Patent Publication Number: US-9404716-B2

Title: Hybrid slat armor

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims priority to Israeli Patent Application No. 225826 filed on 18 Apr. 2013, the disclosure of which is incorporated herein, in its entirety, by this reference. 
     TECHNOLOGICAL FIELD 
     The presently disclosed subject matter relates to slat armor, in particular to slat armor having slat units comprising metal and composite components. 
     BACKGROUND 
     The armor, to which the presently disclosed subject matter refers, is often used inter alia for neutralizing the triggering mechanism of weapons, such as for example a rocket propelled grenade (RPG), known to be a shoulder-fired, anti-tank weapon commonly used against vehicles, which typically fires rockets equipped with an explosive warhead. 
       FIG. 1  is illustrates one example of an RPG warhead  10  having a conductive cone  12  encased in an aerodynamic cover  13 . An electric trigger  11 , which can be for example a piezoelectric fuze, is mounted at the top of aerodynamic c cover  13  and is coupled to the edge of the conductive cone  12 . The warhead  10  further includes a body  16  filled with explosive  17  and a conductor  18 , electrically coupled to conductive cone  12 . Body  16  includes a conical liner  14  which is configured to focus the effect of the explosive&#39;s energy. The rocket  10  is propelled using a motor located in the tail section  19  thereof. 
     When the warhead  10  hits the target, the trigger  11  actuates an electric signal, which is transmitted through conductive cone  12  to conductor  18 , which in return sets off the explosives  17 . The explosive is then urged through an aperture in the conical liner toward the target. 
     Slat armor is known to typically include a rigid grid deployed around the vehicle, which can naturalize the warhead, either by deforming the conical liner, or by short-circuiting the fuzing mechanism of the warhead. The slat armor is in the form of a rigid grid disposed in a predetermined distance from the vehicle, so as to allow the armor to come in contact with the cover of the RPG in order to neutralize it before the trigger hits the vehicle&#39;s body. The distance between the grid and the body of the vehicle is known as the standoff. 
     The slat armor can include a flexible mesh having rigid elements spaced from one another in such a way as not to allow an RPG warhead to hit the mesh without contacting at least one rigid element. Thus, the rigid element neutralizes the devastating effect of the warhead by deforming the conical liner and/or by short-circuiting the fuzing mechanism. 
     GENERAL DESCRIPTION 
     In accordance with one aspect of the subject matter of the present application, there is provided a hybrid slat armor configured for protecting a body against a threat having an anticipated impact direction, said hybrid slat armor comprising a plurality of slat units, each extending along a first longitudinal direction, the units being spaced apart along a second direction perpendicular to the first direction; each slat unit having a strike end configured for facing the anticipated impact direction, a rear end opposite said strike end, a top set of piercing elements and a bottom set of piercing elements, the piercing elements of each set being successively arranged along the longitudinal direction of the slat unit at the strike end thereof and being spaced apart in said longitudinal direction; the piecing elements of the top set being spaced from the piercing elements of the bottom set in the second longitudinal direction to a distance which is considerably smaller than that between adjacent slat-units. 
     When the threat is of a kind having a hollow envelope, such as for example, hollow-charge projectiles such as e.g. RPGs, the piercing elements are configured for piercing this envelope for the purpose of neutralizing it. The piercing elements can be made of a ballistic material having sufficient toughness to penetrate the envelope of the incoming projectile upon its impact with a respective slat. 
     In order to increase the penetration capability of the piercing elements, at least a part of them can each be formed with a plurality of sharp edges, facilitating more efficient penetration thereof into the projectile. In particular, the piercing element can have a body with a plurality of surfaces (either curved or planar) angled with respect to each other, with sharp edges formed at the intersection between two or more of said surfaces. 
     The shape, dimensions and/or orientation of the piercing elements can vary in a direction away from the rear end. This varying can be such that the distance between the piercing elements of the top and bottom sets increase in the direction away from the rear end. The slat unit can have a greater dimension along the second direction at the strike end than at the rear end. The piercing elements of the top and bottom sets can be outwardly tapered in order to increase their penetration capability into the incoming projectile. 
