IL323955A - Torpedo equipped with an early detection system - Google Patents

Description

'TORPEDO PROVIDED WITH AN EARLY IMPACT DETECTION SYSTEM' Cross-Reference to Related Applications This Patent Application claims priority from Italian Patent Application No. 102023000007530 filed on April 18, 5 2023, the entire disclosure of which is incorporated herein by reference.

Technical field The present invention relates to a torpedo provided with an early impact detection system. 10 Technical background As is well known, torpedoes carry an explosive charge which is activated by a pyrotechnic chain consisting of a total of three explosive components: a detonator which typically receives an activation 15 command from an electronic control unit on board the torpedo; a booster explosive which is detonated by the detonator; and a main explosive which explodes as a result of the explosion of the booster if the booster is in contact with 20 the main explosive.

The detonator is the most reactive and sensitive explosive in the chain, the detonation of which would in itself pose no danger to the torpedo and an operator given the small quantity. 25 The booster explosive is an intermediate charge which is less sensitive than the detonator but whose detonation would itself cause a small amount of damage to the torpedo.

In order to prevent an accidental detonation of the main explosive, in some applications, the three components 5 are alternately physically available within the torpedo from a safety position in which an accidental detonator explosion does not propagate and cannot detonate the main explosive to a weapon position in which the three components are physically aligned along one direction and an explosion of 10 the detonator sequentially detonates the booster and main explosive.

Furthermore, other solutions exist in which the three components are always aligned and the detonator operates at high voltage. 15 In the first case, the movement of the three components from the safety position to the weapon position is accomplished by an actuator which moves a device (e.g., a carriage or a rotating carousel, etc.) and is actuated by the electronic control unit, e.g., an actuator with a 20 pyrotechnic trigger is used.

The torpedo must be brought into the weapon position only when two conditions have been verified, the torpedo has been completely ejected from the submarine's launch tube and it has moved away from the submarine by a clearance distance. 25 To be precise, the standards such as STANAG 4187 mention two independent physical stimuli which can only occur as a result of firing. One of the two stimuli must ensure the clearance distance or 'Equivalent Delay.' (see par 6 of STANAG) 5 The first condition can be verified by means of a sensor fitted with an appendage which presses on the launch tube casing when the torpedo is contained in the launch tube and extends outwards from the torpedo when the torpedo has exited the launch tube. 10 Typically, a probe pushed by a spring is used. The displacement of the appendage produces the signal which indicates the exit of the torpedo.

The torpedo distancing condition is instead accomplished by arranging a main source of electrical energy 15 (thermal battery) in the torpedo, which is only fully activated a few seconds after the torpedo has exited the launch tube; the detonator can only be activated when such an electrical energy source has been fully activated and provides a voltage above a limit value. 20 The exit of the torpedo from the launch tube is accomplished by pushing the torpedo mechanically or by means of pressurised fluids, or by using auxiliary batteries which rotate the torpedo propellers.

It is clear from the above that should the main 25 electrical source be activated immediately following the torpedo's exit, the torpedoes of a known type operating with the procedures described above would immediately move into the weapon position following the exit from the launch tube itself and would be inherently dangerous. 5 Any accidental impact of the torpedo against an obstacle (seabed, undetected submerged object or a portion of the submarine) which occurred a few seconds after the exit of the launch tube would be extremely dangerous and could damage the submarine itself. 10 The damaged or even run-aground torpedo could also remain next to the active and armed launch vehicle for the duration of the mission. The equivalent delay may not be sufficient to ensure the safety distance.

The object of the present invention is to make a torpedo 15 which, following its exit from the launch tube, is not dangerous if the impact is detected a few seconds after the launch, viz.: within the 'equivalent delay' to reach the safety distance.

Background prior art. 20 US6105504 US2961961 Solution to Problem The preceding object is achieved by the present invention in that it relates to a torpedo provided with a 25 weapon safety system as envisaged in claim 1.

The present invention further relates to a method of the type envisaged in claim 5.

Brief Description of Drawings The invention will now be illustrated with reference to 5 the attached figures illustrating a non-limiting embodiment wherein: Figure 1 illustrates a longitudinal section of the torpedo provided with a safety system made according to the present invention; and 10 Figure 2 illustrates a circuit of the torpedo of figure 1.

Description of Embodiments Figure 1 shows a torpedo 1 comprising a tubular cylindrical body 2 elongated along an axis H and housing in 15 the back an electric propulsion motor 3 (e.g., an axial-flow electric motor) driving a multi-bladed rear propeller 4.

However, it is clear that the electric motor may also not be with axial flow.

At the front, the body 2 is provided with an acoustic 20 head 5 (of known type) and houses an explosive warhead 6 described later and also of known type.

The body 2 houses a power supply, e.g., a thermal battery 7 (of known type, e.g., a thermal battery which is activated following the entry of seawater), a battery or any 25 other power supply which powers the electric propulsion motor 3 and an electronic control unit 8 which commands a torpedo mission towards a target.

