Method and apparatus for absorbing the energy of bullet impacts
A method for and apparatus absorbing the energy of a projectile strike by a multiplicity of energy dissipating elements of high mass that are contained within a spaced defined by walls. A projectile passing through one of the walls transmits its energy to a multiplicity of energy dissipating elements, such as hardened steel balls or various shaped objects of high mass, by causing energy transfer and distribution through a loose mass of the energy dissipating elements and disintegrating the projectiles. Energy absorbing apparatus embodying this method may take the form of a static or moveable bullet or projectile trap, an energy absorbing external barrier or shelter on vehicles, and portable personnel protection structures for use in a tactical environment. The energy absorbing and dissipating elements are subject to some movement in response to the energy imparted by the projectiles and quickly settle after the energy has been dissipated.
1. Field of the Invention
The present invention relates generally to a method and a wide variety of mechanical devices for absorbing and distributing energy, particularly the energy of projectiles such as bullets, artillery shells, shrapnel, and the energy that may be delivered to structures by blunt force impacts. More particularly, the present invention concerns a wide variety of specific energy absorbing apparatus, such as static or moveable bullet traps, protective walls of structures and protective energy absorbing and dissipating protective shields for vehicles, protective personnel enclosures, etc.
2. Description of the Prior Art:
A projectile trap, more specifically referred to as a bullet trap, is typically provided in the form of an earthen dike or berm that defines a rather abrupt shoulder or embankment. During firearm practice or matches bullets are fired through targets and become embedded within the earth of the dike or berm. Repeated bullet strikes in the earth of the abrupt shoulder or embankment of a dike or berm will result in damage which must be repaired from time to time. Moreover, the earth of the embankment of the dike or berm will accumulate a significant amount of bullet material, such as copper and lead, which may need to be removed from time to time, especially if the continued presence of these materials is objectionable as potentially harmful to the environment. Typically the soil containing the bullet residue will need to be dug out and separated from the soil. This is a very costly and time consuming process which is done only in the event that the soil must be returned as nearly to its original condition as is possible. And of course the bullet materials are lost during typical firing range activities even though these materials are valuable commodities that could be re-used. Therefore, it is desirable to provide a bullet trap system that sustains minimal damage during normal use and which can be easily and quickly repaired with minimal effort and cost. It is also desirable to provide a bullet trap system that enables a high percentage of the bullet materials to be recovered and re-used.
A bullet trap may also be composed of sand bags or bags of other materials, such as sawdust, wood shavings, or the like and can be composed of heavy wooden beams such as railroad cross-ties. However, during firearm shooting activities these materials typically become damaged in a relatively short period of time and must be repaired or replaced at considerable labor and significant expense. It is desirable to provide a bullet trap system that will remain functional for long periods of time and when repair of replacement becomes necessary, can be simply and efficiently repaired or replaced via the use of minimal labor and cost.
Vehicles, such as military trucks, armored personnel carriers and tanks are often provided with armor that renders them somewhat safe from penetration by the projectiles of rocket propelled grenades, bullets of heavy machine guns and light artillery rounds. There are times, during tactical situations, where additional protection is needed to enable such vehicles to absorb a significant amount of ordinance energy. Personnel may come under attack during a tactical situation and may need the protection of temporary energy absorbing shelters to enable them to remain securely protected for the duration of an attack. Therefore, it is desirable to provide an energy absorbing system that can be simply and efficiently used to provide an external barrier of energy absorbing protection as needed for the protection of personnel and equipment within a wide variety of vehicles. It is also desirable to provide an energy absorbing system that may be efficiently installed during field conditions that will enable the establishment of an energy absorbing structure to provide protection for personnel from the otherwise damaging effects of various types of projectiles.
SUMMARY OF THE INVENTIONIt is a principal feature of the present invention to provide a novel energy absorbing system that enables the provision of various types of bullet traps, including static and moveable bullet traps.
