This invention relates to armor modules fitted for attaching to the outside of a body liable to be exposed to attack by projectiles, e.g. shaped-charged warheads, kinetic energy projectiles and the like. Examples of bodies protectable by armor models in accordance with the present invention are, for example, land vehicles such as battle tanks, armored personnel carriers, armored fighting vehicles, armored, self-propelled guns; marine and navy crafts, static structures and enclosures such as buildings, above-ground portions of bunkers, containers of various nature, for the storage of fuel, chemicals, ammunitions, etc. all of which are collectively referred to herein after as a ‘target’.
Reactive armor cassette modules are known in the art for forming an armor adapted to protect a body from an incoming projectile, and are especially effective against hollow charges. Hollow charges usually comprise an explosive charge set behind a liner which is adapted to transform the liner into a powerful and directional jet adapted to penetrate the body to be protected.
A standard reactive armor cassette module usually comprises two plates having sandwiched between them an explosive material, usually referred to as Explosive Reactive Armor (ERA). The explosive material is adapted to explode upon impact of the directional jet therewith, and thereby propel the two plates in essentially opposite directions. The cassette modules are often positioned on the body to be protected at an angle to the expected impact direction of the projectile, whereby upon propulsion of the plates and their subsequent movement, the jet is dispersed upon the plate, whereby its penetration capability is greatly reduced.
In order to increase the efficiency of a reactive armor, a plurality of cassettes in a variety of configurations may be used. The armor cassette modules may be spaced apart to cover a greater area of the body to be protected, be angled to each other and even be compactly packed within an armor module.
For example, U.S. Pat. No. 7,080,587 discloses an armor module comprising a rigid casing having a front face, a top face and a bottom face, and a plurality of multi-layer planner cassettes fixedly mounted within the casing. Each cassette has a top base plate and a bottom base plate, sandwiching between them at least a one other layer. The top base plate of an uppermost cassette constitutes the top face of the casing, and a bottom base plate of a lowermost cassette constitutes the bottom face of the casing.
U.S. Pat. No. 4,741,244 discloses an armor for Protection of land vehicles such as tanks, armored cars or the like against shaped charge projectiles. Protection is achieved by a cover member having suspended therefrom on the side that faces the substrate at least one explosive insert comprising an explosive layer sandwiched between two metal layers, such that when the element is mounted on the substrate the explosive insert remains distanced therefrom.
According to one aspect of the present invention there is provided a reactive armor module adapted to protect a target from an incoming projectile, and comprising an armor cassette formed of a first base plate and a second base plate sandwiching between them at least one layer of energetic material, said first base plate and said second base plate being adapted, upon impact of said projectile with said explosive, to be propelled in opposite directions, said armor module further comprising at least one non-energetic auxiliary plate spaced from said armor cassette and positioned essentially along the expected trajectory of either said first or said second base plate, such that when propelled, the velocity of either said first and/or said second base plate is adapted to be reduced upon collision with said auxiliary plate.
The layer of energetic material sandwiched between said first and said second plate may be of either an explosive or non-explosive material.
The reactive armor module may comprise a plurality of armor cassettes, each having a construction similar to the above described armor cassette, said cassettes may be spaced apart from each other. For example, a reactive armor module may comprise two cassettes.
Said reactive armor module may comprise a number of auxiliary plates, positioned in the front or in the rear of the base plates, ‘front’ and ‘rear’ being defined with respect to the expected direction of said incoming projectile.
According to a specific design, said armor module comprises two auxiliary plates, one being spaced from said front base plate, and another being spaced from said rear base plate, i.e. said cassette being sandwiched between said auxiliary plates.
A longitudinal dimension ‘L’ of the armor cassette, a distance ‘d’ between the auxiliary plate and the respective base plate of about 5-20% ‘L’ was found to provide improved results. For example, if the longitudinal dimension of said base plate is 300 mm, said auxiliary plate may be spaced at a distance of 15 mm therefrom.
It would be readily appreciated that the term ‘plate’ used herein is not restricted and applies for a variety of thicknesses which may range from about 2 to about 10 mm.
According to a specific design variation, the auxiliary plate is positioned substantially parallel to the base plate, such that, when propelled by said explosive, said base plate is designed to collide with said auxiliary plate and have a maximal contact area.
The base plates and the auxiliary plate may be made of a variety of materials. The materials may be chosen such that the collision between either of said base plates and said auxiliary plate is either of plastic or elastic nature. For example, while the base plates may be made of steel, said at least one auxiliary plate may be made both of metallic materials such as soft steel, Aluminum or Titanium and non-metallic materials including Aramid (Kevlar®), HDPE (Dynema®), Zylon® and ceramic materials.
In case ceramic material, and/or any form of ballistic fibers are used for the production of said auxiliary plate, said auxiliary plate may further provide protection against light firearm threats such as automatic machine gun, rifles etc.
