LU85645A1 - FRAGMENTATION ENVELOPE FOR ANTI-INDIVIDUAL WEAPONS, SUCH AS GRENADES - Google Patents

Description

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The present invention relates to improvements to anti-individual weapons and, more particularly, to the presence of controlled grooves in the casing of a fragmentation munition to regularize the size, weight and effective range of the resulting fragments, and the like. .

Anti-individual weapons must meet a number of conflicting needs. Naturally, anti-individual weapons must disintegrate into separate fragments or fragments, of such a size that damage to the human body is maximum. For reasons which will be considered in detail below, and in particular with regard to hand grenades, these fragments must have shapes which allow the resistance of the air to dissipate their energy over short distances for the · - render harmless at a predetermined distance beyond the point of the explosion producing the fragments in question. Naturally, one must also take into consideration the possibilities of assembling the weapon into a complete ammunition for the development of a satisfactory anti-individuals weapon.

It is clear that these requirements have been the subject of considerable study and development for many years.

25 As far as the effective range of the fragments is concerned, hand grenades constitute a danger [day the person who launches them unless they are launched from prepared positions. Because of this danger, NATO has expressed the idea that hand grenades must be lethal within 30 of a radius of 5 meters around the point of explosion, while being harmless at 20 -25 meters from this point. Various "methods have been tried to meet this requirement, but none has been completely successful.

Plastic body grenades are produced in Germany. Inside the grenade are -2- · - housed several thousand small diameter steel balls cast in one piece with the explosive charge. If this grenade is fatal at a distance of 5 meters, some balls can reach a distance of 5 up to 80 meters. In the United States and Great Britain, thin-walled metal foil envelopes have been developed which enclose a coil of thin wire forming an ovoid spring with a closed spiral to form a liner. At defined small intervals, the wire is cut. In addition, the explosive charge is internal to the coil. It is believed that, under these conditions, the explosion bri * will be the thread at the level of the incisions to produce individual fragments of small size. In practice, however, ruptures are not made at all incisions and instead of having single fragments, many multiple fragments are obtained. These multiple fragments have a larger mass and, as a result, they spread further to become fatal beyond the intended distance from the point of explosion.

20 In Italy, experiments were carried out with grenades with plastic bodies in which the individual fragments are shaped to have negative aerodynamic characteristics by sticking the fragments in a thin layer on the internal face of the body of the shell. grenade or of the external envelope then by loading the interior of the envelope with the explosive charge.

Although the latter process produces the desired results, millions of fragments of suitable aerodynamic shape must be made since each grenade contains approximately one thousand fragments. Finally, each fragment must be glued in place which is probably a laborious, difficult and costly * operation.

It has been determined that, in order to obtain the desired results, it is necessary to have fragments having a mass as low as possible and to give them a speed. .

initial as high as possible. High speed is achieved by having a high amount of explosive to give the fragments mass and shape such that air resistance quickly reduces the energy of the fragment.

S Thus, with a high initial speed, the fragment will be fatal in a small radius, and the mass of the fragment and the resistance of the air will dissipate energy for longer rays.

The following data should be taken into consideration.

10 Artillery and mortar projectiles, bombs, land mines, hand grenades and similar ammunition are high density devices and, therefore, have extremely high weights per unit. Naturally, it is quite desirable to reduce the weight of these units so that shipping, handling and shipping to the target are done in the best possible conditions. However, the weight reductions of these munitions are most often achieved by reducing the size of the explosive charge and the weight of the fragmentation envelope. In such cases, improvement in transport and handling is only achieved at the cost of a marked reduction in the effectiveness of the weapon.

The modern hand grenade, among others, is a classic example of the many problems encountered in the design of ammunition. For example, hand grenades must be light so as not to unnecessarily charge combat personnel. If the weight is reduced, the pomegranate loses its effectiveness because - a lighter envelope of fragmentation and a smaller explosive charge are less likely to produce a suitable distribution of the fragments with an appropriate impact effect. It is clearly desirable to obtain better control of the shape and mass of the fragments in order to be able to more closely regulate the effective radius and the impact result of the fragments, but, as was mentioned above about pomegranates • nor -4- - - Italian, this has only been achieved so far by using costly and time-consuming manufacturing processes.

In the past, it was common to cast the outer fragmentation shell 5 of heavy cast iron hand grenades. Usually, these envelopes had segmented exterior surfaces that made them look somewhat like pineapples. The grooves between the segments were intended to create fracture lines when the charge in the envelope exploded to produce bursts of predetermined shape, mass and distribution or dispersion. The results obtained were frequently unsatisfactory. Depending on the quality of the particular envelope, the envelope could fragment according to a uniform pattern of fragments of suitable mass. However, if the envelope was in some way defective, the envelope could burst along a single groove. In the latter case, the grenade produced only a loud noise and either it did not form a splinter, or it gave a very irregular pattern of distribution of splinters completely failing for the intended purpose.

