Abstract:
Projectile with luminous marking of the impact area, in particular a medium-calibre or small-calibre projectile, consisting of a hollow cylindrical body ( 1 ) in which an inertial mass ( 2 ) can move, said inertial mass being subjected to a movement by the positive or negative acceleration involved in the firing process, which movement causes the tearing of a diaphragm ( 3, 4 ) separating two chambers ( 5, 6 ), each containing a liquid with the potential of emitting light by chemiluminescence when they are mixed together. Upon impact, the light-emitting mixture is expelled to the outside through suitable orifices ( 21, 23 ) through the action of internal pressure possibly caused by the chemical generation of gas resulting from the chambers being brought into communication by effect of the diaphragm tearing.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This is a national stage filing in accordance with 35 U.S.C. §371 of PCT/EP2008/050599, filed Feb. 8, 2008, which claims the benefit of the priority of Belgium Patent Application No. 2007/0051, filed Feb. 8, 2007, the contents of each are incorporated herein by reference. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates to a projectile designed to provide for luminous marking of the impact area. Advantageously, this type of projectile makes it possible to remotely and easily mark the points or areas of impact of fired projectiles, including those of small caliber, in order to progressively perfect the accuracy of fire and the training of users. This type of projectile can be used, for example, in a military context or by security forces. Preferably the projectile is intended for training and is non-lethal. 
         [0003]    The projectile in accordance with this invention and its method of utilization are predicated upon the well-known property that some chemical liquids have of emitting chemiluminescence when they are mixed. Because of this, the projectile of the invention is particularly well suited for use in a dark or nocturnal atmosphere. 
         [0004]    Chemiluminescent projectiles which serve a similar purpose have already been proposed. They comprise, inside an ogival body, one or more glass ampoules containing the liquid or liquids in question. This is the case for U.S. Pat. No. 6,990,905, published on Jan. 31, 2006 (inventor Manole Leon R et al.). This device has disadvantages, for example it cannot be used in practice except for very large caliber projectiles, such as the 40 mm described in the patent document in question. Indeed, in order to be manufactured such ampoules containing a liquid require the presence of an internal air space of sufficient volume to allow the sealing of the glass, and thus they cannot be produced in very small sizes. If ampoules simultaneously containing a liquid plus air in a non-negligible quantity were produced, ballisticians will understand that the movements of internal liquid during the trajectory of a projectile are such as to make said projectile uncontrollable. Moreover, the breaking of the glass is not a controllable process: it often occurs in a very incomplete way, with a significant portion of liquid remaining in the ampoule and not participating in the mixing. 
         [0005]    Furthermore, the cost is substantial and there thus remains a need for more economical projectiles. 
         [0006]    In particular, the invention proposes to overcome these disadvantages. 
       SUMMARY OF THE INVENTION 
       [0007]    The invention is based on the effect of breaking one or more membranes separating chambers containing products with chemiluminescent potential during the firing or impact of a projectile. The membrane or membranes, for example, are torn by the deformation of the projectile and/or the movement of an inertial mass internal to or integrated into the projectile, at the time of firing and/or impact. 
         [0008]    According to one embodiment, the invention is based on the movement, inside the main body of the projectile, of an inertial mass which, under the effect of the acceleration or deceleration due to the firing, bursts open one or more membranes separating two or more chambers each of which contains one more components including a liquid with chemiluminescent potential. The mixing of liquids with chemiluminescent potential causes the emission of light. Once illuminated, depending on the type of projectile, the mixture can remain confined inside the main body whose walls must then be translucent, or be expelled in all or in part to the exterior so as to make the target more visible, even if it is mobile. 
         [0009]    In this invention, the chambers that contain the liquid with chemiluminescent potential are separated by a membrane, attached at its periphery to the main body of the projectile, which membrane is intended to be burst by the movement of the inertial mass. Said membrane is preferably composed of thin aluminum foil coated with a polymer varnish. European patent EP 1421314 B1 and its counterpart in the United States No. US 2003/0223219 A1 can be cited in this regard, since they describe a flexible pouch for use as lighting element, comprised of two membranes similar to the one just mentioned, sealed together at their periphery, forming a chamber that the user bursts by means of a ball or other hard pellet. According to this invention there is no involvement of a user. There is an inertial mass that acts on the membrane to cause it to burst, on the one hand as a result of the appropriate shape given to it with a view to this bursting, and on the other hand by acting automatically under the effect of any acceleration (or deceleration) due to firing, and not according to the intention of the user making suitable and appropriate gestures. Moreover, with the flexible pouch and the bursting by a ball or hard pellet, the mixing by the user is necessary in order to have an appropriate mixture, while in this invention the bursting of the membrane and subsequently the chamber is abrupt and occurs by tearing a large surface area compared to the volume concerned, in such a way that the mixture is inevitably satisfactory. Moreover, it is obvious that the purpose of the membrane pouch is not and could not be to equip a projectile, even of large caliber, much less for medium or small caliber. Because a pouch is formed of two membranes sealed together along the peripheral part of their surface, there would be hardly any available volume left if the pouch were to be a few millimeters in size. 