The explosive warhead 6 of known type comprises three explosive components forming a pyrotechnic chain: 5 a detonator 10 which receives an activation command from the control unit 8; a booster explosive 11 which is detonated by the detonator 10; and a main explosive 12 which explodes following the 10 explosion of the booster 11, The three components 10, 11 and 12 are physically available within the torpedo alternately from a safety position in which an accidental detonation of the detonator does not propagate and the explosion of the main explosive 15 12 cannot operate, to a weapon position in which the three components 10, 11 and 12 are physically aligned along one direction and an explosion of the detonator 10 sequentially carries out the explosion of the booster 11 and the main explosive 12 (pyrotechnic chain alignment). 20 The movement of the three components 10, 11 and 12 from the safety position to the weapon position is accomplished by an actuator (of known type and not illustrated) which moves a carriage or other similar device (not illustrated) and is actuated by the control unit 8, can be an actuator 25 with a pyrotechnic trigger or an electric motor.

The power source 7 is configured to activate immediately following the exit of the torpedo 1 from the launch tube (not illustrated) of an underwater vehicle (not illustrated) to provide the voltage required to power the electric motor 5 3. Immediately is intended as a few seconds after the launch.

According to the present invention, the electronic control unit 8 comprises a circuit 20 for detecting a first event when the torpedo has hit an obstacle with a given 10 energy following its entry in water .

With reference to figure 2, the first circuit 20 comprises an accelerometer 21 mounted on the torpedo 1 which produces a signal which is supplied to an input of an integration circuit 22 through a decoupling circuit 23 which 15 prevents the continuous component of the signal of the axial accelerometer 21 from being supplied to the input of the integrator 22.

An axial accelerometer can be used, which is easily installable on the torpedo; however, different 20 accelerometers can be used, for example a biaxial or triaxial accelerometer, which would detect impacts in all directions and not only in the forward direction of the torpedo.

The integrator 22 is configured to begin the integration of the input signal (RESET) at the instant T when a sensor 25 present on the torpedo (not illustrated and of known type) detects the entrance of the torpedo in water. The output of the integrator circuit 22 is fed to a first input 24-a of a comparator circuit 24 which has a second input 24-b to which a signal indicative of a threshold energy E lim indicative of 5 an impact is supplied. When the torpedo hits an obstacle, the acceleration signal increases considerably for a certain time and its integral representing the energy of the impact itself reaches a value above that of the limit Elim so that the output of the comparator circuit representing the output 10 of the first circuit 20 goes from a first logical value indicating no impact (zero in the example) to a second logical value (1 in the example) indicating precisely that the torpedo has hit an obstacle with a given energy following its entry in water. Any rapid fluctuation of the acceleration 15 signal due, for example, to noise does not contribute to producing a signal representing sufficient energy at the output of integrator circuit 24, and the first logical value is therefore maintained.

The electronic control unit 18 comprises a second 20 circuit 30 adapted to measure the time T elapsed from the time T when the torpedo was launched in water and to generate in output a third logical value (e.g., zero) when such time T is below a limit value Tlim (T < Tlim) and a fourth logical value (e.g., one) when such time T is greater than the limit 25 value Tlim(T > Tlim).

An AND logic gate 32 receives at a first input the output signal of the first circuit 20 and at a second input the negated output of the second circuit 30.

The AND logic gate 32 can output either a zero or a 1 5 value corresponding to a deactivation state.

The AND logic gate 32 has an output which communicates with a LATCH circuit 35 which is configured to stably maintain the value 1 when the output of the logic gate 32 goes from zero to one. 10 The latch circuit 35 is configured to act on an inhibition circuit 37 which brings, following the generation of the deactivation state, the torpedo into a safety state in which the explosion of the warhead is prevented.

The inhibition circuit 37 is configured to carry out 15 one of the following operations: 1) Permanently inhibit the arrangement of the torpedo in the weapon position (for torpedoes such as the one described in the example, the pyrotechnic chain remains misaligned); 20 2) Permanently inhibit the generation of the activation signal and thus the explosion of the detonator ; 3) Permanently inert the ammunition by exploding the detonator with the misaligned pyrotechnic chain. 25 In use: - when an impact with insufficient energy is detected, the output of the circuit 32 is still zero, as it receives a first logical value of zero at the first input; - when an impact with energy greater than the limit 5 is detected and the time elapsed from the instant T of torpedo launch in water is less than the limit, the output of the circuit 32 is one (two 'ones' are supplied to the and gate 32 at the input) and therefore the latch circuit 35 activates the inhibition circuit 37 bringing the torpedo 10 into safety; - when an impact with energy greater than the limit is detected and the time elapsed from the instant T of the torpedo launch in water is greater than the limit, the output of the circuit 32 is zero (the circuit 32 receives a 1 and 15 a zero in input) and therefore the inhibition circuit 37 is not activated.