This problem could possibly be overcome by an expensive and careful examination of each cast iron envelope before filling it with the explosive charge and the detonator.

As a result, there is always a demand for lighter and less expensive ammunition without the measures taken to this end compromising their effectiveness. It is also desired to improve the control of the shape of the fragments and the distribution of their mass and of their dispersion. When these questions concern a hand grenade, there is still the need to obtain greater mortality in a small radius and greater safety in a larger radius.

These problems are solved, to a large extent, by the practice of the invention. The shell of the ammunition which characterizes the invention produces fragments offering a suitable resistance to air and which would be very difficult to manufacture individually. The casing, as applied to hand grenades, can be made of a material which is less dense than steel, for example hard anodized aluminum, titanium, ceramic material, etc.

A fragmentation envelope for conventional ammunition 10 which applies the principles of the invention, is formed of stacked rows of rings. A transverse surface of each of these rings has at least one deep groove. The opposite surface of each of these rings has a row of grooves formed in its own surface. The grooves of this row are arranged angularly with respect to * the groove (or grooves) on the other surface of the ring. By varying the number of grooves, their respective depths and their angular orientation, one can carefully control the size, shape, mass and dispersion characteristics of the resulting chips.

By careful adjustment of the depth of the grooves on the opposite sides of the rings, openings or holes can be formed in the structure of the ring at the mutual intersections of the grooves. When the ammunition is filled with explosives, a limited amount of explosives will escape through the openings and fill the volume formed between the outer grooves and the surroundings of the ammunition. As a result, the explosion occurring on both sides of the fragmentation envelope ensures that the envelope will break into individual fragments of predetermined size and shape.

In addition, the grooves promote the formation of acute peaks in the fragmentation material which are characterized by high stress concentrations in conjunction with weak metal bridges. This forces the fragmentation envelope to break into individual fragments and not into groups of fragments. Concentrations of stresses at the vertices can. in addition to being further increased by heat treatment, for example by rapid quenching after heating.

The grooves from which the vertices are formed constitute a grid which can be shaped to fulfill specific requirements among which the obtaining, for example, of light fragments having a mass and a volume greater than those which it has been possible so far, in mass production.

The acute peaks which characterize the embodiment of the invention discussed are clearly more effective on impact and are superior to the cylindrical or spherical fragments which have been characteristic of most previously known munitions.

The rings, as noted above, can be made from hard anodized aluminum to produce fragments of suitable size while being light in weight. In this way, the resulting large fragments are subjected to greater air resistance. These large fragments have an increased efficiency in a close radius, which, for hand grenades, offers better security to the person who launches grenades and from a great distance because the resistance of the air dissipates energy more quickly. of these larger and lighter fragments, which reduces the effective range of the explosion.

Because the fragmentation shell is formed from individual rings, the arrangement of these rings "* offers much more flexibility to give the shards the desired characteristics. It is also easier to examine these rings, and at a lower cost, than a single solid cast iron casing. A manufacturing defect in any one of the rings only leads to failure at this ring. explosive charge explodes, as opposed to what happens in the case of a defective monolithic casing in which a straw can render the weapon totally ineffective.

The use of anodized aluminum according to the present invention, and the better control of the fragmentation that the invention provides, further allows the use of ammunition having a lower unit weight without their effectiveness being reduced.

In summary, an envelope according to the principles of the invention is easier to manufacture than when individual fragments are stuck inside an envelope or in the case of the incised wire coil.

; The fragments produced by an envelope of the type according to the invention have poor aerodynamic coefficients (to better dissipate the force provided by the explosion). These fragments also have a higher impact effect and the desired shape for the fragments is easily obtained.

Although the casing may be formed of dense ferrous material in some applications (mortar or artillery projectiles, for example), for individual ammunition, such as hand grenades or rifles, it is possible to use non-ferrous materials of lower specific mass to reduce the unit mass of each munition 25 without compromising its effectiveness. ,

By filling all the grooves of the envelope, both from the inside and from the outside, the explosive forces acting against all the surfaces of the groove generate respective resultant forces which are concentrated on each of the fragment vertices. These resulting forces therefore increase the possibility of complete disintegration of the envelope into individual fragments, rather than into agglomerates.

Introducing a one-piece envelope into an enclosure is a relatively inexpensive process as opposed to the Italian system of sticking individual fragments onto the inside of an envelope.

