Patent Description:
Several ammunition units comprising warheads with explosive charges are already known in prior art. Such typical warheads consist of explosive charges surrounded by a fragmenting metal case, whereby the fragments are sprayed out around the explosive charge after the detonation. However, the kinetic energy of the fragments not hitting the target is lost.

What is therefore needed is an improved warhead allowing to increase the kinetic energy of the generated fragments in the direction of the target at the expense of the kinetic energy of the missing fragments.

Related prior art equally addressing this problem is found in <CIT> and <CIT>.

It is an object of the invention to provide a warhead allowing the increase of the kinetic energy of the crucial fragments hitting the target.

The invention solves the posed problem with a warhead comprising the features of claim <NUM>, a tubular structure for use in a warhead comprising the features of claim <NUM>, a method of manufacturing and preparing a warhead comprising the features of claim <NUM> and an ammunition unit with a warhead comprising the features of claim <NUM>.

The advantages of the warhead according to the invention are to be seen in the fact that instead of the well-known central initiation, the detonation of the warhead according to the present invention is initiated by means of a channel system being provided either on the outer surface of the tubular structure of the warhead and/or within the wall of the tubular structure, which is filled with explosive substances so that the initiation of the explosive charge placed in the cavity of the warhead occurs in the regions, where detonatively connecting bores are provided in the tubular structure.

The design (shape and geometrical pattern) of the channels allows an optimal initiation of the explosive substance located in the bores depending on the kind of explosive.

The depth or diameter of the channels should be small enough in order to avoid a premature initiation of the underlying main explosive and large enough to allow propagation of a detonation.

Thereby the detonation wave in the main explosive charge is shaped in such a way that the fragments situated on the opposite side of the related bores will be optimally accelerated. The bores must not be necessarily through holes but can also be pocket holes. However, the presence of a plurality of bore/channel systems which are angularly spaced from each other is important so that the initiation of detonation can be selectively chosen at the region of the warhead which is facing the target at the longest crossing distance.

Compared to prior art devices utilizing large-surface explosive layers the warhead according to the invention with its tubular structure comprising a plurality of bores allows a more precise timing and more detailed wave-shaping of the detonation wave. As a consequence the effectivity of the fragments produced is optimized.

The channel system has an additional advantage since it allows also a timing of the bore initiation along the longitudinal axis of the warhead, so that an additional directional effect of the fragment spray can be obtained.

Furthermore the channel systems of the tubular structure according to the invention offer more freedom for the placement of the detonators.

In the context of this invention the following definitions shall be used:.

The TMD corresponds to the upper limit of the density to which the explosive substance can be theoretically pressed.

This known process is described in detail in <CIT> and in <CIT>.

Further advantageous embodiments of the invention can be commented as follows:
In a special embodiment of the warhead the bores are through holes perforating the inner surface and running into the central cavity.

In a further embodiment at least part of the bores are located at the end points of the channels.

In a further embodiment the depth C of the channels on the outer surface or the diameter of the channels within the wall is in the range of <NUM> T < C < <NUM> T and preferably in the range of <NUM> T < C < <NUM> T.

In an additional embodiment the depth C of the channels on the outer surface or the diameter of the channels within the wall is smaller than <NUM>, preferably smaller than <NUM>.

In a further embodiment the depth of the bores is larger than depth C of the channel, preferably more than <NUM> % larger.

In an additional embodiment the cross sectional area of the bores is larger than the cross sectional area of the channels, preferably more than <NUM> % larger.

In a special embodiment the entity of all channels has a volume v, which is smaller than <NUM> % of the theoretical volume V = <NUM>π L (Do<NUM> - Di<NUM>) of the tubular structure without channels. The advantage of the relationship of the size/volume of the channels relative to the size/volume of the tubular structure is to be seen in the fact that due to the relative fine structure of the channels the dimensions of a warhead comprising such a tubular structure between the explosive charge in the cavity and an outer shell can be kept relatively small. Otherwise, if the volume of the explosive in the channels would be too high the detonation of the explosive charge would take place before achieving the bores, i.e. before reaching the explosive in the cavity of the tubular structure, and therefore would occur on the outer surface of the tubular structure of the warhead, which would result in the explosion of the warhead too early and significantly reduce the kinetic energy of the fired fragments.

In a further embodiment the dimensions of the channels are minimal but still large enough so that detonation of the explosive substance in the channels is guaranteed.

In an additional embodiment at least a part of the channels is interconnected to each other.

In a special embodiment the plurality of the channels and/or bores are divided angularly in at least two sectors, preferably three, four, five or six sectors.

In a special embodiment the channels and/or bores of the same sector are connected to each other but not connected with the channels and/or bores of another sector.

In a further embodiment at least one channel and/or through bore of each sector is connected to a detonator.

