Patent Application
20110203475
The present invention relates to an explosive part, intended to form part of an explosive device for combating different targets and combat situations, which explosive part comprises at least two tubular explosive charges comprising an explosive: an inner explosive charge with diameter di and an outer explosive charge with diameter dy, which two explosive charges are arranged coaxially along a common centre axis A-A between two end faces, the explosive charges being separated from each other with at least two insulating layers: an outer insulating layer with layer thickness ty arranged on the outer explosive charge, an inner insulating layer with layer thickness ti arranged on the inner explosive charge, and an air gap with thickness ts between the two insulating layers.
Modern guidable, so-called intelligent active ammunition is used to combat, with high precision, different types of targets, at the same time as every effort is made to avoid injury to own troops and civilians. In this context, it is interesting to be able to choose the form and or direction of action at short notice. It is here desirable that the fragmentation occurs in a predetermined direction and that undesirable fragment dispersion is avoided.
Another desirable characteristic is the facility to be able to abort an attack, due to altered conditions, by sending signals to an explosive device en route to a target so as to disable the explosive part before it reaches the target. If the explosive part detonates at full force, there is a risk of dangerous fragments being dispersed into the environment. If the explosive part is steered away without detonating, then dangerous explosive parts are dispersed into the environment. It is therefore desirable to be able to destroy the explosive part without it detonating at full force. In certain contexts, it is also of interest to be able to realize a number of different action functions, such as effect in different directions, for example in respect of rotary explosive devices. Rotary explosive devices in which activation is realized via sensors sometimes induce the effect in more directions than is intended, which can result in civil material and civilians being harmed.
To remote-detonate explosive devices which have missed their target, “mission abort”, can mean that high-velocity fragments are dispersed into the environment.
Explosive devices having a number of different action functions normally have a detonator for each action function, which makes the explosive devices complicated and expensive. The main object of the present invention is to solve this problem.
There is also a desire to reduce the number of explosive parts, so that fewer explosive parts can effectively combat different types of targets and situations.
The present invention aims also to solve this problem.
Despite the increased demand to combat more target types with fewer explosive parts, this must not be allowed to restrict other functions. Technical advantages which are obtained must be able to be maintained without the explosive device being made more complicated or more expensive.
The object of the present invention is also to solve these problems.
The objects, and other aims which are not listed here, are satisfactorily met within the scope of that which is defined in the present independent patent claims.
According to the present invention, therefore, an explosive part has been produced which is intended to form part of an explosive device for combating different targets and combat situations, which explosive part comprises at least two tubular explosive charges comprising an explosive: an inner explosive charge with diameter di and an outer explosive charge with diameter dy, which two explosive charges are arranged coaxially along a common centre axis A-A between two end faces, the explosive charges being separated from each other with at least two insulating layers: an outer insulating layer with layer thickness ty arranged on the outer explosive charge, an inner insulating layer with layer thickness ti arranged on the inner explosive charge, and an air gap with thickness ts between the two insulating layers.
That which primarily can be deemed characteristic of the discussion explosive part is, inter alfa, that the explosive part also comprises two initiation devices arranged on each end face with connections to the inner explosive charge, the two initiation devices being arranged for optional initiation of the inner explosive charge, with or without an ignition delay Δt, and that the diameter d1 for the inner explosive charge, materials and layer thicknesses ti, ty for the two insulating layers, and the thickness ts for the air gap are chosen such that two colliding detonation fronts at a position Z along the common centre axis A-A are required in order for the initiation to lead to detonation of the outer explosive charge.
Further characteristics are:
According to the invention, there has also been produced an explosive device for different targets, comprising at least three explosive parts having different action functions according to any one of patent claims 1-4, which explosive parts are arranged one after the other along a common centre axis A-A between two end faces, the explosive parts being separated from each other with intervening detonation barriers for preventing flashover ignition between the explosive parts.
The explosive device is characterized, inter alia, in that the inner explosive charges of the explosive parts have been replaced with a common inner explosive charge, which common inner explosive charge is arranged axially through the explosive parts via the intervening detonation barriers, so that one or more explosive parts are optionally detonable through the choice of an initiation position Z along the common centre axis A-A, corresponding to the position for any one of the explosive parts.
Further characteristics of the explosive device are that:
According to the invention, there has also been produced an ammunition unit having different action functions for combating different targets and situations, characterized in that the ammunition unit comprises an explosive device as described above.
