EP2023072A1

EP2023072A1 - Set of pellets for armor protection

Info

Publication number: EP2023072A1
Application number: EP07015705A
Authority: EP
Inventors: Ekkehard Dr. Lutz; Achim Haas
Original assignee: Etec Gesellschaft fur Technische Keramik Mbh
Current assignee: Etec Gesellschaft fur Technische Keramik Mbh
Priority date: 2007-08-09
Filing date: 2007-08-09
Publication date: 2009-02-11

Abstract

The present invention relates to pellets for armor protection, such as armor plates and panels. The pellets are particularly made of ceramics material and are arranged in sets of pellets, each set comprising a plurality of interconnected and integrally formed pellets (1). In a preferred embodiment, the pellets (1) are integrally formed individually and/or in groups before the sintering or during sintering. Preferably, the set comprises any linear, planar and or three-dimensional arrangement of pellets.

Description

Background of the invention

The present invention relates to pellets for armor protection, such as armor plates and panels. The pellets are particularly made of ceramics material and are arranged in sets of pellets, each set comprising a plurality of interconnected pellets. The present invention further relates to the sets of pellets for deployment in a composite armor protection or panel, for absorbing and dissipating kinetic energy from projectiles and to ballistic armor protection incorporating the same. More particularly, the invention relates to sets of pellets for use in armor protection for providing ballistic protection for light and heavy mobile equipment and for vehicles against high-velocity, armor-piercing projectiles or fragments as well as from soft nosed projectiles.

Prior Art

It is known in the art to use a large number of single pellets embedded or bound and retained in plate form, see e.g. DE 1578324 A , EP 843149 B1 , EP 929 788 B1 or EP 1705453 A1 . EP 1707913 A1 describes a composite armor plate for absorbing and dissipating kinetic energy from high velocity, armor-piercing projectiles, as well as from soft-nosed projectiles. The plate comprises a single internal layer of pellets which are bound and retained in plate form by an elastic material, substantially internally within the elastic material, such that the pellets are bound in a plurality of rows and columns providing mutual lateral support, the pellets being made of ceramic material, wherein a majority of each of the pellets is substantially in contact with at least three adjacent pellets. In the prior art great efforts are made in order to arrange the pellets in superposed rows, particularly in these cases when a plurality of them shall be in contact with each other. This is particularly shown in EP 843 149 B1 in its Fig. 5 and the corresponding part of the description. A mould is provided having a bottom, two major surfaces, two minor surfaces and an open top. Pellets are then inserted into the mould wherein the distance of the two major surfaces is between 1.2 to 1.8 times in order to allow molten elastic material to penetrate the pellets so as to later form a solidified material holding the pellets in place. During the pouring of the molten elastic material the pellets are unfavourably rearranged, as is also discussed in this prior art. This shows how difficult it is in the prior art to arrange the pellets properly. The importance of the proper arrangement of the pellets is also emphasised in the prior art, namely that they should be arranged so that an incoming projectile may contact the pellet array in one of three ways: center contact (the impact is alleged to allow the full volume of the pellet to participate in stopping the projectile, which cannot penetrate without pulverizing the whole pellet, an energy-intensive task); flank contact (the impact is alleged to cause projectile yaw, thus making projectile arrest easier, as a larger frontal area is contacted, and not only the sharp nose of the projectile, the projectile is deflected sideways and needs to form for itself a large aperture to penetrate, thus allowing the armor to absorb the projectile energy); and valley contact (the projectile is alleged to be jammed, usually between the flanks of the pellets, all of which participate in projectile arrest. The high side forces applied to the pellets are resisted by the pellets adjacent thereto as held by the substrate or plate, and penetration is prevented).
In EP 1 707 913 A1 the spaces formed between the adjacent cylindrical pellets are only partially filled with a material for preventing the flow of soft metal from impacting projectiles through the spaces, the flow-preventing material being in the form of an insert which is in contact with at most only one of the sides of three adjacent cylindrical pellets, or being integrally formed as part of a special insert pellet. The insert pellets are described to be in the form of a cylinder provided with projections extending only partially into the spaces formed between the sides of six adjacent cylindrical pellets, and blocking a major cross-sectional portion of the spaces, each of the projections being in spaced-apart relationship to at least one of the two adjacent cylinders towards which it projects. The pellets and the flow-preventing material are bound and retained in plate form by a solidified material, wherein the solidified material and the plate are elastic. It is explicitly stated in this prior art that the intended superior multi-hit capability is achieved with more spaces rather than less spaces between the pellets.
Thus, the prior art requires considerable efforts in order to provide armor protection with defined layers. In all the above described embodiments the layers are physically built up by laying out single pellets, either vertically or horizontally. This is time consuming, ineffective and bears the risk that irrespective of the efforts the pellets are finally nevertheless not properly arranged.