The weight of the shell of the ammunition can also be reduced. Plastics or other low density materials can now be substituted for the relatively thick cast iron or steel casings which have been used so far and which, being denser materials, generally do not burst into desired fragments having a more or less uniform size.

Consequently, the invention allows the creation of fragments of predetermined shape, which shape can be quite complicated, this easily and at low cost. Complete and uniform fragmentation is now possible due to the presence of an explosive charge on both sides of the fragmentation envelope. These advantages and others will emerge more fully from the following description given with reference to the appended drawings in which: - Figure 1 is a side elevational view of part of a fragmentation envelope according to the invention, - Figure 2 is a plan view of the part of the fragmentation envelope shown in Figure 1, - Figure 3 is a characteristic fragment of the envelope shown in Figures 1 and 2, - Figure 4 is a view in elevation of a half section of a portion of a hand grenade fragmentation envelope assembled according to the invention, and - Figure 5 is an elevational view of a half section of a portion of a hand grenade envelope that shows.

** · a different embodiment of the invention.

• If we refer to FIG. 1, we see a cylindrical fragmentation ring 10 whose axis bears the reference 12. According to the invention, the outer circumference of the ring 35 10 comprises two concave V-shaped peripheral grooves , the

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-9- »depth of the grooves and the dimensions of the ring being chosen to produce splinters or fragments, of predetermined shape and size as will be indicated below in more detail. At this point, it should also be noted that the ring 10 is preferably formed from anodized aluminum to provide a lighter fragmentation envelope which will explode into larger, low mass fragments.

As is clear from FIG. 2, the ring 10 10 has a row of grooves 15 formed on its internal circumference. These individual grooves which form the row 15 also have a V shape, and each is perpendicular to the concave apex of the grooves 13 and 14, provided on the outer circumference of the ring 10 (Figure 15 1).

It will be understood that the size, shape and distribution of the fragments created when the explosive charge (not shown in FIGS. 1 and 2) causes the ring 10 to break into fragments are regulated by the depth of the grooves 13 and 14 and of the grooves in row 15 as well as by the dimensions of the ring 10. As an example, the depth of the vertices of the concave grooves 13 and 14 at the point of their common intersection with the perpendicular grooves of row 15 form of the 25 diamond flake openings of which the openings 17 and 20 are characteristic. These openings 17 and 20 not only allow the explosive charge to be introduced on both sides of the ring 10, as will be described later, but also they define the size and the shape of the fragments by forming the corners of these . last. Thus, when the ring 10 explodes, the concave vertices of the grooves which join adjacent openings form predetermined fracture lines which create fragments of generally uniform shape and size. A typical fragment * t 35 21 is shown in Figure 3 · As is apparent from * fj -10- · - · “# this Figure 3, the shape of fragment 21 is determined by the sides 22, 23, 24 and 25 of the openings that define its overall size. The effectiveness of the fragment 21 is further increased by ridges 26, 27 provided on its faces 5 opposite the apex of the respective grooves from which the fragment is formed. In some cases, it may also be desirable to produce high stress concentrations at the crests 26, 27. Depending on the material chosen for the fragmentation envelope, these 10 stress concentrations can be obtained by heat treatment, for example. by rapid quenching after heating.

As previously indicated, the thickness and width of the ring 10 (Figure 1), the depth of the grooves 13 and 15 14 and the individual grooves of the rows 15, 16 determine the size and shape of the resulting fragments.

In this case, the fragments generally have an unusual uniformity in shape and mass. Consequently, the scatter pattern and the effective range for any given munition are uniform and entirely predictable.

The shapes and the relative angular orientations of the grooves 13 and 14 and the grooves belonging to the rows 15 and 16 can also be varied to adapt to preferred machining operations, in order to produce explosion patterns and special aerodynamic properties, or other requirements. So instead of having "grooves." transverse 13 and 14 formed in the outer periphery of the ring 10, one or more spiral grooves could be provided. Likewise, the row of 30 grooves 15 could make an acute angle with respect to the grooves 13 and 14, rather than being perpendicular as shown in the drawings.

In another variant of the invention, concave transverse grooves can be formed * on the internal circumference of the ring 10 and axially oriented concave grooves “//” -11- - · * can be formed on the outer circumference of the ring 10.

Referring now to FIG. 4 "which shows a fragmentation envelope 30 of hand grenade 5 assembled according to the principles of the invention, we see a group of rings 31" 32, 33, 34 each of which a different diameter and which are grooved as described with reference to FIGS. 1 and 2 and are aligned with respect to the longitudinal axis 35 · your rings 31, 32, 33 "34 rest 10 in corresponding recesses provided in an external surround 36. The entourage 36 has a cylindrical staircase configuration to adapt to the different diameters of the rings which are housed there and to give the grenade. a general profile of conventional shape which is easier to grasp by hand in view of its launch. The surround 36 can be further formed using a light and resistant plastic or other suitable material to reduce the overall weight of the grenade.

