Barrier system for protection against low-flying projectiles

Abstract

A barrier system acts to gradually decelerate and arrest low-flying projectiles, such as RPGs, to reduce the likelihood of a fuze-detonating impact. The barrier system, which includes a frame-supported net and net suspension, preferably with energy absorbing characteristics, preferably is modular and portable so that similar barrier units can be arranged, and optionally joined together, to form a wider line of defense, such as a defensive perimeter around a potential target area.

1 . Apparatus for protection against low-flying projectiles, comprising:
 a net having a top margin, a bottom margin and side margins; and   a net-supporting frame comprising a base portion adapted to be supported on the ground or floor, and an upper portion suspending the net with its top margin higher than its bottom margin,   wherein the bottom margin of the net is restrained by the frame, and the net is wider than the frame and projects laterally beyond at least one side thereof.   
   
   
       2 . Apparatus according to  claim 1 , wherein the net projects laterally beyond both sides of the frame. 
   
   
       3 . Apparatus according to  claim 2 , wherein the net is resiliently suspended from the upper portion of the frame. 
   
   
       4 . Apparatus according to  claim 3 , wherein the top margin of the net is stiffened and is resiliently suspended from the upper portion of the frame. 
   
   
       5 . Apparatus according to  claim 4 , wherein the top margin of the net is suspended by resiliently extensible cables. 
   
   
       6 . Apparatus according to  claim 5 , wherein each of the cables is extensible against a force exerted by a retraction element. 
   
   
       7 . Apparatus according to  claim 6 , wherein the retraction element comprises a spring. 
   
   
       8 . Apparatus according to  claim 6 , wherein the retraction element comprises a weight. 
   
   
       9 . Apparatus according to  claim 6 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       10 . Apparatus according to  claim 2  or  claim 5 , wherein the bottom margin of the net is stiffened and is resiliently restrained by the frame. 
   
   
       11 . Apparatus according to  claim 10 , wherein the bottom margin of the net restrained through resiliently extensible cables. 
   
   
       12 . Apparatus according to  claim 11 , wherein each of the cables is extensible against a force exerted by a retraction element. 
   
   
       13 . Apparatus according to  claim 12 , wherein the retraction element comprises a spring. 
   
   
       14 . Apparatus according to  claim 13 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       15 . Apparatus according to  claim 2 , wherein:
 the top margin of the net is stiffened and is resiliently suspended from the upper portion of the frame by resiliently extensible cables;   the bottom margin of the net is stiffened and is resiliently restrained by the frame through resiliently extensible cables; and   each of the cables is extensible against a force exerted by a retraction element.   
   
   
       16 . Apparatus according to  claim 15 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       17 . Apparatus according to  claim 16 , wherein the retraction element comprises a spring. 
   
   
       18 . Apparatus according to  claim 2  or  claim 15 , wherein the upper portion of the frame adjustably positions the top margin of the net in a fore/aft direction so as to adjust the angle of the net relative to the vertical. 
   
   
       19 . Apparatus according to  claim 2  or  claim 15 , wherein the base portion of the frame has stabilizer feet. 
   
   
       20 . Apparatus according to  claim 19 , wherein the stabilizer feet extend substantially horizontally for resting on the ground or floor. 
   
   
       21 . Apparatus according to  claim 19 , wherein the stabilizer feet extend downwardly for burial in the ground. 
   
   
       22 . A modular barrier system for protection against low-flying projectiles, comprising a plurality of barrier units arranged side-by-side along a desired barrier locus, each of the barrier units comprising:
 a net having a top margin, a bottom margin and side margins; and   a net-supporting frame comprising a base portion adapted to be supported on the ground or floor, and an upper portion suspending the net with its top margin higher than its bottom margin,   wherein the bottom margin of the net is restrained by the frame, and the net is wider than the frame and projects laterally beyond at least one side thereof, and   wherein the barrier units are arranged so that each portion of each net that projects laterally beyond a side of the frame overlaps the net of the adjacent barrier unit.   
   
   
       23 . A modular barrier system according to  claim 22 , wherein the net of each barrier unit projects laterally beyond both sides of its frame. 
   
   
       24 . A modular barrier system according to  claim 23 , wherein the upper portion of the frame of each barrier unit adjustably positions the top margin of the net in a fore/aft direction so as to adjust the angle of the net relative to the vertical. 
   
   
       25 . A modular barrier system according to  claim 23 , wherein the net of each barrier unit is resiliently suspended from the upper portion of the frame. 
   
   
       26 . A modular barrier system according to  claim 23 , wherein the bottom margin of the net of each barrier unit is resiliently restrained by the frame. 
   
   
       27 . A modular barrier system according to  claim 23 , wherein in each barrier unit:
 the top margin of the net is stiffened and is resiliently suspended from the upper portion of the frame by resiliently extensible cables;   the bottom margin of the net is stiffened and is resiliently restrained by the frame through resiliently extensible cables; and   each of the cables is extensible against a force exerted by a retraction element.   
   
   
       28 . A modular barrier system according to  claim 27 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       29 . A modular barrier system according to  claim 28 , wherein the retraction element comprises a spring. 
   
   
       30 . A modular barrier system according to  claim 23 , wherein the base portion of the frame of each barrier unit has stabilizer feet. 
   
   
       31 . A modular barrier system according to  claim 30 , wherein the stabilizer feet extend substantially horizontally for resting on the ground or floor. 
   
   
       32 . A modular barrier system according to  claim 30 , wherein the stabilizer feet extend downwardly for burial in the ground. 
   
