Impact projectile

An impact projectile which comprises at least two impact bodies centered with respect to one another and disposed one axially behind the other with means for separating the two bodies axially upon approach to the target. The separation can be effected by thermal means controlled by a proximity switch and/or by flight duration. The projectile is especially designed for penetrating armored vehicles having multi-layer armored walls.

CROSS REFERENCE TO RELATED APPLICATION 
This application is related to the commonly assigned copending application 
Ser. No. 068,865 filed Aug. 21, 1979. 
FIELD OF THE INVENTION 
The present invention relates to an impact projectile and, more 
particularly, to a projectile designed to penetrate armored vehicles and 
comprising a plurality of bodies adapted to engage an armored vehicle wall 
successively. 
BACKGROUND OF THE INVENTION 
Modern armored vehicles are provided with multi-layer, e.g. scale-like or 
lamella-like reinforced armored walls which represent multiple and 
structured targets which can be attached with high-velocity impact 
projectiles, e.g. subcaliber projectiles, only with difficulty. In 
practice, when the projectile consists of a single body adapted to impact 
as a unit against the armored wall, considerable energy is lost and the 
impact itself may result in a breakup of the projectile so that 
penetration is not achieved. 
To improve the penetrability of projectiles against multiple and structured 
targets of the aforedescribed type, it has been proposed in U.S. Pat. No. 
3,877,380 to provide a main core over which, in a cap-like manner, a 
plurality of pre-cores are provided so that a multiplicity of bodies of 
high kinetic energy engage the target successively. These various cores 
can be composed of the same material or of different materials, can be of 
the same size and mass or of different sizes and mass, and can be 
separated from one another by layers of soft-tempered copper. 
The purpose of the cap-like configuration of the pre-cores is to prevent 
cracks from being generated in the body upon impact which cause the 
portions of the body to fall away from one another and reduce the 
penetration. 
While such projectiles have an improved penetration over one-piece impact 
projectiles which lose a good part of their kinetic energy upon the 
initial contact of the leading portion of the projectile with the target, 
experience has shown that the multi-core arrangement does not have maximum 
penetrability and can be fabricated only with difficulty. 
The aforedescribed copending application represents an improvement over the 
earlier system and describes a subcaliber projectile designed to be fired 
from a smooth-bore barrel and which is fin-stabilized and provided with a 
drive cage. 
A still earlier copending and commonly assigned application, Ser. No. 
949,067 filed Sept. 5, 1978, describes a multi-core projectile with 
individual cores adapted to impact at high kinetic energy against 
structured and multilayered armored vehicles. 
OBJECTS OF THE INVENTION 
It is the principal object of the present invention to provide an impact 
projectile which represents an improvement over the prior-art systems 
mentioned earlier and those of the earlier commonly assigned copending 
applications. 
Another object of the invention is to provide an impact projectile which is 
especially effective against multiple and structured targets, i.e. 
laminated or multi-layer reinforced or armored vehicles, even when the 
projectile encounters the target at a relatively flat attack angle, which 
can be constructed simply and is free from the manufacturing difficulties 
hitherto encountered. 
Still another object of the invention is to improve upon the systems 
described in the above-mentioned copending applications. 
SUMMARY OF THE INVENTION 
The impact projectile according to the invention comprises a plurality of 
impact bodies which are centered with respect to one another and are 
axially aligned in the direction of travel of the projectile but which are 
releasably connected together so as to separate after a predetermined 
flight time, preferably proximal to the target. In other words, after a 
predetermined flight time, the axial connection of the portions of the 
projectile is released or disengaged. 
According to a feature of the invention, the bodies of the projectile are 
provided with an axial bore traversed by a throughgoing rod or bar which 
is fixed to the first and/or last of these bodies releasably while means 
is provided to spread the bodies apart upon such release. The release can 
be effected by thermal means, e.g. a body of low melting point which can, 
for example, be thermally activated by the heat produced as the projectile 
encounters the air ahead of the traveling projectile or by a proximity 
switch. 
Best results have been found to be obtained when elastic spreading means, 
e.g. a so-called Belleville or dished-disk washer or spring, is provided 
between each pair of successive projectile bodies. 
The impact projectile of the present invention thus enables the individual 
projectile bodies or penetrating bodies, to separate from one another in 
axial alignment after a predetermined time of flight so that they impact 
successively with a predetermined interval between them against the 
target. 
In this manner each impact body attacks the target independently of the 
effect of the attack of any preceding body so that there is no rebound 
effect or loss of kinetic energy of the successive bodies upon impact of a 
preceding body. 
The projectile or portions thereof cannot be destroyed upon impact of the 
leading portion of the projectile against the target and each of the 
subsequently impacting projectile bodies impacts against the target with 
its full kinetic energy. 
The release of the axial connection between the axially aligned bodies can 
be effected in various ways, alluded to earlier. For example, a proximity 
switch or detector responsive to the distance of the projectile from the 
target can induce the release by activating a squib or activating a 
thermally responsive member or the temperature which is developed at the 
nose of the projectile by its passage through the atmosphere at high 
velocity can be used to melt a fusible locking element. 
While the desired spacing can be effected solely by air friction, it has 
been found to be advantageous to provide the elastic spreading means 
mentioned previously.

