Object protection from hollow charges and method for the production thereof

[0001] The present invention relates to a method for producing a protective layer together with rods arranged in a form and protruding from one surface, protecting against unguided and / or moving in the subsonic area of ​​medium-caliber bullets with electric shock fuses.

[0002] For the first time, bullets with cumulative charges were fired against armored objects during World War II. On the one hand, by the United States Armed Forces (it was a weapon under the name Bazooka), and on the other, by Germany (a weapon under the name Panzerfaust and Panzerschreck). Propellants such as charges and propellants were used to accelerate projectiles. Then in the USSR, a widespread weapon was developed, referred to as RPG ( Rocket-Propelled Grenade). The latter is still used in the version produced since 1961, primarily when conducting asymmetrical warfare, as RPG-7, along with various cumulative charges. While the early systems had mechanical impact detonators, the newer ones are equipped with piezoelectric detonators located on the front side and have flat wires between the ignition generator and the ignition system, conducting as part of the galvanic connection. These relatively simple medium caliber shells, usually rocket-propelled, are widespread throughout the world and pose a serious potential threat; they are cheap to manufacture, easy to use and are used in various types of constructions against stationary and movable objects, in particular against light armored vehicles.

[0003] In addition to various active and passive types of armor, as early as 1940 (DE-A-688 526) massive steel rods and prismatic bodies were mounted on the objects to be protected, which were designed to deflect, in particular, anti-tank guns. Another solution of this kind (DT-A1-26 01 562) used special materials resistant to high temperatures, as well as armor plates with massive bodies protruding in the form of a matrix and protruding from one surface (Fig. 1 and Fig. 2) to secure the object subject to protection against exothermic action of explosives.

[0004] From DE 198 25 260 A1, which is the starting point for the preamble of claim 1, a solution is known in which individual interference housings in the form of bars are mounted on the surface of the armor of the object protected against cumulative charges. The interference body can have an armor pin. Thanks to this, the stream of cumulative charge during its creation, that is, before its expansion, should be effectively disturbed.

[0005] According to the invention, a method for particularly economical production of a protective layer will be provided.

[0006] This method according to the invention is accomplished by the fact that U-shaped surfaces are punched out of the sheet strip at equal intervals so that the rods and the bridge remain. Punching tools can also be used for this purpose. Protection is provided by sheet strips in the form of bars; the bridges are used for fastening only and take over the task of the board.

[0007] By using beam treatment (laser, water jet and others), very light and inexpensive protective layers of flat material (sheet metal) can be produced, which can also be integrated into very different systems.

[0008] In another preferred embodiment, the punched sheet metal strips are put on the brackets on their brackets and are connected to them by means of a force closed connection. [0009] In order to limit the weight, recesses are additionally made in the bridges and brackets with low mechanical load at equal intervals.

[0010] Embodiments of the invention will be illustrated and described below based on the drawings. In the drawings:

Figure 1 shows the principle of preventing cumulative charge initiation using a protective layer, with a rod being used as a variant that only exhibits galvanic conduction properties in the end region;

Figure 2 shows the ballistic cap of the projectile when it hits the protective layer;

Fig. 3 shows another view of the oblique flying projectile at the moment of hitting the protective layer;

Fig. 4a shows a security layer rod with a conical tip;

Fig. 4b shows the rod of the protective layer with a sharp-angled pin;

Figure 5 shows a modular base plate with diagonally spaced rods;

Fig. 6 shows a modular protective layer together with an inner crush layer and an outer facing; Fig. 7 shows a variant of a protective layer with an outer facing;

Figure 8 shows the principle of operation of a transparent and adjustable layer protecting against the windscreen of an armored vehicle;

Figure 9 shows an armored personnel carrier with modular and special protective layers, also for sensors and for inlets and outlets; Fig. 10 shows a protective layer which is not part of the invention but which is made of steel mesh together with bars inserted into the nodes of this mesh; Fig. 11 shows a protective layer according to the invention with a light structure made of sheet metal strips punched out in a beam machining process.

[0011] In all figures, elements with similar functions have the same reference numerals.