Claims (6)

1. Torpedo provided with an early impact detection system (1) and comprising a tubular cylindrical body(2) housing in the back an electric motor (3) moving a propeller (4); the tubular body houses a warhead (6), an electrical power supply (7) that powers the electric motor (3) and an electronic control unit (8); the warhead has (6) three explosive parts: a detonator (10) configured to receive an activation command from the electronic control unit (8); a booster explosive (11) that is configured to be detonated by the detonator (10); and a main explosive (12) that is configured to explode following the explosion of the booster explosive (11), characterized by comprising a first circuit (20) configured to detect a first event when the torpedo has hit an obstacle with a predetermined energy after the torpedo has been placed in water; the output of the first circuit (20) is configured to change from a first logical value corresponding to an absence of impacts to a second logical value indicating that the torpedo has hit an obstacle with a predetermined energy after being placed in water; a second circuit (30) is configured to measure time T elapsed from the time T at which the torpedo has been placed in water and to output a third logical value when time T is below a limit value Slim (T < Tlim) and a fourth logical value when time T is greater than limit value Tlim(T > Tlim); a logical circuit (32) configured to receive at its inputs the outputs of the first circuit (20) and the output of the second circuit (30); the output of the logical circuit (32) is configured to switch towards a deactivation state when an impact is detected at a time T below the time limit Tlim; there is provided an inhibition circuit (37) configured to set the torpedo, following the generation of the deactivation state, in a safety state preventing an explosion of the warhead.

2. Torpedo as defined in claim 1, wherein said inhibition circuit (37) is configured to perform one of the following operations: 1) inhibiting in a permanent manner the disposition of the three explosive parts in a position in which the detonator (10) , the booster explosive (11) and the main explosive (12) are physically placed along one line; 2) inhibiting in a permanent manner the generation of the activation command and the explosion of the detonator (10); 3) making inert the warhead (6) by means of the explosion of detonator when the detonator (10) , the booster explosive (11) and the main explosive (12) are not physically placed along one line.

3 . Torpedo as defined in claim 1 or 2 in which the logical circuit (32) is an AND gate configured to receive at one of its inputs the output of the first circuit (20) an at the other input the inverted output of the second circuit (30); the output of the first circuit (20) is configured to switch from a first logical value corresponding to zero when no impact is detected to a second logic value corresponding to one when the torpedo has hit an obstacle with a predetermined energy after being placed in water; the second circuit (30) outputs a third logic value corresponding to zero when time T is below the time limit Tlim (T < Tlim) and a fourth logical value corresponding to one when the time T is greater than the limit value Tlim(T > Tlim); the output of the logic circuit (32) switches to the deactivation state corresponding to one when an impact is detected at a time T below the limit value.

4 . Torpedo according to one of the preceding claims wherein the first circuit (20) comprises an accelerometer (21) mounted on the torpedo (1) and designed to output a signal that is supplied to an input of an integration circuit (22) through a decoupling circuit (23) designed to prevent that the continuous component of the signal of the accelerometer (21) is supplied to the input of the integration circuit (22); the integration circuit (22) is designed to start the integration of the input signal (RESET) at time T at which a sensor placed on the torpedo detects that the torpedo has been placed in water; the output of the integration circuit (22) is supplied at a first input (24-a) of a comparator (24) having a second input (24-b) receiving a signal representing a limit energy value Elim corresponding to an impact .

5. Method of detecting an early impact of a torpedo (1) comprising a tubular cylindrical body (2) housing in the back an electric motor (3) moving a propeller (4); the tubular body houses a warhead (6), an electrical power supply (7) that powers the electric motor (3) and an electronic control unit (8); the warhead has (6) three explosive parts: a detonator (10) configured to receive an activation command from the electronic control unit (8); a booster explosive (11) that is configured to be detonated by the detonator (10); and a main explosive (12) that is configured to explode following the explosion of the booster explosive (11); the method being characterised in that it comprises the steps of: detecting a first event when the torpedo has hit an obstacle with a predetermined energy after being placed in water thus generating a first logical value indicating absence of impacts or a second logical value indicating that the torpedo has hit an obstacle with a predetermined energy after being placed in water; detecting time T elapsed from time T at which the torpedo has been placed in water and generating a third logical value when time T is below a limit value Tlim (T < Tlim) and a fourth logical value when said time T is greater than the limit value Tlim(T > Tlim); performing a logic operation based on the first, second, third and fourth logical value to determine a deactivation state when an impact is detected before the limit value; placing (37), following the generation of deactivation state, the torpedo in a safety state in which the explosion of the warhead is prevented.

6. Method as set in claim 5 wherein the torpedo is placed in a deactivation state according to one of the following operation: 1) Inhibiting in a permanent manner the disposition of the three explosive parts in a position in which the detonator (10) , the booster explosive (11) and the main explosive (12) are physically placed along one line; 2) inhibiting in a permanent manner the generation of the activation command and the explosion of the detonator (10); 3) making inert the warhead (6) by means of the explosion of detonator when the detonator (10) , the booster explosive (11) and the main explosive (12) are not physically placed along one line. Roy S. Melzer, Adv. Patent Attorney G.E. Ehrlich (1995) Ltd. 35 HaMasger Street Sky Tower, 13th Floor Tel Aviv 6721407