WO2018178504A1

WO2018178504A1 - Matrix of fragmentation material and a method for creating the matrix

Info

Publication number: WO2018178504A1
Application number: PCT/FI2017/050227
Authority: WO
Inventors: Juho KALLIALA
Original assignee: Leijona Instituutti Oy
Priority date: 2017-03-31
Filing date: 2017-03-31
Publication date: 2018-10-04

Abstract

This invention relates to a matrix of fragmentation material (6) formed to a 3D dome shape, which dome shape is rotationally symmetrical around the munitions axis (4) and constructed from plurality of curvatures (2) and the matrix is constructed to the dome shape at least partly with multiple sets (5) of seven pieces of fragmentation material (6) where one piece of fragmentation material (6) is surrounded by six other pieces of fragmentation material (6). This invention also relates to a method for creating the matrix.

Description

Matrix of fragmentation material and a method for creating the matrix

This invention relates to matrix of fragmentation material and a method for creating the matrix.

In military operations the use of grenades detonated in the air above the intended target and using a proximity detonator has been known and used since the Second World War. For example there are this type of grenades to be launched from a grenade launcher for short distance, artillery grenades to be delivered from intermediate distance and aerial bombs, missiles and rockets for longer distances. Typically these currently contain munition that are detonated with some kind of modern laser or radar sensor equipped detonator. A grenade detonated in the air above the intended target directs the fragmentation material towards the ground mainly because of the grenade structure and the trajectory velocity of the falling down grenade.

For the military purpose there is a constant demand to improve the accuracy of the warfare, to get the effect of the fragmentation material to direct towards the intended target, not to spread around to a random direction. So basically the effec- tivity of the munition is to be improved and a risk of civil or other surrounding casualties are to be minimized.

For above mentioned purposes are developed weapons that have directed frag- mentation material. These prior art weapons are comprising according to US 9,341 ,454 a housing having a front wall, a back wall a top edge wall, bottom edge wall and side edge walls defining a closed chamber therein, the front wall being formed as a pellet matrix construction including a plurality of compartments formed as recesses on the surface of the front wall facing to the inside of the chamber, the compartments being substantially similar in shape and size to each other and a plurality of pellets having a diameter fixed within the pellet matrix, each compartment containing one pellet therein, explosive material placed into the chamber, the explosive material being sufficient to propel the plurality of pellets from the pellet matrix, and a detonator arrangement for exploding the explosive material. These prior art weapons are constructed to a shape of a part of a cylinder wall or just a planar surface. These solutions are not functional when the matrix of the fragmentation material is curved in two directions. The present invention offers a munition where the efficiency of the munition is improved such that all parts of the fragmentation material is directed to the intended target instead of spreading around to directions where the fragmentation material is wasted or even harmful. Thus the net weight of fragmentation material hitting the possible targets compared to the gross weight of the whole munition including its carrier is improved.

According to an embodiment of the invention the munition is formed as round, square, quadrangle, hexagonal, parallelogram or corresponding shape in a plane direction and a convex shape in the direction perpendicular to the plane, thus the parts effecting to the explosion cone shape of the munition are formed in a dome shape. Typically the other parts of the munition may follow the shape of the munition and thus for example the explosive can be of the same shape as the munition. The convex shape is selected according to the wanted explosion cone. The convex shape can be for example a segment or a part of a spheroidal, parabolical or similar double-curvature surface. In one advantageous embodiment the cross section of the dome shape is formed from several parts different of curvatures.

The explosive is formed as a layer of even thickness or it is shaped to a lens shape having uneven thickness. The shape and thickness of the explosive layer together with the explosive material parameters, such as velocity of detonation and the position of the detonator at the apex, etc., is designed such that an advancing detonation frontal in the explosive launches the fragmentation material to the intended direction. So basically the munition is design according to the primary target properties, the fragmentation unit size is designed and so is the intended detonation altitude, etc. There are plenty of suitable explosives for the purpose, in tradenames or codes such as C-4, PENO, Semtex, etc.

