EP0300255B1 - Digital counter setting apparatus for the initiation of a timed-detonator in a projectile - Google Patents

Description

The invention relates to a device for digitally setting a counter for triggering a time fuse in a projectile after it has been fired, the counter being set inductively by a transmitter coil fastened in front of the weapon via a receiver coil located in the projectile, with a device for measuring the muzzle velocity of the projectile to set the timer trigger trigger depending on this muzzle velocity.

In a known device of this type (see DE Patent No. 26 05 374 and CH Patent No. 589 838) there is a transmitting coil which is able to transmit approximately eight to ten pulses when the projectile passes through this coil . In order to be able to clearly transmit two different signals "0" and "1" from the transmitter coil to the receiver coil in this known device, the transmitter coil is magnetized for the signal "0" in one direction and for the signal "1" in the opposite direction , ie a positive voltage is applied to one signal and then a negative voltage to the transmitter coil for the other signal, so that the current flows through the transmitter coil either in one direction or in the other direction. As a result, the transmitter coil is fully magnetized both for the signal "0" and for the signal "1". The transmitter coil is not magnetized between these signals. With this type of signaling, a dead time between the individual signals of approximately ten times the pulse duration of the signal is required. In order to If at least 8 to 10 pulses can be transmitted in the time available when the projectile passes through the transmitter coil, a transmission frequency of 100 kHz is required if the transmitter coil is 12 cm wide and the projectile speed is assumed to be 1200 m / sec.

In another known arrangement of this type (see DE-OS 23 16 976) a control coil is attached to the muzzle of the weapon barrel, which determines the time to trigger the ignition when the projectile passes through a receiver of the projectile detonator.

In this known arrangement, a current flows through the control coil, the current intensity of which is a measure of the desired value to be set, and the reception circuit has a reception coil and means for evaluating the level of the voltage induced in the reception coil when the control coil flies through.

This arrangement is too imprecise for today's requirements. The level of the voltage induced in the receiving coil when the control coil flies through depends firstly on whether the projectile flies exactly through the center of the control coil and secondly whether the projectile flies through the control coil at the desired initial speed.

The object that is to be achieved with the present invention is to create a device of this type, which is able, firstly, to generate more pulses in the time available when the projectile passes through the transmitter coil from the transmitter coil to the receiver coil second, to improve the redundancy of these impulses in order to achieve a more reliable information transmission and thirdly, to switch off undesired interference pulses which are generated, for example, by the device for measuring the muzzle velocity.

According to the invention, this object is achieved in that the pulses transmitted from the transmitting coil to the receiving coil are double pulses.

• a) parallel zur Sendespule ein ohmscher Widerstand angeordnet ist, um die Zeitkonstante L/R zu optimieren;
• b) parallel zur Empfangsspule ein ohmscher Widerstand angeordnet ist, um die Zeitkonstante L/R zu optimieren;
• c) an die Empfangsspule ein Filter angeschlossen ist, um die Störimpulse, die von der Einrichtung zur Messung der Mündungsgeschwindigkeit ausgestrahlt werden, auszuschalten.

Further features of the invention are contained in the subclaims in particular that

• a) an ohmic resistor is arranged parallel to the transmitter coil in order to optimize the time constant L / R;
• b) an ohmic resistor is arranged in parallel with the receiving coil in order to optimize the time constant L / R;
• c) a filter is connected to the receiving coil in order to switch off the interference pulses which are emitted by the device for measuring the muzzle velocity.

The device according to the invention has the following advantages over the known devices mentioned above:

The generation of double pulses makes it possible to significantly reduce the dead time between the individual signals. Instead of a dead time that is ten times the pulse duration, thanks to the double pulses, a dead time that is the same as the pulse duration is sufficient.

This short dead time is also made possible by shortening the decay time of the pulses. The time constant L / R can be set to approx. 150 ns with a resistance of 3 ohms. This leads to a rapid decay of the induced pulse voltage in the projectile coil and thus to short dead times between the pulses. Thanks to the use of an ohmic resistor in parallel with the induction coil, there is no need for an amplifier to generate the pulses.

• Fig.1 einen Längsschnitt durch eine Rohrmündung mit einer Einrichtung zum Messen der Mündungsgeschwindigkeit und mit einer Sendespule zum Uebertragen von Informationen auf ein aus der Rohrmündung austretendes Geschoss,
• Fig.2 ein Diagramm der gesendeten Impulse,
• Fig.3 ein Blockschema mit der Induktions-Sendespule und den Schaltern zur Erzeugung der Impulse,
• Fig.4 einen Filter an der Empfangsspule.

