GB2235273A

GB2235273A - Mine for combating land vehicles

Info

Publication number: GB2235273A
Application number: GB8133567A
Authority: GB
Inventors: Willi J Petters; Klaus Fischer; Rolf Menne
Original assignee: Dynamit Nobel AG
Current assignee: Dynamit Nobel AG
Priority date: 1979-03-03
Filing date: 1981-11-06
Publication date: 1991-02-27
Anticipated expiration: 2001-11-06
Also published as: GB2235273B; BE890752A; DE2908360C1; FR2654824A1

Abstract

A mine for combating land vehicles, comprising a hollow charge and a space charge for the removal, prior to ignition of the hollow charge, of a camouflage layer usually covering the mine, avoids undesired ignition of the space charge if a track or wheel of the vehicle applies pressure above the mine. Sensor S1 determining pressure4ree passage is activated at time t0 and feeds a signal to gate G1; in the absence of any further signal to G1 the detonators Z1, Z2 for the space and hollow charges are detonated after time intervals DELTA t1, DELTA t2 ( DELTA t2 > DELTA t1). However if after time interval DELTA t3, ( DELTA t3 < DELTA t1), sensor S2 determines pressure loading from a track or wheel, G1 and Z1 are blocked and Z2 is detonated after time interval DELTA t2. <IMAGE>

Description

"MINE FOR THE COMBATING OF LAND VEHICLES" The invention is concerned with a mine for the combating of land vehicles.

Modern mines for use as a defence against tanks comprise hollow charges of different type and form as active charges. These are positioned so as to penetrate the hull of the tank from a definite distance whatever the strength of armouring at the front or at the underside.

Should the mine be run over by the track of the tank, then the hollow charge effect is not developed since the distance is too small. Here the mine only exerts an explosive force as a result of conventional explosion related directly in strength to the amount of explosive present.

Hollow charges for the combating of land vehicles, especially for defence against tanks, are usually buried for camouflage under a layer of earth. Since this at the very least hinders the development of the hollow charge jets, the camouflage layer is usually removed before the release of detonation of the hollow charge with the aid of a special space charge. This space charge consists of propellent powder, for example black powder, and is suspended in the funnel, hemispherical-shaped or the like space which is formed between the hollow charge insert and the mine cover.

Since under certain circumstances large amounts of earth which can also for example have a high strength when frozen, are to be cleared away, the quantity of the space charge must be relatively large. As such, this is alright since an immediate release of the powder gases from the space charge occurs on removal of the camouflage layer. It has however now been shown that there are situations in which the effect of the space charge is extremely damaging. This is the case especially when a tank lies with its track over the buried mine. The buried mine is then tamped particularly downwards and sideways through the largely strengthening body of earth.

Should the camouflage layer now be uncovered by the track and the tank weighing heavily upon it, then the mine is also additionally tamped from above. In this way, the mine is tamped completely therearound so that the powder gases of the space charge are completely dammed and find no release, and hence the effective force of the space charge is additionally increased. Because of the limited possibilities for the gases being spatiafly directed, this force is thus directed predominantly onto the mine located thereunder, and especially on to the hollow charge. This leads to the mine either being completely destroyed structurally or at least so altered that it can only provide a reduced explosive force. This means, in particular, that the mine can no longer carry out its task of destroying the track.

This disadvantageous effect is met not only with tanks, but also with other tracked vehicles and also with wheeled vehicles which when passing over the mine may cause it to be loaded as a result of downward pressure of their track, their wheel or the like, and thereby additionally tamp the space charge therein.

According to the present invention, there is provided a mine for the combating of land vehicles comprising a hollow charge, a space charge for the removal, prior to detonation of the hollow charge of a camouflage layer usually covering the mine and firing arrangement triggered by a sensor system for the said charges, which sensor system is constructed so as to be selectively operable whereby only the detonation of the hollow charge is triggered on passage directly over the mine of said vehicle and application of pressure to the mine and whereby, in the event of pressure free passage of the vehicle detonation of the hollow charge is only triggered after ignition of the space charge has occurred.

