GB2319592A

GB2319592A - Projectile-forming hollow charge liner

Info

Publication number: GB2319592A
Application number: GB9200658A
Authority: GB
Inventors: Klaus Lindstadt; Harald Wich; Michael Hahn
Original assignee: Diehl GmbH and Co
Current assignee: Diehl Verwaltungs Stiftung
Priority date: 1991-03-16
Filing date: 1992-01-14
Publication date: 1998-05-27
Anticipated expiration: 2012-01-14
Also published as: FR2759451B1; DE4108633A1; GB2319592B; GB9200658D0; FR2759451A1; DE4108633C2

Abstract

A projectile-forming hollow-charge liner (11), in particular for armour-piercing seeker-fuze submunition, has at least one apex-symmetrical predetermined breaking point (18) in the curvature region (16) between the liner dome region (15) and the encircling edge zone (13). This predetermined breaking point (19) causes a tearing-apart of the compact projectile (12) into partial projectiles (12i) in which are as far as possible of identical mass and which have a correspondingly shorter flight range and therefore make possible a reduced safety zone for practice operations.

Description

1 A PROJECTILE-FORMING HOLLOW-CHARGE LINER 2319592 The invention relates

to a liner in accordance with the definition of the species of claim 1.

Such a liner and its stretching transformation, initiated by the detonation of the hollow charge, into a projectile is shown in the Internationale Wehrrevue 8/1984, page 1063, Figure 17. In particular it is a matter, in the case of the liner in accordance with the species, of the effective part of an armour-piercing seeker-fuze submunition, as is described in more detail with respect to its action In WEHRTECHNIK 10/1985, pages 114, 115 and 118. The operational cycle is thus based, after the spin- stabilised delivery by means of a carrier projectile, on ejecting the submunitions therefrom the allowing them in each case to descend on a parachute into the target area, the target area being scanned in a spirally narrowing manner by means of the seeker-fuze sensors, in order, upon the detection of a target object that is to be attacked, to detonate the hollow charge. The effective direction of its proj ectileforming liner is thus upon the detonation, corresponding to the sensor line of sight, orientated almost vertically. However, it cannot be precluded that, by reason of external disturbing influences or internal malfunctions, the warhead is already initiated shortly after the ejection of the submunition from its carrier projectile and in so doing the effective direction is not orientated vertically, but in the most unfavourable case 2 even momentarily arranged generally f acing the horizontal. However, this then means that the projectile explosiveshaped from the liner does not land in the region under the release of the submunition from its carrier, but far beyond this effective region predetermined by way of the mission range of the carrier.

This most unfavourable conceivable constellation of a possibly irregular function of the munition has to be taken into account upon the definition of the safety measures for practice operations with live munition in addition to the desired target area and therefore leads to such enlarged safety zones that, for example, in the territory of the Federal German Republic practice operations with live submunition under realistic conditions of use is not feasible and, instead thereof, costly and less realistic practices have to be set up on larger spaces of friendly countries. This is because a conceivable practice firing with inert submunition is less meaningful, since only live submunition leads to the effect in the standard target object made available for the practice.

In recognition of these factors, the problem underlying the invention is more especially to indicate a liner of the type in accordance with the species with which a tactical practice firing with live seeker-fuze submunition is realisable with a restricted danger area.

3 In accordance with the invention, this problem is essentially solved in that the liner is designed in accordance with the characterising part of the main claim.

In accordance with this solution, also for the practice operations the seeker-fuze submunitions are delivered with a live-munitioned P-charge, but the explosive-initiated stretching procedure for the transformation of the liner now leads (contrary to the conditions in the case of the tactical design of the munition) not to the formation of substantially only one very compact projectile, but to the tearing-apart thereof into at least two partial projectiles, preferably mutually of identical mass. Since, under otherwise identical factors, the partial projectile of smaller mass indeed describes substantially the same flight path as the compact projectile, but flies only a distance which is shortened in accordance with the reduced mass, by modification of the insert for the taking to pieces of the compact projectile into individual partial projectiles the necessary safety zone that is to be estimated according to the most unfavourable initiation orientation of the submunition can be reduced perceptibly, so that the danger zone is reduced to an order of magnitude which is e.g. available also in the Federal German Republic.