An exemplary embodiment of the device according to the invention for digitally setting a counter for triggering a time fuse in a floor is described in detail below with reference to the accompanying drawing. It shows:

• 1 shows a longitudinal section through a pipe muzzle with a device for measuring the muzzle velocity and with a transmitter coil for transmitting information to a projectile emerging from the pipe muzzle,
• 2 shows a diagram of the transmitted pulses,
• 3 shows a block diagram with the induction transmitter coil and the switches for generating the pulses,
• 4 shows a filter on the receiving coil.

1, the weapon barrel muzzle 10 is surrounded by a three-part cage 11, 12, 13, which projects beyond the weapon barrel muzzle 10. In the middle part 12 of the cage there is a first measuring coil 14 and in the front part 13 of the cage there is a second measuring coil 15 and a transmitting coil 16. The fastening of the three-part cage 11, 12, 13 to the weapon barrel muzzle 10 and the connection of the three parts with each other is assumed to be known and is neither shown nor described here. Lines 17 and 18 are provided for the electrical supply of the two measuring coils 14 and 15. A number of soft iron rods 19 are inserted in the three-part cage 11, 12, 13 to shield the entire measuring system from interference from magnetic fields, of which only two are visible in FIG. The transmitter coil 16 consists of a single turn 20 and a coil body 21. A projectile 22 flies in the direction of arrow A through the device for measuring the initial speed and for transmitting information, ie through the two measuring coils 14 and 15 and through the transmitter coil 16 . The device described so far differs from known devices of this type essentially in that the transmitter coil 16 consists of a single turn 20 and is relatively narrow. In order to determine the initial or muzzle velocity of the projectile 22, the time t which the projectile 22 needs to get from the coil 14 to the coil 15 is measured. The speed V _o = a / t results from the distance a between these two coils 14, 15 and this time t. Taking this muzzle velocity of the projectile 22 into account, the time until the projectile 22 reaches the target can be calculated. A timer 24 located in the projectile 22 can thus be set or "temped" so that the projectile 22 is ignited in the area of the target. This time, which the projectile needs to reach the destination when it exits the pipe mouth 10, is transmitted in digital form from the transmitting coil 16 to a receiving coil 23 in the projectile 22. As usual, the transmission takes place inductively. To set the timer 24 with the desired accuracy, at least twelve pulses should be transmitted from the transmitter coil 16 to the receiver coil 23. Since, as already mentioned, the projectile 22 flies through the transmitting coil 16 at a speed of approximately 1200 meters per second, it is necessary to transmit the twelve pulses at a relatively high frequency at the right time. The correct time for sending the pulses is determined with the help of the front measuring coil 15 of the device for measuring the muzzle velocity. As soon as the projectile 22 has flown through the coil 15, the information can be transmitted from the transmitter coil 16 to the receiver coil 23.

So that the pulses with the required frequency are transmitted from the transmitting coil 16 to the receiving coil 23 , it is necessary on the one hand to make the inertia of the induction coil 16 as small as possible and to replace other inert elements such as amplifiers by other less inert elements.

The measures for increasing the frequency with which the pulses are transmitted inductively from the transmitting coil 16 to the receiving coil 23 are explained below with reference to FIGS. 2 and 3.

2, the signal "1" consists of two pulses or a double pulse, the first part of the double pulse being generated by a positive voltage "+ U" and the second part of the double pulse being generated by a negative voltage "- U". Likewise, the signal "0" consists of two pulses or a double pulse, the first part of the double pulse being generated by a negative voltage "- U" and the second part of the double pulse being generated by a positive voltage "+ U". Both the positive pulse "+ U" and the negative pulse "- U" last e.g. 400 nanoseconds, i.e. the time required for the double pulse is 800 nanoseconds and 800 nanoseconds are sufficient for the dead time between the individual double pulses. Thanks to these double impulses, it is possible to get by with ten times less dead time than before.

According to Figure 3, the inductive transmitter coil 16 is connected to two switches 25 and 26, with which either positive or negative pulses "+ U" respectively. "- U" can be generated. In order to optimize the time constant L / R _ that is, the time in which the pulse decays _, an ohmic resistor 27 is connected in parallel to the transmitter coil 16. This ohmic resistor 27 can be switched off by a capacitor 28 so that it only is effective at the desired time. Thus, the previously common power amplifier for modulating the transmitter coil is replaced by a switching stage.