     The tapering angle between the piercing elements of the top set and of the bottom set can be chosen not to exceed 100°, more particularly not to exceed 80°, even more particularly not to exceed 60°, still more particularly not to exceed 40° and still more particularly not to exceed 20°. 
     The top and bottom sets can be aligned with one another so that piercing elements of the top set are aligned in the second direction with corresponding piercing elements of the bottom set. Alternatively, the top and bottom sets can be arranged at an offset so that piercing elements of the top set are directly opposed the space between the piercing elements of the bottom set. 
     It is appreciated however that when the piercing elements of the top and the bottom slats are aligned, i.e. the spacing between two neighboring piercing elements of the top slat is opposite the spacing between two neighboring piercing elements of the bottom slat, bending stresses within the slat unit (upon impact of a projectile) are reduced since the slat unit can bend, in a direction perpendicular to the impact direction, more easily. 
     The piercing elements of each of the top and bottom sets can be integrally formed as a unitary body. Moreover, each such unitary body can comprise a rear portion extending from the piercing elements towards the rear end of the slat unit. In particular, the extension of the rear portion along the anticipated impact direction can be considerably greater than the extension of the piercing elements along this direction. 
     One or more of the piercing elements can have an extension towards said anticipated impact direction which does not exceed twice the maximal width of the piercing element, thereby providing the piercing element with a required robustness to penetrate the envelope of the projectile. 
     In accordance with a particular design, each of the top set and the bottom set can have a serrated or a saw-like design, with a succession of teeth extending along the longitudinal axis of the slat unit, the teeth constituting the piercing elements. 
     The piercing element of a set (top, bottom or both) can be integrally formed with the strike end of the slat unit, i.e. the strike end and the piercing elements constituting a unitary body made of a single material. In particular, the arrangement can be such that the length of the piercing elements along the anticipated impact direction is considerably smaller than the remainder of the slat in the same direction. 
     According to one example, the slat unit can be pre-formed as a single, unitary slat body, the strike end of which is made to create the top set and the bottom set of piercing elements. 
     According to another example, the slat unit can comprise a top sub-slat and a bottom sub-slat being formed with a top set and a bottom set of piercing elements, respectively. The top sub-slat and the bottom sub-slat can be attached to each other along respective side surfaces thereof in order to form the slat unit. 
     In addition, each of the sub-slats can be constituted by a plurality of sub-slat members spaced from one another along the first longitudinal direction. Such an arrangement of discrete separated sub-slat members can facilitate reduction of bending stresses within the slat unit upon impact of the threat. Furthermore, under such an arrangement, if the slat unit bends, it may then return to its original shape while only the sub-slat portion directly impacted by the threat is damaged and/or deformed while the other sub-slat members remain intact. 
     According to a variation on the above example, the slat unit can comprise a spacer layer sandwiched between the top sub-slat and the bottom sub-slat and providing the required spacing between the top and bottom sets. In particular, the spacer layer can be made of a material having a lower toughness and/or ballistic capability than that of each of the sub-slats. In accordance with a specific design of the slat unit, the spacer material can be a composite material while each of the sub-slats can be made of metal. The composite material can be made, for example, of any of the following: Polyester, vinyl ester and epoxy. The composite material can be encapsulated by a binding cover made of a fiber-reinforced resin. According to one particular example, the fiber reinforcement of the binding cover can be provided, e.g. by fiberglass. 
     The sub-slats can be fixedly attached to the spacer material to constitute an integral body. In particular, attachment between the spacer material and the sub-slats can be provided by any of the following: bolting, welding, adhesive material, external wrapping etc. 
     Under a particular design, the sub-slats are attached to the spacer layer by rivets passing through the spacer material and having one end fixedly attached to the top sub-slat and another end fixedly attached to the bottom sub-slat. 