SPECIFIC DESCRIPTION 
The projectile shown in FIGS. 1 and 2 can be of the type otherwise 
illustrated and described in the aforementioned copending applications, 
i.e. a subcaliber projectile adapted to be fired from a smooth-bore barrel 
against a multiple-armored target such as a tank, armored personnel 
carrier or armored weapons carrier. In the application Ser. No. 068,865 
filed Aug. 21, 1979, for example, there is described a projectile which is 
received in a cartridge casing and has a fin-stabilized structure with a 
drive cage separating upon emergence of the projectile from the barrel. A 
similar structure can be applied here. 
Thus the subcaliber projectile 2, which has a pointed or arrow shape, 
comprises a plurality of impact bodies, namely, a pointed nose 4 and three 
successively disposed impact bodies or cores 6, 8, 10, as well as a tail 
body 12 with a fin structure 14 for stabilizing the projectile. 
The principles of such multiple-impact bodies are described in the 
aforementioned application Ser. No. 949,067 filed Sept. 5, 1978. 
The impact bodies 4, 6, 8, 10, 12 all have axial longitudinal bores 20 in 
which a rod 22 is received with such clearance or tolerance that an axial 
mobility of the members 6, 8, 10, 12 relative to the rod 22 is possible. A 
threaded portion 24 of the rod 22 is screwed into the tail body 12. 
At its forward end, the rod 22 is turned down at 26 and carries a cap 28 
which can be soldered or otherwise fused to the rod 22. 
Between each pair of impact bodies 6, 8; 4, 6; 8, 10 and 10, 12 there are 
provided respective dished-disk springs or Belleville washers represented 
at 18 which, upon removal of the cap 28 from the rod 22, drive the bodies 
4, 6, 8, 10, 12 axially apart (see FIG. 2) for successive and independent 
impacts against the target. 
The subcaliber projectile 2 carries the drive cage 16 for firing from the 
smooth-barrel weapon in the manner previously described. The details of 
the drive cage 16 and its connection with the subcaliber projectile 2 can 
correspond to those shown and described in German patents 17 03 507 and 22 
36 142. 
As previously mentioned, the cap 28 is composed of a metal of low melting 
point, e.g. Woods metal alloy, the melting point being selected so that, 
when the subcaliber projectile 2 travels at its usual speed which can be a 
multiple of the speed of sound, the temperature developed at the nose or 
cap 28 is sufficient to cause melting of the cap to release the rod 22. 
As FIG. 2 shows, the spring 18 drives the projectile bodies apart so that 
they successively and independently from one another impact against the 
target. 
The mass and melting point of the cap 28 are so selected that the 
projectile has the desired flight time before separation occurs. 
As can be seen from FIG. 3, the cap 128 may also contain a proximity switch 
or other proximity detector, represented generally at 128', which responds 
to a predetermined distance of the projectile from the target, and which 
can connect a battery 130 in series with a fusible pin 131 connecting the 
tail body 112 to the rod 122. The latter may be formed with a central bore 
122' through which the wires necessary for the connection are provided. 
For safety purposes, the cap 128 may also be composed of fusible metal and 
can be threaded at 126 to the rod 122. The tail piece 112 utilizes the 
rear portion of the bore 120 to receive the battery 130. The 
fin-stabilizing structure has been represented at 114. In place of the pin 
131, an explosive squib can be activated to separate the tail piece 112 
from the rod 122. Alternatively, a squib or like proximity switch 
activated member can disconnect the cap 128 from the rod 122. 
The effect of the spacing of the bodies 4, 6, 8, 10, 12 from one another by 
releasing the connection at least at one end of the rod, is comparable to 
the effect achieved with hollow charges whose maximum penetration obtains 
when the individual particles upon impact have a predetermined spacing 
from one another. This spacing in the case of a hollow charge is a result 
of the intrinsic velocity gradient which is characteristic thereof. A 
penetration which is optimized to a maximum because of the spacing as a 
function of flight time of the particles resulting from the use of a 
hollow charge is comparable to the optimization of penetration obtained 
with the present invention whether the separation of the bodies is brought 
about solely by friction or also with the aid of the elastic members.