Patent Publication Number: US-2015084284-A1

Title: Projectile recovery chamber

Description:
TECHNICAL FIELD OF THE INVENTION 
     The present invention relates to a projectile recovery chamber or also known as bullet trap which is to provide a projectile recovery chamber of reduced size that allows rapid recovery of a projectile, obtaining the samples with the ballistic mode footprint, of the particular rifling imparted by each firearm, consistently reproduced, eliminating possible changes in the barrel markings on the bullet. To a large extent, this assists forensics experts in performing their comparisons with greater precision. 
     BACKGROUND OF THE INVENTION 
     In forensics examinations that are usually performed in ballistics laboratories, the aim is to establish whether a specific firearm is the firing origin of bullets or shells gathered as evidence of alleged criminal acts. There are various solutions currently on the market for achieving this objective, but they perform inadequately or inefficiently and, above all, too much time is required to recover reference projectiles for forensics use. 
     The review and examination of the prior art revealed US patent application US 2005/0093243 A1 (Steven L. Larson, et al.), published on May 5, 2005. The document relates to a backstop for decelerating and trapping projectiles generally, and it includes a support structure having an inclined surface and a projectile-trapping medium disposed on the inclined surface. The projectile-trapping medium may be a resilient granular ballistic medium or a combination of a ballistic medium with a hydrated superabsorbent polymer (SAP) gel. Preferably, the support structure is made of a shock-absorbing, foamed, fiber-reinforced concrete, such as SACON®. In the various embodiments, the support structure also includes a housing. The additives may also be mixed into the projectile-trapping medium to control alkalinity and to prevent leaching of heavy metals. 
     Said invention, in addition to not being used to recover reference bullets for forensics use, likewise does not include the same configuration as the invention for which protection is sought. There is no chamber but, rather, an open trap for trapping projectiles, in which use is made of a trapping medium that may, among other options, be a superabsorbent polymer (SAP) gel. 
     Spanish patent application ES 2049964 (Impresa Construzioni Soc. FRA SA a RL), entitled “Assembly and separation unit for ballistic projectile stopping devices”, was found, which relates to a unit allowing transportation of the mixture of the impact material and exploded projectiles and separation of the latter before said impact material is returned to the top part of the mound of impact material. 
     The only relevant aspect of that patent application is the separation of the projectiles from the impact material before the latter is recirculated, and that it is not used in the recovery of reference bullets for forensics use. 
     Spanish patent application ES2061892 (Peter Kanauf, et al.) was found. Therein, use is made of a projectile retention material that comprises a thermoplastics material that brakes and/or collects the projectiles, characterized in that the layer ( 1 ,  20 ) comprises at least one molded component ( 10 ) of synthetic thermo-plastics material that is shape-stable at ambient temperature and that, at a temperature of at most 200° C., preferably 150° C., has a viscosity that allows it to flow and wherein the thermoplastics material may be removed in its entirety from the projectile simply by means of heating. 
     Japanese patent JP4101642 states, as problem to be solved, the recovery of disperse, fired bullets accumulated against a bank built up behind a target, wherein there is practically no recovery work and it is still not possible to recover and to recycle the bullets. The solution given is an impact receiver that has a sufficiently thick gel material stored in a bag and placed behind the target. 
     Although the solution given by the Japanese application includes the use of a gel to trap bullets, there is no mention of the rheopectic properties of the gel nor any reference to the fact that the gel is in continuous movement. In addition to the fact that it does not have an application in forensic ballistics. 
     United States patent application US 2009/0303982 relates to an apparatus for induction braking a projectile, wherein the apparatus has a one-way conductor with a closed conduction path surrounding the passage of the projectile in motion. The one-way conductor allows the current to flow therethrough substantially in a single direction right along the corridor. As the projectile and its associated movement progress via the one-way conductor, the movement of the magnetic field induces a current flow across the closed conductive path, which in turn generates a magnetic field behind the projectile with the same polarity as the field of the projectile. Both fields are attracted to one another, as long as a braking force is exerted on the projectile, tending to align the two magnetic fields. Alignment of these fields centers the projectile remote from the wall of the apparatus. Owing to the fact that the one-way conductor allows the current to flow substantially only in the direction that produces a field having the same polarity as the field in motion, the repelling opposite polarity of a magnetic field that could otherwise generate a deviation of the projectile on its passage. 