Summary of the Invention

It is the object of the present invention to provide improved arrangement of pellets for armor protection, improved plates and panels with such arrangement as well as an improved method of manufacturing such pellets, protection, plates, panels etc.
The present invention relates to a set of pellets for armor protection comprising a plurality of pellets being integrally formed. The term "pellets" are intended to comprise the general meaning and the general shape as known in the relevant field of armor or ballistic protection. It is preferred that pellets comprise a three-dimensional body with a defined shape which is formed by raw ceramic material, such as ceramic powder or granular material, which is pressed and sintered. The preferred general shape of a pellet according to the present invention is cylindrical, oval and/or polygonal. It preferably has at least a generally convex, conical, spherical, pyramidal and/or cone-shaped projection at a first end.
The term "integrally formed" is intended to comprise the general meaning in technology. It is a preferred embodiment of the invention that the pellets and potential connections between them are made of the same and more preferably continuous material formation.
The present invention is also directed to a method of manufacturing a set of pellets for armor protection with the step of integrally forming a plurality of pellets.
More preferably, the pellets are either individually or in groups integrally formed before the sintering or integrally formed during sintering. The latter option embraces an arrangement of individual pellets before sintering in a manner that they bond to each other or merge integrally during sintering. The most preferred embodiment is a forming of the sets of pellets when forming and/or pressing the raw ceramic material before sintering. Preferably, a pressing tool is provided for forming/pressing a set of pellets, in said mould or tool cavity.
Preferably, the set comprises any linear, planar and/or three-dimensional arrangement of pellets. More preferably, the invention comprises one or more of a line of pellets being integrally formed side by side, a triangle, a rectangle, a rhomboid and/or a hexagon of pellets and/or any combination thereof. Lines of pellets are preferred in case a more individual arrangement of pellets is the goal or in case the space available is more narrow. For larger areas larger arrangements as the other ones mentioned before are preferred wherein at the margins of an armor protection or armor shields, lines of pellets or in some cases even individual pellets can be used in order to fill out the respective area.
The preferred advantage of the present invention is to save substantial time during the layup of the pellets by using sets or groups of pellets of certain shape that occur repeatedly, preferrably within the hexagonal arrangement of the pellets, within a layer. Besides linear sets of pellets these groups or sets range from a triangular star of 3 pellets, a parallelogram made of 4 pellets in contact, a hexagonal ring comprising 6 pellets that are bound together, a parallelogram comprising 8 pellets as well as a triangle set composed of 9 pellets as described further down in more detail. The afore mentioned arrangements can also contain a further pellet within the ring. That is, the parallelogram contains 9 pellets, the triangle contains 10 pellets and so forth. In addition, greater groups can be produced that are composed of elements of the above units. This constitutes a modular concept. These groups of pellets can be manufactured in situ through dry pressing of the pellets as well as through the firing cycle due to the sintering behavior and nature of the compacted powder.
Depending on the needs, neighbouring pellets of the set can be preferably connected by at least a merger, an integral ridge and/or an integral bridge in case neighbouring pellets should be kept at a defined distance, e.g., to better guide or trap projectiles. In case the individual projectiles are arranged for example in a close packing, the holes between then can be filled with an integral fillet and/or an integral inlay as will also further be described below.
At least some and preferably all pellets comprise a preferably cylindrical, oval and/or polygonal body with at least a generally convex, conical, spherical, pyramidal and/or cone-shaped projection at a first end thereof. (hier sollten wir auch abgestumpfte Enden wie z.B. Pyramidenstumpf zulassen - wie ausdrücken?)
According to a preferred embodiment, the projection of the pellets is generally oriented into the same direction forming to an outer impact receiving face of the pellets. This assists in the stopping power of the set of pellets within the armor protection.
In a preferred embodiment of the present invention, there is provided an armor protection as defined above, wherein said projections are in the form of lateral protrusions from substantially vertical surfaces of said substantially cylindrical insert pellet, said protrusions being separated from each other by convexly curved surface areas of said pellet. Preferably, the height of said projection is less than the height of the body from which they project, preferably with a ratio of about 0.1 to 0.7 (height of projection / height of body). In yet other preferred embodiments of the present invention wherein said projections emerge slantingly from a cylindrical pellet, they have substantially semi-circular surfaces, and end face that merges with a convexly curved end face of said cylindrical pellet. The height of the lateral protrusions along the vertical surface of the ceramic body from which they depend can be from 10-100% of the vertical axis.
The pellets have at least one axis of greatest length of preferably at least about 3 mm, up to 40 mm, more preferably ranging from about 6 to 30 mm.
Preferably the pellets each have a major axis and said pellets are arranged with their major axes substantially parallel to each other and oriented substantially perpendicularly relative to said outer impact-receiving major surface of said panel. Thus, there may be provided an armor protection such as a composite armor plate wherein a majority of said pellets have at least one convexly-curved end face oriented to substantially face in the direction of an outer impact receiving major surface of said plate.