Finally, according to the invention, a method has been produced comprising at least two tubular explosive charges: an inner explosive charge with diameter di and an outer explosive charge with diameter dy for combating different targets and combat situations, which two explosive charges are arranged coaxially along a common centre axis A-A between two end faces, the explosive charges being separated with at least two insulating layers: an outer insulating layer with layer thickness ty, which is arranged on the outer explosive charge, and an inner insulating layer with layer thickness ti, which is arranged on the inner explosive charge, as well as an air gap with thickness ts between the two insulating layers.
The method is characterized, inter alfa, in that two initiation devices are also provided, one on each end face of the explosive part, the two initiation devices being electrically connected to the two initiation devices, and in that the two initiation devices are arranged for optional initiation of the inner explosive charge, with or without an ignition delay Lt, and in that the diameter d1 for the inner explosive charge, materials and layer thicknesses ti, ty for the two insulating layers, and the thickness ts for the air gap, are arranged such that two colliding detonation fronts at a position Z along the common centre axis A-A are required in order for the initiation to lead to detonation of the outer explosive charge.
The method is further characterized:
As a result of the proposed, a number of advantages are obtained:
Reduced risk for civil material and civilians through the facility to choose between detonation or non-detonation of one or more explosive parts and by virtue of the fact that the action function can take place in a selectable direction.
Cost-effective construction as a result of only two initiation devices being required in order to initiate a plurality of charge devices.
Simple design/construction by virtue of a continuous choice of initiation position along a common centre axis A-A in an explosive part or in an explosive device comprising two or more explosive charges.
A preferred embodiment of an explosive device according to the invention is described in detail below with simultaneous reference to the appended figures, in which:
The fragment-forming elements 6 can also be cubic or cylindrical in shape. The fragment-forming elements 6 can be arranged directly in the explosive casing 4, for example by casting or moulding, or in separate action layers arranged on the explosive casing 4 (not shown). The inner explosive charge 2, preferably configured as a string with circular cross section, is arranged along the centre axis A-A of the explosive part 1, between the two end walls 5.
Adjoining the two end walls there are arranged two initiation devices 7, which can be constituted by detonators, for initiating the inner explosive charge 2. The outer explosive charge 3, which is preferably cylindrical, is fixedly mounted between the two end walls 5 of the explosive part 1. The inner and outer explosive charges 2, 3 are separated, firstly with an outer insulating layer 8 arranged on the inner limit face of the outer explosive charge 3, and secondly with an inner insulating layer 9 arranged on the outer limit face of the inner explosive charge 2, the two insulating layers 8, 9 being separated with an air gap 10.
The inner and the outer explosive charge 2, 3, the two insulating layers 8, 9 and the air gap 10 are dimensioned such that, upon initiation of one end face end 5 of the explosive charge 2, a detonation front is formed, the energy of which is sufficient to detonate the outer explosive charge 3. The result is that the outer explosive charge 3 is initiated without detonation occurring. Instead, a deflagrative combustion takes place, in which the outer explosive charge 3 is destroyed and ejected from the explosive part 1. This means, in turn, that the fragment-forming elements 6 are ejected from the explosive part 1 without causing damage to the environment. By explosive effect is meant the pressure effect which is formed upon detonation of the outer explosive charge 3, in combination with the fragmentation from the fragment-forming elements 6.
In order that the outer explosive charge 3 shall detonate, an initiation energy equivalent to two colliding detonation fronts is required. This is achieved by the two end face ends of the explosive charge 2 being initiated with the two initiation devices 7, simultaneously or with a time difference Δt. The two formed detonation fronts move towards each other along the common centre axis A-A of the explosive part 1 and collide at a set position Z. The position Z is determined by the time difference Δt, the length L for the inner explosive charge 2, and by the detonation velocity d of the explosive, according to the relationship:
Z=(L+Δt·d)/2.
Through the choice of position Z, it is possible to vary the action function of the explosive part 1, firstly by arranging fragment-forming elements 6 of different sizes in the explosive casing 4, and secondly by configuring the explosive casing 4 with different shapes, such as convex, concave or flat shape, or combinations thereof. A convex shape gives wider fragment distribution than a flat or concave shape.
The best result for attaining detonation in the outer explosive charge 3 with the said method has been gained with explosive parts 1 in which the calibre is 120 mm, in which the inner explosive charge 2 has a diameter di of 20 mm, in which the outer insulating layer 8 comprises copper and has a layer thickness dy of 3 mm, in which the inner insulating layer 9 comprises plastic and has a layer thickness di of 3 mm, and in which the thickness ts of the air gap 10 is 7 mm. Suitable explosives include dynamite, trinitrotoluene (TNT), octogen (HMX), or cyclonite (RDX). Other combinations of explosives are also possible.