   
       33 . Apparatus for protection against low-flying projectiles, comprising:
 a net having a top margin, a bottom margin and side margins; and   a net-supporting frame adapted to be supported on the ground or floor and suspending the net with its top margin higher than its bottom margin,   wherein the top margin of the net is stiffened and is resiliently suspended from the frame, and the bottom margin of the net is stiffened and is resiliently restrained by the frame.   
   
   
       34 . Apparatus according to  claim 33 , wherein:
 the top margin of the net is suspended by resiliently extensible cables;   the bottom margin of the net is restrained through resiliently extensible cables; and   each of the cables is extensible against a force exerted by a retraction element.   
   
   
       35 . Apparatus according to  claim 34 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       36 . Apparatus according to  claim 35 , wherein the retraction element comprises a spring. 
   
   
       37 . Apparatus according to  claim 33 , wherein the portion of the frame from which the net is suspended adjustably positions the top margin of the net in a fore/aft direction so as to adjust the angle of the net relative to the vertical. 
   
   
       38 . Apparatus according to  claim 33 , wherein the frame has stabilizer feet that contact the ground or floor. 
   
   
       39 . Apparatus according to  claim 38 , wherein the stabilizer feet extend substantially horizontally for resting on the ground or floor. 
   
   
       40 . Apparatus according to  claim 38 , wherein the stabilizer feet extend downwardly for burial in the ground. 
   
   
       41 . Apparatus for protection against low-flying projectiles, comprising:
 a net having a top margin, a bottom margin and side margins; and   a net-supporting frame adapted to be supported on the ground or floor and suspending the net with its top margin higher than its bottom margin,   wherein the bottom margin of the net is restrained by the frame, and the top margin of the net is stiffened and is resiliently suspended from a portion of the frame that adjustably positions the top margin of the net in a fore/aft direction so as to adjust the angle of the net relative to the vertical.   
   
   
       42 . Apparatus according to  claim 41 , wherein:
 the top margin of the net is suspended by resiliently extensible cables;   the bottom margin of the net is stiffened and is restrained through resiliently extensible cables; and   each of the cables is extensible against a force exerted by a retraction element.   
   
   
       43 . Apparatus according to  claim 42 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       44 . Apparatus according to  claim 43 , wherein the retraction element comprises a spring. 
   
   
       45 . Apparatus according to  claim 41 , wherein the frame has stabilizer feet that contact the ground or floor. 
   
   
       46 . Apparatus according to  claim 45 , wherein the stabilizer feet extend substantially horizontally for resting on the ground or floor. 
   
   
       47 . Apparatus according to  claim 45 , wherein the stabilizer feet extend downwardly for burial in the ground. 
   
   
       48 . Apparatus for protection against low-flying projectiles, comprising:
 a net having a top margin, a bottom margin and side margins; and   a net-supporting frame adapted to be supported on the ground or floor and suspending the net with its top margin higher than its bottom margin, wherein:   the top margin of the net is suspended from the frame,   the bottom margin of the net is restrained by the frame,   the side margins of the net are unrestrained,   at least a portion of the net is adapted to deflect rearwardly upon frontal impact by a low-flying projectile, and   the frame has a clear space behind the net to accommodate said net deflection substantially without interference by the frame.   
   
   
       49 . Apparatus according to  claim 48 , wherein at least one of the top and bottom margins is resiliently restrained. 
   
   
       50 . Apparatus according to  claim 49 , wherein the top margin of the net is resiliently suspended from the frame. 
   
   
       51 . Apparatus according to  claim 50 , wherein the bottom margin of the net is resiliently restrained by the frame. 
   
   
       52 . Apparatus according to  claim 50  or  claim 51 , wherein the top margin of the net is stiffened. 
   
   
       53 . Apparatus according to  claim 52 , wherein the bottom margin of the net is stiffened. 
   
   
       54 . Apparatus according to  claim 53 , wherein:
 the top margin of the net is suspended by resiliently extensible cables;   the bottom margin of the net is restrained through resiliently extensible cables; and   each of the cables is extensible against a force exerted by a retraction element.   
   
   
       55 . Apparatus according to  claim 54 , wherein each cable is guided by at least one pulley carried by the frame. 
   
   
       56 . Apparatus according to  claim 55 , wherein the retraction element comprises a spring. 
   
   
       57 . Apparatus according to  claim 48 , wherein the portion of the frame from which the net is suspended adjustably positions the top margin of the net in a fore/aft direction so as to adjust the angle of the net relative to the vertical. 
   
   
       58 . A method of protecting an area from low-flying projectiles, comprising erecting a modular barrier system adjacent the area to be protected on a barrier locus along which there is a potential threat from low-flying projectiles, the modular barrier system comprising a plurality of ground- or floor-supported barrier units each having a net suspended from a frame with the top margin of the net higher than the bottom margin of the net, wherein the barrier units are arranged so that a side marginal portion of each net overlaps a side marginal portion of each adjacent net. 
   
   
       59 . A method according to  claim 58 , wherein the net of each barrier unit is wider than the frame and projects laterally beyond both sides of the frame, and the barrier units are placed in a staggered arrangement. 
   
   
       60 . A method according to  claim 58  or  claim 59 , comprising anchoring the frame of each barrier unit to the ground or floor. 
   
   
       61 . A method according to  claim 60 , wherein the floor comprises a deck of a ship. 
   
   
       62 . A method according to  claim 61 , comprising anchoring each frame to the deck using mechanical fasteners.