According to an embodiment the matrix of fragmentation material comprises metallic, ceramic, plastic materials or combinations thereof. An average mass of one fragment unit of the fragmentation material is in the range of 0.0001 kg to 0.200 kg. The design weight of one fragment unit depends on the intended target and its armouring. For no-armoured or very light armoured targets the unit weight may be smaller and for heavier targets for instance in armoured personel carrier vehicles the unit weight is selected to be heavier. High density and high hardness materials are among preferred materials.

The body part forms a shell around the explosive and the matrix of the fragmenta- tion material. The body part may be of fiber reinforced plastic, glass fiber coated plastic, metallic material, etc. The main function of the body part is to give the correct shape to the explosive and protect the munition for any deterioration during storage, handling and launching. The body part can also be used in the manufacturing phase as a cast mold for explosive material to be cast to a void space inside or on the body part.

The munition can have aerial guiding means such as a parachute or aero foils to stabilize the movement of the munition during delivery in the air. The aerial guiding means can be active or passive so that it is activated on certain altitude or for example due to the opening of the carrier, or it is passive so that the fixed aero foils cause a predetermined angle of attack and possible rotation for stabilizing effect of the munition as a projectile.

According to an embodiment the matrix of fragmentation material is produced by manufacturing a preselected place for every piece of fragmentation. This preselected place is a recess formed to the dome shaped outer body part. The matrix of fragmentation material is designed so that the fragmentation material is directed in controlled way to intended target. The matrix of fragmentation is formed in 3D geometry.

An object of the invention is to eliminate the disadvantages of the prior art which are for example uneven distribution of fragmentation material to the target area. This is obtained by the present invention which includes munition with predetermined 3D matrix of fragmentation and a method for creating the matrix.

Another object of the invention is to introduce a method to manufacture a munition having predetermined matrix of fragmentation.

In the following the present invention is explained in more detail in reference to at- tached drawings wherein

Fig. 1 presents a schematical cross section of the munitions outer, dome shaped, surface,

Fig. 2 presents the basic group of the fragmentation material,

Fig. 3 presents the placing of the basic groups of the fragmentation material to the dome shaped surface, Fig. 4 presents the placing of the fragmentation material to the outer dome shaped surface,

Fig. 5 presents how the fragmentation material is laid to the dome, and

Fig. 6 presents a general view of the munition in action. Fig. 1 presents a schematical cross section of the munitions outer, dome shaped, surface 1 . The outer surface 1 is constructed with several pieces of different curvatures 2. The points where the curvature 2 is changed to another curvature are marked in Fig. 1 with dots 3. The outer surface 1 is rotationally symmetrical around the axix 4. The shape of the outer surface 1 can be advantageously constructed with 4 to 20 separate different curvatures 2. The curvatures are forming a 3D shape to the dome. The aim is to achieve even distribution of the fragmentation material to the target area. The hits per square meter can also be affected by the detonation height and the amount/size of the fragmentation material. The munition is launched from the ground to the air or released in the air and stabilized with aer- ial guiding means such as parachute or aero foils to stabilize the movement of the munition during free fall in the air towards the target area at the ground.

Fig. 2 presents the basic group 5 of the fragmentation material 6. It is constructed of seven pieces of fragmentation material 6 which are forming the group 5. One piece of fragmentation material 6 is in the middle and six other pieces of fragmen- tation material 6 are evenly distributed around the middle piece. With this solution the filling of the munition with the fragmentation material 6 is effective considering the filling rate and even distribution of the fragmentation material to the target area.