By constructing a mine according to the invention, use is made of a novel concept to obtain an optimum form of mine whereby should a tank travel over the mine with its prow or its hull then the camouflage layer is removed in known manner by the space charge. Immediately thereafter, the hollow charge is brought to detonation.

Should, in contrast, the tank travel over the mine with its track, then according to this invention, the space charge is not ignited and the hollow charge is immediately detonated and operates in the manner of a normal explosive charge and destroys the track. Likewise, if the underside or a wheel of a wheeled vehicle finds itself positioned over the mine, a corresponding effect is achieved.

There is provided a selectively operative mine which has the advantage that the space charge is not ignited and consequential damage to functioning is avoided, if the mine is pressure loaded by the vehicle and therefore is additionally tamped. The question of whether this loading condition applies will be generally determined by a sensor system in the triggering process and which, according to the invention, distinguishes between the two conditions "pressure free passage by for example prow or hull" and "weight loading passage by for example track".

Known types of sensor are usable for this purpose. For example, with tracked vehicles, a sensor can be used which provides a signal on detecting alterations to the earth's magnetic field by the vehicle or when subject to the magnetic field of the vehicle itself. Sensors of the latter type are preferred. These field-alteration sensors or field sensors are equipped with two different threshold values for signalling. With passage thereover by, for example, the prow or hull of a tank, a lower threshold value is exceeded and hence the sensor emits a signal for the presence of a tank. If, within a predetermined period of time which follows, there is no additional information owing to exceeding of the second higher threshold value, then the mine is triggered in known manner, that is the space charge is then ignited.Should the tank however approach the sensor with its track and pass over this then, almost immediately after exceeding the first lower threshold value, the second higher threshold value of the sensor is exceeded, since the track of the sensor is much nearer the mine than the prow or the hull and accordingly the magnetic field alteration or the sensed magnetic field is correspondingly greater.

When the second threshold value is exceeded, then the ignition signal is given directly to the hollow charge, that is the preceding ignition of the space charge is delayed. The different firing impulses to the space charge and hollow charge or only to the hollow charge are achieved by means of an evaluation apparatus connected to the sensors, which can be constructed in many known ways from electronic components. One example of such evaluation electronics is given by way of explanation subsequently herein.

Naturally the two intensity thresholds can also be set by two separate sensors of like or different type.

In a preferred arrangement embodying the invention, there is provided a selective sensor system construction comprising a combination of two or more sensors, of which at least one always operates at pressure (pressure-sensitive) and at least one operates as a proximity sensor for detecting pressure-free passage of the vehicle. Numerous constructional forms are known for such sensors. For example, for the recognition of the vehicle, especially a tank, there can be used for example a proximity sensor as such which operates on contacting by a vehicle, when subject to the magnetic field of the vehicle, on altera tion of the magnetic field of the earth by the vehicle or on earth vibrations or the like caused by the vehicle.

Should only the situation "presence of a vehicle" be recognised, then after reaching predetermined threshold values of this sensor, the complete customary functional chain of the mine - ignition of the space charge and then detonation of the hollow charge - is set in operation by the evaluator arrangement connected thereafter. Should however the pressure sensor additionally sense "pressure" then, according to the invention, only the detonation of the hollow charge is provided by the signal evaluating signal operation which follows. There are, of course, numerous known forms of pressure sensor which may be used.

Especially with a mine for defence against tanks with its necessarily demarked size, it is preferred to employ as a sensor, a sensor which emits a signal on pressure loading which is actuable by the deformation of the mine taking place under load and which is brought about, in fact, through the covering layer. Once again, there are numerous known forms of deformation sensors which can be used, for example elastic elements, capacitative, inductive or piezoelectrically operating elements and mechanical-electrical contact makers. These and the types of sensors indicated previously are only given by way of example and in no way are intended to be limitative of the types of sensors usable for the operating concept according to this invention.