     In accordance with a specific example, the spacer layer can be in the form of a longitudinal spacer slab formed with a front portion and a rear portion. The front portion can be formed with two cut-outs (one—at its top, and the other—at its bottom) configured for receiving therein the top and bottom sub-slats respectively, the body of the front portion being therefore thinner than the rear portion in the second direction. The dimensions of the cutout and the sub-slats can be such that, when the top and bottom sub-slats are positioned within the respective cut-outs of the front portion of the spacer layer, a top surface of the top sub-slat is flush with a top surface of the rear portion of the spacer slab and a bottom surface of the bottom sub-slat is flush with a bottom surface of the rear portion of the spacer slab. In addition, a rear surface of each of the top and bottom sub-slats can be mated against a front surface of the rear portion of the spacer slat. 
     Under the above arrangement, the top and bottom surfaces of the front portion of the spacer layer can be configured for supporting a majority of the body of each of the top and bottom sub-slats so that, during impact of said incoming projectile, the rear portion of the spacer slab provides ballistic support and cushioning for the top and bottom sub-slats. In particular, such support can result in the reinforcement of the entire hybrid slat armor against bending stresses generated during impact of the threat. 
     The entire slat unit can be provided with protective cover encapsulating at least a majority of the slat unit and of the piercing elements and configured for at least one of the following:
         protecting individuals handling the slat-armor from injury by the piercing elements;   providing each of the slat units with a tight packaging facilitating the holding together of the various components of the slat unit; and   providing the slat unit with survivability, weather resistance, water-tight sealing and/or anti-vandalism capabilities.       

     The protective cover can be made of an elastic material configured for expanding and contracting. According to a particular example, the protective cover can be in the form of a longitudinal sleeve into which said slat unit is configured for being inserted. The elastic nature of the material can allow inserting the slat unit into the sleeve, whereafter the sleeve contracts around the slat unit in order to the provide the above mentioned tight packaging. The sleeve can be made of a shrinkable material, in which case after the slat is inserted therein, the sleeve is brought into conditions required for the material to first shrink and then be fixed in the shrunk state such as, e.g. heating and cooling of the sleeve. 
     In accordance with a further aspect of the subject matter of the present application, there is provided a hybrid slat armor configured for protecting a body against a threat having an anticipated impact direction, said hybrid slat armor comprising a plurality of slat units, each extending along a first longitudinal direction, the units being spaced apart along a second direction perpendicular to the first direction; each slat unit having a strike end configured for facing the anticipated impact direction, a rear end opposite said strike end, a top set of piercing elements and a bottom set of piercing elements, the piercing elements of each set being successively arranged along the longitudinal direction of the slat unit at the strike end thereof and being spaced apart in said longitudinal direction; at least a majority of each of said slat units being tightly encapsulated by a protective cover. 
     It is appreciated that encapsulating each of the slat units within a protective sleeve provides both for facilitating mechanical integrity of the slat unit (in operation as well as in transport) and for prevention of injuries to personnel by the piercing elements. 
     It is further noted that the basic design of a slat armor requires the existence of spacing between each two neighboring slat units, so as to minimize the risk of the fuse of the incoming threat from impacting solid material and causing detonation of the hollow charge. Therefore, each of the slat units can be provided with an individual covering sleeve (rather than simple encapsulation of the entire slat armor with a covering sleeve), providing the above advantages while maintaining the required spacing between slat units. 
     It is also noted that the covering sleeve is designed such that, on the one hand, it is configured to maintain its integrity (i.e. not to tear or rupture) during transport and non-impact operation (thereby providing the required protection from the piercing elements) and, on the other hand, is configured to lose its integrity and tear upon impact of the incoming threat, exposing the piercing elements to the latter. 
     Thus, it should be understood that in term of the incoming threat, the covering sleeve is essentially non-existent in the sense that it does not interfere with the piercing elements in their required piercing operation of the envelope of the incoming threat. 