It is another feature of the present invention to provide a novel energy absorbing system that is applicable to bullet traps and provides for the recovery of bullet materials, such as copper and lead, and enables a bullet trapping environment to be maintained essentially clean of bullet material accumulation.
It is also a feature of the present invention to provide a novel energy absorbing system that can be designed for the protection of various types of vehicles and can be quickly and easily attached to the vehicle structure to provide an additional outer layer or barrier which has the capability for absorbing a significant amount of the energy of projectiles that may strike the vehicle.
It is another feature of the present invention to provide a novel energy absorbing system that can be efficiently employed to erect a temporary protective barrier or enclosure that has the capability for absorbing and dissipating much of the energy of a projectile striking the barrier or enclosure and is capable of providing protection for personnel behind a protective barrier or within a protective enclosure.
Briefly, the various objects and features of the present invention are realized through the provision of an energy absorbing barrier or shelter having spaced walls and with the space between the walls being at least partially filled with a multiplicity of energy absorbing elements, such as hard and dense metal balls or other metal or non-metal objects, that can be moved in response to the application of the energy of a projectile strike. Movement of the energy absorbing and dissipating elements causes the transfer of force and energy dissipation to other surrounding energy absorbing elements. When the energy of a projectile strike has been absorbed and dissipated the energy absorbing elements will quickly settle by the action of gravity. The energy absorbing elements also cause a projectile, such as a bullet, to be disintegrated to a particulate form within the loose mass of energy absorbing and dissipating elements and to descend through the loose mass and fall from the bullet trap. The resulting bullet material particulate may then be collected and re-used.
The outermost one of the walls of the energy absorbing system is readily replaceable and is composed of a material that is relatively easy to be penetrated by a projectile and yet maintain sufficient structural integrity for effective retention of the energy absorbing elements. Such a wall structure may be composed of a tough, resilient and durable polymer material, such as polyethylene, for example. The outermost wall or front wall panel should have sufficient structural integrity and elastic memory to retain the moveable energy absorbing elements within the space between the walls and permit multiple projectiles to penetrate the wall panel material without impairing its structural integrity and with minimal resistance and to impact and impart energy to the energy absorbing elements. The energy that is imparted to one or more of the energy absorbing elements will move the energy absorbing elements against the resistance of the weight and mass of all or most of the other energy absorbing elements, thus distributing the energy of the projectile throughout the loose mass of energy absorbing elements that are present within the wall space. Movement of the energy absorbing elements will be minimal when impacted by a firearm projectile or other type of projectile, because the energy of the projectile will be efficiently transferred from element to element within the loose mass of energy absorbing elements and because the mass of the projectile will typically be much less than the combined mass of the energy absorbing elements.
The innermost wall of the energy absorbing system can be composed of a material that is quite resistant to penetration by the energy of a projectile and which provides an inner layer of protection which can be penetrated only by a direct strike of the projectile against the innermost wall, a condition that is not expected to occur. The innermost wall of the energy absorbing system can be composed of a panel or plate of a durable metal such as steel, particularly a hardened steel material having a thickness in the range of from ⅛″ to about ¾″.
The energy absorbing elements can be provided in a wide variety of geometric forms, such as spheres or balls, oval objects, triangular objects, square objects, etc., which can be placed in the space between the inner and outer walls as a random mass and which will be moveable as the energy of the projectile is distributed within the mass. The energy absorbing elements are composed of a metal having considerable mass, such as hardened steel, and will be resistant to excessive deformation by the energy of a projectile.
It has been determined through tests that hardened steel balls, such as concrete grinding balls, having a size in the range of about one inch in diameter serve quite well for energy absorption in a bullet trap that is impacted by bullets in the size range of up to .50 caliber. In this test case the outer or front wall of the bullet trap was composed of a polymer material such as polyethylene and the rear wall of the bullet trap was composed of a hardened steel plate having a thickness of about ⅜″. After having been impacted by the bullets of approximately 1,000 to 1,500 rounds of rifle ammunition having a size up to .50 caliber and with approximately 70% of the ammunition having a size of 0.762 mm, the polymer wall panel was replaced, though it still had the capability for retention of the hardened steel balls. The steel plate forming the innermost or rear wall of the bullet trap was essentially undamaged at this point.