In Fig. 3 is presented how these basic groups 5 of seven pieces of fragmentation material 6 are situated to the munition. In Fig. 3 the surface is flat and the fragmentation material 6 is evenly distributed. When the outer surface of the munition is dome shaped as described in Fig. 1 the matrix of the fragmentation material 6 is not evenly distributed to the surface. If the fragmentation material 6 is freely placed to the dome shaped munitions outer surface the matrix of the fragmentation mate- rial 6 is not forming even pattern. Somewhere in to the matrix are formed uneven gaps between the fragmentation material 6 pieces. These uneven gaps are causing uneven distribution of the fragmentation material 6 to the target area. Therefore it is necessary to predetermine a place for every piece of the fragmentation material 6. This is done for example producing small recesses to the inside of the outer, dome shaped, surface, which recesses keep the pieces of fragmentation material 6 in place during the manufacturing of the munition. Whit these recesses in the inside of the dome shaped outer surface the gaps between the pieces of fragmentation material 6 can be evenly distributed along the fragmentation matrix. This produces even distribution of the fragmentation material 6 to the target area.

The filling of the dome is done in the center of the dome with basic groups 5 of seven fragmentation material 6 pieces. At the outer edge of the dome the filling figure is comprising alternating shapes of triangulars 7 and rectangles 8, which have some curved sides to match the shape of the dome. This filling pattern is presented in Fig. 4. The use of triangulars 7 and rectangles 8 are producing more efficient fill rate at the outer edge of the dome. The line 9 where the basic groups 5 are switched to triangulars 7 and rectangulars 8 is dependent on the shape of the dome. The triangulars 7 and rectangulars 8 are fitted to the shape of the dome. The switch of the fill pattern is done when the fill rate of the outer pattern is better than the fill rate of the center pattern. In some cases the filling pattern can only be constructed with basic groups 5 of seven fragmentation material. This is caused by advantageous 3D shape of the dome.

Fig. 5 presents in top view how the fragmentation material 6 pieces is laid to the dome. The dome is filled with the fragmentation material 6 pieces. The fragmenta- tion material 6 pieces are spread to the dome and to the recesses by rotating the dome in relation to the elongated guiding mean(s) 10 or by rotating the elongated guiding mean(s) and keeping the dome in place. The elongated guiding means can be for example made at least partially with some kind of brush, foamed plastic or other suitable plastic material. With this elongated guiding mean(s) the fragmen- tation material 6 pieces can be guided from the top to engage with free recesses of the dome (not shown in the Fig. 5).

Fig. 6 presents the operating principle of the munition 100. The munition 100 is launched from ground to the air and is then dropping freely towards the ground. Aerial guiding means are used to stabilize the movement of the munition 100. The shape of the dome in Fig. 1 is also controlling the angle of the fragmentation material 6 distribution (explosion cone). It is advantageous to have angle of spread (apex angle of the cone shaped pattern) close to 90 degrees. A range from 70 to 1 10 degrees is acceptable for effective impact to the whole target area.

A method for creating the matrix comprises the following steps: - arranging a dome shaped outer surface 1 to the munition 100,

- arranging recesses to predetermined places for every piece of the fragmentation material 6, and

- providing the fragmentation material 6 to the recesses. The dome shaped outer surface 1 can be constructed from several different curvatures 2 and the dome surface is rotationally symmetrical 3D surface around the axis 4.

The pieces of the fragmentation material 6 can be placed to the outer dome of the munition 100 with for example a machine that engages to the pieces of fragmenta- tion material 6 with vacuum and fills automatically every recess in the dome. Another method for placing the pieces of fragmentation material 6 is just pouring multiple pieces of fragmentation material to the dome and rotate the dome around the rotationally symmetrical axis 4. At the same time the pieces of fragmentation material 6 can be guided from the top to engage with free recesses with an elongated guiding means 10 that helps the pieces to distribute evenly to the dome.

As evident to those skilled in the art, the invention and its embodiments are not limited to the above-described embodiment examples. The scope of protection is determined by the following set of claims.

