A DEVICE TO ENABLE TARGETS TO BE COMBATED BY A SHAPED CHARGE FUNCTION

Abstract: A device arranged to enable the engagement of targets (5) by means of a shaped charge function. An ammunition unit is arranged to operate with at least two configuration modes where in the first mode the ammunition unit comprises solely a first modular charge (3). In the second mode the first modular charge is conjoined with a second modular charge (4). The modular charges each effect their own type of shaped charge function. Another feature is that the ammunition unit is arranged to enable changeover from the first configuration to the second before firing, launch or release of the ammunition unit.

Description: A device to enable targets to be combated by a shaped charge function The present invention relates to a device to enable the engagement of targets using a shaped charge function. The use of a unit of ammunition in the form of a projectile, shell, missile, etc to engage a target by the application of a shaped charge function is already known. The shaped charge is thus matched to the type of target, and there are thereby shaped charges arranged to operate at short standoff distances to the target or surface of the target, compared with a so-called jetting shaped charge function that operates at a very small standoff distance (e.g. 100 millimetres) from the surface of the target to achieve a hole in, or an impact on, the target. The use of EFP (explosively formed projectile/penetrator) shaped charges with which one can begin to attack a target or surface of a target at considerably larger standoff distances (e.g. 50 metres) is also already known. Consequently, there are major differences in effectiveness against different types of target, and to optimise effect in each case it is vital to use the correct ammunition unit with the correct shaped charge. The use of different ammunition units optimised for different engagement situations is thereby already known. There is a need, however, to be able to reduce the assortment of ammunition units. The objective of the present invention is to resolve this problem, and to propose that modular charge components be used to enable one and the same ammunition unit to be matched to, or be re-configured for, the type of target in question, i.e. so that the ammunition unit can be assigned a shaped charge function at the deployment site (e.g. prior to firing, launch or weapon release) that is optimised for the target to be engaged on the occasion in question. It is thus necessary that re-configuration for the various engagement occasions can achieve optimisation for the target in question, and that it can be performed in a safe and, primarily, technically simple manner. There is even a desire that the new function with modular charges shall not unduly intrude upon the total costs in the system as such. The present invention is envisaged to resolve this problem too. The main characteristic features of the arrangement initially mentioned are, among other things, that an ammunition unit in the form of a projectile, shell, missile, etc is arranged to operate with at least two modular charge configurations, in the first of which the ammunition unit incorporates a first modular charge or modular array that projects a first shaped charge function— such as a jetting shaped charge— while in the second configuration the first modular charge or modular array is conjoined with a second modular charge or modular array that projects a second shaped charge function such as an EFP function. Another feature is that the ammunition unit is arranged to enable changeover from the first configuration to the second before firing, launch or release of the ammunition unit. Thus in embodiments of the invention concept the second modular charge or modular array eliminates the shaped charge function effected by the first modular charge or modular array when the modules or arrays are arranged in conjoined mode. The first modular charge incorporates a liner— forwards facing and in the form of a funnel or cone— that produces the first shaped charge function. The second modular charge is thus designed with a rear section that exhibits a corresponding form to that of the said funnel or cone form. In the second case the second modular charge is conjoined with the first modular charge via the said rear section which, in conjoined mode, is inserted in the funnel or cone form of the first modular charge. In a preferred embodiment the fit between the form of the rear section of the second modular charge and the funnel or cone form of the first modular charge is a salient feature, and exhibits an extremely precise fit in the preferred embodiment. The liner that produces the second shaped charge function exhibits a lateral face that conjoins with the lateral face of the first modular charge, and the first mentioned lateral face can be considered to form a continuation or constituent part of the latter mentioned lateral face. The said rear section preferably consists of or contains explosive material, and the first modular charge preferably incorporates an essentially cylindrical container enclosing the explosive material of the first modular charge. Parts of the explosive material in the first and second modular charges conjoin with each other in the said conjoined mode. In a preferred embodiment the ammunition unit at delivery incorporates both modular charges or modular arrays in conjoined state. If the first charge configuration shall be used the second modular charge or modular array is thus removed. The ammunition device in one embodiment is arranged with a casing or structural element that is removable when changing over between the first and second configuration modes. After the changeover it shall be possible to refit the said casing or structural element to enable the ammunition unit to be fired, launched or released. Additional variants of the present invention are disclosed in the subsequent Patent Claims and the detailed description. The above proposals enable the new changeover function to be achieved without any significant financial burden to the system in its entirety. The present invention exploits the insight that the explosive charge represents a relatively small value with regard to the total system, in which the functions for