In order, instead ofthe one penetration-optimised projectile of the tactical design, but without 4 interventions in the munition function otherwise, for the practice design to transform the liner into a predetermined number of partial projectiles which are respectively approximately of equal mass, in accordance with the invention thus the cross-sectional geometry, corresponding "per se" to the live original, of the liner that is to be transformed is axially-symmetrically so weakened that indeed still not in the course of the detonation acceleration (as for instance in the case of a hand-grenade casing), but immediately thereafter in the course of the stretching procedure the mass, which finds itself in transformation, of the liner specifically tears apart. Since the partial projectiles fly substantially the same path as the full projectile, the perceptible hits in the hard-armoured target object allow an appraisal of the reliability of the mode of operation of this seeker-fuze submunition in the case of the operationally approximately vertically downwardly orientated effective direction of the munition; whilst, with a disturbance-dictatedly non- specific position of the submunition in space, a triggering of the projectile-forming charge (translator's note: here a word seems to be missing in the German text; probably "fuehrt" = "leads") taskwise to a very reduced flight path of the partial projectiles beyond the actually acquired target area and thus produces a correspondingly restricted safety zone.

The solution in accordance with the invention has, in 4 addition to this, the considerable advantage that the practice munition can in the case of def ence nevertheless again immediately be used as tactical munition, namely now against half-hard armoured targets such as for instance armoured personnel carriers. This is because the two or three partial projectiles hit in the case of a regular mode of operation of the munition with only slight scatter into the acquired target object and thereby multiply the secondary splinter effect in the interior of the target as compared with the mere penetration of the compact projectile dimensioned for hard targets.

It is finally additionally to be considered as an advantageous economical side effect that inserts, the shaping of which after the transformation from the starting material do not correspond sufficiently to the tightly toleranced specifications for the design of a stably flying compact projectile, can however still as a result of chipremoving point-symmetric weakening zones be processed into liners for tearing-apart projectiles of practice munition and thus, as demonstrated, remain available both for the practice operations and in the event of defence also for use against more weakly armoured target objects.

Additional alternatives and further developments as well as further features and advantages of the invention will become apparent from the further claims and, also taking into account what is set forth in the abstract, from 6 the following description of preferred examples of realisation regarding the solution in accordance with the invention which are shown in the drawings along with a restriction to that which is essential in an abstracted manner and not entirely true to scale.

Fig. 1 shows in broken-away axial-section representation an explosive liner for detonative transformation into a projectile, Fig. 2 shows in reduced broken-away axial-section representation a projectile shaped and torn apart from a liner in accordance with Fig. 1 and Fig. 3 shows various particularly suitable notch geometries (Fig. 3a to Fig. 3d) for a specific tearing apart in the course of the stretching phase upon the projectile transformation from a liner in accordance with Fig. 1.

The sensor-detonated (sub)munition 10, shown in Fig.

1, with a rotation- symmetrical projectile-forming hollow charge liner 11 is in the course of the explosive transformation "per se" intended to result in a single projectile 12, stable in flight, in accordance with Fig. 2, which is distinguished by high penetrating capacity against hard-armoured target objects. For this, provided in front of the hollow charge 11 is a liner 11 which is produced from a roundshaped starting material for instance by way 7 of extrusion transformation and can be described as a hollow body 14 which is shallow in a spherical -cap- like manner and which arches in a hat- or plate-shaped manner from an encircling edge zone 13 (directed in a shallow frustoconical manner contrary to the direction of acceleration B somewhat relative to the cross-sectional plane). The central dome region 15 thereof has a substantially constant material thickness, which then decreases somewhat along a more pronounced curvature region 16 in the radial direction towards the edge zone 13. The acceleration superimposition thereby brought about in the axial and radial direction produces upon the detonative transformation of such a liner 11 made from a metal of high stretching ability such as iron, but preferably of even higher density such as tantalum, the desired crosssectional geometry of the projectile 12 with a radiallyannularly protruding and thereby flight- stabilising tail region 17.