In an additional embodiment the warhead comprises a plurality of detonators, whereby each sector is connected to another detonator. This embodiment allows an asymmetric initiation of the warhead and consequently firing with a higher kinetic energy in a desired direction.

In a special embodiment the explosive substance (<NUM>) is selected from the group of: pentaerythrit, trinitrotoluene (TNT), hexanitrostilbene (HNS), hexogen (RDX), and octogen (HMX).

In a further embodiment the explosive substance in the channels and in the bores belongs to a first type of explosive and the inner explosive charge belongs to a second type of explosive.

In a further embodiment the density of the explosive substance in the channels and the bores is at least <NUM> %, preferably at least <NUM> % of the theoretical maximum density (TMD) of the explosive substance.

In a special embodiment the channels and the bores are filled with the explosive substance by the process of isostatically pressing.

In a further embodiment the bores and/or channels are distributed over the wall symmetrically relative to virtual planes comprising the central axis.

In a further embodiment the wall thickness T is maximum <NUM>, preferably maximum <NUM>.

In a special embodiment the orthogonal section of the channels is U-shaped.

In further embodiment the diameter of the bores is maximum <NUM>, preferably maximum <NUM>.

In a special embodiment of the method for manufacturing and preparing the tubular structure of the warhead the channels filled with an explosive material are subsequently sealed.

In a special embodiment of the tubular structure for use in a warhead the outer surface is provided with a plurality of channels and/or a plurality of channels is provided within the wall, whereby the channels are connected to the holes.

In a further embodiment the depth C of the channels on the outer surface or the diameter of the channels within the wall of the tubular structure is in the range of <NUM> T < C < <NUM> T and preferably in the range of <NUM> T < C < <NUM> T.

In a further embodiment the channels and the bores of the tubular structure are filled with an explosive substance.

In a special embodiment an ammunition unit comprising a warhead further comprises a target sensor and a fuse. Examples of such ammunition units are missiles, torpedos or rockets.

In a further embodiment the outer surface of the tubular structure comprises plurality of fragments being preferably interconnected to each other by means of a matrix, in which each fragment is at least partially embedded. The matrix may comprise the following materials: polymer and/or reactive metal foam.

Several embodiments of the invention will be described in the following by way of example and with reference to the accompanying drawings in which:.

<FIG> illustrates a tubular structure <NUM> of a warhead <NUM> according to the present invention. The tubular structure <NUM> comprises a wall <NUM> and a central cavity <NUM> for an inner explosive charge to be placed therein. The tubular structure has a front end <NUM>, a rear end <NUM> and a central axis <NUM> connecting the front end <NUM> and the rear end <NUM>. The tubular structure <NUM> has an outer diameter DO and an inner diameter DI as well as a wall thickness being equivalent to T = <NUM> (DO - DI) and a length L > <NUM> measured parallel to the central axis <NUM>. The tubular structure comprises an inner surface <NUM> facing the central cavity <NUM> and an outer surface <NUM>. The wall <NUM> of the tubular structure <NUM> is provided with a plurality of bores <NUM> penetrating into the wall <NUM> from the outer surface <NUM> of the tubular structure <NUM>. The bores <NUM> being suitable to be filled with an explosive substance.

The bores <NUM> are arranged in the tubular structure <NUM> with their bore axes extending at different central angles with respect to a reference radius of the tubular structure <NUM> and/or with their bore axes extending at different spacings from the rear end <NUM> of the tubular structure <NUM> measured in the direction of the central axis <NUM>.

Typically, if there are no compatibility problems the bores <NUM> are configured as through bores <NUM> perforating the inner surface <NUM> of the tubular structure <NUM> and running into the central cavity <NUM> of the tubular structure <NUM>. Else the depth of the bores is exemplarily in the range of <NUM> % to <NUM> % of the wall thickness.

Furthermore, each of the bores <NUM> has a diameter d, which can be exemplarily, but not limiting <NUM>. If some or all of the bores <NUM> have a different diameter, the diameters of the bores <NUM> are in a range between <NUM> and <NUM>.

The wall <NUM> of the tubular structure <NUM> shown in <FIG> is further provided with a plurality of channels <NUM>, wherein the channels <NUM> form a number of channel systems each comprising channels <NUM> which are interconnected with each other. Each channel system connects a number of the bores <NUM> together. Furthermore, the channels <NUM> connect all of the bores <NUM> to a detonator (not shown in <FIG>).

The number of channel systems formed by interconnected channels <NUM> is typically multiple and then the bores <NUM> that are connected by means of the channels <NUM> of the respective channel system are arranged in at least two different (angularly separated) segments of the peripheral surface of the tubular structure <NUM>.

Furthermore, a channel system in one of the different segments or wall portions is not connected to the channel systems of the other segments or wall portions. Exemplarily, one channel <NUM> and/or bore <NUM> of each channel system is connected to a detonator.