So that the manner in which the above recited features, advantages and objects of the present invention are attained and can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to the preferred embodiment thereof which is illustrated in the appended drawings, which drawings are incorporated as a part hereof.
It is to be noted however, that the appended drawings illustrate only a typical embodiment of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
In the Drawings:
Referring now to the drawings and first to
The front and rear wall panels are disposed in spaced relation, having a spacing from about 6 inches to about 12 inches and defining a space or compartment 18 which contains a multiplicity of the hard and dense energy absorbing elements 14 which may comprise hardened steel concrete grinding balls having a diameter of about one inch. These grinding balls are relatively inexpensive and are readily available since they are widely used for grinding concrete and rendering it to a state for re-use. Preferably, the energy absorbing elements 14 are deposited within the space or compartment 18 in the form of a loose mass of energy absorbing elements that are in contact with one another and some of the energy absorbing elements are in contact with the inner surfaces of the front and rear wall panels. The bullet trap also includes a top wall 19 side walls 20 and 22 and a bottom wall 24 that have sufficient structural integrity for containment of the heavy and dense energy absorbing elements. The bottom wall 24 and, if desired, the side walls as well define openings or perforations to permit bullet components to fall from the bullet trap structure, rather than accumulating in the lower part of the compartment 18. The energy absorbing elements 14 are essentially poured through an access opening 26 of the top wall into the space or compartment 18 and constitute a loose mass and are in contact with one another and are in contact with the bottom and side walls. Since the energy absorbing elements are not connected with one another they are free for movement relative to one another in response to the energy of a projectile strike. It is not necessary that the compartment 18 be completely filled with the energy absorbing elements 14, it being only necessary that the energy absorbing element have the capability for energy responsive movement as energy is imparted to the mass of energy absorbing elements, such as by the strike of a bullet or other type of projectile. A hinged closure 27 for the top opening 26 is provided with a locking mechanism 25 so that it can be secured in its closed condition.
For servicing of the bullet trap apparatus, the loose mass of energy absorbing elements can be poured from the compartment 18 by unlocking and opening the hinged closure 27 of the access opening 26 and by inverting the bullet trap. Alternatively, by releasing the front wall panel 12 from its support framework the hardened steel grinding balls 14 will be released and will descend from the compartment 18. The hardened steel grinding balls 14 or other energy absorbing elements can also be removed from the compartment 18 by cutting away a lower portion of the front wall panel 12 to make as large an exit opening as is needed for controlled exit and recovery of the energy absorbing elements. Typically, servicing of the bullet trap apparatus will be done when the front panel 12 has been damaged by bullet penetration to the point that it has become unserviceable and requires replacement. It is not necessary to discard the energy absorbing elements when replacing the front wall panel because they will have little or no deformation from being used many times. After a new front wall panel has been installed the energy absorbing elements will typically be poured back into the compartment 14.
The bullet trap structure is typically formed by a generally rectangular framework, shown generally at 30, having front and rear generally rectangular frames 32 and 34 that are each composed of vertical and horizontal structural members. The front and rear frames 32 and 34 are interconnected by side frame members 36 and 38. The side and bottom wall structures may be composed of any of a number or materials such as sheet metal, heavy duty wire, expanded metal, in fact any material that is capable of providing for secure containment of the energy absorbing elements 14 and having the durability and structural integrity to accommodate movement of the energy absorbing elements in response to the energy of a bullet strike. The front wall panel 12 and the rear wall panel 14 are fixed to the generally rectangular framework by means of bolts, screws or by any other suitable means for attachment.