The pellets are preferably formed of a ceramic material selected from the group consisting of sintered oxide, nitrides, carbides and borides of aluminum, magnesium, zirconium, tungsten, molybdenum, titanium and silica and/or any mixture and/or combination thereof. Further preferably pellets are formed of a material selected from the group consisting of alumina, boron carbide, boron nitride, titanium diboride, silicon carbide, silicon oxide, silicon nitride, spinel , silicon aluminum oxynitride and/or any mixture and/or combination thereof. Most preferably, the pellets are formed of Al₂O₃, preferably with a content thereof of between about 90 to 99.9 %. Pellets are preferred being made of ceramic materials sintered, hot-pressed or isostatically pressed to high density values of at least 97.0 % of the material's theoretical desity.
The present invention is also directed to armor protection of all known kinds with at least one set of pellets according to the preceding or following description. Such armor protection can be an armor plate or panel of the unilayer, multi-layer or composite type, with the sets of pellets being applied to them or being internal. One or a plurality layers of pellets can be put together for these purposes. Sets of pellets can be retained by a retainer material which is preferably binding, gluing and/or adhering the sets of pellets in any known manner.
The present invention is also directed to an armor protection comprising a backing opposite to an impact receiving side, preferably made of a fiber material with high tensile strength, more preferably made of aramid, glass, polyamide, carbon, and any available industrial product, such as Kevlar®, Twaron, Dyneema or Famaston®. An impact receiving face of the set of pellets can be covered with a cover. The solidified material preferably embedding at least partially or internally the pellets can be any suitable material, such as aluminum, a thermoplastic polymer such as polycarbonate, or a thermoset plastic such as epoxy or polyurethane. The composite armor plate or protection can be used in conjunction with and as an addition to the standard steel plates provided on armored vehicles or as add on armor for armored vehicles having aluminum or titanium containing rigid surfaces, as well as in conjunction with the laminated armor. When preparing the armor protection according to the present invention, the pellets do not necessarily have to be completely covered on both sides by said solidified material, and the term embedded as used herein is intended to denote that the pellets are either completely or almost completely covered by said solidified material. The outer face surfaces of the armor protection are formed from the solidified material, the plate having an outer impact receiving face, at which face each pellet is either covered by the solidified material, touches said solidified material which forms surfaces of said outer impact receiving face or, not being completely covered by said solidified material which constitutes surfaces of said outer impact receiving face, bulges therefrom.
According to a further aspect of the invention, there is provided a multilayered armor protection or panel, comprising an outer, impact-receiving layer formed by a composite armor plate as hereinbefore defined for deforming and shattering an impacting high velocity projectile; and an inner layer adjacent to said outer layer and, comprising a ballistic material for absorbing the remaining kinetic energy from said fragments. Said ballistic material will be chosen according to cost and weight considerations and can be made of any suitable material such as Dyneema, Kevlar, aluminum, steel, titanium, or S2.
Due to the hardness, stiffness and compressive strength of the ceramic layer the tip of a projectile is either blunted or destroyed at the initial stage when impacting the pellets. This causes a greater surface area of the projectile to contact the set of pellets during the initial stage of the penetration process in which the remainders of the projectile is fractured and potentially pulverized. This causes the projectile to be shattered, and at least a considerable portion of its impacting energy is absorbed. A backing material is particularly provided for stopping the fractured projectile while the binder layer embedding the pellets holds the pellets or their pieces in a region closed to the location of impact and keeps them from moving transversally.
The present invention also embraces the use of a set of pellets, armor protection and/or a method as described above or below for the use of protecting any vehicle, such as a tank, an automobile, a truck, an aircraft or vessel against armor or projectiles, such as armor piercing projectiles.
The invention has particularly the preferred advantage that the sets of pellets, the plates and panels comprising such sets and the manufacturing method according to the present invention provide more efficient armor protection by minimizing the efforts and costs at the same time.
The preferred advantage of the present invention is to save substantial time during the layup of the pellets by using groups of pellets of certain shape that occur repeatedly, preferrably within the hexagonal arrangement of the pellets within a layer. Besides linear sets of pellets these groups or sets range from a simple triangular star of 3 pellets, a simple parallelogram made of 4 pellets in contact, a hexagonal ring comprising 6 pellets that are bound together, a parallelogram comprising 8 pellets as well as a triangle set composed of 9 pellets as is shown in further detail in the attached figures. In addition, all greater groups can be produced that are composed of elements of the above units. These groups of pellets can be manufactured in situ through dry pressing of the pellets as well as through the firing cycle due to the sintering behavior and nature of the compacted powder.