         [0010]    Finally, in the present invention it is possible, and often even desirable, to obtain the expulsion to the exterior of all or part of the luminous liquid, which is not provided or desirable with the membrane pouch. To that end, the projectile according to the invention is provided with orifices through which the luminous liquid can be ejected, either as a result of the pressure due to the movement of the inertial mass (piston effect) or by a gas-generating chemical reaction obtained by the mixing of two components at the time of the bursting. These two effects can also be combined. 
         [0011]    Thus the invention proposes a projectile which enables luminous marking of the impact area, comprised of a hollow cylindrical body in which one or more inertial masses can move, placed in motion by the positive or negative acceleration involved in the process of firing, which motion causes the bursting of one or more membranes inside the hollow ogival body, separating two or more chambers each of which contains a liquid with chemiluminescent potential, which liquids emit light when mixed. 
         [0012]    According to one embodiment, when placed in motion the inertial mass or masses act like a piston inside the hollow main body, causing the expulsion of the light-emitting liquid mixture to the exterior through orifices made in the walls of the projectile. 
         [0013]    Preferably the membrane or membranes to be burst, besides providing a physical separation of the chemical liquids prior to their mixing, also provide a barrier against the diffusion of any element of which said liquids are comprised, which diffusion could hinder the preservation of the integrity of their properties during storage. 
         [0014]    The membrane or membranes, for example, are comprised of thin aluminum foil lacquered on at least one of its faces with a heat-sealable polymer varnish, intended to adhere by means of instantaneous application of heat, to the body of the projectile, or ad hoc intermediate piece, so as to form the required chamber or chambers. 
         [0015]    The heat-sealable polymer varnish is preferably neutral without chemical influence on the composition or preservation of the liquids with chemiluminescent potential with which it is in contact, and is itself not dissolved by the solvents of said liquids, for example a product such as MORPRIME™ from Morton, a division of Rohm &amp; Haas (USA). 
         [0016]    Moreover, the projectile according to the invention can be provided at the front with a cylindrical-shaped plug that can slide inside the main body while extending beyond it in the front, in such a way that it is the first surface that meets the target upon impact, said cylinder being provided with hollow longitudinal fluting on its peripheral surface that allows the exiting of the luminous mixture under pressure, the hollow fluting comprising channels of small enough cross sections to ensure a slight lamination of the liquid whose mixture is desired. 
         [0017]    Alternatively, a duct providing communication between the interior of the projectile and the external atmosphere can be provided, which duct can allow the expulsion of the illuminated liquid and can be provided with a plug intended to be released during impact upon arrival. 
         [0018]    According to another embodiment the main body is sealed, without orifices allowing the expulsion of the luminous liquid, but has translucent or transparent walls. 
         [0019]    According to another aspect of the invention, the projectile can be provided, in addition to the above mentioned liquids, in one or more of its chambers, with compounds that can have a gas-emitting reaction when they are mixed together following the bursting of one or more membranes separating the chambers. 
         [0020]    The material of which the main body of the projectile and/or plug is made can advantageously be an elastomeric polymer. 
         [0021]    According to yet another aspect, in the front part of the ogival body, the walls thereof have accordion-like folds so as to facilitate crushing against a target with reduction of volume. 
         [0022]    It will be understood that the inertial masses can be provided, on the side facing a membrane, with a pointed or pyramidal structure for bursting. 
         [0023]    The invention will be described below in more detail, with reference to the attached figures which illustrate non-limiting but particularly representative examples. In particular, a person skilled in the art will understand that the different characteristics described in the figures can often be combined and/or can be generalized. 