It has also proved beneficial, with a damping insulating layer (not shown) arranged on the inner side of the explosive casing 4, to damp out possible reflections which might occur against the explosive casing 4, possibly causing unwanted detonation of the outer explosive charge 3. The damping insulating layer is preferably constituted by a plastic having a layer thickness within the range 2-4 mm.
The explosive casing 4 of the first explosive part 12 comprises two bearings, arranged one upon the other, having small metal balls 6, whilst that of the second explosive part 13 comprises a single bearing having large metal balls 6, and that of the third explosive part 23 comprises a single bearing having small metal balls 6. The choice of position Z1 means that the explosive part 12 detonates, at the same time as the other two explosive parts 13, 14 are destroyed by deflagration. The result is an action function having a large number of small fragments of low velocity. The choice of position Z2 means that the explosive part 13 detonates, at the same time as the other two explosive parts 12, 14 deflagrate. The result is an action function having a smaller number of larger fragments with low velocity. Finally, the choice of position Z3 means that the explosive part 14 detonates, at the same time as the other two explosive parts 12, 13 are destroyed. The result is an action function having fewer small fragments 6 with high velocity.
In a special variant (not shown), only one of the two end faces 16 is configured for RSV function, which means that only one of the two adjoining explosive parts can be detonated. By applying the principle involving RSV function to explosive devices having more than two explosive parts 12, 13, 14, it is possible to increase the number of combination options.
The explosive device 30 in
The different action directions X, Y and V are achieved by the fact that on each explosive casing 4 there are arranged fragment-forming elements 6 on delimited regions 34, 35, 36, instead of on the whole of the explosive casing 4. The perpendicular to each such delimited region 34, 35, 36 corresponds to the action directions X, Y and Z of the explosive parts 31, 32, 33. The delimited regions 34, 35, 36 are preferably flat square or rectangular areas 34, 35, 36 with length l and width B, in which l is less than or equal to the length L of the explosive parts 31, 32, 33, and B is less than or equal to ⅔ of the diameter D of the explosive parts 31, 32, 33. The delimited regions 34, 35, 36 can have different configuration, for example a flat circular shape where a circular form of effect is sought, or a convex shape for convex effect distribution, or a concave shape for concave effect distribution. Combinations of the above may also be of interest.
The action direction X, Y and V of the explosive device 30 is determined by which of the explosive parts 12, 13, 14 detonates,
In a variant of the explosive device 30 (not shown), one or more of the action layers 31, 32, 33 is/are configured for enhanced RSV.
The outer explosive charge 3 is divided into three equal-sized charge segments 42. The detonation barriers comprise three axially arranged slots 43 arranged along the common centre axis A-A. The slots 43 constitute well defined openings 43 between the inner explosive charge 2 and the three charge segments 42.
The detonation barriers 41 in
Initiation of the explosive charge 2 at a position Z corresponding to any one of the action sections I, II, III means that one of the two charge segments 42 will detonate, whilst the other two charge segments 42 deflagrate. Which charge segment 42 detonates depends on that orientation of the slot 43 in which the two detonation fronts collide along the centre axis A-A. The fragment dispersion is determined by the shape, length L and width B of the respective action layer 44. Different action directions X, Y, V and fragment dispersion can therefore be chosen through the choice of position Z.
Initiation at a position Z corresponding to the action section I means detonation of charge segments 42 with the action direction X, at the same time as other charge segments 42 are destroyed by deflagration. Initiation at a position Z corresponding to the action section II means detonation of charge segments 42 with action direction Y, at the same time as other charge segments 42 are destroyed. Initiation at a position Z corresponding to the action section III means detonation of charge segments 42 with action direction V, at the same time as the other charge segments 42 are destroyed.
In a special variant of the explosive device 40 (not shown), the inner detonation barriers 41 comprise two slots 43 instead of one, which allows simultaneous detonation of two different charge segments 42. This, in turn, allows simultaneous action in two different directions.
The present invention is not limited to the embodiments shown, but can be subject to modifications within the scope of the following patent claims.
| Number | Date | Country | Kind |
|---|---|---|---|
| 0801932-5 | Sep 2008 | SE | national |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/SE09/00382 | 8/18/2009 | WO | 00 | 5/10/2011 |