guidance, propulsion, actuation, etc represent the major costs. The redundancy thereby achieved by the use of two different types of modular charges or modular arrays in which one modular charge or modular array is discarded in certain engagement situations is thus not a burden to the system as such. Changeover can be arranged in an already known way, such as by means of screw joint(s), by means of which the casing or structural element can be removed and then refitted to achieve reliable closure. The modular charges as such can also consist of conventional constructions and designs. A currently proposed design for a device as claimed in the present invention is described below with reference to the appended Figures 1 and 2 in which Figure 1 shows a longitudinal section of a modular charge configuration comprising first and second modular charges in conjoined mode, and Figure 2 shows a longitudinal section of the modular charges illustrated in Figure 1, but with the second modular charge removed from the first modular charge. Number lin Figure 1 symbolises parts of an ammunition unit in accordance with the above. The ammunition unit comprises, among other things, an explosive charge arrangement denoted 2. The explosive charge arrangement incorporates an initiation function symbolised by 3. As claimed in the present invention the explosive charge arrangement comprises two modular charges, of which the first modular charge is designated 3 and the second modular charge is designated 4. Modular charge 3 comprises explosive 3a and a trumpet formed, shaped charge effecting inner cone illustrated in Figure 1 by sections 3b and 3c. This inner cone 3b, 3c extends from the frontal part 3d of the modular charge 3 inwards towards the central part of the modular charge. Sections 3b, 3c show the curvature of the inner cone, and that it forms a funnel shaped space. Sections 3b and 3c can exhibit other curvatures or extensions and, for example, may be essentially cone shaped. The second modular charge 4 comprises a rear section 4a comprising or consisting of explosive. The second modular charge also comprises a frontally concave frontal liner 4b that effects shaped charge function. The rear section 4a thus exhibits a form that conjoins with walls of the space formed between 3b, 3c. As claimed in the present invention the fit between the outer surface 4a' of the rear section and the inner surfaces 3c' and 3b' is very precise. Sections 3b, 3c are also arranged so that the first modular charge can effect a jetting shaped charge function when in a mode separated from the second modular charge. In the conjoined mode for modular charges 3 and 4 illustrated in Figure 1 the explosive charge arrangement operates with a shaped charge function effected by liner 4b. The latter function in the embodiment example constitutes an EFP shaped charge function. The explosive charge arrangement 2 can thus function for a large standoff A to a target 5 that is to be engaged using the shaped charge function in question, and the resultant explosively formed projectile 6 will attack the target in a concentrated zone 5a. The standoff distance A may be, for example, 50 metres. In Figure 2 the second modular charge 4 has been separated from modular charge 3. The space in the funnel shaped part bounded by sections 3b, 3c is designated 3e. Figure 2 shows the shape of the rear section 4a of modular charge 4 and its matching shape in relation to space 3e. The shape of surfaces 3c' and 4a' is also illustrated. In this embodiment modular charge 4 is not used and is discarded. Modular charge 3 thus operates independently from modular charge 4, and can effect its shaped charge function which is of said jetting type. Consequently, the ammunition unit or explosive charge arrangement 2 can in this case be used to engage a target that is at standoff distance A' when ammunition unit 1 is triggered, standoff A' being relatively small— e.g. 100 millimetres— in relation to standoff A. The shaped charge jet projected by modular charge 3 is designated 6'. In Figure 2 a screw joint on the casing of the device is symbolised by 7. The screw joint can comprise an internal and external thread of already known type. The casing or structural element la can thereby be temporarily separated from the casing or structural element lb. The ammunition unit is supplied with the explosive charge arrangement in conjoined mode as illustrated in Figure 1. For a possible changeover to the mode illustrated in Figure 2 the casing or structural element la is thus unscrewed to enable modular charge 4 to be removed, after which the casing or structural element la is screwed back onto casing or structural element lb. It is envisaged in accordance with the above that modular charge 3 in principle can comprise a number of first modules, explosive compositions and other configurations, and that in such cases reference is made to a first modular array. In a corresponding way the second modular charge 4 can consist of more than one module, whereby such an arrangement can be envisaged as a second modular array. As claimed in the present invention the first modular charge can interact with a second modular array, and the second modular charge can interact with a first modular array. Figure 2 also shows that the rear section 4a exhibits a rear plane 4a" that is circular and extends at right angles to the plane of the figure illustrated. In the conjoined mode illustrated in Figure 1 this end plane 4a" butts against an inner surface 3a' in the explosive 3a of the first modular charge. Thus in conjoined mode there is mechanical contact between parts 4a and 3a. Liner 4b on the second modular charge 4 exhibits a lateral face 4b'. This lateral face extends adjacent to an outer surface 3 f of the casing or structural element of the first modular charge. Lateral face 4b' can be considered to constitute a continuation of outer surface 3f. The first modular charge in principle comprises a casing that encases the explosive 3a, with the said initiating device 3' arranged at the rear of the said casing. Rear section 4a consists of a self-supporting explosive charge. The present invention is not limited to the design examples described above, but can be subjected to modifications within the framework of the subsequent Patent Claims and the invention concept.