Brief discussion of the drawing

Fig. 1 shows a schematic drawing of two of a set of pellets in a composite armor protection panel.
Fig. 2 shows an alternative arrangement of two of a set of pellets in a composite armor protection panel.
Fig. 3 shows a sample of preferred sets of pellets which are integrally arranged to each other with a certain repeating pattern.
Fig. 4 shows alternative preferred sets of pellets which are integrally arranged to each other in another repeating pattern.
Fig. 5 shows still further preferred sets of pellets which are integrally arranged to each other with another repeating pattern.

Detailed discussion of the drawing

The embodiments of the present invention are exemplified in the foregoing and following description of preferred embodiments of the invention.
Fig. 1 shows an arrangement of a set of pellets 1 side by side with their bodies 2 merging at a merger illustrated by line 4. Only two pellets 1 are shown and it goes without saying that in real life more or even many more of such pellets 1 and sets of pellets 1 are provided. The bodies 1 are shown with a cylindrical shape. The bottoms thereof can be planar or concave or convex according to the needs as particularly regards the ballistic properties and the ability to be laid out, laid up or assembled on a plane etc. The pellets 1 also show cone-shaped projections 3. As mentioned above any other convex or also concave shape could be used although the generally convex shapes are preferred in order to increase the stopping power of the set of pellets, as is generally known in the art.
In Fig. 1 an armor protection is shown with one specific repeating pattern of sets of pellets 1. Instead of the shown arrangement, the set of pellets can also be used alone or with other components, such as further hard materials, soft materials or fiber materials. E.g. the set of pellets 1 can be inserted into the hollow parts of a vehicles body. The armor protection according to Fig. 1 further shows a preferred cover 10 for further supporting the pellets 1, withstanding any mechanical impacts or vibrations etc. and/or for providing a plane surface.
A backing 20 is further preferably provided which has the function as discussed above. The structure shown should be as compact and light weighted as possible in order to provide a barrier for projectiles of given mass, speed, hardness etc.
It will discussed further below with respect to Figs 3 to 5 where a connection 4 can be provided between two or more pellets 1 being integrally formed as described above and below.
Fig. 2 shows two pellets 1 with bodies 2 and integrally formed projections 3. The embodiment shown further has a ridge or bridge 5 which can keep the pellets 1 away from each other in any distance required. Such a distance may be useful for further guiding and jamming the bullets or projectiles between the bodies 2 in order to absorb energy. The present invention is nevertheless able to provide a set of pellets 1 in an integral manner to increase the handling and manufacturing function of the set. The ridge or bridge 5 can have any form being able to keep the set of pellets as integral as formed previously. The ridge 5 could also be arranged close or in the area of the projections or could extend with a smaller or larger height as shown.
Fig. 3 shows a cut out from a layer of pellets. Arrangements of sets with six or seven integral pellets 1 are highlighted with a hexagon 7 connecting the respective six surrounding the remaining pellet. This central pellet can also be a part of the respective set of pellets. Alternatively, the set can only comprise the ring without the central pellet. This holds also true for the further embodiments described below. In the embodiment shown such a set of seven pellets 1 are integral and merge into the neighbouring pellet, and the layer of pellets is composed of such sets. Alternatively, some of the pellets could be introduced alone or in sets with a different number or pattern of pellets.
Fig. 4 shows a sample of a generally rhombus-shaped sets or rhomboids 8 of pellets 1 with eight pellets surrounding the remaining ninth pellet. It is also derivable how in this embodiment the layer of pellets is composed of the respective rhomboids 8. In this figure it is also exemplified by the two inlays or fillets 6 that the rhomboids may be formed integrally by these inlays or fillets 6 either in addition or alternatively to the merging configuration of pellets 1 described above.
Fig. 5 shows triangles 9 with nine pellets 1 surrounding one pellet in their middle. Instead of this the triangles could also be formed by another row of pellets surrounding the triangles shown so that eighteen pellets are additionally surrounding the triangles 9 shown and are integral therewith. This could be continued and is also applicable for the other before described arrangements of sets of pellets.
The invention also covers all further features shown in the figures individually although they may not have been described in the afore description.
The present invention covers further embodiments with any combination of features from different embodiments described above.
The present invention also covers the exact terms, features, values and ranges etc. in case these terms, features, values and ranges etc. are used in conjunction with terms such as about, around, generally, substantially, essentially, at least etc. (i.e., "about 3" shall also cover exactly 3 or "essentially radial" shall also cover exactly radial).