     In accordance with still further aspect of the subject matter of the present application, there is provided a hybrid slat armor configured for protecting a body against a threat having an anticipated impact direction, said hybrid slat armor comprising a plurality of spaced-apart slat units extending between a first support member and a second support member, the slat units being oriented generally parallel to one another and having two longitudinally opposed ends, each slat unit comprising a first attachment module, which at least in use receives therein a first end of the slat unit in a first manner and is attached to said first support member in a second manner, and a second attachment module which at least in use receives therein the second end of the slat unit in one of said first and second manners and is attached to said second support member, in the other of said first and second manners, at least one of said first and second manners being configured to provide detachable attachment. 
     Under the above arrangement, each of the slat units can be individually and selectively removable from the hybrid slat armor by at least one of the following:
         detachment of the first and second attachment modules from the respective first and second ends of the slat unit; and   detachment of the first and second attachment modules from the respective first and second support member.       

     In accordance with a particular example, the attachment modules can be configured for being permanently attached to one of the support members and be detachably attached to one end of one of the slat units. 
     In particular, the attachment module can have an open cavity sized and shaped for receiving therein a respective end of the slat unit. The attachment module can further comprise securing elements configured for securely detachably attaching the sleeve portion to the respective end of the slat unit. 
     The securing elements can be bolts. Under one design configuration, the arrangement can be such that tightening the bolt can entail both securing of the slat to the sleeve portion as well as tightening the sleeve portion about the support member. 
     According to one example, the attachment modules, though permanently attached to the support members, can be configured for sliding displacement along the support members, allowing a modular design of the hybrid slat armor in which the spacing between the slat units and, possibly, their number can be dynamically changed based on ballistic requirements. 
     The support members can comprise end attachment units configured for articulation of the entire hybrid slat armor to a body to be protected, for example a vehicle. In particular, the end attachment units can be configured for suspending the hybrid slat armor from a designated portion of the body to be protected, providing a stand-off distance between the hybrid slat armor and the body. 
     In accordance with a particular example, the support members can be flexible. In particular, the support members can be in the form of cables along which the attachment modules are attached. 
     In accordance with still another aspect of the subject matter of the present application there is provided a hybrid slat armor configured for protecting a body against a threat having an anticipated impact direction, said hybrid slat armor comprising a plurality of slat units, each extending along a first longitudinal direction, the units being spaced apart along a second direction perpendicular to the first direction; each slat unit having a strike end configured for facing the anticipated impact direction, a rear end opposite said strike end, and comprises a base layer and at least one slat attached thereto, the slat being made of metal and comprising at least one piercing element configured for penetrating an envelope of the threat upon impact of the latter on the hybrid slat armor, and the base layer being made of material other than that of the slat and being incapable of said penetrating if said slat was made therefrom. 
     The material of the base layer can be other than metal, e.g. it can be composite material, and it can have a lower hardness than that of said metal. In particular, the metal can be a ballistic metal such as steel whereas the material of the base layer can be Polyester, vinyl ester, epoxy etc. The composite material can be encapsulated by a binding cover made of a fiber-reinforced resin, and, according to one particular example, the fiber reinforcement of the binding cover can be provided by fiberglass. 
     In addition, the ratio between the thickness of a front portion of the base layer and the thickness of the slat (measured along the second direction in a cross-section taken along a plane of the first direction) can range between 3:1 to 1:5, more particularly 2:1 to 1:4, even more particularly 1:1 to 1:2. 
     In the case each slat unit comprises a bottom slat and a top slat (each attached to a different surface of the front portion of the base layer, the thickness of the layer defines the distance between the top and the bottom slat. Thus, such a thickness should correspond to the requirement that the distance between the top and the bottom slat is considerably greater than the distance between two neighboring slat units. 
     In addition, the thickness of a rear portion of the base layer can be greater than the thickness of the front portion, thereby providing cushioning to a rear portion of the slat. Thus, the ration between the thickness of the rear portion of the base layer and the thickness of the slat (measured along the second direction in a cross-section taken along a plane of the first direction) can range between 6:1 to 1:3, more particularly 5:1 to 1:2, even more particularly 4:1 to 1:1. 