     Another invention for trapping projectiles is the “Snail” deceleration chamber that comprises a deceleration chamber with a reduced entry angle that guides the projectile to a circular chamber where the projectile revolves until it loses energy, dropping down for collection, the projectile residues being deformed or fragmented and therefore unusable in forensics examinations. 
     Various inventions have been developed in order to trap projectiles, but none of those found includes a modular system in which it is possible to increase the length of the chamber, and likewise no chambers have been found that contain a rheopectic fluid for braking the projectile, and still less, chambers that have a positioning system for proper placement of the firing weapon. 
     Other systems use horizontal water tanks that are fairly heavy, not only on account of their metallic structure but also on account of the quantity of water they have to contain. These systems have no automatic projectile recovery system. 
     Another type of recovery system uses fibers, such as Kevlar or cotton fibers, to retain projectiles, which makes recovery of the projectile problematic. 
     Therefore, a projectile recovery system or chamber for recovering reference projectiles for forensics use such as that now being proposed does not exist on the market or in the prior art. 
    
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         FIG. 1  is a lateral view of the projectile recovery chamber. 
         FIG. 2  shows different views of the flanges that connect the cylindrical modules that make up the various sections of the projectile recovery chamber. 
         FIG. 3  shows different views of the cylindrical modules that make up the projectile recovery chamber. 
         FIG. 4  shows the assembly of the flanges with the cylindrical modules. 
         FIG. 5  is a view of the assembly of the flanges, the packing and the cylindrical modules. 
         FIG. 6  is a perspective view of the projectile recovery chamber, showing the sections that make up the chamber. 
         FIG. 7  is a lateral view of the firing chamber in the inclined position, as it must be placed. 
         FIG. 8  is a detail of the assembly of the front cover of the projectile recovery chamber. 
         FIG. 9(   a - d ) shows different views of the assembled front cover of the projectile recovery chamber. 
         FIG. 10(   a - c ) shows different views of the rear cover of the projectile recovery chamber. 
         FIG. 11  is a plan view of the metallic platform of the projectile recovery chamber. 
         FIG. 12  is a detail of one of the supports connecting the projectile recovery chamber to the metallic platform. 
         FIG. 13  shows the mechanisms for adjusting height, for shock absorbing, and the movement carriage for the projectile recovery chamber. 
         FIG. 14  is a perspective view of the projectile recovery chamber. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION: 
     According to  FIG. 1 , the projectile recovery chamber ( 1 ) of the present invention comprises a cylindrical body formed by coupled cylindrical sections ( 2 ), the number of which may vary depending on the length required for the projectile recovery chamber ( 1 ), being at least three in number, wherein the cylindrical sections ( 2 ) are produced preferably from stainless steel and are connected by means of flanges ( 4 ) with intermediate packing ( 5 ). 