According to the embodiment of <FIG> the detonator of the warhead <NUM> is placed outside of the tubular structure. However, alternative embodiments of a warhead with a detonator being placed within the tubular structure <NUM> are possible which are also is fully functional.

According to the schematic view of <FIG> the plurality of the bores <NUM> are placed in only one section of the tubular structure <NUM>. However, the plurality of the bores <NUM> can be placed over the complete tubular structure <NUM>, whereby the plurality of the bores <NUM> is connected by means of the channels <NUM> provided either on the outer surface <NUM> and/or within the wall <NUM> of the tubular structure <NUM> to at least one detonator.

The main explosive charge will be initiated at the position of the bores in a timed fashion by the detonation running through the channels.

In a special embodiment the plurality of the bores <NUM> are angularly divided in plurality of sectors, whereby the through bores <NUM> of each angular sector are connected to another detonator as the bores <NUM> of another sector. A target sensor <NUM> (<FIG>) capturing the position of a target can then supply the information which detonator has to be initiated for obtaining the optimal effect of high kinetic energy of the presumably hitting fragments.

<FIG> illustrates an embodiment of the warhead <NUM> according to the invention comprising the tubular structure <NUM> of <FIG> and a fragmental material adjacent the outer surface <NUM> of the tubular structure <NUM>. The fragmental material includes a plurality of fragments <NUM> which are exemplarily, but not limiting, interconnected to each other by means of a matrix made of a polymer in which each fragment <NUM> is at least partially embedded. Alternatively, the matrix comprises a reactive metal foam.

<FIG> shows an ammunition unit <NUM> (missile) being suitable to carry a warhead <NUM> to the target. The missile <NUM> comprises a forward end <NUM> and front region <NUM> adjoining the forward end <NUM> and a backward end <NUM> and a backward region <NUM> adjoining the backward end <NUM> and comprising a warhead <NUM> according to the present invention. The missile further comprises a middle axis <NUM> connecting the forward end <NUM> and the backward end <NUM> of the missile, whereby the middle axis <NUM> is coincident with the central axis <NUM> of the tubular structure <NUM> of the warhead <NUM>, whereby the both axes are also coincident with the roll axis of the fired missile. Further, the ammunition unit <NUM> comprises an azimuthal target sensor <NUM> and a fuse <NUM>.

As shown in <FIG> a plurality of fragments <NUM> are placed on the outer surface <NUM> of the tubular structure of the warhead <NUM> of the ammunition unit <NUM>. The fragments <NUM> comprise a plurality of pre-formed fragments (spherical and non-spherical), whereby the fragments are partially embedded in a matrix for their fixation on the outer surface of the tubular structure <NUM>.

Claim 1:
Warhead (<NUM>) with asymmetric initiation comprising an inner explosive charge and a tubular structure (<NUM>) and being connectable to detonator means and target sensor (<NUM>) for activating the detonator means;
A) the tubular structure (<NUM>) comprising a wall (<NUM>) and a central cavity (<NUM>) for the inner explosive charge, an outer diameter Do, an inner diameter DI, a wall thickness T = <NUM> (DO - DI), a front end (<NUM>), a rear end (<NUM>), a central axis (<NUM>) connecting the front end (<NUM>) and the rear end (<NUM>) and a length L measured parallel to the central axis (<NUM>); and further comprising an inner surface (<NUM>) facing the central cavity (<NUM>) and an outer surface (<NUM>);
B) the warhead further comprising a fragmentable material adjacent to the outer surface (<NUM>) of the tubular structure (<NUM>),
wherein
C) the wall (<NUM>) comprises a plurality of bores (<NUM>) angularly and/or axially spaced from each other and extending from the outer surface (<NUM>) in direction to the inner surface (<NUM>);
D) the bores (<NUM>) are filled with an explosive substance (<NUM>) by means of isostatic pressing;
E) the outer surface (<NUM>) of the wall (<NUM>) is provided with a plurality of channels (<NUM>) and/or a plurality of channels (<NUM>) is provided within the wall (<NUM>), whereby
F) the plurality of channels (<NUM>) connects at least a part of the plurality of the bores (<NUM>) and is filled with an explosive substance by means of isostatic pressing;
G) the plurality of bores (<NUM>) is connected to a detonator by means of an explosive substance provided in the plurality of channels (<NUM>);
H) the depth C of the channels (<NUM>) on the outer surface (<NUM>) or the diameter of the channels (<NUM>) within the wall (<NUM>) is in the range of <NUM> T < C < <NUM> T;
I) the depth of the bores (<NUM>) is larger than depth C of the channels (<NUM>); and
K) the entity of all channels (<NUM>) has a volume v, which is smaller than <NUM> % of the theoretical volume V = <NUM>π L (Do<NUM> - Di<NUM>) of the tubular structure without channels.