Claims: PATENT CLAIMS We hereby claim and desire to secure by Letters Patent the following. 1. A device to satisfy the engagement of targets (5, 5') with a shaped charge function h e r e i n an ammunition unit (1), for example in the form of a projectile, shell, missile, etc, is arranged to operate with at least two modular charge configurations in the first of which the ammunition unit comprises only a first modular charge (3) or modular array that effects a first shaped charge function, such as a jetting shaped charge, and that in the second configuration the first modular charge (3) or modular array is conjoined with a second modular charge (4) or modular array that effects a second shaped charge function, such as an explosively formed projectile/penetrator (herein abbreviated EFP) shaped charge, and that the ammunition unit is arranged to enable changeover from the first configuration to the second configuration or vice versa prior to firing, launch or release of the said ammunition unit. 2. A device as claimed in Claim 1 w h e r e i n the second modular charge (4) or the second modular array eliminates the shaped charge function effected by the first modular charge (3) or first modular array when the modules or modular arrays are arranged in conjoined mode. 3. A device as claimed in Claim l or 2 w h e r e i n the first modular charge (3) incorporates the liner effecting the first shaped charge, which liner is directed forwards and forms a funnel or cone shape, and the second modular charge (4) incorporates a rear section (4a) that exhibits a shape matching that of the said funnel or cone shape. 4. A device as claimed in any of the previous Claims h e r e i n that in the second configuration mode the second modular charge is conjoined with the first modular charge via the said rear section (4a) which, in conjoined mode, is inserted into the funnel or cone shaped space (3e) of the first modular charge. 5. A device as claimed in any of the previous Claims wherein the fit between the shape of the rear section (4a) of the second modular charge and the funnel or cone shape (3e) of the first modular charge is significant and, for example, exhibits a high degree of precision. 6. A device as claimed in any of the previous Claims wherein the liner (4b) in the second modular charge (4) that effects the second shaped charge function exhibits a lateral face (4b') that conjoins with an outer surface (3f) of the first modular charge, and can be considered to form a continuation of, or be a constituent part of, the latter mentioned outer surface (3f). 7. A device as claimed in any of the previous Claims herein the said rear section (4a) is embodied with or comprises explosive relating to or incorporated in the second modular charge (4). 8. A device as claimed in any of the previous Claims herein the first modular charge exhibits an essentially cylindrical container encasing the explosive of the first modular charge. 9. A device as claimed in Claim 8 wherein the first modular charge exhibits an igniting or initiating device (3') arranged at the rear of the cylindrical container. 10. A device as claimed in any of the previous Claims herein the end plane (4a") of the rear section of the second shaped charge function has direct contact with the inner plane (3a') of the first shaped charge function. 11. A device as claimed in any of the previous Claims wherein the ammunition unit (1) when delivered incorporates both modular charges (3 and 4) or modular arrays in conjoined state, and that when selecting the first modular charge configuration the second modular charge or modular array is excluded (removed). 12. A device as claimed in any of the previous Claims h e r e i n the ammunition unit is arranged with a casing or structural element (la) that is removable when changing over between the first and second configurations, and is re-installable or closable after the changeover. 13. A device as claimed in any of the previous Claims w h e r e i n the disjoinable casing or structural element is joined to another casing or structural element (lb) via a joint that is disjoinable and reconnectable under field conditions to enable manual removal and refitting of the casing or structural element (la). 14. A device as claimed in any of the previous Claims h e r e i n each explosive charge (3a, 4a) incorporates a number of initiation points which, depending on quantity and position, when initiated simultaneously enable the shaped charge to effect a jet, or a knife-blade or cruciform shaped projectile, or alternatively primarily fragmentation effect.

Inventors: JOHANSSON NILS, ROENN TORSTEN, JOHANSSON, NILS, ROENN, TORSTEN
Applicants: BOFORS DEFENCE AB, JOHANSSON NILS, ROENN TORSTEN, JOHANSSON, NILS, ROENN, TORSTEN
Application year: 2001
Main classification: F42B11
IPC codes: F42B1, F42B12