The rear wall panel may be somewhat permanently secured to the rectangular framework, since it is quite durable and will seldom need replacement. However, the front wall panel 12, since it is penetrated by each bullet or projectile that strikes the bullet trap, will need replacement after having been penetrated by many hundreds of bullets. Consequently, the front wall panel is preferably removably secured to the rectangular framework 30, such as by means of screws or bolts so that its replacement can be accomplished quickly through the use of simple and readily available tools.
Referring to
When one or more of the energy absorbing elements is impacted by a bullet or other type of projectile, the energy absorbing element that receives the energy of the impact will transfer a portions of the energy to adjacent energy absorbing elements with which it is in contact. This will typically result in some movement of the energy absorbing elements which have been subjected to bullet impact or have received energy from adjacent energy absorbing elements. The energy will be transferred in the form of force vectors as shown by the energy transfer arrows as illustrated diagrammatically in
While the present invention is described herein particularly as it relates to static bullet traps, such as shown in
A rotatable bullet trap device, shown generally at 40 in
The energy absorption and dissipation compartment 54 is defined in part by one or more peripheral containment walls 56 that are mounted to the rear and front wall support framework structures 44 and 46 and serve to provide for containment of a multiplicity of energy absorption and dissipation elements 58. The energy absorption and dissipation elements 58 are composed of a hard and dense material such as steel. It has been determined, as mentioned above, that hardened steel concrete grinding balls having a size in the range of about 1″ are relatively inexpensive, readily available, and serve quite well for resisting damage by firearm projectiles and dissipating the energy of firearm projectile strikes. However, the energy absorption and dissipation elements may take many other forms within the spirit and scope of the present invention and may be composed of other hard, dense and durable materials as desired.
The rear wall panel 50 is preferably composed of a hard and dense plate of material such as steel, and has a thickness in the range of from about ⅛″ to about ¾″. The thickness of the rear wall panel 50 is sufficient to resist penetration by any bullets or other projectiles that pass through the front wall panel 52 and enter the energy dissipation and distribution compartment 54. Since the front wall panel is intended to be penetrated by the projectiles, it is mounted to the front framework structure 46 in a manner that promotes simple and quick replacement. The front wall panel is preferably composed of a tough, pliable and durable material such as polyethylene or any other suitable polymer material. It is necessary that the tough and durable polymer material have an elastic memory, made possible by its long chain polymer characteristics, so that holes or paths that are formed in the front wall panel by projectile passage will be substantially closed by the elastic memory of the material. This feature enables the energy absorption and dissipation elements to be efficiently retained within the compartment 54 even when the front panel has been penetrated by many hundreds or thousands of firearm projectiles. However, when replacement of the front wall panel becomes necessary, it may be replaced in a short period of time through the use of simple and readily available tools.
During use of the bullet trap apparatus of
With reference to
As an alternative to the method and apparatus that is described above in connection with
As shown in
If desired, the inner and outer wall assemblies may be supported by a simple portable foundation and may have a simple and portable wall cap that helps to maintain proper spacing between the inner and outer wall assemblies. A multiplicity of energy absorbing and distributing elements 88 are placed in the compartment 86 so as to substantially fill the compartment space. The energy absorbing and distributing elements are of similar composition and function as described above. When the protective enclosure is no longer needed at a particular site, it may be simply and quickly disassembled, transported to a different site and installed as needed. The protective enclosure may also be used to provide for protection of personnel from the damaging effect of wind propelled debris, hail and the like in the event storms are encountered during field conditions.
In view of the foregoing it is evident that the present invention is one well adapted to attain all of the objects and features hereinabove set forth, together with other objects and features which are inherent in the apparatus disclosed herein.
As will be readily apparent to those skilled in the art, the present invention may easily be produced in other specific forms without departing from its spirit or essential characteristics. The present embodiment is, therefore, to be considered as merely illustrative and not restrictive, the scope of the invention being indicated by the claims rather than the foregoing description, and all changes which come within the meaning and range of equivalence of the claims are therefore intended to be embraced therein.