The openings 17 and 20 (shown in FIG. 1 20 but not in FIG. 4) offer communication between the interior of the respective rings 31 ”32, 33” 34 and the surface which is in contact with the external surround 36.

Thus, while the molten explosive charge (not shown in the drawings) is poured into the hollow cavity 25 defined by the rings 31 "32, 33" 34, part of this charge flows through the openings to fill the grooves in the outer circumferences of the respective rings.

During the explosion, the charge explodes on both sides of the grooves, producing a force which concentrates on the vertices of the external surface and even better guarantees the disintegration of the envelope 30 into individual fragments.

Another embodiment of the invention is represented in FIG. 5. As can be seen, each of the grooved and axially aligned rings 37, 40, 41, 42 creating a fragmentation envelope 43 for hand grenade are . It ”-12- -.

# each joined to the neighboring ring by means of a border arranged transversely 44> 45, 46 · In this way, a monolithic fragmentation envelope is obtained from the base rings. Although the fragmentation envelopes 5 shown in the drawings are assembled in the form of stacked rings, a cylindrical or hexagonal envelope, as well as any other suitable shape, could be used to implement the invention, which, as indicated above, depends to a large extent on the formation of mutually intersecting grooves of suitable depth and cross-section on the inner and outer surfaces of the fragmentation shell to give suitable splinters.

It should be noted, in relation to FIGS. 4 and 5, that the different diameters of the rings 31 to 34 and 37, 40 to 42 respectively, are such that these rings result in giving an ovoid shape to the grenade without producing fragments of smaller size as we approach the ends of the ammunition.

Thus, the invention provides a method and an apparatus for forming a fragmentation envelope for a munition. The technique shown and described produces lighter ammunition whose effectiveness is not reduced and in which the size, shape, mass and pattern of distribution of the fragments can be regulated within much narrower limits than what has been possible so far.

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Claims (6)

1- Fragmentation envelope comprising a ring (10) having a series of grooves (Ί3, 14) formed in its external surface and a series of grooves (15) formed in its internal surface, said grooves (15) of the surface ' internal being angularly oriented relative to said grooves (13, 14) of the external surface to form with them mutual intersections, and another ring (10) 10 stacked with the previous one having a series of grooves (13, 14. formed in its external surface and a series of grooves (15) formed in its internal surface, said internal surface grooves (15) being oriented angularly with respect to said external surface grooves (13, 14) to form mutual intersections therewith, thereby achieving a fragmentation envelope, all the series of grooves being deep enough in said rings to create openings (17, 20) at said mutual intersections and to increase the disintegration of the envelope e n individual fragments (2l). 2- Fragmentation envelope according to claim 1, characterized in that said rings (31-34, 37, 40-42) each have a different diameter. 3- Fragmentation envelope according to claim 2, characterized in that transverse edges (44-46) join together said rings (37, 40-42) at their neighboring stacked surface. * 4 ~ Fragmentation envelope according to claim 2, characterized in that said rings (10, 31-34, 37, 30 40-42) are formed of anodized aluminum. 5- Hand grenade formed of a series of stacked rings (10 ,, 31-34, 37, 40-41) each of which has a diameter different from the diameters of the rings adjacent to each stack, each of said rings having a series of grooves (13, 14) formed on its outer surface and a series of grooves (15) formed // -14- - »· φ / on its inner surface and arranged angularly with respect to the previous ones, the different internal grooves (15) and external (13, 14) forming a series of mutual intersections which create a series of openings (17, 20) at said 5 intersections, and a filling 'of explosive charge inside said rings and in said external grooves (13 , 14) to increase the complete fragmentation of the pomegranate. 6- Ammunition structure adapted to produce anti-individual fragments comprising an envelope, said envelope having an internal surface and an external surface, a series of grooves (15) formed on its internal surface and a series of grooves (13, 14 ) formed on its outer surface, said grooves being oriented angularly with respect to each other to establish a series of mutual intersection points, said grooves (13, 14, 15) being deep enough to create an opening (17, 20 ) in said envelope at mutual points of intersection to produce anti-individual fragments (21) of predetermined size and shape. Drawings: _______ 2u ....... plates - yf.5 ...... pages of which ...... A ..... cover page description pages ......... .oU .. claim pages ....... descriptive abstract 'Luxembourg, 21) N0VJ984 The mandate / e / fj Alain Me Alain RMma hIIjIJIA / a il