Claims

Set of pellets for armor protection comprising a plurality of pellets (1) being integrally formed.
Set according to claim 1, wherein the pellets (1) are made of ceramic material and integrally formed in the set individually or in groups before the sintering or during sintering.
Set according to claim 1 or 2, wherein the set comprises any linear, planar and/or three dimensional arrangement of pellets (1), preferably one or more of a line of pellets being integrally formed side by side, a triangle (9), a rectangle, a rhomboid (8) and/or a hexagon (7) of pellets (1), and/or any combination thereof.
Set according to any of the preceding claims, wherein neighbouring pellets (1) of the set are connected by at least a merger (4), an integral ridge (5), an integral bridge (5), an integral fillet and/or an integral inlay (6).
Set according to any preceding claims, wherein at least some and preferably all pellets (1) comprise a preferably cylindrical, oval and/or polygonal body (2) with at least a generally convex, conical, spherical, pyramidal (Pyramidenstumpf) and/or cone-shaped projection (3) at a first end thereof (eigenlich sollten alle Geometrien auch als "abgestumpft" mit geschützt werden).
Set according to claim 5, wherein the projection (3) of the pellets (1) is generally oriented into the same direction forming an outer impact receiving face of the pellets (1).
Set according to any one of the preceding claims, wherein the height of said projection (3) is less than the height of the body (2) from which they project, preferably with a ratio of about 0.1 to 0.7.
Set according to any one of the preceding claims, wherein said pellets (1) have at least one axis of at least about 3 mm, upt to 40 mm, preferably ranging from 6 to 30 mm
Set according to any one of the preceding claims, wherein said pellets (1) are formed of a ceramic material selected from the group consisting of sintered, hot-pressed or isostatically pressed oxide, nitrides, carbides and borides of alumina, magnesium, zirconium, tungsten, molybdenum, titanium and silica and/or any mixture and/or combination thereof, exhibiting a densification of at least 97.0 % of the materials theoretical density.
Set according to any one of the preceding claims, wherein said pellets (1) are formed of a material selected from the group consisting of alumina, boron carbide, boron nitride, titanium diboride, silicon carbide, silicon oxide, silicon nitride, spinel, silicon aluminum oxynitride and/or any mixture and/or combination thereof.
Set according to any one of the preceding claims, wherein said pellets (1) are formed of Al₂O₃, preferably with a content thereof of between about 90 to 99.9 %.
Armor protection with at least one set of pellets (1) according to any one of the preceding claims.
Armor protection according to claim 12, further with a plurality of sets of pellets (1) which are retained by a retainer material (30) which is preferably binding glueing and/or adhering the sets of pellets (1).
Armor protection according to claim 12 or 13, further comprising a backing opposite to an impact receiving side, preferably made of a fiber material with high tensile strength, more preferably made of aramid, glass, polyamide, carbon, Kevlar®, Twaron, Dyneema or Famaston®.
Armor protection according to any one of claims 12 to 14, wherein an impact receiving face of the set of pellets is covered with a cover (10).
Method of manufacturing a set of pellets for armor protection, particularly according to any one of the preceding claims, comprising the step of integrally forming a plurality of pellets.
Method according to claim 16, with the step of forming the set of pellets by integrally forming or composing them from individual pellets and/or groups of pellets before the sintering and/or integrally forming them during sintering.
Method according to claim 16 or 17, wherein a mould is provided for forming a set of pellets and moulding the set of pellets in said mould.
Use of a set of pellets, armor protection and/or a method according to any of the respective preceding claims for the use of protecting any vehicle, such as a tank, an automobile, a truck, an aircraft or vessel against armor or projectiles, such as armor piercing projectiles.