Claims
1. A projectile energy absorbing and dissipating device for absorbing and dissipating the energy of a class of projectiles, comprising:
- a support structure;
- a rear wall being mounted to said support structure and being resistant to penetration by the class of projectiles;
- a front wall being mounted in spaced relation with said rear wall and defining a compartment therewith, said front wall being readily penetrable by the class of projectiles;
- containment walls defining closures for said compartment; and
- a multiplicity of energy absorbing elements being arranged in loose and moveable relation within said compartment and being disposed in engagement with adjacent energy absorbing elements and being contained by said front, rear and containment walls.
2. The projectile energy absorbing and dissipating device of claim 1, comprising:
- said support structure being a support framework;
- said rear wall and said front wall being mounted to said support framework and being secured in spaced relation; and
- said containment walls being mounted to said support framework and being cooperative with said rear and front walls for ensuring against displacement of said energy absorbing elements from said compartment.
3. The projectile energy absorbing and dissipating device of claim 1, comprising:
- said projectile energy absorbing and dissipating device being a bullet trap for the class of projectiles including small arms projectiles up to 50 caliber;
- said rear wall being composed of a hard and dense material of sufficient thickness to resist being penetrated by the class of projectiles; and
- said front wall being composed of a material that is penetrable by the class of projectiles and which ensures minimal damage to said front wall by projectiles passing through it.
4. The projectile energy absorbing and dissipating device of claim 1, comprising:
- said rear wall being defined by a panel composed of steel; and
- said front wall being defined by a panel composed of a polymer material.
5. The projectile energy absorbing and dissipating device of claim 3, comprising:
- said containment walls being composed of a material of sufficient structural integrity for containment of energy absorbing and dissipating elements composed of dense hard material and being sufficiently perforate to permit projectile component residue to pass therethrough and be deposited for collection.
6. The projectile energy absorbing and dissipating device of claim 1 being in the form of an exterior protective device for vehicles, comprising:
- said rear wall being mounted externally of a vehicle structure.
7. The projectile energy absorbing and dissipating device of claim 1 being in the form of an exterior protective device for vehicles, comprising:
- said rear wall being defined by an external surface of a vehicle and constituting said support structure.
8. The projectile energy absorbing and dissipating device of claim 1, wherein said device is in the form of a rotatable bullet trap, said device comprising:
- said support structure being mounted for rotation;
- said containment walls defining perforations of sufficient dimension to permit projectile component debris to pass therethrough and to prevent said energy absorbing elements from passing therethrough; and
- during rotation of said device projectile component debris descending through said multiplicity of energy absorbing elements, passing through said perforations of said containment walls and being deposited for collection.
9. The projectile energy absorbing and dissipating device of claim 1, wherein said device is in the form of a protective enclosure for personnel, said device comprising:
- said rear wall being defined by rear wall panels arranged at a site to form an inner enclosure wall structure having an opening for personnel entrance and exit;
- said front wall being defined by front wall panels disposed in spaced relation with said rear wall panels and arranged to form an outer enclosure wall structure and to define said compartment; and
- said The projectile energy absorbing and dissipating device of claim 1 poured into said compartment and defining a mass of loose energy absorbing elements.
10. The projectile energy absorbing and dissipating device of claim 9, comprising:
- said rear wall and said front wall being of portable nature and being recoverable for use at a different site when use of said protective enclosure is no longer needed at the site; and
- said multiplicity of projectile energy absorbing and dissipating elements being recoverable for use at a different site.
11. A projectile energy absorbing and dissipating device for absorbing and dissipating the energy of a designated class of non-explosive firearm projectiles including small arms projectiles up to 50 caliber, comprising:
- a support framework structure;
- a rear wall being panel being mounted to said support framework structure and being resistant to penetration by the class of firearm projectiles, said rear wall defining a perimeter;
- a front wall panel being mounted to said support framework structure and being disposed in spaced relation with said rear wall panel and defining a compartment therewith, said front wall being readily penetrable by the class of firearm projectiles and defining a perimeter;
- containment walls closing said perimeters of said rear and front wall panels and defining closures for said compartment; and
- a multiplicity of energy absorbing elements composed of hard and dense material and being arranged in loose and moveable relation within said compartment and being disposed in engagement with adjacent energy absorbing elements, said energy absorbing elements being contained by said front, rear and containment walls.
