a signal is generated by the sensor element 22, which transmits the first securing element 21 by means of sensor element 22 to the logic unit in the igniter 14. The logic unit checks this signal via a setpoint / actual adjustment. If the signal corresponds to the desired value or desired signal, then the signal of the second fuse element 24 is checked. As a result, a first timer in the Entsicherungsverfahren is included. The second securing element 24 senses as a second environmental condition the departure of the individual sabot segments 13.1 to 13.3. For this, the individual MR sensors register the sensor element 22 of the second fuse element 24 each have a sudden change in resistance. The sensor element 22 calculates three signals 32.1 to 32.3 from this. The signals 32.1 to 32.3 are transmitted from the second securing element 24 by means of sensor element 22 to the logic unit in the igniter 14. The logic unit checks these signals 32.1 to 32.3 via a setpoint / actual adjustment. In addition, the logic unit checks whether the departure of each sabot segment 13.1 to 13.3 occurred within a time window 33 and sends an arming signal for releasing the igniter 14 only if the departure of the individual sabot segments 13.1 to 13.3 is within the predetermined time window 33. The MR sensors in the projectile body 11 are located in the outermost periphery of the projectile axis 15, so that the distance from each sensor to the corresponding permanent magnet 23 is as small as possible. Thus, the permanent magnet 23 is arranged both in the sabot segments 13.1 to 13.3 and in the slipping guide band 12 in the projectile body near. As a result, the outer magnetic fields are each arranged close to the corresponding MR sensor and a significant signal can be generated.

LIST OF REFERENCE NUMBERS

10

Sub-caliber projectile

11

projectile body

12

guide band

13

sabot

13.1 - 13.3

Sabot segments

14

fuze

15

projectile axis

21

first fuse element

22

sensor element

23

permanent magnet

24

second fuse element

31

first signal

32.1 - 32.3

second signal

33

Time window

Claims (6)

1. Subcalibre projectile (10) having a fuse (14) and a safety device for the fuse (14), having the following features:

   - the subcalibre projectile (10) comprises a projectile body (11), a sliding driving band (12) and a sabot (13) consisting of sabot segments (13.1, 13.2, 13.3),

   - the safety device comprises two safety elements (21, 24) for sensing ambient conditions and is designed such that a signal can be generated

   - the safety device comprises at least one logic unit

   - the safety device is designed such that the signal of the safety elements (21, 24) can be evaluated using the logic unit and an arming signal for arming the fuse can be generated,

   the safety device is characterized in that:

   a. a first safety element (21) comprises a sensor element (22) and at least one permanent magnet (23) and

   - the sensor element (22) comprises a magnetic sensor, especially a magnetoresistive sensor, in the projectile body (11) and

   - the permanent magnet (23) is disposed to correspond to the magnetic sensor and to extend radially from the magnetic sensor in the driving band (12) and

   - the first safety element (21) is designed such that a frequency of rotation of the driving band (12) can be sensed as the first ambient condition and a first signal (31) can be generated,

   b. a second safety element (24) comprises a sensor element (22) and at least one permanent magnet (23) and

   - the sensor element (22) comprises at least one magnetic sensor, especially a magnetoresistive sensor, in the projectile body (11) and

   - the permanent magnet (23) is disposed so as to correspond to the magnetic sensor and to extend from the magnetic sensor radially in at least one sabot segment (13.1, 13.2, 13.3) and

   - the second safety element (24) is designed such that the separation of the sabot segment (13.1, 13.2, 13.3) can be sensed as a second ambient condition and a second signal (32) can be generated.
2. Subcalibre projectile (10) according to Claim 1,
   characterized
   in that the first safety element (21) comprises a (sensor element (22) and at least two permanent magnets (23) and

   - the permanent magnets (23) are disposed so as to correspond to the magnetic sensor and so as to extend radially from the magnetic sensor at a specified angle relative to each other and

   - the first safety element (21) is designed such that a first frequency of rotation and at least one time offset second frequency of rotation of the driving band (12) can be sensed as the first ambient condition.
3. Subcalibre projectile (10) according to any one of the Claims 1 to 2,
   characterized
   in that the second safety element (24) comprises a sensor element (22) and a plurality of permanent magnets (23) and

   - the sensor element (22) comprises magnetic sensors, especially magnetoresistive sensors, corresponding to the number of sabot segments (13.1, 13.2, 13.3) in the projectile body (11) and

   - at least one permanent magnet (23) is disposed so as to correspond respectively to a magnetic sensor and to extend radially from the magnetic sensor in each sabot segment (13.1, 13.2, 13.3) and

   - the second safety element (24) is designed such that the separation of each sabot segment (13.1, 13.2, 13.3) can be sensed as a second ambient condition.
4. Arming method of a safety device for a fuse (14) of a subcalibre projectile (10) with the features according to any one of the Claims 1 to 3,
   characterized in that

   - the first safety element (21) senses a frequency of rotation of the driving band (12) as a first ambient condition and sends a frequency of rotation signal to the logic unit

   - the logic unit carries out a first target/actual comparison of the frequency of rotation signal

   - the second safety element (24) senses separation of the sabot segment (13.1, 13.2, 13.3) as a second ambient condition and sends at least one sabot separation signal to the logic unit

   - the logic unit carries out a second target/actual comparison of the sabot separation signal

   - the logic unit sends an arming signal or no arming signal for arming the fuse.
5. Arming method according to Claim 4,
   characterized
   in that the arming method involves at least one first timing element such that the logic unit only sends the arming signal for arming the fuse if the sabot separation signal occurs within a specified time window (33) after the frequency of rotation signal.
6. Arming method according to Claim 4 or 5,
   characterized
   in that the arming method involves at least one second timing element such that the logic unit only sends the arming signal for arming the fuse if the separation of each sabot segment takes place within a specified time window (33).

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