In order to reduce a trajectory range, not orientated vertically, of the liner mass transformed and accelerated in the direction B, the effective projectile mass is now reduced to partial masses in that the liner 11 is provided with at least one encircling predetermined breaking point 18, in the region of which the projectile 12 which is being fashioned after the detonation acceleration in the course of the stretching procedure finally tears apart into partial projectiles 12i. For this, the predetermined 8 breaking point 18 is preferably so placed that partial projectiles 12i respectively of the same mass are produced - in particular behind a more flow-favourably shaped leading partial projectile 12i a partial projectile 12i 5 which is axially shorter and comprises the tail region 17. These partial projectiles 12i then describe a substantially identical flight path (shortened compared with the ideal projectile 12). In the event of several radially mutually offset predetermined breaking points 18 in the liner 11 correspondingly several partial projectiles of even lower mass arise. For the interests of practice it is, however, meaningful to provide only one or two predetermined breaking points 18 for correspondingly two or three partial projectiles 12i, because with too severe subdivision the probability becomes less that the material of the liner 11 in the course of the stretching procedure actually tears apart as desired into specific partial projectiles 121 of mutually as far as possible identical mass.

The change, conceived as a predetermined breaking point 18, of the ideal shape of the projectile-forming hollow-charge liner 11 to the effect that after the detonation acceleration in the course of the stretching procedure in the curvature region 16 it leads to a tearing apart of the projectile 12 can already be compelled by a mere modification of the radius of curvature 19 according to its position (between the edge zones 13 and the dome region 15) and/or according to its radius length, with the 9 result that the stretched projectile 12 tears apart into (apart from low-mass splinters) mainly two partial projectiles 12i approximately in the centre region. This taking-apart also occurs when, in the third of the liner 11 which is near the centre, the mass thereof is reduced., e.g. by local concentric reduction of the liner wall thickness by about 5 up to 10 in this ring-shaped region. If, on the other hand, a change of the radius of the cross sectional contour of the liner 11 is shifted further into the outer radius third and thus more towards the edge zone 13, a tearing- off substantially as merely the tail region 17 of the projectile 12 is effected all the more reliably.

Provision can thus also be made, as is likewise taken into account in Fig. 1, to weaken the wall thickness of the liner 11 in the curvature region 16 by acting on the rearward (convex) and/or on the frontal (concave) surface of the liner 11. For this, the corresponding region of the round- shaped semiproduct starting material can already be weakened for the non-cutting transformation into the final geometry for the liner 11, or upon the transformation for instance in the cold extrusion process the corresponding ring zone of reduced material thickness is deliberately impressed as predetermined breaking point 18, as shown in a somewhat exaggerated manner from Fig. 3a on the convex rearward surface of the liner 11. Also this leads respectively to the reliable tearing- apart of the projectile 12, which finds itself in the stretching phase, into partial projectiles 12i on both sides of this predetermined breaking point 18.

In product i on- technology respects it can be simpler and more advantageous, also with respect to the desired realistic factors for the practice version of a projectileforming seeker-fuze munition, to retain initially unvaried the geometry, optimised for the live munition, of the liner 11 in the course of the series production and then to single out from this series production those liners 11 which are to be modified for practice munition. This modification then consists in a deliberate ring-shaped weakening of the original liner 11 by mechanical material removal, in turn feasible on the convex and/or on the concave side of the liner 11, in the form of the grooving of at least one predetermined breaking point 18 as a concentrically encircling groove 20 of for instance symmetrical (rectangular or triangular) cross-sectional shape in accordance with Fig. 3b or Fig. 3c or respectively of unsymmetrical (for instance sawtooth-shaped) crosssectional shape in accordance with Fig. 3d. Such specific weakening predetermined breaking points 18 lead to commensurately more reliable tearing-apart of the projectile 12, which is being stretched, into partial projectiles 12i which are really specifically predeterminable with respect to their mass and remaining longitudinally sectional geometry; particularly since such weakening predetermined breaking points 18 can be applied and dosed in the form of cuttingly introduced ring grooves in an extremely reproducible manner, so that possible marginal influences of different batches of material have practically no effect on the predetermined mass distribution and shape of the partial projectiles 12i.