[0012] In Figure 1, the number 1 indicates the protective layer. In the base plate 2, matrix-forming rods 3 are inserted, attached from the back with the flanges 4 on the base-plate 2. The rods 3 protrude above the inner surface 2 'at length l1. The projectile 100 hitting the object O to be protected in the direction of flight F penetrates at the place of its impact fuse 102 between the rods 3. The thin-walled double ballistic cap 101 of the projectile 100 is punctured and a short circuit occurs as a result of the action of the end areas 3b of the rods 3, whereby the frontal impact fuse 102 and the piezoelectric stop working.

with its sensor The double ballistic cap 101, in physical terms, is a flat two-wire connection for generating ignition energy. It connects the impact fuse 102 in a generally known manner to an ignition system (not shown) accelerating the cumulative charge. The diagonal distance a between the bars 3, 3a, 3b in a matrix including many bars 3 is smaller than the caliber K of the projectile. In any case, the double ballistic cap 101 is in effect "pierced" and there is a short circuit, or at least crushing; see partial view in Fig. 1. The total length 10 of the ballistic cap 101, measured from the tip of the shock fuse 102 to the largest diameter of the lining 104 of the cumulative charge 103, is shorter than the free length l1 of the bars 3. This ensures that the ballistic cap

101 that has penetrated the protection layer 1 will be damaged before the impact fuse can be activated

102. The tops 3 'of the rods 3 have an acute-angular structure and are made of hardened steel and / or have a galvanically conductive coating.

[0013] Experiments carried out with rocket-propelled cumulative charges hitting protective layer 1 at a speed of 300 m / s have shown that the initiation of cumulative charge can be avoided with a probability close to 100% when the direction of flight F is parallel to the rods 3. The tests were carried out with using 85 mm bullets and a matrix with 3 rods with a diameter of 6.5 mm, made of high-strength steel, with 3 'hardened vertices. The maximum distances a between bars 3 (measured diagonally in the matrix) were 50 mm, their length l1 was determined at

140 mm.

[0014] Fig. 2 shows the unfavorable case of a bullet hitting the rods 3 obliquely, with only its ballistic cap 101 and the impact fuse being marked in the drawing.

102. In this case, the piezoelectric generator can be activated before the ballistic cap 101 is punctured, which necessitates the use of further protective measures in protective layer 1.

[0015] Fig. 3 shows a similar situation, with the probability of ignition of the cumulative charge being much lower here, because the rod 3 has already managed to pierce the ballistic cap 101 before the impact fuse 102 contacts the next rod, which caused a short circuit.

[0016] Figs. 4a and 4b show elements intended to increase the protective effect. Namely, it turned out that piezoelectric shock fuses, which hit directly on the 3 'tops of the rods 3, are often completely damaged before they generate a sufficiently high ignition voltage. The condition for such damage is extremely high pressure, i.e. impulses that can be obtained in the case of obtuse cone 5 with acute-pointed apex 6 (Fig. 4a) or in the case of a sharp-angled pin 7 with a diameter of 1 to 2 mm (Fig. 4b). [0017] Assuming the situation shown in Figs. 2 and 3, according to Fig. 5, rods 3 are inserted into the base plate 2 at an angle of inclination α, with the fictitious direction of flight Ff being adopted, which corresponds to the emergency.

The inner surface of the base plate 2 is again marked with 2 '. This solution, as shown in Fig. 5, also allows optimal protection of the oblique surfaces. [0018] Fig. 6 shows the protective layer 1 with an inner crush layer 8 made of corrugated perforated steel, which is able to absorb kinetic energy when the projectile penetrates obliquely and / or its charge ignites. In this case, the action of the cumulative charge stream is also limited because the optimal distance from the target, i.e. from the O protected object, has been exceeded, reaching a value of two to three times the caliber (Stand off). In order not to exceed the lower limit of the effective value of length l1 (cf. Fig. 1) of rods 3, the highest position of the surface 2 ', i.e. the "wave crest" of layer 8 was used as the basis for the measurement. To prevent unintended mutilations as well as contamination and gripping of various objects (branches and other), the rods 3 are covered with lightweight foam material 9 (polymer available on the market). On the sides there are covers 10 of thin-walled aluminum plates.

[0019] An analogous construction is shown in Fig. 7, here the crushed layer 8 is made of a metal and plastic sandwich panel. Also here, the area 2 'was assumed as the basis for measuring the length l1 of the bars 3. In contrast to Fig. 6, the cover of the modular protective layer 1 is used here from all sides using plastic panels resistant to UV radiation.

[0020] Fig. 8 shows the windshields of an armored vehicle 110, equipped with a protective layer 1 which is transparent and can be adjusted.

Tilted in rows R1 to Rn, in side supports 13 ', the rods 3 can be positioned using drive 13 and articulation joints 12 according to the current state of emergency. The drive 13 is embedded in the known roof protection 16 and is therefore marked with a dashed line.

[0021] Obviously, an analogous arrangement can also be used for side windows that are not secured in the drawing.