The explosive layer between said first base plate and second base plate may be a sheet of energetic (reactive) material as known per se, adapted to explode upon impact of said projectile therewith.
The armor may be directly mounted onto the target to be protected and may be positioned thereon in a slanted orientation with respect to the expected direction of said incoming projectile. A slanted orientation may provide for greater efficiency of the armor as known per se. a plurality of armor modules may be mounted onto the target body allowing better coverage and overlap so as to provide improved protection thereof.
By a particular design of the invention, the armor cassette is confined within a casing having at least two walls to form an armor module adapted to be mounted onto the target body to be protected. Said walls may be made of a variety of materials, e.g. steel, metal etc. The walls of the armor module may be so designed as to allow mounting of a plurality of similar armor modules onto said target in a tessellated form, e.g. a top wall of one module extending adjacent or flush against a bottom wall of an adjacent module.
According to a specific design variation, the armor module comprises a casing formed with two side walls and the cassette and the auxiliary plate extend between said side walls. The extremities of said auxiliary plate are attached to the side walls of said casing, thereby increasing structural strength of the armor module. More particularly, said extremities may be inserted into pre-formed punctures/slots/ apertures in said side walls and then soldered or otherwise attached thereto. In addition, said auxiliary plate and said casing may be made of the same material, which provides for a more simplified production. According to another specific design, said auxiliary plate may be constituted a part of said casing.
The armor module may comprise one or more armor cassettes and corresponding auxiliary plates disposed therein, and the cassettes may be inclined with respect to each other so as to provide protection against various expected directions of an incoming projectile.
In operation, when an incoming projectile, for example a hollow charge, impacts the armor module, the jet formed by the hollow charge may likely initiate explosion of the energetic material sandwiched between the first and second base plates. The explosion of the energetic material then propels the first and second base plates very rapidly in opposite directions, normal to the surface of the plates, the first base plate moving outwards of the target to be protected and the second base plate moving inwards. The energetic material thus allows quick reaction to the impact of the jet, and causing its disruption.
The first base plate and/or the second base plate may plastically collide with an associated stationary auxiliary plate. Such collision will result in mutual movement of the auxiliary plate with the base plate colliding with it, in essentially the same direction, however at a reduced mutual speed. Said reduced mutual speed may be determined based on the initial velocity of said base plate and the masses of both said base and auxiliary plate.
Alternatively, said collision may be of fully or partially elastic nature, whereby said auxiliary plate is adapted to gain movement upon collision of said base plate therewith, whereby said the velocity of said base plate is consequently reduced. The velocity of movement of said auxiliary plate, and the reduced velocity of said base plate may be determined by the initial velocity of said base plate and the mass ratio between said base plate and said auxiliary plate.
When directional jets are concerned, it is known that the leading end of the directional jet usually travels with a greater speed than that of the trailing end of the directional jet. For example, the velocities of the leading and trailing ends may be 5 Km/s and 1 Km/s respectively. Thus, when designing armor panels, although a very short time interval is desired for reaction to the impact of said leading end, it is not desired for the plates to move too quickly, thus being unable to absorb and scatter the trailing end of said directional jet.
Thus, it would be appreciated, that by controlling the number of auxiliary plates used in one reactive armor module, the material from which they are made and additional design parameters such as mass, distance, thickness etc. it is possible to manipulate said armor module to provide, upon impact of a directional jet therewith, an array of moving plates the velocity and orientation of which correspond to the various velocities of the directional jet from leading to trailing end.
According to one such example of an armor module, said armor module comprises two auxiliary plates. Thus, activation of the energetic material may result in four moving plates, each having a different velocity which provides for an encounter of the plates with various portions of various velocities of the directional jet. However, this is achieved, compared to an armor module having two reactive armor cassettes, with the use of only one armor cassette module, allowing a substantial reduction ob about 30% in the overall weight of the armor module.
In particular, another important advantage of the present invention is noticed when a reactive armor module is mounted on a body to be protected such that said at least one auxiliary plate is positioned between said armor cassette and a hull of said body to be protected. In this case, a predetermined distance is formed between said rear base plate and the hull of said body to be protected. According to the present invention, due to the reduction of the velocity of the moving base and/or auxiliary plate, the time required to displace along said predetermined distance is prolonged, effectively increasing the contact time between said moving plate and said directional jet, providing for better use of said distance.