     According to  FIG. 1 , the projectile recovery chamber ( 1 ), at the rear end thereof, has a has a hydraulic system that comprises a self-aspirating pump ( 6 ) that has a basket-type filter ( 7 ) used for the recovery of the fired projectile, a suction pipe ( 8 ) that extracts a fluid from the projectile recovery chamber ( 1 ) via the suction hole ( 27 ) and a return pipe ( 9 ) that returns the fluid to the interior of the projectile recovery chamber ( 1 ) via the return hole ( 26 ); the hydraulic system is controlled by a programmable logic controller PLC located on a control panel ( 3 ). The rear cover ( 10 ) of the chamber is a plate covering the circular rear end of the projectile recovery chamber ( 1 ) and has a vertical upward projection ( 28 ) from the rear cover, ending in a folded portion that forms a horizontal surface ( 29 ) with an internal angle of less than 90° where the self-aspirating pump ( 6 ) and the basket-type filter ( 7 ) rest; the projectile recovery chamber ( 1 ) has, in the front part thereof, a cover called front cover ( 11 ) of the chamber that has a rectangular hole ( 35 ) through which the weapon barrel is inserted and a basket ( 12 ) for trapping shells for the trapping and recovery of shells from automatic weapons. The projectile recovery chamber is held by front ( 13 ) and rear ( 14 ) supports that are coupled to a metallic platform ( 15 ), said supports have the form of a circular section ( FIG. 12 ) of a cylindrical section ( 2 ) that forms the projectile recovery chamber ( 1 ) and are connected by means of screws to the flanges ( 4 ), wherein said supports slide on grooves, two rear grooves ( 16   a  and  16   b ) that are parallel, and a central groove ( 17 ), that cross the metallic platform ( 15 ) that supports the projectile recovery chamber ( 1 ); wherein the rear support ( 14 ) slides on the rear grooves ( 16   a  and  16   b ) that cross the metallic platform ( 15 ) and the front support ( 13 ) slides on a central groove ( 17 ) that crosses the metallic platform ( 15 ). In the lower part of the metallic platform ( 15 ) the rear support ( 14 ) is coupled to a pneumatic shock absorber ( 18 ) which is longitudinally aligned with the metallic platform ( 15 ), wherein the front end of the pneumatic shock absorber ( 18 ) is fixed to the metallic platform ( 15 ) and the rear end thereof is connected to the rear support ( 14 ) of the projectile recovery chamber ( 1 ) in such a manner that if there is a movement of the projectile recovery chamber ( 1 ) same is moved along the metallic platform ( 15 ), owing to the fact that the supports slide on the rear grooves ( 16   a  and  16   b ) and central groove ( 17 ), but the travel thereof is halted by the pneumatic shock absorber ( 18 ) connected to the rear support ( 14 ), in such a manner as to allow the return of the projectile recovery chamber ( 1 ) to its initial position. 
     The metallic platform ( 15 ) ( FIG. 11 ) has, on the lower face thereof, means for coupling to the industrial carriage ( 19 ); between the industrial carriage ( 19 ) and the metallic platform ( 15 ) there is a raising mechanism ( 20 ) that allows modification of the position of the front end of the projectile recovery chamber ( 1 ), adjusting the elevation thereof to the stature of the shooter or to the person actuating the weapon. The carriage has industrial-use wheels ( 21 ) for supporting the weight of the entire assembly. The assembly also has a control panel ( 3 ) for actuating the self-aspirating pump ( 6 ) when the weapon is positioned in the rectangular hole ( 35 ). 
     The industrial carriage ( 19 ) has, on the upper face thereof, a pair of rear bearings ( 22 ) and a pair of front bearings ( 23 ), each coupled by a steel bar ( 24 ), the bearings in the rear part ( 22 ) allow movable coupling between the metallic platform ( 15 ) and the industrial carriage ( 19 ) while the bearings in the front part ( 23 ) are in the center of the carriage and are used to hold the raising mechanism ( 20 ) in the rear part of said mechanism, allowing movable coupling by means of a steel bar ( 24 ); additionally, two lower bearings ( 25 ) are connected to the lower face of the metallic platform ( 15 ) and in turn allow securing of the front part of the raising mechanism ( 20 ), the raising mechanism ( 20 ) being secured in the rear part by the front bearings ( 23 ) that are connected to the front part of the industrial carriage ( 19 ) and by the lower bearings ( 25 ) connected to the front part of the metallic platform ( 15 ) on the lower face thereof. 
     According to  FIGS. 2 to 5 , the projectile recovery chamber is constructed by connecting three or more cylindrical sections ( 2 ) by means of flanges ( 4 ) that allow one section to be secured to another. By way of example, three cylindrical sections ( 2 ) are connected by means of flanges ( 4 ) between which packing ( 5 ) made from a high-density polymer is placed, to prevent leakage of the fluid. Once the cylindrical sections ( 2 ) have been connected, the rear cover ( 10 ) of the chamber which comprises a circular section that has two holes is positioned; a return hole ( 26 ), in the center of the circular section, and a suction hole ( 27 ) in the lower part of the circular section, the rear cover is secured to the body of the chamber by means of a flange ( 4 ) and packing ( 5 ) to prevent leaks. The rear cover ( 10 ) of the chamber shown in  FIG. 5  has a vertical projection ( 28 ) extending vertically from the upper part of the circumference of the rear cover ( 10 ) of the chamber, and in the upper end thereof the vertical projection ( 28 ) has a folded portion at an angle such as to form a horizontal surface ( 29 ) where the self-aspirating pump ( 6 ) will rest. 