Claims

1 . A matrix of fragmentation material (6), characterized in that, the matrix is formed to a 3D dome shape which dome shape is rotationally symmetrical around the munitions axis (4) and constructed from plurality of curvatures (2) and the ma- trix is constructed at least partly to the dome shape with multiple sets (5) of seven pieces of fragmentation material (6) where one piece of fragmentation material (6) is surrounded by six other pieces of fragmentation material (6).

2. The matrix of fragmentation material (6) according to claim 1 , characterized in that, the matrix is constructed to the center of the dome shape with multiple sets (5) of seven pieces of fragmentation material (6) and to the outer edge with alternating triangulars (7) and rectangulars (8) fitted to the dome shape.

3. The matrix of fragmentation material (6) according to claim 2, characterized in that, the line (9) where the filling pattern is changed is related to the 3D shape of the dome and that pattern with better fill rate is chosen to be used.

4. The matrix of fragmentation material (6) according to any of claims 1 -3, characterized in that, the fragmentation material (6) are in predetermined places defined by recesses in the dome shaped outer surface.

5. The matrix of fragmentation material (6) according to any of claims 1 -4, characterized in that, the gaps building up between the multiple fragmentation material (6) sets (5) are evenly distributed around the 3D dome shape.

6. A method for creating the matrix of fragmentation material (6), characterized in that, it comprises the steps of: arranging a dome shaped outer surface (1 ) to the munition (100), arranging recesses to predetermined places for every piece of the fragmenta- tion material (6), and providing the fragmentation material (6) to the recesses.

7. The method for creating the matrix of fragmentation material (6) according to claim 6, characterized in that, the dome shaped surface is constructed from plurality of curvatures (2).

8. The method for creating the matrix of fragmentation material (6) according to claim 6 or 7, characterized in that, the fragmentation material (6) are situated to the pre-determined places defined by recesses in the dome shaped outer surface.

9. The method for creating the matrix of fragmentation material (6) according to any of claims 6-8, characterized in that, the matrix is constructed to the dome shape at least partly with multiple sets (5) of seven pieces of fragmentation material (6) where one piece of fragmentation material (6) is surrounded by six other pieces of fragmentation material (6).

10. The method for creating the matrix of fragmentation material (6) according to any of claims 6-9, characterized in that, the matrix is constructed to the center of the dome shape with multiple sets (5) of seven pieces of fragmentation material (6) and to the outer edge with alternating triangulars (7) and rectangulars (8) fitted to the shape of the dome.

1 1 . The method for creating the matrix of fragmentation material (6) according to claim 10, characterized in that, the line (9) where the filling pattern is changed is related to the 3D shape of the dome and that pattern with better fill rate is chosen to be used.

12. The method for creating the matrix of fragmentation material (6) according to any of claims 6-1 1 , characterized in that, the gaps building up between the multi- pie fragmentation material (6) sets (5) are evenly distributed around the dome shape.

13. The method for creating the matrix of fragmentation material (6) according to any of claims 8-12, characterized in that, the placing of the fragmentation material (6) to the recesses of the outer dome is done with a machine that engages to the pieces of fragmentation material (6) with vacuum and fills automatically every recess in the dome.

14. The method for creating the matrix of fragmentation material (6) according to any of claims 8-12, characterized in that, the placing of the fragmentation material (6) to the recesses of the outer dome is done pouring multiple pieces of fragmen- tation material (6) to the dome and rotate the dome around the rotationally symmetrical axis (4) and at the same time the pieces of fragmentation material (6) are guided from the top to engage with free recesses with an elongated guide member (10) that distributes the pieces evenly around the dome.

15. The method for creating the matrix of fragmentation material (6) according to any of claims 8-12, characterized in that, the placing of the fragmentation material (6) to the recesses of the outer dome is done pouring multiple pieces of fragmentation material (6) to the dome and rotate elongated guide member (10) around the dome and at the same time the pieces of fragmentation material (6) are guided from the top to engage with free recesses around the dome.