12. The projectile energy absorbing and dissipating device of claim 11, comprising:
- said rear wall panel being composed of a hard and dense metal composition that is resistant to penetration by non-explosive firearm projectiles of the designated class;
- said front wall panel being composed of a material that is subject to penetration by the designated class of non-explosive firearm projectiles; and
- said multiplicity of energy absorbing elements being composed of a hard and dense metal material that is resistant to deformation by the designated class of non-explosive firearm projectiles.
13. The projectile energy absorbing and dissipating device of claim 12, comprising:
- said multiplicity of energy absorbing elements being composed of hardened steel and being in the form of spheres
14. The projectile energy absorbing and dissipating device of claim 12, comprising:
- said rear wall panel being composed of steel plate material having a thickness of from about ⅛″ to about ¾″; and
- said front wall panel being composed of a material that substantially closes the path of a projectile penetration and maintains the capability for containment of said energy absorbing elements after having been penetrated many hundreds of times by the designated class of non-explosive firearm projectiles.
15. The projectile energy absorbing and dissipating device of claim 14, comprising:
- said front wall panel being composed of a polymer material having a long chain polymer structure providing an elastic memory for substantially closing projectile penetration paths after having been penetrated by the designated class of non-explosive projectiles.
16. The projectile energy absorbing and dissipating device of claim 11 being in the form of a rotatably moveable bullet trap, and comprising:
- said support framework structure having an axis and being supported for rotation about said axis; and
- said containment walls having perforations of a dimension preventing movement of said multiplicity of energy absorbing elements therethrough and permitting movement of bullet fragment residue therethrough for deposit and collection.
17. The projectile energy absorbing and dissipating device of claim 11 being in the form of a protective barrier for personnel and vehicles, and comprising:
- said rear wall being defined by rear wall panels of portable nature and being arranged to form an inner barrier wall structure and being moveable for re-use;
- said front wall being defined by front wall panels disposed in spaced relation with said rear wall panels and arranged to form an outer barrier wall structure and to define said compartment;
- said energy absorbing and dissipating elements being poured into said compartment and defining a mass of loose energy absorbing elements; and
- said multiplicity of projectile energy absorbing and dissipating elements being recoverable for re-use.
18. A method for absorbing and dissipating the energy of projectile strikes by a class of non-explosive firearm projectiles up to 50 caliber, by shrapnel and by other fast moving objects, comprising:
- positioning front and rear walls in spaced relation defining an energy absorption and dissipation compartment therebetween, said front wall being readily penetrable by the projectiles and said rear wall being resistant to penetration by the projectiles;
- positioning a multiplicity of hardened energy absorbing elements of high mass within said energy absorption and dissipation compartment, said hardened energy absorbing elements of high mass being in contact with said front and rear walls;
- projectiles penetrating said front wall striking at least one of said hardened energy absorbing elements and imparting energy thereto; and
- transferring and dissipating the energy of a projectile strike through said multiplicity of hardened energy absorbing elements, causing disintegration of the projectile and providing penetration protection for said rear wall and for objects located beyond said rear wall.
19. The method of claim 18, comprising:
- positioning said rear and front walls in portable fashion for movement and re-use; and
- recovering said multiplicity of hardened energy absorbing elements of high mass.
Type: Application
Filed: Jul 23, 2011
Publication Date: Jan 24, 2013
Inventor: Mark C. Larue (Leander, TX)
Application Number: 13/136,084
International Classification: F41H 5/04 (20060101); F41H 7/02 (20060101);