[0022] Fig. 1 shows a further solution that particularly reduces weight. The rod 3a is made of a rigid composite with carbon fibers. To improve conductivity on its surface 3a, facing the danger, up to one-third of the entire length I1 was metallized and 3 'metal tips were used. As a galvanically conductive layer, it is possible to use as hard as possible a coating m, which in the present case is made of the choice of titanium carbide nitride (TiCN) or titanium nitride (TiN). The color of the coating is selected according to the masking color of the object. Another advantage of this embodiment is that it has a small "cross-section", that is, it contributes little to radar recognition and does not adversely affect the other means of "camouflage". The rods in this embodiment were used essentially for the needs of movable protective layers, in analogy to Fig. 8. [0023] The armored tracked vehicle shown in Fig. 9 is an armored personnel carrier 111 intended for the secure transport of military troops, and it is equipped with modular protective layers 1 shown in Fig. 7. In addition, both movable optical sensors 112 (controlled thermal imaging cameras) are protected against direct fire by matching side covers 10 (protective layers) with integrated rods 3. For the sake of clarity, the current layer of lightweight foam material is not included here either, cf. Fig. 6 and

7.

[0024] Such protective layers 10 should be used for all inlets and outlets, for example also for air inlets and exhaust holes in stationary vehicles and installations. For example, with respect to the armored personnel carrier 111 shown here, lateral air intakes 17 are equipped with rods 3, thereby protecting them.

[0025] A variant of the protective layer 1 ', which is not part of the invention, includes the known steel mesh shown in Fig. 10, in which nodes 14 rods 3 are mounted. The rods 3 are secured in each case against twisting with a bracket 15. Again behind the base for measuring the length of rods 3, a surface 2 'is assumed here, which corresponds to the maximum height of the bracket 15. The welding locations in the brackets 15, which provide the necessary stability for rods 3, are not shown. The nodes 15 take over, together with the mesh eyes 2a, the function of the plate 2, 2 '; compare: fig. 1 to fig. 7. However, unlike the plate, the net 2a can easily be adapted to the shape of the object to be protected.

[0026] In addition to reducing weight and reducing costs, this embodiment allows to effectively and in the shortest possible time protect against threatened objects, such as entrances, windows, windows and the like.

[0027] In the version with the lightweight construction according to the invention, shown in Fig. 11, the bars of the 3 "protective layer are made of sheet metal strips 50, laser cut. The sheet metal strip height 50 corresponds to the length l1 and the width of the bridge 51 adapted to the structure, which is determined depending on the base plate or brackets R1-Rn. To reduce the weight, cavities A were made. The parts fitted to form a positive fit are welded together - which is not shown in Fig. 11 - and forcibly connected. The sheet metal used for the production of 3 "rods is a few millimeters thick steel sheet, but high-strength aluminum sheets can also be used. To this end, a known method of high pressure water jetting can also be used.

[0028] In this case, the bridges take over the function of the plate (Fig. 1 to Fig. 7). This variant also allows for immediate retrofitting of the facility security. With proper dimensioning of the bridges (using flexible profiles), you can also cover convex surfaces with a protective layer without leaving gaps.

[0029] The protective layers made as shown in Fig. 11 have - in contrast to typical security measures - a relatively low basis weight of 40 kg / m² (average value). The subject-matter of the invention can be adapted to a wide range of emergency situations. The materials and technologies used are typical and can be replaced on an ongoing basis by new and better materials, including composite materials. In addition, this object can also be analogously adapted to measures already present on the protected object counteracting detection using electromagnetic radiation, or they can be integrated.

[0030] With regard to all embodiments, it is recommended to combine metal bars and metal parts 3, 3b,

3 "; R1-Rn with mass (grounding), so that all potentials generated during the activation of the igniter are discharged safely before they can reach the ignition system. [0031] The subject of the invention is not limited to bullets with cumulative charges. It can be used against any projectiles whose ignition process may be disturbed by a short circuit or a flat connecting cable connected to the ground. It can be derived from the fact that the nominal ignition energy of the shock fuse is necessary to initiate the active charge, and further that the partial currents that may still be present are not sufficient for this purpose.

List of markings [0032] protective layer

1 'steel mesh

1a protective layer for inlets and outlets base plate

2a mesh (meshes)

2 'inner surface of the rod (round steel rod)

3a coiled rod (carbon fiber)

3b free end area 3

3 'front sides 3

3 "rod (flat rod) flange cone apex (sharp) sharp-angled pin crushed layer light foam material (polymer layer) side covers / protective layers sandwich panel articulated joint drive for 12

13 'side support bracket bracket (brace) roof protection side air intakes sheet metal bridge width

100 bullet

101 ballistic cap

102 impact fuse with piezoelectric generator or piezoelectric sensor

103 cumulative charge

104 lining

110 armored vehicle

111 armored personnel carrier

112 optical sensors / cameras

A cavities and the largest distance between two bars α angle of inclination of the bar / base plate

F bullet flight direction (at the target)

Ff fictitious flight direction (threat)

K caliber of the bullet length of the ballistic bonnet rod length (measured from 2 ') m metal coating

O object to protect R1-Rn row supports 3

23285 / PE / 13 EP 2 382 437