In the event several armor cassettes are used in a single module, an explosion in one of the reactive cassettes, and subsequent propulsion of the base plates may cause one of the base plate to impact an adjacent cassette armor. This may cause a chain reaction or ‘domino’ effect in which each cassette armor is activated by a propelled base plate or at least displaced or deformed thereby. This effect is usually referred to in the art as ‘sympathetic detonation’. In order to prevent the ‘sympathetic detonation’, a shock absorbing layer may be coupled to the armor cassettes, such that a propelled base plate encounters said layer prior to impact with said adjacent cassette armor, the shock absorbing layer being adapted to reduce the kinetic energy of said propelled base plate. The shock absorbing layer may in the form of a one or more layers of elastic material, which in turn may be reinforced.
The following advantages may arise from the above described invention:
The above described reactive armor module and armor module may typically be mounted on a passive armor of the target body to be protected. Thus, among other advantages of the present invention is the fact that the weight of such a passive armor may be increased due to the reduction in the overall weight of the reactive armor. Increasing the weight of said passive armor subsequently increases it's effectiveness, allowing it to better withstand explosions and impact of Improvised Explosive Devices (IED).
According to another aspect of the present invention there is provided an armor module adapted to protect a target from an incoming projectile, said armor module comprising at least one armor module cassette confined between two side walls of a casing, said module comprising an armor cassette formed of a first base plate and a second base plate with at least one layer sandwiched of energetic material therebetween, said first base plate and said second base plate being adapted, upon impact of said projectile with said explosive to be propelled thereby at a predetermined velocity and in opposite directions, said armor module further comprising at least one non-energetic auxiliary plate spaced from said armor cassette and positioned essentially along the expected trajectory of either said first or said second base plate, such that when propelled, the velocity of either said first and/or said second base plate is adapted to be reduced due to collision with said auxiliary plate.
The present invention calls also for a method for protection a target body against projectiles, the method comprising the following steps:
fitting the body on an outside thereof with at least one armor module for protection against said projectiles and shaped-charged warheads, said armor module comprises at least one armor module cassette confined between two side walls of a casing, said module comprising an armor cassette formed of a first base plate and a second base plate with at least one layer sandwiched of energetic material therebetween, said first base plate and said second base plate being adapted, upon impact of said projectile with said explosive to be propelled thereby at a predetermined velocity and in opposite directions, said armor module further comprising at least one non-energetic auxiliary plate spaced from said armor cassette and positioned essentially along the expected trajectory of either said first or said second base plate, such that when propelled, the velocity of either said first and/or said second base plate is adapted to be reduced due to collision with said auxiliary plate.
In order to understand the invention and to see how it may be carried out in practice, several embodiments will now be described, by way of non-limiting examples only, with reference to the accompanying drawings, in which:
As best seen in
The second, thinner armor cassette 5b also comprises two steel plates 7b, 8b with and energetic material 9b sandwiched therebetween. The second armor module 5b is thinner than the armor cassette 5a due to a thinner layer of energetic material 9 and absence of the additional steel plate 11 is positioned along with a rubber layer 13 provided in armor cassette 5a.
Turning to
The casing 21 is formed of a rear wall 22, two side walls 28, a front wall 26, a bottom edge 24, and top and bottom edges 24 and 25 respectively. The rear wall is in the form of two flanges 22′ adapted to be connected to a target body to be protected (not shown), for example by a bolt and but assembly (not shown) through apertures 22″ (
In accordance with a particular embodiment, the rear steel plate 36 has a longitudinal dimension ‘L’ (
With reference to
Turning to
As opposed to a standard armor cassette previously described, after exciting the explosive material and propelling the rear plate 36 towards the auxiliary plate 40, the rear plate 36 together with the auxiliary plate 40 acquire a velocity VB′ whereby VB′<VB′ and where VB<VU′ designated by arrow 69 in
It would thus be readily appreciated that an array of auxiliary plates 40 may be employed within the armor module 10, whereby the velocity of the base plates 34, 36 is gradually reduced to correspond to the varying velocity of the jet 60, providing high efficiency of the armor module 10.
It would also be appreciated, that due to the presence of the auxiliary plate 40, and subsequent reduction in velocity of the base plate 34, the time required for the plate 34 to travel from its initial position to the body to be protected 5 lengthens. This lengthening in time is equivalent to an effective contact time with the jet 60. Thus, according to the present invention, the distance ‘w’ is better utilized compared to an armor module 1 according to the prior art.
Turning to
It would thus be appreciated that a variety of modules 10 according to the present invention may be construed, including ones having auxiliary plates 40 both in front and behind the armor cassette 30, and any combination thereof including more than two auxiliary plates 40.
Turning to
An armor module 10 according to the present invention allows reducing the overall weight of the reactive armor while achieving a similar, if not better result.
It is noted that owing to the reduction in overall weight of the armor assembly 81, the steel passive armor plate 83 can be substantially thicker and thus provide improved protection and withstand additional threats, for example, an IED.
With further reference to
Those skilled in the art to which this invention pertains will readily appreciate that numerous changes, variations, and modifications can be made without departing from the scope of the invention, mutatis mutandis.
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