     Per the above, the volume of the base layer can constitute between 20-60% of the overall volume of the entire slat unit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In order to better understand the subject matter that is disclosed herein and to exemplify how it may be carried out in practice, embodiments will now be described, by way of non-limiting example only, with reference to the accompanying drawings, in which: 
         FIG. 1  is a schematic longitudinal isometric cross-sectional view of a prior art RPG missile; 
         FIGS. 2A and 2B  are schematic isometric and front views of a hybrid slat armor according to the subject matter of the present application; 
         FIGS. 3A to 3C  are schematic isometric views of a slat unit used in the hybrid slat armor shown in  FIGS. 2A and 2B  during various assembly stages thereof; 
         FIG. 4A  is a schematic isometric view of an end portion of the slat unit shown in  FIGS. 3A to 3C , with an attachment module; 
         FIG. 4B  is a schematic isometric view of the slat unit shown in  FIG. 4A , when attached to a support member of the hybrid slat armor; and 
         FIG. 4C  is a schematic perspective view of a support member of the hybrid slat armor having mounted thereon a plurality of attachment modules as shown in  FIGS. 4A and 4B . 
     
    
    
     DETAILED DESCRIPTION OF EMBODIMENTS 
     Attention is first drawn to  FIGS. 2A and 2B , in which a hybrid slat armor of the present application is shown, generally being designated as  1  and comprising a plurality of slat units  20  suspended between two support members  30 . The slat units  20  are articulated to the support member  30  via attachment modules  40  and the entire hybrid slat armor  1  is configured for being attached to a body to be protected (e.g. a vehicle) by end attachments  50  disposed at each end of each of the support members  30 . 
     The hybrid slat armor  1  is configured for protecting a body from the RPG  10 , and so the spacing between the slat units  20  is chosen according to the diameter of the RPG  10 . In particular, the arrangement is such that the spacing is approximately equal to half the maximal diameter of the RPG  10 , ensuring that when impacting the hybrid slat armor  1 , the conical envelope  12 ,  13  of the RPG  10  will encounter the slat units  20 . 
     Turning now to  FIGS. 3A to 3C , the slat unit  20  is shown comprising a composite base  60  and a plurality of slat panels  70  disposed on each side of the composite base  60  to be spaced from one another. 
     The composite base comprises a rear support portion  62  having a rear surface  65  and a front substrate portion  64  having a strike surface  63 , the substrate portion being configured for positioning thereon of the slat panels  70 . The rear support portion  64  has a greater thickness than the front substrate portion  62  so that there are formed two seats configured for accommodating therein the slat panels  70 . 
     The arrangement is such that when the slat panels  70  are positioned within the seats, the bottom/top surfaces of the panels are mated with the top and bottom surfaces  68 T,  68 B respectively, and a rear surface of each of the slat panels  70  is mated against support surfaces  69 T,  69 B of the rear support portion  62  of the composite base  60 . 
     Each of the slat panels  70  comprises a main body  72  having a generally rectangular shape and formed with perforations  74  extending therealong in the first longitudinal direction, configured for allowing articulation between the top and bottom slat panels  70  and the base composite  60 . 
     Each of the slat panels  70  comprises a set of piercing elements  80  having a tapering extension  85  towards the impact direction, each being formed with a sharp edge  84  configured for tearing/deforming the envelope of the incoming threat. The piercing elements  80  are spaced from one another  83  facilitating more efficient penetration into the threat envelope upon impact therewith. 
     Top and bottom slat panels  70  are affixed to one another and to the base composite  60  using rivets (not shown) passing through the perforations  74  and through base composite  60 . 
     It is appreciated that the slat unit  20  comprises a plurality of both top and bottom slat panels  70  which are spaced from one another. This arrangement provides the slat unit  20  with a greater flexibility and allows reducing bending stresses upon impact of the incoming threat. 