For a better understanding of the invention and to show how the same can be carried into effect, reference will now be made by way of example only to the accompanying drawing which is a circuit diagram of a suitable form of sensor circuit for use therein.

Referring to the drawing, a sensor S1 which may be of rod-form and actuated on contact at time to by a vehicle, gives a signal to an evaluator SB1 connected after it with built-in memory. The signal evaluator SB1 evaluates in known manner the signal obtained from sensor Sorr recognising its target, for example concerning amplitude, time interval and if necessary frequency, in order to avoid causing errors by contacts not originating from a vehicle. Should the criteria fed to the signal evaluator SB1 be fulfilled, that is should a target be recognised, then the signal is fed to an incorporated memory and to an AND gate G1 connected through inverted input E.Simultaneously, the time-signal transmitter ZG is controlled by an impulse to time point to, which for its part gives, after passage of a predetermined time interval A t1, At for example 100 ms, a signal to the 1' second input of the gate G1.

If no signal has been given at the latest on the elapse of the time interval At to the inverted input E of the gate G1, then this gate switches the time signal from the memory of the signal evaluator SB1 through to time point to + At which then achieves on the one o hand the triggering of the ignition arrangement Z1 of the space charge and on the other hand is fed onto the input of a further AND gate G2. After elapse of the time interval A t2 > # t1 - for example 300 ms, then the time signal transmitter ZG gives a signal to the other input of the gate G2. This thereupon switches through and the signal is given to OR gate G3 via the detonation arrangement Z2 for the hollow charge and this is thus triggered later than the space charge.The detonationtignition arrangements Zl and Z2 are disposed with their other poles on the mass M.

As an alternative to the foregoing, it may now be assumed that the second sensor S2 which emits a signal when subject to pressure at the time point to + A t3 on account of passage thereover by a track, wheel or the like, will provide a signal to the signal evaluation arrangement SB2 with incorporated memory connected thereafter. For the time span3, the condition A t3 tl applies. An evaluation of the signal, for example with respect to amplitude or length of time is carried out in the signal evaluator SB2, as with evaluator SB1 in order to establish with certainty that in fact a signal emission resulting from passage of a track, a wheel or the like is indeed taking place.If this is the case, the signal will be switched through as a continuous delay signal and be given to the inverted input E of the gate G1. This will act as a block so that after receipt of the signal from time signal transmitter ZG no through switching to the detonation arrangement Zl is achieved.

The ignition of the space charge is therefore prevented.

However, the continuous signal from the signal evaluation arrangement SB2 is also fed to a further AND gate G4, which is switched through after receipt of a second signal from the time signal transmitter ZG for time to + A t2 t 2 to operate the OR gate whereby this is switched through and the triggering only of ignition arrangement Z2 of the hollow charge is achieved. The size of time intervals At1 and At2 is to be chosen corresponding to the relationships in the individual cases and depends for example on about how much later in practice the sensor S2 in contrast to the sensor S1 is to emit a signal and what time interval is to separate triggering of detonation of the hollow charge from triggering of ignition of the space charge. The elements arranged after the sensors S1 and S2 with the exception of the ignition arrangements Z1 and Z2 represent the evaluation arrangement which together with the sensors make up a selective sensor system according to the invention.

Claims

Claims:

1. A mine for the combating of land vehicles, comprising a hollow charge, a space charge for the removal, prior to detonation of the hollow charge of a camouflage layer usually covering the mine and a firing arrangement triggered by a sensor system for the said charges, which sensor system is constructed so as to be selectively operable whereby only the detonation of the hollow charge is triggered on passage directly over the mine of said vehicle and application of pressure to the mine and whereby, in the event of pressure free passage of the vehicle detonation of the hollow charge is only triggered after ignition of the space charge has occurred.