Also the predetermined breaking points 18 can advantageously already be introduced in the form of encircling grooves 20 into the round semiproduct, which is then as previously transformed completely non-cuttingly into the final geometry of the liner 11 and, in so doing, allready lhas 4-1,,e -redetermined breaking points 18.

1 1_. A to Since the predetermined breaking points 18 in the form of grooves 20 plunge-cut before or after the transformation into the liner 11 are very specifically reproducible and, moreover, do not af f ect any assembly or functional SCHNITTELLEN (translator's note: there is no such word in German - I presume SCHNITTSTELLEN is intended, meaning "interfaces") of the original projectile, this treatment of the liner 11 appears to be optimum. This is because a fully equivalent function of all the components in the case of the practice projectile as well as in the case of the combat projectile without a weakened liner 11 remains ensured, so long as identical moments of inertia preclude variations in the descent behaviour of the seekerfuze munition.

If more than two partial projectiles 12i are desired, 12 then (as already mentioned above) several concentrically ring-shaped weakening regions can be produced as radially mutually offset predetermined breaking points 18. In particular for the taking-apart into three partial projectiles 12i it is, however, more expedient to combine one predetermined breaking point 18 in the form of a groove 20 plunge-cut into the outer curvature region 16 with the amplified curvature of the smaller radius 19 at the transition from the dome region 15 to the inner curvature region 16. This is because in this way in a desirable manner the temporal functional cycle is fostered to the effect that in the course of the stretching procedure of the projectile 12 initially a front and relatively faster partial projectile 12i tears off, before the remaining residue of the projectile 12 tears off once again in front of the tail region 17 at the groovepredetermined breaking point 18/20 and flies behind as slowest partial projectile 121, without impairing the kinematics of a central partial projectile flying ahead of this. Such a specific tearing apart into more than two partial projectiles 12i produces a particularly high efficiency in the case of the combatwise use, already mentioned at the beginning hereof, of this design, conceived "per se" as practice munition, against half-hard target objects, because three partial projectiles 12i hit the same target object with slight flight-path scatter shortly after each other.

13

Claims

Claims

1. A projectile-forming hollow-charge liner (11), in particular for armour-piercing seeker-fuze submunition (10), characterised in that it is designed with at least one axially- symmetrically extending predetermined breaking point (18) at which, after the acceleration of the detonating hollow charge upon the stretching transformation of the liner (11) into a compact projectile (12) which is stable in flight, this tears apart into partial projectiles (12i) on both sides of the predetermined breaking point (18).

2. A liner according to claim 1, characterised by at least one predetermined breaking point (18) for partial projectiles (12i) which are mutually of identical mass.

3. A liner according to claim 1 or 2, characterised in that a predetermined breaking point (18) is fashioned as a reduced radius of curvature (19) in the curvature region (16) between the dome region (15) and the edge zone (13) of the liner (11).

4. A liner according to one of the preceding claims, characterised in that one predetermined breaking point (18) is fashioned as an encircling zone of weakened material thickness in the curvature region (16) between the dome region (15) and the edge zone (13) of the liner (11).

14 5. A liner according to claim 4, characterised in that the weakening is impressed non-cuttingly as a concave indentation into the surface of the liner (11).

6. A liner according to claim 4, characterised in that the weakening is cut cuttingly (translator's note: can also mean: in a chip-removing manner) as a groove (20) into the surface of the liner (11).

7. A liner according to claim 4, characterised in that the weakening is already worked into a starting material round from which the liner (11) is extrusion-shaped.

8. A liner according to one of claims 4 to 7, characterised in that the weakening is fashioned on the convex rearward surface and/or on the concave frontal surface of the liner (11).