     The front cover ( 11 ) of the chamber shown in  FIG. 6  is formed by two circular steel plates, a front plate ( 30 ) and a rear plate ( 31 ), connected by a steel ring ( 32 ) 10 cm wide, wherein the rear plate ( 31 ) is coupled to the upper flange of the projectile recovery chamber ( 1 ); in the same rear plate of the front cover ( 31 ) a circular hole ( 33 ) two inches in diameter has been made through which the projectiles will pass into the projectile recovery chamber ( 1 ). Likewise, and specifically on the side of the rear plate ( 31 ) in contact with the liquid in the chamber, two flexible polymer coverings have been installed, adhered to a steel sheet (which are not shown), which acts as core, small transverse cuts in the form of a star being made in the center thereof, wherein said structure has the function of opening and closing rapidly when each bullet is fired to the interior of the projectile recovery chamber ( 1 ), and this prevents expulsion of the fluid to the exterior of the projectile recovery chamber ( 1 ). In the middle of the two plates is a centering device ( 34 ) or guide in the form of a “V” approximately three inches in length mounted on the stainless-steel rear plate ( 31 ), where a powerful permanent magnetic field is generated by means of small magnets ( 36 ) placed in the lower part of the centering device ( 34 ), wherein the magnetic field has the function of attracting and correcting the direction of the steel housings and barrels of firearms. 
     Meanwhile, a cut was made in the center of the front plate to form a rectangular hole ( 35 ) three inches in height by two inches in width, and in the lower part of the rectangular hole ( 35 ) the centering device ( 34 ) is installed. The height of the rectangular hole ( 35 ) allows the insertion of firearm barrels that incorporate very tall forward sights, as in the case of AK-47 type rifles. 
     Method of Operation of the Invention: 
     A fundamental component of the present invention is that, unlike other firing chambers, the chamber of the invention does not use water, pellets or fibers. Instead, it uses a ballistic gel developed specifically for this application. 
     The gel used is a gel with rheopectic properties, i.e. 
     in its normal state it behaves like a liquid but, when kept in constant movement and rapidly agitated, the gel behaves like an elastic solid that substantially increases its viscosity, thereby offering greater resistance to the passage of projectiles in such a manner that it halts them in a shorter distance, without generating traces other than the particular rifling of the firearm barrel since the gel tends to envelop and to trap the bullets as if it were a three-dimensional mesh formed by particles suspended in water, and therefore it likewise does not cause substantial erosion on the projectile structure. 
     The gel used has a property known as “rheopexy”, which corresponds to the behavior of non-Newtonian fluids. In this type of fluid, viscosity changes in relation to temperature and to the shear force applied, such that the gel used does not have a defined, constant viscosity value. 
     To take advantage of the properties of the gel, it was necessary to identify the appropriate direction and the quantity of flow of gel to be impelled by a self-aspirating pump ( 6 ) inside the projectile recovery chamber. 
       FIG. 5  shows that the main body of the projectile recovery chamber ( 1 ) is built as three cylindrical sections ( 2 ); in this case, use was made of grade 304 10 gauge stainless steel; with a size for each one of 50 cm length and 50 cm diameter in each cylindrical section ( 2 ), connected by means of laser-cut connection flanges ( 4 ) likewise produced from grade 304 stainless steel measuring 1.0×0.25 inches, in order to form a total length for the body of the chamber of 150 cm, with a capacity of 260 liters of ballistic gel and packing ( 5 ) was placed between every two sections to prevent leaks. 
     To support the projectile recovery chamber ( FIG. 13 ), use is made of an industrial carriage ( 19 ) produced from steel plate, with four industrial-type wheels ( 21 ) for heavy loads, on which the projectile recovery chamber ( 1 ) is mounted. 
     For the recovery of reference bullets, a hydraulic pump or self-aspirating pump ( 6 ) was installed, which has a 2.0 HP motor, basket-type filter ( 7 ) and a control panel ( 3 ), wherein the motor of the self-aspirating pump ( 6 ) has speed variation and 220 volt electrical power supply. 