     In addition, it is noted that aligned top and bottom panels  70  are arranged such that the piercing elements  80  of a top slat panel  70  are aligned opposite the piercing elements  80  of a bottom slat panel  70 , and, consequently, the spaces between two neighboring piercing elements  80  are also aligned opposite the spaces between neighboring piercing elements  80  of the bottom panel. This arrangement also serves for reducing bending stresses. In particular, if the arrangement were misaligned, i.e. a piercing element  80  of the bottom slat panel  70  were aligned opposite a space between two neighboring piercing elements  80  of a top slat panel  70 , upon a bending force applied to the slat unit  20  at the above space, the piercing element  80  of the bottom slat panel would receive all the bending stresses. 
     With particular reference being made to  FIG. 3C , once the slat panels  70  have been mounted to the base composite  60  and affixed thereto, a protective cover  90  is applied to encapsulate the base composite  60  and slat panel  70  assembly. The protective cover  90  is in the form of a resilient sleeve which can be heated, pulled over the base composite  60  and slat panels  70  and then cooled to compactly encapsulate them and form the slat unit  20 . 
     Attention is now drawn to  FIGS. 4A to 4C , in which the attachment module  40  of the hybrid slat armor  1  are shown. In particular, each attachment module  40  is in the form of a sheet bent cup  41  having a main cavity  49  configured for receiving therein an end of the slat unit  20 . 
     The cup  41  comprises two flanges  44   a ,  44   b  configured for closing over the slat unit  20  and a deformable extension  42  configured for being bent around the support members  30  for the purpose of attachment thereto. The cup further comprises a recess  43  for receiving therein the support member  30 . In addition, the cup  41  comprises securing hole  45  for receiving therein a securing bolt  100  ( FIG. 4C ) and a depression hole  47  configured for applying pressure to the slat unit  20  in order to both secure and align the slat unit  20  during assembly. 
     In assembly, the cup  41  is positioned on the support member  30  (a cable) so that the recess  43  receives therein a portion of the support member  30 . Thereafter, the deformable extension  42  is bent to close around the support member  30 . In this position, by applying appropriate pull, the attachment module  40  can be displaced along the support member  30 . 
     In addition, the support member  30  can comprise a mounting sleeve (not shown) circumferentially surrounding the support member  30  along a portion thereof corresponding to the width of the attachment module  40  so that, when mounted, the deformable extension  42  closes over the sleeve and not the support member itself. The sleeve thus serves both for indicating the location/s at which the attachment modules  30  should be mounted as well as for guarding the support member  30 . 
     Once the attachment modules  30  are mounted as above, an end portion of the slat unit  20  is inserted into the cavity  49  of the cup and a bolt and nut assembly  100  is passed through holes  45  of the attachment module  40 , so that tightening of the bolt and nut assembly  100  brings the flange portions  44   a ,  44   b  towards one another. This serves two purposes: (a) affixing the slat unit  20  to the attachment module  40 ; and (b) narrowing of the recess  43  so as to affix the attachment module  40  to the support member  40 . 
     In addition, once tightened, the depression hole  47  pushes in against the protective cover so that a depressed tip thereof aligns itself opposite the base composite  60  and between the top and bottom slat panels  70 . 
     The entire hybrid slat armor  1  can be suspended from the body (not shown) to be protected using the end attachment  50 . In particular, the body can comprise a stand-off arrangement extending perpendicular to the body in the impact direction so that the hybrid slat armor  1  can be suspended vertically from the stand-off arrangement. 
     In operation, when an incoming threat (e.g. RPG) impacts the hybrid slat armor  1 , in most cases, the top of the RPG passes between two neighboring slat units  20 . As such, the interaction with the envelope of the RPG takes place with the bottom slat panels  70  of the top of the two slat units  20  and the top slat panels  70  of the bottom of the two slat units  20 . 
     Upon impact, the piercing elements  80  penetrate the conical envelope of the RPG and are supported, along the impact direction, by the width of the slat panels  70  and by the rear support portion  62  of the base composite  60 . 
     Upon further progression of the RPG towards the body to be protected, due to the tapering shape of the piercing elements  80  and their penetration into the RPG, the bottom slat panels  70  of the top of the two slat units  20  and the top slat panels  70  of the bottom of the two slat units  20  are detached from the base composite  60  and continue together with the RPG (which is already neutralized due to breech of its envelope.