9. A liner according to one of claims 4 to 8, characterised in that, for the separation of a partial projectile (12i) flying ahead in the acceleration direction (B), one predetermined breaking point (18) is worked-in in the form of a reduced radius of curvature (19) in the region of the transition from the liner dome region (15) to the radially outside adjoining curvature region (16) and moreover, for the separation of a tail-sided partial projectile (12i), a further predetermined breaking point (18) is worked-in as a material weakening in the region of the transition from the liner curvature region (16) to the edge zone (13).

10. A liner according to one of the preceding claims, characterised in that, in the region of its third near the centre, a local reduction of the liner mass is provided.

11. A liner according to claim 10, characterised in that the region of local mass reduction is afforded by a reduction of the liner wall thickness in the order of magnitude of about. 5 up to 10%.

t o ( Amendments to the claims have been filed as follows 1. A seeker-fuze munition having a hollow-charge and a domed projectile-forming liner which is generally of a kind configured to produce a single armour-piercing compact projectile having a nose portion and a tail portion which is stable in flight, characterised in that the liner is additionally provided with at least one axiallysymmetrically extending predetermined breaking zone of the liner by the stretching transformation of the liner into a compact projectile, the stretching compact projectile tears apart at a point or points, between the nose and tail portions, corresponding to the or each predetermined breaking zone to form a small predetermined number of solid individual partial projectiles instead of a single projectile.

arranged so that, after the acceleration detonation of the hollow charge, during 2. A munition as claimed in Claim 1, characterised in that the predetermined breaking zone or zones is or are arranged so that the partial projectiles are of substantially identical mass.

3. A munition as claimed in Claim 1 or 2, wherein the liner includes a curvature region between an edge zone and a central dome region, and characterised in that the or one predetermined breaking zone is formed as a reduced radius of curvature in the curvature region of the liner.

1-7 4. A munition as claimed in Claims 1 or 2, wherein the liner includes a curvature region between an edge zone and a central dome region, and characterised in that the or one predetermined breaking zone is formed as an encircling weakening of lesser material thickness in the curvature region of the liner.

5. A munition as claimed in Claim 4, characterised in that the weakening is impressed non-cuttingly as a concave 10 indentation into the surface of the liner.

6. A munition as claimed in Claim 4, characterised in that the weakening is cut or machined as a groove in the surface of the liner.

7. A munition as claimed in Claim 4, characterised in that the weakening is pre-worked into a starting material round from which the liner is pressure-shaped.

8. A munition as claimed in any one of Claims 4 to 7, characterised in that the weakening is fashioned on the convex rearward surface and/or on the concave frontal surface of the liner.

g. A munition as claimed in any one of Claims 4 to 8, characterised in that, for the separation of a partial projectile flying ahead in the acceleration direction, one predetermined breaking zone is worked-in in the form of a v reduced radius of curvature in the region of the transition from the liner dome region to the radially outside adjoining curvature region and, for the separation of a tail-sided partial projectile, a further predetermined breaking zone is worked-in as a material weakening in the region of the transition from the liner curvature region to the edge zone.

10. A munition as claimed in Claim 1 or 2, characterised in that, said breaking zone is formed in the region of the liner about a third from the centre, by a local reduction of the liner mass.

11. A munition as claimed in any preceding claim, characterised in that the or each predetermined breaking zone is provided by a local reduction of the liner wall thickness of the order of magnitude of about 5% up to 10%.

12. A munition as claimed in any preceding claim made by a method which includes the step of selecting from liners each formed to produce a single compact projectile, a liner (or liners) which does not correspond sufficiently to liner specification for forming a stably flying projectile, and providing in that selected liner (or liners) the predetermined breaking point or points.

13. A munition having a liner substantially as hereinbefore described with reference to FIGURES 1 and 2 or i 9 FIGURES 1 and 2 as modified by FIGURES 3a, 3b, 3c, or 3d of the accompanying drawings.

14. A projectile-forming liner constructed and arranged to constitute the liner of a munition as claimed in any preceding claim, wherein the liner includes a curvature region between an edge zone and a central dome region, and wherein at least one predetermined breaking zone is formed in the curvature region of the liner.

is