     The shock-absorbing system of the chamber is constituted by three linear guides that are three grooves ( 16   a,    16   b ) and ( 17 ) on a metallic platform ( 15 ) to allow sliding of the projectile recovery chamber ( 1 ) and a pneumatic shock absorber ( 18 ) with 750 kg capacity, which at one of its ends is fastened to the metallic platform ( 15 ) and at the other end is coupled to the rear support ( 14 ) of the projectile recovery chamber that moves along the linear grooves ( 16   a,    16   b ) and ( 17 ). 
     The raising mechanism ( 20 ) of the chamber comprises a tensioning device with an endless screw for height adjustment. 
     The centering device ( 34 ) or guide for the firearm barrel comprises a broad magnetic field created by magnets ( 36 ) applied to a support component in the form of a “V” that has a signal presence or interruption sensor (not shown) such that when the weapon is placed in position it activates a signal that allows the self-aspirating pump ( 6 ) to be switched on. 
     The chamber has an ozonifier (not shown) for eliminating bacteria that have accumulated in the gel, thereby maintaining its consistency. 
     Once the projectile recovery chamber ( 1 ) has been set up, it is charged with approximately 260 liters of rheopectic gel, adjusting the height of the front end of the projectile recovery chamber ( 1 ), where the basket ( 12 ) for trapping shells is located, to the height of the shooter or the person actuating the weapon, using the raising mechanism ( 20 ). When the shooter or the person firing the weapon rests the weapon in the rectangular hole ( 35 ), the sensors detect the weapon and automatically switch on the self-aspirating pump ( 6 ), which begins to remove gel from the projectile recovery chamber ( 1 ) through the suction hole ( 27 ) and returns it via the return hole ( 26 ) to the projectile recovery chamber ( 1 ). At this time, the agitation produced by the pump causes the increase in viscosity of the gel; at the same time, the weapon is attracted by the magnets ( 36 ) of the centering device ( 34 ) and lies in the appropriate position for firing, and the sensors switch on an alarm to advise that the test has started. All the sensors are controlled by a system of PLC (programmable logic controller) type, which is mounted on a control panel ( 3 ). 
     Once firing has taken place, the bullet is halted in its trajectory through the rheopectic gel and falls under gravity to the lowest point of the projectile recovering chamber ( 1 ), where it is sucked out together with the gel by the self-aspirating pump ( 6 ). The sucked-out gel passes through a basket-type filter ( 7 ) where the bullet is trapped and separated from the gel, which returns to the projectile recovery chamber ( 1 ) and it is thus possible to perform repeated firings in order for the bullets to be trapped. 
     The safety of the shooter or the person firing the weapon is ensured by a wire basket ( 12 ) for trapping shells, which retains the shells from the fired bullets. 
     The shock-absorbing system of the chamber absorbs the inertial movement caused by the energy of the fired projectiles. Once firing has been performed, the chamber moves rearward on the metallic platform ( 15 ), and therefore the pneumatic shock absorber ( 18 ) absorbs the firing energy and returns the projectile recovery chamber ( 1 ) to its initial position. 
     Once the tests have been completed, a bullet fired by a firearm can be recovered within an average of 1.5 seconds. 
     The principal components of the present invention are listed below:
         1. Projectile recovery chamber   2. Cylindrical sections   3. Control panel   4. Flanges   5. Packing   6. Self-aspirating pump   7. Basket-type filter   8. Suction pipe   9. Return pipe   10. Rear cover of the chamber   11. Front cover of the chamber   12. Basket (for trapping shells)   13. Front support   14. Rear support   15. Metallic platform   16. Rear grooves (a, b)   17. Central groove   18. Pneumatic shock absorber   19. Industrial carriage   20. Raising mechanism   21. Wheels   22. Rear bearings   23. Front bearings   24. Steel bar   25. Lower bearings   26. Return hole   27. Suction hole   28. Vertical projection (of the rear cover)   29. Horizontal surface (of the rear cover)   30. Front plate (of the front cover)   31. Rear plate (of the front cover)   32. Steel ring   33. Circular hole (of the rear plate of the front cover)   34. Centering device   35. Rectangular hole   36. Magnets