     
    
     
       BRIEF DESCRIPTION OF THE FIGURES 
         [0024]      FIGS. 1A and 1B  are cross-sectional views of an embodiment of ballistic projectile according to the invention, with ejection of luminous liquid upon arrival.  FIG. 1A  describes a projectile prior to impact, and  FIG. 1B  this same projectile after impact; 
           [0025]      FIG. 2  describes a variation of a projectile prior to impact; 
           [0026]      FIG. 3  is a cross-sectional view of another possible embodiment of a projectile according to the invention with emission of liquid to the exterior; 
           [0027]      FIG. 4  is a cross-sectional view of a possible embodiment without emission of liquid to the exterior; 
           [0028]      FIGS. 5 to 9  illustrate details of the way the transverse membranes inside the body of the projectile can be connected to said body; and 
           [0029]      FIG. 10  is a cross-sectional view of yet another possible embodiment of a projectile according to the invention with emission of liquid to the exterior. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0030]      FIG. 1A  shows that the projectile comprises a body  1 , the hollow interior of which is cylindrical in shape. Located in this space is a plug  2  that extends forward from the body  1  while being inserted therein over a certain length, which length guides said plug when, under the effect of the impact on arrival, it will move inside the body  1  to reach the position illustrated in  FIG. 1B . Depending on said guide length, the plug  2  should be sufficiently tight in the body  1  to prevent it from being released under the effect of the violent acceleration as the projectile leaves, but free enough to allow the abovementioned sliding. Next to the plug  2  and toward its rear a pyramid-shaped piece  7  is located, composed of three or four blades intended to burst the membranes  3  and  4  and thus to cause the mixing and activation of the two liquids with chemiluminescent potential which have been disposed respectively in the space  5  located between the membranes  3  and  4  and in the space  6  located between the space  4  and the end of the hollow part of the projectile. The plug  2  can advantageously be made of a flexible material, while the pyramid  7  with cutting sides is made of hard, relatively dense material. This part may or may not be attached to the plug  2 . If it is not, it can be arranged so that it will move toward the rear, already under the effect of the acceleration due to being fired, and in this case, it will pierce the membranes  3  and  4  causing illumination while still in trajectory. Otherwise, during impact upon arrival it will be pushed by the plug  2  and the bursting will take place at that time. The plug  2  is provided at its cylindrical periphery with fluting or grooves  21 , which provide hollow ducts allowing the ejection of the activated liquid toward the front of the projectile, where it is supposed to drench the target. Represented by  10  is an optional set of fins or tail assembly, which could be advisable if it is desired to improve the behavior of the projectile during its ballistic course. The rear part  8  of the projectile can be inserted into a cartridge or casing in a conventional manner for normal rounds. Represented by  14  are grains of chemical product that can have a gas-emitting action if they are brought into contact with an appropriate reagent. For example, said reagent can be hydrogen peroxide which is normally present in one of the liquid components with chemiluminescent potential. Such gas-emitting reagents would have the role of increasing the internal pressure and facilitating the expulsion of the luminous liquid content. 
         [0031]      FIG. 2  represents a quite similar embodiment, but here the fluting or grooves  21  do not extend the full length of the plug  1  [sic]. The rear of said plug has a smooth periphery, thus ensuring a better seal. And against said smooth part, the body  1  narrows in diameter, which also promotes this sealing. In this  FIG. 2  the pyramid  7  fitted with blades is represented in the detached embodiment of the plug  2 . Moreover, in this  FIG. 2  the arrangement of the chambers  5  and  6  containing the chemiluminescent liquids has been simplified. Illustrated by  22  is a “skirt,” an optional element that can increase the stability in trajectory. 
         [0032]    In  FIG. 3 , the body  1  is preferably made of an elastomeric polymer material, in this instance for three reasons. First, this embodiment will facilitate the collapse against the target of the entire front part of the projectile, with considerable decrease in the internal volume, thus resulting in a beneficial increase of the pressure providing for the ejection of the liquid. It will be noted that for this purpose there is an accordion-like bend  12  in the design of the hollow ogival body  1 . Secondly, an embodiment in an elastomer can also be justified by the concern for making the round more harmless in the event a person is located in its trajectory. Finally, an embodiment in an elastomer allows the use of a conical-shaped plug  11  made of a harder material, housed in the front of the body  1 —said housing also being conical shaped, of course—to provide a seal prior to the impact. This plug is provided with a mushroom head  13 , which, if the projectile strikes a target obliquely with respect to its trajectory, will facilitate the slight movement of the plug required for release. The bursting of the membrane  3  is caused by the inertial recoil movement of the mass  2  when the projectile is launched, and said inertial mass  2 , in the embodiment considered here, is not connected to the plug  11  and acts independently of the release of the latter. The liquids with chemiluminescent potential are disposed respectively in the chambers  5  and  6 . The first chamber is formed by the space in front of the membrane  3 , and the second behind said membrane  3 . Obviously, among various possible combinations, it can be considered that the present document claims that the chamber  5  is situated between two membranes, as in  FIG. 1 . The considerations expressed above in the case of  FIG. 1  concerning the possible existence of a tail assembly, and grains of chemicals with gas-emitting action, are still applicable. At  9 , because an elastomeric embodiment is concerned, a metal cup crimped to the end of the ogival body has been optionally provided to improve its insertion into the casing or cartridge. 