According to FIG. 4, a resistor 33 is connected to the receiving coil 23 located in the floor 22, which forms a time constant L / R with the receiving coil in the usual way. A filter 29 is connected to this combination, which is constructed in the usual way from ohmic resistors 30 and capacitors 31 and is referred to here as a high-pass filter. This filter 29 prevents pulses from the measuring device for the muzzle velocity of the projectile 22 from being transmitted as interference pulses from the receiving coil 23 to the igniter 24 via the counter 32 (FIG. 1).

• a) Sendespule 16-0,5 µH (Mikrohenry)
• b) ohmscher Widerstand 27-4Ω (Ohm)
• c) Kondensator 28-50 nF (Nanofarad)
• d) die elektrischen Schalter 25 und 26 sind handelsüblich und unter der Bezeichnung IRF 540 bzw. IRF 9540 erhältlich
• e) Kondensatoren 31-120 pF (Picofarad)
• f) Widerstände 30-22 kΩ (Kilo ohm)
• g) Widerstand 33-6,8 kΩ (Kilo ohm)

The components of the transmit and receive circuits shown in FIGS. 3 and 4 have the following electrical properties:

• a) transmitter coil 16-0.5 µH (microhenry)
• b) ohmic resistance 27-4Ω (Ohm)
• c) capacitor 28-50 nF (nanofarad)
• d) the electrical switches 25 and 26 are commercially available and are available under the names IRF 540 and IRF 9540
• e) capacitors 31-120 pF (picofarad)
• f) resistors 30-22 kΩ (kilo ohms)
• g) Resistance 33-6.8 kΩ (kilo ohms)

The structure of the entire transmitter system is shown in Fig. 5. On the one hand, the two measuring coils 14 and 15 (FIG. 1) are connected to a process computer 133, on the other hand a register 34 and finally a toggle switch 35 which is separated by two undates 36 and 37 is formed. The process computer 133 receives the information from the measuring coils 14 and 15 that the projectile 22 is in the area of the two measuring coils 14 and 15. The process computer 133 is therefore able to calculate when the projectile 22 passes through the transmitter coil 16 (FIG. 1). The process computer 133 can thus send a signal to the toggle switch 35 which initiates the transmission of the usual information stored in the register 34 by the process computer 133. A multivibrator 38 is connected to the toggle switch 35 and can deliver pulses to a counter 39 in the usual manner at regular intervals. This multivibrator 38 is put into operation by the toggle switch 35. A selector 40 is arranged between the register 34 and the counter 39. This selector 40 selects the numbers contained in the register 34 in accordance with the numbers formed in the counter 39 by the multivibrator 38 and forwards this information to the inputs of four undates 41-44. Two univibrators 45 and 46 are also connected to the inputs of these undates 41-44. These univibrators 45 and 46 generate a pulse of a given pulse duration, for example 1 .mu.sec, for each piece of information. The outputs of the two undates 41 and 42 are common to a further undate 47 and the outputs of the two undates 43 and 44 are common to another undate 48 connected. The outputs of the two und gates 47 and 48 are connected to a driver stage 50. This driver stage 50 controls the switches 25 and 26 shown in FIG. 3. Negative pulses arrive at the switch 26 from the und gate 47 and positive pulses arrive at the switch 25 from the und gate 48. The double pulses shown in FIG generated. From the transmitting coil 16, the signals on the receiving coil 23 of the Storey 22 (Fig.1) forwarded.

The counter 39 is connected to the toggle switch 35 via a gate 51, as a result of which the entire transmission system shown in FIG. 4 can be reset to its starting position after each transmission process.

Claims (4)

1. Digital counter-setting apparatus (32) for the initiation of a timed detonator (24) in a projectile (22) after its firing, whereby the counter (32) is set inductively by a sending coil (16) in front of the gun via a receiving coil (23) located within the projectile (22), with a device (14, 15) for measuring the muzzle velocity (V_o) of the projectile (22), in order to set the counter (32) to trigger the timed detonator (24) in dependence on said muzzle velocity, characterised in that the pulses, which are transmitted from the sending coil (16) to the receiving coil (23), are double pulses.

2. Apparatus according to claim 1, characterised in that an ohmic resistor (27) is arranged in parallel with the sending coil (16), in order to optimise the time constant L/R for the transmission of information.

3. Apparatus according to claim 1, characterised in that a resistor (33) is arranged in parallel with the receiving coil (23), in order to optimise the time constant L/R for the transmission of information.

4. Apparatus according to claim 1, characterised in that a filter (29) is connected to the receiving coil (23), so as to exclude transient pulses from the device (14, 15) for measuring the muzzle velocity.

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