2. A mine according to claim 1, wherein the space charge is housed in the space in the mine formed between the hollow charge insert of the mine and the mine cover.

3. A mine according to claim 1 or 2, wherein the sensor system comprises at least two sensors of which one emits a signal in the event of its being subject to pressure loading through the vehicle and of which the other emits a signal on pressure free passage over the mine of the vehicle.

4. A mine according to claim 3, wherein the sensor which emits a signal when subject to a pressure loading is actuable by the deformation of the mine taking place when the mine is subject to a load.

5. A mine according to any one of the preceding claims, which is constructed so as to be effective in the combating of tanks or other tracked vehicles.

6. A mine according to any one of the preceding claims, wherein the sensor emitting a signal on pressurefree passage of the vehicle is one which is actuated by the magnetic field of the vehicle.

7. A mine for the combating of land vehicles, substantially as hereinbefore described with reference to the accompanying drawing.

8. A firing arrangement for use in a mine for the combating of land vehicles1 which arrangement comprises a first sensor actuated on passage directly thereover of a said vehicle and application of pressure and a second sensor actuated only in the event of pressure free passage of a said vehicle thereover, which sensors have associated therewith a detonator for a hollow charge and an igniter for a space charge for removal prior to ignition of the hollow charge of a camouflage layer used in covering the mine and are selectively operable so that in the event that the first sensor is subject to a said pressure, no signal is transmitted to the igniter for the space charge and such that in the event that the arrangement is subject to pressure free passage of the vehicle thereover, the igniter for the space charge is triggered before the detonator for the hollow charge.

9. A firing arrangement for use in a mine forth combating of land vehicles, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

9. An arrangement according to claim 8, additionally comprising, associated with each sensor, an evaluator for screening out signals not originating from passage of a said vehicle.

10. A firing arrangement for use in a mine for the combating of land vehicles, substantially as hereinbefore described with reference to and as shown in the accompanying drawing.

Amendments to the claims have been filed as follows

1. A mine for the combating of land vehicles, comprising a hollow charge, a space charge for the removal, prior to detonation of the hollow charge, of a camouflage layer usually covering the mine and a firing arrangement triggered by a sensor system for the said charges, which sensor system is constructed so as to be selectively operable whereby the detonation of the hollow charge only is triggered by the close proximity of a part of a said vehicle contacting said mine or earth directly thereover and whereby, in the event of the remoter proximity of a part of a said vehicle passing directly over but not making contact with said mine or earth thereover detonation of the hollow charge is only triggered after igniti$on of the space charge has occurred.

5. A mine according to any one of the preceding claims, wherein the sensor emitting a signal in the event of the said remoter proximity of a part of a said vehicle is one which is actuated by the magnetic field of the vehicle.

6. A mine for the combating of land vehicles, substantially as hereinbefore described with reference to the accompanying drawing.

7. A firing arrangement for use in a mine for the combating of land vehicles, which arrangement comprises a first sensor actuated by the close proximity of a part of a said vehicle contacting said mine or earth directly thereover and a second sensor actuated only in the event of the remoter proximity of a part of a said vehicle passing directly over but not making contact with said mine or earth thereover, which sensors have associated therewith a detonator for a hollow charge and an igniter for a space charge for removal prior to ignition of the hollow charge of a camouflage layer used in covering the mine and are selectively operable so that in'the event that the arrangement is subject to the close proximity of a part of said vehicle contacting a said mine comprising said arrangement, or earth thereover, no signal is transmitted to the igniter for the space charge and such that in the event that the arrangement is subject to the remoter proximity of a part of said vehicle passing directly over but not making contact with said mine or earth thereover, the igniter for the space charge is triggered before the detonator for the hollow charge.

8. An arrangement according to claim 7, additionally comprising, associated with each sensor, an evaluator for screening out signals not originating frompassage of a said vehicle.