         [0033]      FIG. 4  concerns an embodiment that is simpler than the previous ones, in that there is no ejection of luminous liquids outside the ogival body. Said body is then made of transparent or translucent material. The inertial mass  2  is supposed to move toward the back as soon as it is fired and cause the activation. The functionalities described previously are still applicable. The target will not be sprayed with luminous liquid, but if the luminous round remains visible on or beside the target, the purpose could be considered as having been achieved if the circumstances lend themselves to it. 
         [0034]      FIGS. 5 to 9  represent details of possible means of accomplishing the junctions between membranes and ogival body. The membranes are of very thin aluminum foil coated with a heat-sealable varnish. In  FIG. 5 , the peripheries of the membranes are heat-sealed to the main body, to shoulders provided for that purpose. In  FIG. 6 , they are sealed to a cylindrical element with shoulders, which element is then inserted into the interior of the main body, which can facilitate the operations, particularly if it is taken into account that precise filling with the liquids is required prior to sealing. Represented in  FIG. 7  are two cylindrical elements one behind the other, and four membranes, of which  4  and  4 ′ are side by side. Represented in  FIG. 8 , in a case in which the main body  1  is produced from an elastomer, is the possibility of using sealing lips molded with the rest of the ogival body for the assembly between cylindrical element and ogival body, in order to economize the sealing operation. In the embodiment represented in  FIG. 9 , the main body is quite simply formed from two pieces, here numbered  1  and  26 , which are sealed to each other with the interposition of the varnished aluminum membrane  3  between them. In this case, the aluminum membrane has received the heat-sealing varnish on each of its two faces. 
         [0035]      FIG. 10  represents an additional variation of a projectile according to the invention. Here, the projectile has a small diameter hole  23  in the front through which the luminous liquid will be ejected. The membrane  3  separates two chambers respectively provided with liquids with chemiluminescent potential, and will be burst upon firing by the inertial movement of the pyramid  7  with blades. The membrane  25  separates two gas-generating chambers, one containing a liquid and the other an appropriate chemical reagent, here represented in the form of crystals  14 . The bursting produces the generation of gas upon firing, but the speed of this reaction can be controlled. There is an intermediate membrane  4  that separates the “luminous liquid” and “gas generation” functions; it will be burst by the inertial action of the ring  24  that has at its center a pointed “syringe needle,” which will only produce a hole of modest size, ensuring the transmission of pressure between the back and the front. 
       Example of Embodiment 
       [0036]    A projectile according to the invention was produced essentially in accordance with the above mentioned  FIG. 1 . The caliber of the main body  1  is 12.5 mm in diameter. The total length is 43 mm. The elastomer plug  2  is a cylinder 16 mm long by 10.5 mm in diameter, with a conical front. The body  1  is made of polypropylene homopolymer in order to have suitable mechanical strength. The “blades” arranged in a pyramid, which provide for the penetration and bursting of the membranes, are made of aluminum with a density of 2.5, or of charged polypropylene homopolymer with a density on the order of 1.8. The end of the blades is sharply pointed. There are two membranes. Between them is situated a first chamber with a volume of 0.12 cubic centimeter, in which one of the liquids with chemiluminescent potential is located. The second chamber is located between the second membrane and the bottom of the hollow ogival body, and it is filled with the second chemical liquid with chemiluminescent potential. Its volume is 0.35 cubic centimeter. The membranes are aluminum foil 0.30 mm thick, coated on their sealing face with a layer 4 microns thick of polypropylene base heat-sealable varnish. The sealing of these aluminum disks is done, around their periphery, to the appropriate shoulder inside the ogival body by means of a hot brass ring, the main body being placed in the vertical position in order to facilitate the filling of liquid that occurs just prior to sealing the membrane. The plug is tightly fitted into the front of the ogival body over a length of 6 mm. The tightness is sufficient to prevent it from being released under the effect of the acceleration that occurs during firing. However, it allows the movement of the plug at the moment it strikes the target. The diameters concerned have been calculated and produced with the necessary precision. The plug is provided with eight longitudinal flutings around its entire periphery, each fluting being 1 mm deep and 2 mm wide, intended for the release of the liquid ejected on impact, composed of two components mixed during the bursting, or in the process of being mixed. It can be considered that the passage of this mixture through these channels of relatively modest cross section causes a certain lamination that contributes to homogenization. After the impact, a good portion of the liquid content is spread over the target, and in a nocturnal setting is visible at a great distance. By using a solution of trichloro-carbopentoxyphenyl oxalate associated with a rubrene coloring, which solution is mixed with an activator with hydrogen peroxide base, constituting the second liquid, the result can clearly be seen at 200 meters and beyond in a nocturnal setting in clear weather.